Patent Publication Number: US-2023149033-A1

Title: Smart aspiration system

Description:
PRIORITY 
     The present application claims priority to U.S. Provisional Patent Application No. 63/279,912, titled SMART ASPIRATION SYSTEM, filed Nov. 16, 2021 and U.S. Provisional Patent Application No. 63/403,692, titled SMART ASPIRATION SYSTEM, filed Sep. 2, 2022, each of which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     Many of the most common and deadly diseases afflicting mankind result from or in the presence of undesirable material, most notably blood clots, in the blood vessels and heart chambers. Examples of such diseases include myocardial infarction, stroke, pulmonary embolism, deep venous thrombosis, atrial fibrillation, infective endocarditis, and so on. The treatment of some of these conditions, which involve smaller blood vessels, such as myocardial infarction and stroke, has been dramatically improved in recent years by targeted mechanical efforts to remove blood clots from the circulatory system. Other deadly conditions, which involve medium to large blood vessels or heart chambers, such as pulmonary embolism (½ million deaths per year) or deep venous thrombosis (2-3 million cases per year) have not benefited significantly from such an approach. Present treatment for such conditions with drugs or other interventions is not sufficiently effective. As a result, additional measures are needed to help save lives of patients suffering from these conditions. 
     In the systemic circulation, this undesirable material can cause harm by obstructing a systemic artery or vein. Obstructing a systemic artery interferes with the delivery of oxygen-rich blood to organs and tissues (arterial ischemia) and can ultimately lead to tissue death or infarction. Obstructing a systemic vein interferes with the drainage of oxygen-poor blood and fluid from organs and tissues (venous congestion) resulting in swelling (edema) and can occasionally lead to tissue infarction. 
     Many of the most common and deadly human diseases are caused by systemic arterial obstruction. The most common form of heart disease, such as myocardial infarction, results from thrombosis of a coronary artery following disruption of a cholesterol plaque. The most common causes of stroke include obstruction of a cerebral artery either from local thrombosis or thromboemboli, typically from the heart. Obstruction of the arteries to abdominal organs by thrombosis or thromboemboli can result in catastrophic organ injury, most commonly infarction of the small and large intestine. Obstruction of the arteries to the extremities by thrombosis or thromboemboli can result in gangrene. 
     In the systemic venous circulation, undesirable material can also cause serious harm. Blood clots can develop in the large veins of the legs and pelvis, a common condition known as deep venous thrombosis (DVT). DVT arises most commonly when there is a propensity for stagnated blood (long-haul air travel, immobility) and clotting (cancer, recent surgery, especially orthopedic surgery). DVT causes harm by (1) obstructing drainage of venous blood from the legs leading to swelling, ulcers, pain and infection and (2) serving as a reservoir for blood clot to travel to other parts of the body including the heart, lungs (pulmonary embolism) and across a opening between the chambers of the heart (patent foramen ovale) to the brain (stroke), abdominal organs or extremities. 
     In the pulmonary circulation, the undesirable material can cause harm by obstructing pulmonary arteries, a condition known as pulmonary embolism. If the obstruction is upstream, in the main or large branch pulmonary arteries, it can severely compromise total blood flow within the lungs and therefore the entire body, resulting in low blood pressure and shock. If the obstruction is downstream, in large to medium pulmonary artery branches, it can prevent a significant portion of the lung from participating in the exchange of gases to the blood resulting low blood oxygen and build up of blood carbon dioxide. If the obstruction is further downstream, it can cut off the blood flow to a smaller portion of the lung, resulting in death of lung tissue or pulmonary infarction. 
     Depending upon the state of the undesirable material, the undesirable material can be can be eliminated by mechanical means. Mechanical treatments involve the direct manipulation of the material to eliminate the obstruction. This can involve aspiration, maceration, and compression against the vessel wall, or other types of manipulation. The distinct advantage of mechanical treatment is that it directly attacks the offending material and eliminates the vascular obstruction independent of the specific content of the offending material. Mechanical treatments, if feasible, can usually prove to be superior to biologic treatments for vascular obstruction. Procedural success rates tend to be higher. The best example of this advantage is in the treatment of acute myocardial infarction. Although thrombolytic therapy has had a major impact on the management of patient with myocardial infarction, this option is now relegated to a distant second choice. The clear standard of care today for an acute myocardial infarction is an emergency percutaneous coronary intervention during which the coronary artery obstruction is relieved by aspiration, maceration, or balloon compression of the offending thrombus. This mechanical approach has been shown to decrease the amount of damaged heart tissue and improve survival relative to the thrombolytic biological approach. 
     Catheter pulmonary embolectomy, where the pulmonary emboli are removed percutaneously using one of several techniques, can be subdivided into three categories. With fragmentation thrombectomy, the clot is broken into smaller pieces, most of which migrate further downstream, decreasing the central obstruction but resulting in a “no-reflow” phenomenon. It is sometimes used in combination with thrombolytics which preclude their use as an alternative to thrombolytics. With the rheolytic thrombectomy, high velocity saline jets create a Venturi effect and draw the fragments of the clot into the catheter. Finally the aspiration techniques draw the clot into a catheter via suction. With a Greenfield embolectomy, the catheter with the attached clot is repeatedly drawn out of the vein. All of these techniques rely on catheters which are small compared to the size of the clots and blood vessels. Their limited success is likely related to their inability to achieve a complete en bloc removal of the material without fragmentation. 
     Some currently existing systems utilized for clearing vascular debris are designed to aspirate the subject&#39;s blood to assist in capturing and removing the vascular debris. However, there are several problems with such systems when aspirating blood, including removing or aspirating a large volume of blood and the aspiration lumen becoming blocked or occluded during a procedure (which, in turn, limits aspiration efficiency). If the vacuum level of the aspiration system becomes compromised, it can result in an incomplete removal of the undesirable material and increase the risk of emboli. In addition, applying high suction forces at the catheter tip may induce injury to the vessel if the high suction forces are applied without a blockage being present. 
     Accordingly, there is a need in the prior art for vascular treatment systems utilizing aspiration that are able to control the aspiration flow rate in a smart, efficient manner in response to changing conditions during treatment of the subject. 
     SUMMARY 
     The present disclosure is directed to control systems for vascular treatment systems that are configured to aspirate the subject&#39;s blood during removal of the undesirable intravascular material. 
     In one embodiment, the present disclosure is directed to an aspiration system comprising: a catheter configured to be inserted within a vasculature of the subject; a canister coupled to the catheter, the canister configured to receive fluid from the catheter; a pressure source coupled to the catheter, the pressure source configured to generate a vacuum pressure through the catheter for aspirating the fluid; a sensor configured to sense a parameter associated with at least one of the catheter, the canister, or the pressure source; and a computer system coupled to the sensor, the computer system comprising a processor and a memory, the memory storing instructions that, when executed by the processor, cause the computer system to: cause the pressure source to initiate the vacuum pressure throughout the catheter, receive a measurement of the parameter from the sensor, determine whether the measurement violates a threshold associated with the parameter, and modulate the vacuum pressure in response to a determination that the measurement violates the threshold. 
     In one embodiment, the present disclosure is directed to a computer-implemented method for removing undesirable intravascular material (UIM) from a subject using a system, the system comprising a catheter configured to be inserted within a vasculature of the subject, a canister coupled to the catheter, the canister configured to receive fluid and the UIM from the catheter, a pressure source coupled to the catheter, the pressure source configured to generate a vacuum pressure through the catheter for aspirating the fluid and the UIM, and a sensor configured to sense a parameter associated with at least one of the catheter, the canister, or the pressure source, the method comprising: causing, by a computer system coupled to the pressure source and the sensor, the pressure source to initiate the vacuum pressure throughout the catheter; receiving, by the computer system, a measurement of the parameter from the sensor, determining, by the computer system, whether the measurement violates a threshold associated with the parameter; and modulating, by the computer system, the vacuum pressure in response to a determination that the measurement violates the threshold. 
     In one embodiment, the present disclosure is directed to a system for aspiration of fluid from the body comprising: an aspiration catheter; a waste container coupled to the aspiration catheter, the waste container configured to receive the aspirated fluid from the body; a pump coupled to the catheter, the pump configured to generate a negative pressure through the catheter; a weight sensor configured to sense a parameter associated with the waste container; a pressure sensor configured to sense the negative pressure; and a computer system coupled to the sensor, the computer system comprising a processor and a memory, the memory storing instructions that, when executed by the processor, cause the computer system to: cause the pump to initiate the negative pressure, receive a first measurement of the parameter from the weight sensor and a second measurement of the negative pressure from the pressure sensor, determine whether at least one of the first measurement or the second measurement violates a threshold associated with the parameter or the negative pressure, and modulate the negative pressure in response to a determination that at least one of the first measurement or the second measurement violates the threshold. 
     In some embodiments, the system can further comprise a sensor configured to detect a UIM within the system. 
     In some embodiments, the UIM comprises a soft thrombus. 
     In some embodiment, the sensor configured to detect the UIM comprises at least one of an optical sensor, an ultrasonic sensor, an inductive sensor, a magnetic sensor, a sensor configured to detect electric conductivity, or a turbine sensor. 
     In some embodiments, the system can further comprise a filter configured to capture a UIM within the system. 
     In some embodiments, the filter is positioned between the canister and the catheter. 
     In some embodiments, the filter is positioned within the canister. 
     In some embodiments, the sensor is configured to determine a weight of the filter and the computer system is configured to subtract the weight of the filter from a weight of the canister to determine one or more parameters associated with the system. 
    
    
     
       FIGURES 
         FIG.  1 A  shows a perspective view of a tip section of an illustrative hybrid catheter in accordance with an embodiment of the present disclosure. 
         FIG.  1 B  shows an end view of the tip section of the hybrid catheter of  FIG.  1 A . 
         FIG.  1 C  shows a cross-sectional view of the tip section of the hybrid catheter of  FIG.  1 A  inside a vessel with partial plaque blockage. 
         FIG.  2    shows a view of the tip section of the hybrid catheter of  FIG.  1 A  inside a vessel with partial plaque blockage. 
         FIG.  3 A  shows an image of an illustrative vascular treatment system in accordance with an embodiment of the present disclosure. 
         FIG.  3 B  shows a block diagram of the vascular treatment system of  FIG.  3 A . 
         FIG.  4 A  shows a block diagram of an illustrative vascular treatment system including a flow sensor in accordance with an embodiment of the present disclosure. 
         FIG.  4 B  shows a perspective view of the embodiment of the vascular treatment system shown in  FIG.  4 A . 
         FIG.  5 A  shows a block diagram of an illustrative vascular treatment system including a pressure sensor. 
         FIG.  5 B  shows a perspective view of the embodiment of the vascular treatment system shown in  FIG.  5 A . 
         FIG.  5 C  shows a block diagram of an illustrative vascular treatment system including a differential pressure sensor. 
         FIG.  6 A  shows a block diagram of an illustrative vascular treatment system including a pressure sensor assembly in accordance with an embodiment of the present disclosure. 
         FIG.  6 B  shows a perspective view of the embodiment of the vascular treatment system shown in  FIG.  6 A . 
         FIG.  7 A  shows a block diagram of an illustrative vascular treatment system including a weight sensor in accordance with an embodiment of the present disclosure. 
         FIG.  7 B  shows a perspective view of the embodiment of the vascular treatment system shown in  FIG.  7 A . 
         FIG.  8 A  shows a block diagram of an illustrative vascular treatment system including an air flow sensor in accordance with an embodiment of the present disclosure. 
         FIG.  8 B  shows a perspective view of the embodiment of the vascular treatment system shown in  FIG.  8 A . 
         FIG.  9    shows a block diagram of an illustrative vascular treatment system including a UIM sensor in accordance with an embodiment of the present disclosure. 
         FIG.  10 A  shows a block diagram of an illustrative vascular treatment system including a plurality of sensor types in accordance with an embodiment of the present disclosure. 
         FIG.  10 B  shows a block diagram of an illustrative vascular treatment system including a pressure sensor and a weight sensor in accordance with an embodiment of the present disclosure. 
         FIG.  10 C  shows a block diagram of an illustrative vascular treatment system including a UIM filter in accordance with an embodiment of the present disclosure 
         FIG.  11 A  shows a block diagram of an illustrative vascular treatment system including a valve control element in accordance with an embodiment of the present disclosure. 
         FIG.  11 B  shows a perspective view of a first embodiment of the vascular treatment system shown in  FIG.  11 A . 
         FIG.  11 C  shows a perspective view of a second embodiment of the vascular treatment system shown in  FIG.  11 A . 
         FIG.  12 A  shows a block diagram of an illustrative vascular treatment system including an air leak control element in accordance with an embodiment of the present disclosure. 
         FIG.  12 B  shows a perspective view of an embodiment of the vascular treatment system shown in  FIG.  12 A . 
         FIG.  13 A  shows a block diagram of an illustrative vascular treatment system including a second pump control element in accordance with an embodiment of the present disclosure. 
         FIG.  13 B  shows a perspective view of a first embodiment of the vascular treatment system shown in  FIG.  13 A . 
         FIG.  13 C  shows a perspective view of a second embodiment of the vascular treatment system shown in  FIG.  13 A . 
         FIG.  14    shows a block diagram of an illustrative vascular treatment system including a pressure source controller in accordance with an embodiment of the present disclosure. 
         FIG.  15    shows a block diagram of an illustrative vascular treatment system including a boost reservoir control element in accordance with an embodiment of the present disclosure. 
         FIG.  16    depicts a flow diagram for an illustrative process for modulating aspiration flow in a vascular treatment system based on a sensed parameter in accordance with an embodiment of the present disclosure. 
         FIG.  17    depicts a flow diagram for an illustrative process for modulating aspiration flow in a vascular treatment system based on whether an obstruction is identified in accordance with an embodiment of the present disclosure. 
         FIG.  18    depicts a flow diagram for an illustrative process for modulating aspiration flow in a vascular treatment system based on a target aspiration flow rate in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure is not limited to the particular systems, devices and methods described, as these may vary. The terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the disclosure. 
     The following terms shall have, for the purposes of this application, the respective meanings set forth below. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. 
     As used herein, the singular forms “a,” “an,” and “the” include plural references, unless the context clearly dictates otherwise. Thus, for example, reference to a “device” is a reference to one or more devices and equivalents thereof known to those skilled in the art, and so forth. 
     As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used. Therefore, about 50 mm means in the range of 45 mm to 55 mm. 
     As used herein, the term “consists of” or “consisting of” means that the device or method includes only the elements, steps, or ingredients specifically recited in the particular claimed embodiment or claim. 
     In embodiments or claims where the term “comprising” is used as the transition phrase, such embodiments can also be envisioned with replacement of the term “comprising” with the terms “consisting of” or “consisting essentially of.” 
     As used herein, the term “subject” includes, but is not limited to, humans and non-human vertebrates such as wild, domestic, and farm animals. 
     As used herein, the term “undesirable intravascular material” (UIM) refers to intravascular debris including, but not limited to, blockages in a vessel due to plaque, calcium, atheroma, thrombus, embolus, clot, vegetative growth, infected vegetative growth (such as endocarditis), pulmonary embolism, tumor, arterial clots, undesirable material trapped in dialysis grafts and/or stents, and other undesirable natural and/or unnatural foreign bodies to be removed from a subject&#39;s body. 
     As used herein, the term “en bloc” refers to entirely, wholly, and/or without significant fragmentation. 
     As used herein, the terms “vacuum pressure,” “suction force,” and/or “vacuum force” refer to the negative pressure created by removing air from a space creating a pressure differential resulting in the force that a vacuum exerts upon the UIM. A drive force refers to the pressure differential generated by the device that exerts a force upon the UIM. 
     As used herein, the term “differential pressure” refers to the difference in pressure between two given points. Positive pressure refers to a pressure at a first point that is greater than a pressure at a second point. Negative pressure refers to a pressure at a first point that is lower than a pressure at a second point. 
     As used herein, the term “vacuum” refers to a differential pressure, including decreases in pressure (i.e., negative pressure) below atmospheric pressure. 
     As used herein, the term “aspiration flow rate” refers to the flow rate of aspirated fluid, blood, UIM, and/or other substances from the vasculature of the patient, through the vascular treatment system, in response to the vacuum pressure generated by a pressure source (e.g., a pump). 
     Target vessels, treatment sites, or target areas include, but are not limited to, systemic venous circulation (e.g., inferior vena cava and/or superior vena cava, pelvic veins, leg veins, neck and arm veins); arterial circulation (e.g., aorta or its large and medium branches); heart chambers, such as in the left heart (e.g., the left ventricular apex and left atrial appendage), in the right heart (e.g., right atrium and right ventricle), or on its valves; small blood vessels; medium blood vessels; large blood vessels; iliofemoral vein; peripheral vasculature; and/or the pulmonary circulation (e.g., pulmonary veins and/or pulmonary arteries). In some embodiments, other treatment sites or target areas could include other nonvascular tubular structures, such as ducts or any other avascular tubular tissue. In some embodiments, other treatment sites or target areas could include pacemaker leads, stents, or other artificial implanted medical devices. 
     This disclosure relates to devices and methods for minimally invasive removal of UIM from a vessel or other hollow anatomical structure of a subject. In particular, the disclosure is directed to smart aspiration control for atherectomy and thrombectomy systems. 
     Vascular Treatment Systems 
     Described herein are systems and methods to facilitate the removal of UIM from the interior walls of a target vessel or treatment site of a subject. Although primarily described in the context of atherectomies, the embodiments described herein may be useful in various vascular applications, such as atherectomy, angioplasty, debulking of plaque in in-stent restenosis, leads extraction, thrombectomy in chronic peripheral and coronary artery diseases and for management of acute blockage of vessels in coronary and neurovascular applications and venous thrombectomy applications. Another example is the use of embodiments in gastroenterology, such as for removal of sessile and flat lesions in the GI tract, Barrett&#39;s Esophagus management and in analogous applications requiring removal of tissue from the inner walls in gynecology and urology interventions. 
     The embodiments described herein can make use of a “hybrid” catheter that utilizes a combination of laser and mechanical removal (also “debulking”) of UIM from a bodily lumen. In vascular interventions, the catheter may be configured to weaken and/or even cut and detach UIM with a laser and then, even in cases where the plaque material was not entirely removed, detaching the rest of the plaque material by mechanical means, such as using a blade. The laser may change the mechanical characteristics of tissue, and thereby improve performance of mechanical tools such as various types of blades or shavers. By way of example, the laser may make a soft tissue crispier so it can be effectively crushed using the mechanical tool. 
     According to some embodiments, the catheter comprises a tip section, which may be essentially in a cylindrical shape, having circumferentially directed laser optics, optionally in the form of one or more optical fibers, configured to deliver laser radiation, and a circular-action cutter including one or more blades configured to assist in cutting and/or detaching undesired materials (also “deposits”) from an inner surface of a blood vessel. The one or more optical fibers may be circumferentially directed, namely, they may be located along an inner surface of the cylindrical tip section, which is near the periphery of the tip section. Alternatively, the circumferentially directed optical fibers may be located elsewhere but directed, by way of orientation and/or optical focusing, to radiate an area in front of the circumference of the tip section. 
     The laser may be selected according to the selected resonator optics; for example, fluoride fiber lasers may be used to emit laser radiation on the 2.9 μm transition and Thulium fiber lasers may be used to emit radiation on the 1.9-2.1 μm transition. An advantage of an embodiment using a laser in the region of 2.9-3 micron is that the absorption is very high and results in a very short length of absorption, on the order of 15 microns. Therefore, the relaxation time is shorter so the pulse rate may be increased above 100 Hz in order to accelerate the procedure. In some embodiments, a 355 nm laser could be used because the energy from 355 nm lasers is highly absorbed in blood products and the laser energy can be delivered with standard fused silica fibers. 
     In addition to the laser beam that interacts with the undesired material, a laser with controlled pulse rate and/or power may be used to interact with the liquid between the fiber tip (exit of laser beam) and tissue, either to allow for “opening” of a passage for the beam (e.g., a channel where light is not absorbed when UV radiation is used) to the tissue prior and adjunctive to the required interaction with the tissue, and/or to facilitate the process (when mid-IR radiation is used) benefiting from the “water spray” effect. By way of clarification, the tip can be in mechanical contact with the tissue being ablated or not. 
     Reference is now made to  FIGS.  1 A,  1 B and  1 C , which show an exemplary cylindrical tip section  100  of a hybrid catheter in perspective, front and cross-section views, respectively, in accordance with an exemplary embodiment. The remainder of the catheter&#39;s shaft (not shown) may, in some embodiments, be biocompatible polymer tubing, optionally coated, to minimize friction with the vessel&#39;s walls. 
     Tip section  100  is positioned at the distal end (i.e., the end which is inserted into the blood vessel) of the hybrid catheter. Tip section  100  may include a housing  102 , for example a cylindrical one, at least one optic fiber(s)  104  positioned along an inner surface of housing  102 , and a circular-action cutter (or simply “cutter”)  106  positioned inwardly of the optic fibers. Alternatively, in an embodiment (not shown), the circular-action cutter may be positioned outwardly of the optic fibers. It is intended that the following description of the embodiments in which the circular-action cutter is positioned inwardly, be applied, mutatis mutandis, to the alternative, not-shown embodiment. Optionally, optic fiber(s)  104  are delimited and/or supported by a first inner wall  108 . Further optionally, cutter  106  is delimited and/or supported by a second inner wall  110 . 
     In accordance with some embodiments, the catheter is used with a standard guidewire. 
     In accordance with some embodiments, the catheter is connected to a suction pump that generates low pressure to collect undesired material, saline and/or the like through the catheter. The pump may be a peristaltic pump, which mounts externally to the fluid path, to avoid any contamination of the pump. Optionally, this obviates the need to use disposable parts. In other embodiments, a diaphragm pump or piston pump may be used. 
     Optic fibers  104 , serving as the laser optics of the present hybrid catheter, may be connected, at their proximal end (not shown), to a laser source characterized by one or more of the parameters laid out herein. Optic fibers  104  may deliver the laser beams from the source towards the intervention site in the body. In tip section  100  of  FIG.  1 C , optic fibers  104  are shown as they emit laser towards undesired material  114 . One or more areas  116  in undesired material  114  may consequently be modified or even ablated by the laser. Then, cutter  106  may more readily cut into undesired material  114  and detach at least a part of it from the vessel&#39;s walls  118 . 
     Cutter  106  is optionally an annular blade extending to a certain depth inside tip section  100  and coupled to a suitable motor (not shown), located in the tip section or further in the shaft, supplying rotary and/or vibratory power to the blade. Optionally, one or more flexible members, such as a spring  112  ( FIG.  1 A ), may interact with cutter  106  at its base, to allow it to retract and protrude from housing  102 . Tip section  100  of  FIGS.  1 A-C  is shown with cutter  106  in its protruding position, while tip section  100   b  of  FIG.  1 C  is shown with the cutter, now marked  106   b , in its retracted position. The length of protrusion of catheter  106  out of housing  102  may be, for example, up to about 350 microns when treating blood vessels. When protruding, cutter  106  is used for detaching undesired material (also “deposit”)  114  from an inner surface  118  of a blood vessel  120 . According to some embodiments, when a certain force (for example, above a predetermined value) is applied to cutter  106  from the front, which may be a result of blockage in blood vessel  120 , the cutter  106  may shift its position and retract into housing  102 . 
     The annular blade of cutter  106  may have sufficiently thin edges, such as around 100 microns. Suitable blades may be tailor-made by companies such as MDC Doctor Blades, Crescent and UKAM. The blade may optionally be mounted at the end of a rotatable tube. Such tubes are available from manufacturers such as Pilling, offering a line of laser instrumentation and blade manufacture. The blade may be metal or manufactured by molding a material such as plastic, which is optionally coated with a coating having proper characteristics for in-vivo use. 
     An exemplary tip section may have an external diameter of approximately 5 mm, an internal diameter (within the innermost layer, be it the cutter or an extra wall) of approximately 3.4 mm, and optical fibers each having an approximately 0.1-0.2 mm diameter. 
     Reference is now made to  FIG.  2   , which shows an exemplary tip section  200  of a hybrid catheter, which may be similar to tip section  100  of  FIG.  1    with one or more alterations: First, one or more fibers  222  of the optical fibers existing in tip section  200  may be used for imaging the lumen of a blood vessel  220  by transporting reflected and scattered light from inside the lumen to an external viewing and/or analysis device (not shown) located externally to the body. This may aid in avoiding perforation of vessel  220  and allowing for on-line monitoring of the intervention process. Second, tip section  200  may be maneuverable, so as to allow different viewing angles and/or in order to align the laser beams and a cutter  206  differently. Third, a cleaning channel (not shown) may be present inside tip section  200  and extending outside the body, through which channel suction  224  is applied in order to evacuate debris of the undesired material which were treated by the lasers and/or cutter  206 . These optional alternations are now discussed in greater detail. 
     A conventional manner for detection of plaque and other lesions and for monitoring of vessel treatment is based on ultrasound and fluoroscopy. Here, however, one or more fibers  222  may be utilized for detection of lesions and/or to monitor the intervention process on-line, based on the reflection and/or scattering of the laser light from the vessel and/or the deposits. Alternatively or additionally, a different source of illumination may be used, such as through one or more other fibers. The captured light may be transmitted to a sensor such as a charge-coupled device (CCD), a metal-oxide-semiconductor (MOS), or a complementary MOS (CMOS). The sensing may include a filter or means for spectral imaging to gain information about the material characteristics (plaque, tissue, calcified plaque, blood clot, etc.). This may enable a quick and effective procedure with minimal risk of perforation and may enable debulking procedures wherein a guidewire cannot or should not be used. 
     The angle of tip section  200  may be controlled to enable, by means of tip deflection, material removal in a cross-section larger than the catheter size. This may be done by mechanical means, such as by selective inflation and deflation of at least two balloons (not shown) attached to the tip section externally at different angles, or a balloon with different compartments  226   a - d . In another embodiment, the angle of the tip section  200  may be controlled by using links forming a joint  228 . In such an embodiment, the links of the joint  228  may be controllable from outside the body using one or more wires (not shown). 
     The laser optics of some embodiments will now be discussed in greater detail. The laser beam may be directed through fibers each having a core diameter optionally in the range of 40-250 microns. In a configuration where the catheter&#39;s circumference is, for example, 15 mm, using fibers with an outer diameter of 50 microns will result in using approximately 300 fibers with a cross-section area smaller than 1 mm 2 , so that for a coupling efficiency of 75%, the energy at the exit of each fiber will be close to 40 mJ/mm when pumped with a 50 mJ laser. Adequate fibers for some embodiments may be all-silica fibers with a pure silica core. These fibers can usually withstand about 5 J/cm 2  in the input. Some embodiments include fibers with a numerical aperture (NA) in the range of 0.12-0.22. Examples of a relevant fiber are FiberTech Optica&#39;s SUV100/110AN fiber for UV application and the low OH version SIR100/140AN for use with a laser in the 1900-2100 nm range, and Infrared Fiber Systems, IR Photonics and A.R.T. Photonics GmbH fibers for transmission of radiation in the 2900-3000 nm range. Some embodiments may include microlenses at the tip area to manipulate the beam at the exit of each individual fiber. 
     The power required for effective ablation with 355 nm, 10 nsec pulses (approximately 30-60 mJ/mm 2 ) is close to the damage threshold of certain fibers or above it, which may lead, in existing products, to the need of extended pulse length, for example. According to some embodiments, high peak power is maintained and, accordingly, the catheter may include means for delivery of the laser power through relatively bigger optical fibers, e.g., 100 or even 300 micron fibers that do not extend all the way to the end of the tip section. 
     Additional information regarding embodiments of atherectomy devices and/or systems can be found in U.S. patent application Ser. No. 16/436,650, published as U.S. Patent Application Pub. No. 2019/0321103A1, titled HYBRID CATHETER FOR VASCULAR INTERVENTION, filed Jun. 10, 2019; and U.S. patent application Ser. No. 17/395,799, published as U.S. Patent Application Pub. No. 2021/0361355A1, titled SYSTEM FOR TISSUE ABLATION USING PULSED LASER, filed Aug. 6, 2021, each of which is hereby incorporated by reference herein in its entirety. 
     The hybrid catheter embodiments described herein can be used as components of a vascular treatment system  300 , such as is illustrated in  FIG.  3 A  and shown schematically in  FIG.  3 B . The vascular treatment system  300  can include a catheter  302  that is configured to be placed into the vasculature of a subject for the treatment and/or removal of UIM, such as the embodiments that are described above in connection with  FIGS.  1 A- 2   . The vascular treatment system  300  can further include a canister  306  (or “waste container”) coupled to the catheter  302  via tubing  304 . The canister  306  can receive and store the blood and/or UIM that is removed from the subject during treatment for subsequent disposal. The catheter  302  can further be operably coupled to a pressure source  308  (e.g., a pump) that is configured to generate the suction  224  through the catheter  302  for removal and aspiration of the UIM. Further, the vascular treatment system  300  can include a computer system  310  for monitoring the status of the treatment procedure and controlling the operation of the other components of the system  300 . The computer system  310  can include a processor  311 A coupled to a memory  311 B such that the processor  311 A can execute instructions stored in the memory  311 B to perform various functions embodied by the instructions. In some embodiments, the computer system  310  can provide a graphical user interface (GUI) that allows users to input various parameters, including a target aspiration flow rate, vacuum pressure levels, and so on. Accordingly, the vascular treatment system  300  can be utilized to aspirate UIM in either native or stented vasculature for removal of the UIM from the subject. 
     The aspiration flow rate results from the vacuum pressure generated by the pressure source  308 . In other words, the pressure source  308  (e.g., a pump) generates a vacuum pressure (i.e., negative pressure) that draws fluid (e.g., blood) and/or UIM from the patient&#39;s vasculature, through the catheter  302  into the canister  306 . Further, the vascular treatment system  300  can modulate the aspiration flow rate through the action of one or more control elements  314  through a variety of different mechanisms of action that are described in greater detail below. The control elements can change the aspiration flow rate by, for example, changing the vacuum pressure sensed by the catheter tip. The control element  314  can in turn be controlled by the computer system  310 . In some embodiments, the computer system  310  can control the control element  314  to modulate the aspiration flow rate in response to measurements from one or more sensors  312 , which is described in greater detail below. 
     In some embodiments, it can be advantageous to maintain a continuous aspiration flow rate during a procedure. In one embodiment, the vascular treatment system  300  could be configured to maintain an aspiration flow rate of 20 mL/min to 100 mL/min. In one embodiment, the vascular treatment system  300  could be configured to maintain an aspiration flow rate of 20 mL/min to 50 mL/min. In some embodiments, the pressure source  308  can be configured to generate from, for example and without limitation, 20 torr to 300 torr. If there is a blockage in the catheter  302  and/or other components of the system  300 , the vacuum level can be increased (e.g., to about 25 torr to 100 torr) to clear the blockage. Under normal flow conditions (e.g., about 20 mL/min to about 50 mL/min), the vacuum level can be maintained at about 120 torr to 750 torr to minimize blood aspiration. In some embodiments, the generated aspiration flow rate may be modulated (i.e., increased or decreased), but never fully ceases. It can be advantageous to never fully cease the aspiration flow during treatment because blood coagulates when it stops flowing. Additionally, stopping flow entirely could risk clot particles being released from the catheter to the blood stream (i.e., falling back into the blood stream), thereby causing an emboly. Maintaining continuous flow overall throughout the treatment mitigates this risk. If the system  300  paused the aspiration flow for any reason, the subject&#39;s blood could coagulate, which could create additional blockages within the catheter  302  and/or other components of the system  300 . Conversely, it would not be desirable for the system  300  to always be run at the highest vacuum pressure levels in order to attempt to avoid the formation of blockages because it would result in too much blood being removed from the subject. Accordingly, the ability of the vascular treatment system  300  to dynamically modulate the vacuum pressure sensed by the catheter tip can be advantageous because it allows the system to clear obstructions, while reducing the amount of blood loss in doing so. Therefore, it would be desirable for the vascular treatment system  300  to be able to dynamically shift between different vacuum levels based on sensed conditions within the system  300 . 
     Smart Aspiration for Vascular Treatment Systems 
     Vascular treatment systems, such as the embodiments described above, can be configured to aspirate the bodily fluids during removal of the targeted UIM. In some embodiments, the vascular treatment systems can include one or more sensors that are configured to sense various parameters associated with the system and modulate the vacuum level at the tip of the catheter  302  using various control elements.  FIG.  3 B  illustrates a diagram of a vascular treatment system  300  that includes a sensor  312  that is configured to sense one or more parameters associated with one or more components of the system  300  (or the connections between the components of the system  300 ) and a control element  314  that is configured to modulate the vacuum level at catheter tip in response to the sensed parameter. In particular, the control element  314  can modulate the vacuum level through a variety of different mechanisms of action (e.g., valves, booster reservoirs, or controlled leaks), which are described in greater detail below. Further, various embodiments of the vascular treatment system  300  can include a plurality of sensors  312  and/or a plurality of control elements  314 . In one embodiment, the vascular treatment system  300  can modulate (i.e., increase or decrease) the vacuum level via the action of the control element  314  without stopping the flow (i.e., causing the flow rate to be zero) during aspiration. This embodiment can be advantageous because when blood flow stops, the blood can begin to coagulate, which in turn can cause blockages (e.g., in the catheter  302 ) that can negatively impact the performance of the vascular treatment system  300 . 
     As indicated in  FIG.  3 B , the sensor  312  can be configured to sense a parameter associated with the computer system  310 , the pressure source  308 , the canister  306 , the tubing  304 , the catheter  302 , the control element  314 , or any of the connections between the aforementioned components. As likewise indicated in  FIG.  3 B , the control element  314  can be operably coupled to the computer system  310 , the pressure source  308 , the canister  306 , the tubing  304 , the catheter  302 , or any of the connections between the aforementioned components such that the control element  314  can control the corresponding component to modulate the vacuum level for the vascular treatment system  300 . In some embodiments, the sensor  312  and/or computer system  310  could further be coupled to the control element  314  and configured to sense a parameter and/or state of the control element  314 . For example, in an embodiment where the control element  314  includes a valve, the valve could include an encoder or another device that is configured to output the state (e.g., position) of the valve to the computer system  310 . Accordingly, the computer system  310  could sense a parameter and/or state of the control element  314  as part of the feedback control of the control element  314 . 
     In various embodiments, the sensor  312  can include a pressure sensor, an air flow sensor, a pump current sensor, a level sensor, a weight sensor, a blood flow sensor, an ultrasound sensor, an optical sensor or a temperature sensor. In various embodiments, the control element  314  can include a solenoid valve, a pinch valve, a proportional pinch valve, a peristaltic pump, a pump controller (e.g., a pulse width modulation controller or a voltage controller), a pump with multiple pump heads, multiple pumps or a booster pump. Embodiments including various combinations of the sensors  312  and control elements  314  will be discussed in greater detail below. Additionally, in some embodiments, the sensor  312  can monitor the state of the control element  314 . For example, the sensor  312  could monitor whether the control element  314  is opened or closed, or an amount that the control element  314  is opened or closed. In other embodiments, the control element  314  itself can include an internal sensor or encoder for monitoring openness or closedness of the control element  314 . 
     As an example, when a normal or steady aspiration flow rate is observed within the system  300 , such flow rate may be about 20-50 mL/min. At this state, the vacuum level at the catheter tip is maintained and held at about 120-750 torr. When the sensed aspiration flow rate is below about 20 mL/min, there may be a partial blockage (i.e., not a complete blockage or clog). In this state, the control element  314  could be utilized to increase the vacuum level as will be sensed by the catheter tip thereby helping to clear the partial blockage. When the sensed aspiration flow rate is below approximately 10 mL/min, there may be a complete blockage or clog. In this state, the control element  314  may be completely opened to increase the vacuum level as will be sensed by the catheter tip (e.g., to 25-100 torr or to the maximum available vacuum level) thereby helping to clear the complete blockage or clog. In some embodiments, the computer system  310  may also be equipped with an alert for alerting the user that the computer system  310  is nearing a maximum level of blood aspiration by the system  300  (e.g., about 400 mL). In some embodiments, a first alert or warning can be triggered to notify a user of about 300 mL of blood aspiration by the system  300  and then once blood aspiration reaches about 400 mL, the computer system  310  can issue a second alert or warning or even be configured to automatically shut off. 
       FIGS.  4 A and  4 B  illustrate an embodiment of a vascular treatment system  300  where the sensor  312  includes a flow sensor  360 . The flow sensor  360  could be positioned at different locations along or within the vascular treatment system  300 . In one embodiment, the flow sensor  360  could be operably coupled to or along the tubing  304  coupling the canister  306  to the catheter  302 . The flow sensor  360  can be configured to sense the rate of blood flow through the tubing  304 . The flow sensor  360  can include a blood flow sensor, a temperature sensor, or a combination thereof. In an illustrative embodiment shown in  FIG.  4 B , the flow sensor  360  could include a contactless ultrasonic flow meter that is connected to one of the two ends of the tubing  304 . The ultrasonic flow meter could be, for example, clamped over the tubing  304  and sense the flow therethrough. The ultrasonic flow meter can output a signal indicative of the sensed flow rate through the fluid line  330 . In another illustrative embodiment (not shown), the flow sensor  360  could include a turbine infrared (IR) flow meter that is positioned in-line with the tubing  304 . This flow meter can include a turbine component that is rotated as fluid flows therethrough and an IR sensor that can count the number of rotations of the turbine, which can in turn be used to determine the flow rate. Where a temperature sensor is used, the temperature sensor measures a temperature of the catheter  302  and/or tubing  304  and based on heat transfer principles, estimates the flow rate through the catheter  302  and/or tubing  304 . Such heat transfer may be based on temperature of the blood due to body temperature. For example, normal or stable flow through the catheter  302  and/or tubing  304  may measure approximately 37° C. and a reduced temperature when there is no or limited flow through the catheter  302  and/or tubing  304  due to a clog. 
     The computer system  310  may be communicably coupled to the flow sensor  360  such that it can receive an output signal or data from the flow sensor  360 . Further, the computer system  302  can modulate the vacuum pressure at the catheter tip (e.g., via a control element  314 ) in response thereto. For example, if the computer system  310  senses that the flow rate has dropped below a threshold, the computer system  310  can determine that a clog has occurred (e.g., in the tubing  304  or in the catheter  302 ) and modulate the vacuum pressure at the tip of the catheter  302 ) accordingly (e.g., increase suction to facilitate the removal of the clog). TABLE 1 sets forth various illustrative outputs of the flow sensor  360 , the states that those measurements would correspond to, and the corresponding response that the vascular treatment system  300  can initiate in response thereto, as described in greater detail below. These values are simply provided to illustrate potential measurements and responses in some embodiments of the vascular treatment system  300  and should not be understood to be limiting in any way. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Response (vacuum 
               
               
                   
                   
                 pressure at the 
               
               
                 State 
                 Output of Flow Sensor 
                 catheter tip) 
               
               
                   
               
             
            
               
                 Normal or 
                 20-50 mL/min 
                 Maintain vacuum level 
               
               
                 stable flow 
               
               
                 Clog 
                 Decrease to below 20 
                 Approximately 20-100 
               
               
                   
                 mL/min 
                 torr to be applied 
               
               
                 Clog release 
                 Increase to over 30 
                 Approximately 120-750 
               
               
                   
                 mL/min 
                 torr to be applied 
               
               
                   
               
            
           
         
       
     
       FIGS.  5 A and  5 B  illustrate an embodiment of a vascular treatment system  300  where the sensor  312  includes a pressure sensor  362 . The pressure sensor  362  can be configured to sense the vacuum pressure within the tubing  304 , catheter  302 , or other components of the vascular treatment system  300 . The pressure sensor  362  could be positioned at different locations along or within the vascular treatment system  300 . In one embodiment, the pressure sensor  362  could be coupled to or along the tubing  304  connecting the canister  306  to the catheter  302  to sense the vacuum pressure within the tubing  304 . In another embodiment, the pressure sensor  362  could be configured to sense the vacuum pressure within the catheter  302 . For example, the pressure sensor  362  could be placed directly within or adjacent to the handle of the catheter  302 . As another example, the pressure sensor  362  could be positioned externally to the catheter  302  and coupled to the handle of the catheter  302  via tubing. In an illustrative embodiment shown in  FIG.  5 B , the pressure sensor  362  is coupled to the tubing  304  at a distal end thereof adjacent to the connection point to the catheter  302 . In other embodiments, the pressure sensor  362  can be positioned in a line parallel to the catheter  302  and/or tubing  304 . 
     The computer system  310  can be communicably coupled to the pressure sensor  362  such that it can receive an output signal or data from the pressure sensor  362 . Further, the computer system  310  can modulate the vacuum pressure at the catheter tip (e.g., via a control element  314 ) in response thereto. If the aspiration flow is stable, the pressure within the catheter  302  and/or tubing  304  may remain at a relatively steady state. However, if a clog occurs, the vacuum pressure level may suddenly drop. Therefore, the vacuum pressure dropping below a threshold value or the rate of change of the vacuum pressure dropping by at least a threshold value can be indicative of a clog in the catheter  302  and/or the tubing  304  and a drop in the aspiration flow rate. For example, if the computer system  310  senses that the vacuum pressure has dropped below a threshold value, the computer system  302  can determine that a clog has occurred (e.g., in the tubing  304  or in the catheter  302 ) and modulate the vacuum pressure at the tip of the catheter  302 ) accordingly (e.g., increase suction to facilitate the removal of the clog). TABLE 2 sets forth various illustrative outputs of the pressure sensor  362 , the states that those measurements would correspond to, and the corresponding response that the vascular treatment system  300  can initiate in response thereto, as described in greater detail below. These values are simply provided to illustrate potential measurements and responses in some embodiments of the vascular treatment system  300  and should not be understood to be limiting in any way. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 Response (vacuum 
               
               
                   
                   
                 pressure at the 
               
               
                 State 
                 Output of Pressure Sensor 
                 catheter tip) 
               
               
                   
               
             
            
               
                 Normal OR 
                 120-750 torr 
                 Maintain vacuum level 
               
               
                 stable flow 
               
               
                 Clog 
                 Decrease in pressure at a 
                 Approximately 20-100 
               
               
                   
                 rate of approximately equal 
                 torr to be applied 
               
               
                   
                 to or over 15 torr/second 
               
               
                 Clog release 
                 Increase of pressure at a rate 
                 Approximately 120-750 
               
               
                   
                 of approximately equal to or 
                 torr to be applied 
               
               
                   
                 over 10 torr/second 
               
               
                   
               
            
           
         
       
     
     In another embodiment shown in  FIG.  5 C , the pressure sensor  362  could include a differential pressure sensor  363 . The differential pressure sensor  363  could be coupled at or to two or more components of the vascular treatment system  300  and be configured to measure the vacuum pressure differential between the two or more components of the vascular treatment system  300 . In the depicted embodiment, the differential pressure sensor  363  could include a first input coupled between the canister  306  and the tubing  304  and a second input coupled between the tubing  304  and the catheter  302 . In other embodiments, the inputs of the differential pressure sensor  363  could be coupled at or to other locations or components of the vascular treatment system  300 . Accordingly, the differential pressure sensor  363  could sense the pressure differential between these two locations within the vascular treatment system  300 . As with the embodiment described above in connection with  FIGS.  5 A and  5 B , the differential pressure sensor  363  could be coupled to the computer system  310  such that the computer system  310  can receive a signal and/or measurement data therefrom. Accordingly, if the computer system  310  determines that the pressure differential is at or about zero (i.e., there is no pressure differential between two or more of the sensors of the sensor assembly  364 ), the computer system  310  can determine that a clog has occurred and modulate the vacuum pressure at the catheter tip accordingly. 
       FIGS.  6 A and  6 B  illustrate an embodiment of a vascular treatment system  300  where the sensor  312  includes a pressure sensor assembly  364 , i.e., a plurality of pressure sensors. In the depicted embodiment, the pressure sensor assembly  364  includes a first pressure sensor  364 A configured to sense the vacuum pressure between the canister  306  and the tubing  304  and a second pressure sensor  364 B configured to sense the vacuum pressure between the tubing  304  and the catheter  302 . In other embodiments, the pressure sensor assembly  364  could include different numbers of pressure sensors (i.e., more than two) and/or pressure sensors arranged in other configurations or coupled to other components of the vascular treatment system  300 . In this embodiment, the various individual pressure sensors of the sensor assembly  364  could be positioned at the same or different locations throughout the vascular treatment system  300 . In an illustrative embodiment shown in  FIG.  6 B , the pressure sensor assembly  364  can include a first pressure sensor  364 A coupled to the tubing  304  at a first or upstream position and a second pressure sensor  364 B coupled to the tubing  304  at a second or downstream position. The computer system  310  be communicably coupled to each of the pressure sensors making up the pressure sensor assembly  364  such that it can receive an output signal or data therefrom. In this embodiment, the computer system  310  could individually monitor the sensed pressure at each of the locations or monitor the pressure differential between the various sensors of the sensor assembly  364 . For example, if the computer system  310  senses that the vacuum pressure has dropped below a threshold at one or more of the sensors of the sensor assembly  364 , the computer system  302  can determine that a clog has occurred (e.g., in the tubing  304  or in the catheter  302 ) and modulate the vacuum pressure at the tip of the catheter  302  accordingly (e.g., increase suction to facilitate the removal of the clog). Alternatively, if the computer system  310  determines that the pressure differential between two or more of the sensors of the sensor assembly  364  is at or about zero (i.e., there is no pressure differential between two or more of the sensors of the sensor assembly  364 ), the computer system  310  can determine that a clog has occurred and modulate the vacuum pressure at the catheter tip accordingly. 
       FIGS.  7 A and  7 B  illustrate an embodiment of a vascular treatment system  300  where the sensor  312  includes a weight sensor  366 . The weight sensor  366  could include, for example, a load cell. The weight sensor  366  can be configured to sense the weight of the contents within the canister  306 . In an illustrative embodiment shown in  FIG.  7 B , the weight sensor  366  can include a load cell positioned at the base of a holder  320  that is configured to receive the canister  306  such that the base surface of the canister  306  bears against the load cell when placed within the holder  320 . Accordingly, the weight sensor  366  can detect the weight of the canister  306  throughout treatment. 
     The computer system  310  can be communicably coupled to the weight sensor  366  such that it can receive an output signal or data from the weight sensor  366 . Further, the computer system  310  can modulate the vacuum pressure at the catheter tip (e.g., via a control element  314 ) in response thereto. Because the change in weight of the canister  306  increases with respect to the flow rate (because the rate at which the weight of the canister  206  is increasing will correspond to the rate at which fluid and/or UIM is being removed from the subject), the computer system  310  can monitor the aspiration flow rate during treatment via the weight of the canister  306 . Further, if the rate at which the weight of the canister  306  stops or slows by a threshold amount, the computer system  310  can determine that a clog has occurred and modulate the aspiration flow rate accordingly. The weight sensor  366  can provide highly accurate estimates for the aspiration flow rate and the total volume of blood that has been aspirated, which can be advantageous because although some other sensor types can identify the occurrence of obstructions with minimal time delay, they may not be able to directly measure the actual aspiration flow rate. Therefore, the weight sensor  366  can be advantageous to incorporate into various embodiments of the vascular treatment system  300 . TABLE 3 sets forth various illustrative outputs of the weight sensor  366 , the states that those measurements would correspond to, and the corresponding response that the vascular treatment system  300  can initiate in response thereto, as described in greater detail below. These values are simply provided to illustrate potential measurements and responses in some embodiments of the vascular treatment system  300  and should not be understood to be limiting in any way. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 Response (vacuum 
               
               
                   
                   
                 pressure at the 
               
               
                 State 
                 Output of Weight Sensor 
                 catheter tip) 
               
               
                   
               
             
            
               
                 Normal or 
                 Increase of 20-50 grams/min 
                 Maintain vacuum level 
               
               
                 stable flow 
               
               
                 Clog 
                 Increase of under 
                 Approximately 20-100 
               
               
                   
                 approximately 15 grams/min 
                 torr to be applied 
               
               
                 Clog release 
                 Increase of approximately 30 
                 Approximately 120-750 
               
               
                   
                 grams/min 
                 torr to be applied 
               
               
                   
               
            
           
         
       
     
       FIGS.  8 A and  8 B  illustrate an embodiment of a vascular treatment system  300  where the sensor  312  includes an air flow sensor  368 . The air flow sensor  368  can be configured to sense the air flow rate to the pressure source  308 . The air flow sensor  368  can be configured to sense the air flow rate from or within the canister  306  or other components of the vascular treatment system  300 . More particularly, the air flow sensor  368  is configured to measure the air flow between the pressure source  308  and the canister  306 . The air flow sensor  368  could be positioned at different locations along or within the vascular treatment system  300 . In an illustrative embodiment shown in  FIG.  8 B , the air flow sensor  368  can be positioned between the pressure source  308  and the canister  306 . 
     The computer system  310  can be communicably coupled to the air flow sensor  368  such that it can receive an output signal or data from the air flow sensor  368 . Further, the computer system  310  can modulate the vacuum pressure at the catheter tip (e.g., via a control element  314 ) in response thereto. If the air flow rate stops or decreases by at least a threshold value, that can indicate that there is a clog in the catheter  302  and/or the tubing  304 . Accordingly, the computer system  310  can monitor the air flow rate via the air flow sensor  368  and modulate the vacuum pressure at the tip of the catheter  302  accordingly. TABLE 4 sets forth various illustrative outputs of the air flow sensor  368 , the states that those measurements would correspond to, and the corresponding response that the vascular treatment system  300  can initiate in response thereto, as described in greater detail below. These values are simply provided to illustrate potential measurements and responses in some embodiments of the vascular treatment system  300  and should not be understood to be limiting in any way. 
     
       
         
           
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                 Response (vacuum 
               
               
                   
                   
                 pressure at the 
               
               
                 State 
                 Output of Air Flow Sensor 
                 catheter tip) 
               
               
                   
               
             
            
               
                 Normal or 
                 500-4000 mL/min 
                 Maintain vacuum level 
               
               
                 stable flow 
               
               
                 Clog 
                 Decrease in air flow rate of 
                 Approximately 20-100 
               
               
                   
                 approximately 10 mL/min 
                 torr to be applied 
               
               
                 Clog release 
                 Increase in air flow of 
                 Approximately 120-750 
               
               
                   
                 approximately 5 mL/min 
                 torr to be applied 
               
               
                   
               
            
           
         
       
     
       FIG.  9    illustrates an embodiment of a vascular treatment system  300  where the sensor includes a UIM sensor  369 . The UIM sensor  369  could include an optical sensor, an ultrasonic sensor, an inductive sensor, a magnetic sensor, a sensor configured to detect electric conductivity, or a turbine sensor, or a variety of other sensors configured to detect the presence of a thrombus or other UIM within the vascular treatment system  300 . In one embodiment, the UIM sensor  369  could include an optical sensor, image sensor, or camera that is positioned to identify material that passes through the catheter  302  and/or visually monitor for the presence of UIM (or other obstructions). For example, an optical sensor could be positioned at various locations with respect to the tubing  304  and/or catheter  302 . The computer system  310  could then use image analysis techniques on data received from the optical sensor to identify blood and/or UIM passing through the catheter  302 . Accordingly, the computer system  310  could modulate the aspiration flow in response to the identified substances. For example, the computer system  310  could utilize a control element  314  to increase the aspiration flow rate in response to soft thrombus or other UIM being detected via the optical sensor. 
     Embodiments of the vascular treatment system  300  that are configured to identify thrombi or other UIM could be beneficial because some UIM (particularly, soft thrombi) may flow relatively easily through the vascular treatment system  300  and may not be detected as a clog under certain conditions. However, even if soft thrombi passing through the vascular treatment system  300  are not creating a clog, it would nonetheless be desirable to maintain a high vacuum level (e.g., the same or similar vacuum level applied in response to a clog being a detected) to ensure that the soft thrombi are cleared from the tubing  304  and/or catheter  302 . Notably, some embodiments described herein monitor the flow rate and total volume aspirated using different sensors  312 . However, if a soft thrombus is present, the sensors  312  could mistakenly interpret the thrombus as blood. If a soft thrombus is mistakenly interpreted to be blood by the sensors  312 , the computer system  310  could calculate the flow rate and total volume of blood loss incorrectly (i.e., the actual blood loss may be lower than calculated). Therefore, it can be beneficial for some embodiments of the vascular treatment system  300  to further include a UIM sensor  369  to monitor for the presence of soft thrombi or other UIM in order to ensure that the system  300  is properly determining other parameters. 
     In addition to the sensor types described above, alternative embodiments of the vascular treatment system  300  can include additional sensors, including a level sensor  370  coupled to the canister  306  or a current sensor  372  coupled to the pressure source  308 , as shown in  FIG.  10 A . The level sensor  370  could be used to sense the amount of fluid and/or UIM that has been removed from the subject and is contained within the canister  306 . Because the rate at which the amount of fluid and/or UIM in the canister  306  is increasing corresponds to the aspiration flow rate, the computer system  310  could accordingly monitor the aspiration flow rate using the level sensor  370 . Further, the current sensor  372  could be configured to monitor the current drawn by the pressure source  308 . In some embodiments, the current drawn by the pressure source  308  could correspond to force or torque exerted by a pump motor that is configured to generate the vacuum pressure. Therefore, an increase in the sensed pressure source current could indicate that a clog has occurred because the motor (e.g., a DC motor) could be attempting to compensate for a disruption in the fluid inflow. Therefore, the computer system  310  could accordingly monitor the aspiration flow rate using the current sensor  372 . Further, the vascular treatment system  300  could include an aspiration pump that is configured to provide constant flow regardless of the load applied to the system  300  (e.g., the presence of a clog). 
     Embodiments of the vascular treatment system  300  can include one or more of any of the aforementioned sensors  312  in any combination. For example,  FIG.  10 A  illustrates an embodiment of the vascular treatment system  300  that incorporates all of the sensors described above to sense parameters associated with the system  300  and modulate the aspiration flow accordingly. Further, embodiments of the vascular treatment system  300  can include different sensors  302 , either in lieu of the aforementioned sensors or in combination thereof. In particular, it could be advantageous to use various combinations of sensors because each sensor type has its own strength. Further, various embodiments of the vascular treatment system  300  could include multiple control elements  314 . For example, the embodiment illustrated in  FIG.  10 A  includes a first control element  314 A (e.g., a control valve) interposed between the pressure source  308  for controlling the aspiration flow therethrough and the canister  306  and a second control element  314 B (e.g., a proportional pinch valve) configured to control aspiration flow between the tubing  304  and the catheter  302 . Various embodiments of the control elements  314  are described in greater detail below. 
     As another example,  FIG.  10 B  illustrates an embodiment of the vascular treatment system  300  that includes a pressure sensor  362  in combination with a weight sensor  366 . In alternative embodiments, the vascular treatment system  300  could include a differential pressure sensor  363  or a pressure sensor assembly  364  in lieu of or in addition to the pressure sensor  362 . As described above and indicated in  FIG.  10 B , the pressure sensor  362  could be coupled to a variety of different components of the vascular treatment system  300  and/or be other configured to sense the internal vacuum pressure between a variety of different components of the vascular treatment system  300 . In this embodiment, the pressure sensor  362  can identify blockages with a relatively minimal time response. Further, the weight sensor  366  for the canister  306  can provide highly accurate estimates for the aspiration flow rate, but has a relatively high time delay because the canister  306  is downstream from the catheter  302 . Therefore, it could be beneficial for embodiments of the vascular treatment system  300  to use a combination of the pressure sensor  362  and the weight sensor  366  in order to both quickly identify blockages and obtain highly accurate measurements of the aspiration flow rate. Additional embodiments of the vascular treatment system  300  could utilize other combinations of sensor types to obtain different benefits or simply provide measurement redundancy from the different sensor types. 
     As discussed above, the one or more sensors  312  can be operably coupled to a control element  314  that is configured to modulate the vacuum pressure generated through the catheter  302 . Embodiments of the vascular treatment system  300  can include a variety of different control elements  314  that can be configured to control the computer system  310 , the pressure source  308 , the canister  306 , the tubing  304 , the catheter  302 , or any of the connections between the aforementioned components to modulate the vacuum pressure at the catheter tip for the vascular treatment system  300 . 
     Referring now to  FIG.  10 C , there is shown an embodiment of the vascular treatment system  300  include a UIM filter  316 . As noted above with respect to the embodiment illustrated in  FIG.  9   , it can be beneficial for the vascular treatment system  300  to identify the presence of UIM such as soft thrombi or UIM fragments. However, it could be further beneficial for the vascular treatment system  300  to remove soft thrombi from the fluid lines of the system  300 . The UIM filter  316  could include a filter or barrier that is configured to capture a soft thrombus or other UIM. In the embodiment illustrated in  FIG.  10 C , the vascular treatment system  300  can include a UIM filter  316  positioned in-line between the catheter  302  and the canister  306 . As an example, the UIM filter  316  could be positioned before a flow sensor  360  so that any soft thrombi are prevented from reaching the flow sensor  360  and, thus, would not affect any measurements by the flow sensor  360 . In another embodiment, the UIM filter  316  could be positioned within the canister  306 . In this embodiment, the UIM filter  316  could be coupled to a separate weight sensor (i.e., a distinct weight sensor from the weight sensor  366 ) that is configured to weigh a thrombus captured by the UIM filter  316 . The computer system  310  could further be coupled to the UIM filter weight sensor (not shown). Accordingly, the computer system  310  could subtract the weight of the captured thrombus (e.g., as determined by the UIM filter weight sensor) from the total weight of the canister  306  (e.g., as determined by the weight sensor  366 ). In yet another embodiment, the vascular treatment system  300  could include a sensor configured to detect a level of material within the canister  306  (e.g., an ultrasonic level sensor), which can in turn be utilized by the computer system  310  to determine the volume and flow rate of the aspirated fluid remove from the subject, without the UIM (e.g., a soft thrombus) being present within the canister  306  to affect those calculations. In these embodiments, the computer system  310  could compensate for the presence of a UIM and thereby accurately determine various parameters associated with the system  300 , such as the actual blood loss by the subject. In some embodiments, these data or parameters could further be provided to the user by the computer system  310 . 
       FIGS.  11 A-C  illustrate an embodiment of a vascular treatment system  300  where the control element  314  includes a valve  380  configured to modulate the vacuum pressure at the catheter tip therethrough. The valve  380  can be positioned at various locations within the vascular treatment system  300  for modulating the aspiration flow therethrough, including being coupled to the tubing  304  connecting the catheter  302  to the canister  306 . The valve  380  can include a proportional valve, a solenoid valve, a pinch valve, or a gate. In an illustrative embodiment shown in  FIG.  11 B , the valve  380  includes a modulated solenoid valve  380 A that is placed on the catheter tubing  304 , adjacent to the canister  306 . In another illustrative embodiment shown in  FIG.  11 C , the valve  380  includes a pinch valve  380 B that is positioned similarly to the embodiment shown in  FIG.  11 B . In one embodiment, the valve  380  can be controlled by the computer system  310  to open and close according to a duty cycle, which is set by the computer system  310  in response to the sensed aspiration flow state. For example, the duty cycle of the valve  380  could be modulated to increase the vacuum pressure at the catheter tip when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ). In yet another illustrative embodiment, the valve  380  could include a proportional valve and the amount or degree to which the valve is closed could be controlled by the computer system  310 . Accordingly, the computer system  310  could modulate the vacuum pressure at the tip of the catheter  302  by controlling the amount or degree to which the proportional valve is opened or closed in response to the sensed aspiration flow state. 
       FIGS.  12 A and  12 B  illustrate an embodiment of a vascular treatment system  300  where the control element  314  is configured to utilize an air leak control element  382  to modulate the vacuum pressure at the catheter tip. The air leak control element  382  is configured to controllably permit air to enter the vascular treatment system  300  in order to modulate the generated vacuum pressure at the catheter tip. In various embodiments, the aperture of an air leak control element  382  could range from about 0.3 mm to about 0.6 mm. By allowing air in the system  300 , the air leak control element  382  can effectively control the strength of the vacuum pressure experienced by the catheter  302 , which in turn affects the aspiration flow rate generated thereby. In other words, as more air is permitted to enter the vascular treatment system  300 , the vacuum pressure may decrease. By controlling the degree of air leakage through the air leak control element  382 , the computer system  310  could accordingly control the aspiration flow rate. The air leak control element  382  could include a variety of different valves, nozzles or gates configured to permit air inflow therethrough. In an illustrative embodiment shown in  FIG.  12 B , the air leak control element  382  includes a solenoid valve that is positioned at a junction between the pressure source  308  and the canister  306  to modulate the vacuum pressure generated by the pressure source  308 . In one embodiment, the air leak control element  382  can be controlled by the computer system  310  to open and close according to a duty cycle, which is set by the computer system  310  in response to the sensed aspiration flow state. For example, the duty cycle of the air leak control element  382  could be modulated to increase the vacuum pressure at the catheter tip (i.e., decrease the air leakage inflow, which in turn increases the vacuum pressure) when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ). In another embodiment, the aperture size of the air leak control element  382  could be controllable in response to the sensed aspiration flow state. For example, the aperture size of the air leak control element  382  could be decreased to increase the vacuum pressure at the catheter tip (i.e., decrease the air leakage inflow, which in turn increases the vacuum pressure) when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ). 
       FIGS.  13 A-C  illustrate embodiments of a vascular treatment system  300  where the control element  314  includes a secondary pump  384  configured to modulate the vacuum pressure at the catheter tip therethrough. The pump  384  could differ from the pressure source  308  described above. The pump  384  can be positioned at various locations within the vascular treatment system  300  for modulating the aspiration flow, including being coupled to the tubing  304  connecting the catheter  302  to the canister  306 . In an illustrative embodiment shown in  FIG.  13 B , the pump  384  includes a peristaltic pump  384 A that is coupled to the catheter tubing  304  adjacent to the canister  306 . In another illustrative embodiment shown in  FIG.  13 C , the pump  384  includes a DC pump  384 B that is coupled to the catheter tubing  304  adjacent to the canister  306 . The pump  384  can be configured to pump fluid and/or UIM at varying speeds as determined by the computer system  310  in response to the sensed aspiration flow state. For example, the speed of the pump  384  could be increased, which in turn increases the vacuum pressure at the catheter tip, when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ). 
       FIG.  14    illustrates an embodiment of a vascular treatment system  300  where the control element  314  includes a controller  386  configured to directly control the pressure source  308  to modulate the aspiration flow. The controller  386  could include a variety of different hardware, software, and/or firmware controllers that are configured to control the output of a pressure source  308  (e.g., a pump). In some embodiments, the controller  386  could include a pulse width modulation (PWM) or voltage controller. In one illustrative embodiment, the pressure source  308  could be controlled by the computer system  310  via a PWM signal or direct voltage control to control the speed of the pressure source  308 . The controller  386  could control the pressure source  308  to modulate the vacuum pressure at the catheter tip as generated thereby as determined by the computer system  310  in response to the sensed aspiration flow state. For example, the controller  386  could increase the speed (e.g., rotations per minute) of the pump when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ). In another embodiment where the pressure source  308  includes a multi-headed pump, the computer system  310  could modulate the arrangement of the pump heads via the controller  386 . In particular, when it is desired to increase the vacuum level (e.g., in response to a clog being detected), the pump heads could be connected in series with each other. Conversely, when it is desired to decrease the vacuum level, the pump heads could be connected in parallel. 
       FIG.  15    illustrates an embodiment of a vascular treatment system  300  where the control element  314  includes a booster reservoir  388  that can be utilized to modulate the aspiration flow. In this embodiment, the booster reservoir  388  could be used as an additional source of vacuum pressure that can be selectively coupled to the canister  306  and/or another component of the vascular treatment system  300  in order to modulate the vacuum pressure at the catheter tip. In particular, the booster reservoir  388  could be coupled to the vascular treatment system  300  in order to increase the vacuum pressure of the system  300 , which in turn would increase the vacuum pressure at the catheter tip and thereby allow for obstructions to be cleared as necessary. The booster reservoir  388  could be coupled to one or more of the other components of the vascular treatment system  300  (e.g., the catheter tubing  304 ) via a valve or another device that allows for the access to the booster reservoir  388  to be controlled, which in turn dictates the amount by which the generated vacuum pressure is modulated thereby. In an illustrative embodiment shown in  FIG.  15 B , the booster reservoir  388  is coupled to the catheter tubing  304 , adjacent to the canister  306 , via a solenoid valve. The computer system  310  can be configured to control the solenoid valve in response to the sensed aspiration flow state in order to control the amount of additional vacuum pressure that is provided by the booster reservoir  388 , which in turn affects the vacuum pressure experienced at the catheter tip. For example, when the computer system  310  detects that a clog may be present (e.g., via the sensor  312 ), the computer system  310  could control the valve to couple the booster reservoir  388  to the canister  306  to increase the vacuum pressure in order to clear the clog. In one embodiment, the booster reservoir  388  could be coupled to the vascular treatment system  300  via a proportional valve or another connector to allow the amount of supplemental vacuum pressure provided by the booster reservoir  388  to be modulated by controlling the amount or degree to which the valve is opened. 
     As described throughout, the vascular treatment system  300  can sense various parameters associated with the system  300  and modulate the aspiration flow rate generated through the catheter  302  accordingly. Various embodiments processes  500 ,  600 ,  700  for modulating the aspiration flow rate are shown in  FIGS.  16 - 18   . In one embodiment, the processes  500 ,  600 ,  700  can be embodied as instructions stored in a memory (e.g., the memory  311 B) that, when executed by a processor (e.g., the processor  311 A), causes the computer system  310  to perform the processes  500 ,  600 ,  700 . In various embodiments, the processes  500 ,  600 ,  700  can be embodied as software, hardware, firmware, and various combinations thereof. In various embodiments, the processes  500 ,  600 ,  700  can be executed by and/or between a variety of different devices or systems. For example, various combinations of operations of the processes  500 ,  600 ,  700  could be executed by the computer system  310  and/or other components of the vascular treatment system  300 . In various embodiments, the computer system  310  executing the process  500  can utilize distributed processing, parallel processing, cloud processing, and/or edge computing techniques. For brevity, the processes  500 ,  600 ,  700  are described below as being executed by the computer system  310 ; however, it should be understood that the functions can be individually or collectively executed by one or multiple devices of the vascular treatment system  300 . 
     Referring now to  FIG.  16   , there is shown one embodiment of a process  500  for modulating the aspiration flow. Accordingly, the computer system  310  executing the process  500  can cause the vascular treatment system  300  to initiate  502  aspiration through the catheter  302  (e.g., by activating the pressure source  308 ). During aspiration, the computer system  310  can receive  504  a sensor measurement from one or more of the sensors  312 . The received sensor measurement could include, for example, direct (e.g., via a flow sensor  360 ) or indirect (e.g., via a canister weight sensor  366 ) measurements of the aspiration flow rate. Further, the computer system  310  can determine  506  whether the received sensor measurement violates a threshold (e.g., exceeds a threshold value or falls below a threshold value). The threshold could include a default value, a range of values, a baseline measurement for the vascular treatment system  300 , a rate of change of the sensed parameter (or another derived measurement), and so on. If the sensor measurement violates the threshold, the computer system  310  can modulate  508  the vacuum pressure at the catheter tip using the control element  314  accordingly. For example, if the sensed flow rate falls below a threshold value, the computer system  310  can utilize the control element  314  to increase the vacuum pressure at the catheter tip. Conversely, if the sensed measurement does not violate the threshold, the computer system  310  can take no action or otherwise maintain  510  the vacuum pressure (thereby maintaining the present aspiration flow rate). In one embodiment, the level at which the aspiration flow and/or vacuum pressure are maintained 510 could be dependent upon the state of a secondary device associated with or within the vascular treatment system  300 . For example, if the laser of the catheter  302  is activated, the vacuum pressure could be maintained at a first level; conversely, if the laser is not activated, the vacuum pressure could be maintained at a second level. In some embodiments, when the laser is not activated, and before the procedure starts the control element  314  can restrict the aspiration flow rate completely (i.e., no flow). As indicated in  FIG.  15   , regardless of whether the computer system  310  modulates  508  or maintains  510  the vacuum pressure at the catheter tip, the computer system  310  can continue receiving  504  sensor measurements and acting accordingly to control the vacuum pressure at the catheter tip. 
     Referring now to  FIG.  17   , there is shown another embodiment of a process  600  for modulating the aspiration flow. Similarly as described above with respect to the process  500  depicted in  FIG.  16   , the computer system  310  executing the process  600  can cause the vascular treatment system  300  to initiate  602  aspiration through the catheter  302  and receive  604  a sensor measurement from one or more of the sensors  312  during the aspiration. In this embodiment, the computer system  310  can determine  606  whether an obstruction is present. The computer system  310  could determine  606  that an obstruction is present either directly (e.g., by UIM being detected by an optical sensor) or indirectly (e.g., based on a drop in the pressure differential across one or more components of the vascular treatment system  300  or the sensed aspiration flow rate dropping below a threshold) via one or more sensors  312 , as described throughout the present disclosure. Similarly to the aforementioned embodiment, if the computer system  310  identifies the presence of an obstruction, the computer system  310  can modulate  608  the vacuum pressure at the catheter tip using the control element  314  accordingly (e.g., increasing suction). Conversely, if the computer system  310  does not identify the presence of an obstruction, the computer system  310  can take no action or otherwise maintain  610  the vacuum pressure (thereby maintaining the present aspiration flow rate). As with the aforementioned embodiment, the aspiration flow and/or vacuum pressure could be maintained at different levels depending upon the state of a secondary device associated with or within the vascular treatment system  300 . As indicated in  FIG.  17   , regardless of whether the computer system  310  modulates  608  or maintains  610  the vacuum pressure at the tip of the catheter  302 , the computer system  310  can continue receiving  604  sensor measurements and acting accordingly to control the vacuum pressure at the catheter tip in response to the detection of any obstructions. 
     Referring now to  FIG.  18   , there is shown another embodiment of a process  700  for modulating the aspiration flow. Accordingly, the computer system  310  executing the process  700  can cause the vascular treatment system  300  to initiate  702  aspiration through the catheter  302  at a target aspiration flow rate. In one embodiment, the target aspiration flow rate could be input by a user via a GUI provided by the computer system  310 , for example. In one embodiment, the target aspiration flow rate could be automatically determined by the computer system  310  based on the size of the catheter  302 . For example, the vascular treatment system  300  could include a sensor (e.g., an RFID reader) that is configured to detect the type of catheter  302  being utilized, which can in turn be used to determine the size of the catheter  302 . Based on the size of the catheter  302 , the computer system  310  could set the target aspiration flow rate and a variety of other parameters for the system  300  (e.g., vacuum level) accordingly. The target aspiration flow rate could be a particular value or a range of values. In one embodiment, the target aspiration flow rate could be about 20 mL/min to about 100 mL/min. In another embodiment, the target aspiration flow rate could be about 20 mL/min to about 50 mL/min. Further, the computer system  310  can receive  704  a sensor measurement from one or more of the sensors  312  during the aspiration and determine  706  whether the intraprocedural aspiration flow rate deviates from the target aspiration flow rate value or range. In one embodiment, the computer system  310  could directly measure the aspiration flow rate (e.g., via a flow sensor  360  or a weight sensor  366 ) or indirectly measure the aspiration flow rate via one or more sensors  312 , as described throughout the present disclosure. If the computer system  310  determines that the intraprocedural aspiration flow rate deviates from the target value or range, the computer system  310  can modulate  708  the vacuum pressure at the catheter tip using the control element  314  to bring the intraprocedural flow rate into alignment with the target aspiration flow rate. Conversely, if the computer system  310  determines that the intraprocedural aspiration flow rate does not deviate from the target value or range, the computer system  310  can take no action or otherwise maintain  710  the vacuum pressure at the catheter tip (thereby maintaining the present aspiration flow rate). As with the aforementioned embodiment, the aspiration flow and/or vacuum pressure could be maintained at different levels depending upon the state of a secondary device associated with or within the vascular treatment system  300 . As indicated in  FIG.  18   , regardless of whether the computer system  310  modulates  708  or maintains  710  the vacuum pressure at the catheter tip, the computer system  310  can continue receiving  704  sensor measurements and acting accordingly to control the vacuum pressure at the catheter tip in response to the detected intraprocedural aspiration flow rate. 
     It can be advantageous for the vascular treatment system  300  to maintain a target aspiration flow rate, regardless of the load being experienced by the system  300  from the aspiration flow, for a number of different reasons. For example, the pressure source  308  can react directly to the load on the system  300  or the pressure source  308  can be optimized for particular restrictions or loads. Accordingly, it can be beneficial for some embodiments of the computer system  310  to execute the process  700 . 
     While the present disclosure has been illustrated by the description of exemplary embodiments thereof, and while the embodiments have been described in certain detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to any of the specific details, representative devices and methods, and/or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the Applicant&#39;s general inventive concept. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     In addition, even if a specific number is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of “two recitations,” without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, et cetera). In those instances where a convention analogous to “at least one of A, B, or C, et cetera” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, et cetera). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, sample embodiments, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” 
     In addition, where features of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group. 
     Various of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.