OCCLUSION BALLOONS AND DISTAL THROMBECTOMY CATHETERS WITH BLOOD FLOW SENSORS AND AUTOMATED INFLATION

Catheter devices and methods are disclosed and described. A catheter device (100) can include a longitudinal lumen (104) and having a proximal end (104a) and a distal end (104b). The distal end (104b) is capable of insertion into at least the internal carotid artery. The catheter device (100) can include an occlusion balloon (120b) connected to the distal end (104b) and operable to occlude blood flow in a blood vessel (102) by inflation and deflation using a pressurization fluid. The catheter device (100) can include a pressure sensor (110b) associated with the distal end (104b) and operable to measure blood pressure data from at least one of a downstream (103b) and upstream (103a) location of the occlusion balloon (120b) and transmit the blood pressure data to a controller (150). The occlusion balloon (120b) can be operable to inflate or deflate based on inflation control information. The catheter device (100) can be used to treat cerebral thrombectomy in a subject.

BACKGROUND

In the United States, someone dies of a stroke every 4 minutes. Stroke is the fifth leading cause of death for Americans, representing1out of every 20 deaths, and is one of the leading causes of long-term disability. Each year about 800,000 people in the United States have a stroke—87% of which are classified as acute ischemic strokes (AIS). When recognized early, long-term brain damage from these ischemic strokes can be moderated using therapies aimed at removing the clot and restoring blood flow termed “mechanical thrombectomy.”

Nonetheless, ineffective clot retrieval, clot fragmentation, and embolization during mechanical thrombectomy for large vessel occlusions can result in life-threatening conditions. Multiple devices and techniques have been used for mechanical thrombectomy, but not all mechanical thrombectomy procedures are successful. In some cases, the clot cannot be safely removed with these technologies. In other cases, the clot fragments, and pieces migrate downstream into a vessel from which it is not safe to remove them, frequently leading to irreversible tissue damage and stroke.

SUMMARY

In one embodiment, a catheter device can comprise a catheter including a longitudinal lumen and having a proximal end and a distal end. In one aspect, the distal end is capable of insertion into at least the internal carotid artery. In another aspect, the catheter device can include an occlusion balloon connected to the distal end and operable to occlude blood flow in a blood vessel by inflation and deflation using a pressurization fluid. In another aspect, the catheter device can include a pressure sensor associated with the distal end and operable to measure blood pressure data from at least one of a downstream and upstream location of the occlusion balloon and transmit the blood pressure data to a controller. In yet another aspect, the controller can be operable to receive the blood pressure data from the pressure sensor, generate inflation control information based on the blood pressure data, and transmit the inflation control information to the occlusion balloon. In one aspect, the occlusion balloon can be operable to inflate or deflate based on the inflation control information by changing a selected volume of the pressurization fluid within the occlusion balloon.

In another embodiment, a method of using a catheter device to treat cerebral thrombectomy in a subject can comprise inserting a catheter device into a cerebral vasculature of a subject such that a distal end of the catheter device is adjacent a patient thrombus. In one aspect, the method can comprise measuring blood pressure data using a pressure sensor located at least at one of a downstream and upstream position of an occlusion balloon of the catheter device. In another aspect, the method can comprise inflating or deflating the occlusion balloon based on the blood pressure data to achieve a desired degree of occlusion.

These drawings are provided to illustrate various aspects of the invention and are not intended to be limiting of the scope in terms of dimensions, materials, configurations, arrangements or proportions unless otherwise limited by the claims.

DETAILED DESCRIPTION

While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. Thus, the following more detailed description of the embodiments of the present invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the present invention, to set forth the best mode of operation of the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the present invention is to be defined solely by the appended claims.

Definitions

The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an edge” includes reference to one or more of such surfaces and reference to “the sensor” refers to one or more of such features.

As used herein, the term “about” is used to provide flexibility and imprecision associated with a given term, metric or value. The degree of flexibility for a particular variable can be readily determined by one skilled in the art. However, unless otherwise enunciated, the term “about” generally connotes flexibility of less than 2%, and most often less than 1%, and in some cases less than 0.01%.

As used herein, the terms “treat,” “treatment,” or “treating” and the like refers to administration of a therapeutic agent or therapeutic action to a subject who is either asymptomatic or symptomatic. In other words, “treat,” “treatment,” or “treating” can refer to the act of reducing or eliminating a condition (i.e., symptoms manifested), or it can refer to prophylactic treatment (i.e., administering to a subject not manifesting symptoms in order to prevent their occurrence). Such prophylactic treatment can also be referred to as prevention of the condition, preventative action, preventative measures, and the like.

As used herein, a “subject” refers to an animal. In one aspect the animal may be a mammal. In another aspect, the mammal may be a human.

As used herein, an “acute” condition refers to a condition that can develop rapidly and have distinct symptoms needing urgent or semi-urgent care. By contrast, a “chronic” condition refers to a condition that is typically slower to develop and lingers or otherwise progresses over time. Some examples of acute conditions can include without limitation, a stroke, an asthma attack, bronchitis, a heart attack, pneumonia, and the like. Some examples of chronic conditions can include without limitation, arthritis, diabetes, hypertension, high cholesterol, and the like.

As used herein, comparative terms such as “increasing,” “increased,” “decreasing,” “decreased,” “better,” “worse,” “higher,” “lower,” “enhancing,” “enhanced,” “maximizing,” “maximized,” “minimizing,” “minimized,” and the like refer to a property, result, or effect of a device, composition, formula, component, treatment, regimen, method, or activity that is measurably different from a property, result, or effect of other devices, compositions, formulas, components, treatments, regimens, methods, or activities. Furthermore, comparative terms can refer to a different biological state, presence, absence, activity level, or operation that is measurably different than an endogenous biological state, presence, absence, activity level, or operation. Comparative terms can be used to indicate differences in a surrounding or adjacent area, for example, regions of tissue. Comparative terms can also be used to indicate differences in chemical or biological structure or activity (e.g., therapeutic activity or effectiveness). Additionally, comparative terms can be used to indicate differences in biologic or physiologic result, activity, or status as compared to a previous, or other biologic or physiologic result, activity, or status. In some cases, comparison may be made simply between the points in time (e.g., endogenous state versus treated state). In other cases, the comparison can be made between the results achieved by two different applied formulations or treatment.

The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that any terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.

The term “coupled,” as used herein, is defined as directly or indirectly connected in a biological, chemical, mechanical, electrical, or nonelectrical manner. “Directly coupled” structures or elements are in contact with one another and are attached. “Fluidly coupled” objects, structures, or components are in a sufficient relationship so as to allow movement or transfer of fluid from one of the objects, structures, or components to the other. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used.

Occurrences of the phrase “in one embodiment,” or “in one aspect,” herein do not necessarily all refer to the same embodiment or aspect. Reference throughout this specification to “an example” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment.

As used herein, the term “at least one of” is intended to be synonymous with “one or more of.” For example, “at least one of A, B and C” explicitly includes only A, only B, only C, or combinations of each.

Numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted to include not only the explicitly recited limits of 1 to about 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than about 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

Example Embodiments

An initial overview of invention embodiments is provided below and specific embodiments are then described in further detail. This initial summary is intended to aid readers in understanding the technological concepts more quickly, but is not intended to identify key or essential features thereof, nor is it intended to limit the scope of the claimed subject matter.

Over the last two decades, the mechanical thrombectomy device market has witnessed a surge of technological innovations that have shaped product design. In the late 1990's, endovascular treatment for acute stroke focused on trying to break apart the clot within the vessel using aspiration, chemical compounds, or both, but this approach can result in clots that become increasingly difficult to remove when they are fragmented, thereby leading to poor clinical outcomes. In some cases, these small fragments travel further into the brain and introduce additional complications.

Treatment with thrombectomy to treat large vessel occlusion can utilize a balloon guide catheter (BGC) in a cervicocerebral artery. Most times, the balloon guide catheter can be advanced through an introducer sheath in the common femoral artery, retrograde through the aorta, and into the common carotid to the internal carotid artery (ICA). The balloon can then be inflated in the ICA, which momentarily stops blood flow while the thrombectomy is performed. The use of a balloon guide catheter can increase first pass success rates, increase total clot removal, prevent migration of the clot to new vessels, and result in better long term neurological outcomes.

Despite data supporting the use of balloon guide catheters that arrest flow in the vessel while the clot is removed, these devices inflate a balloon in the mid-neck while the clot is removed at the base of the brain. Even though flow arrest can increase success and lead to better patient morbidity and mortality outcomes, there are a fair number of cases in which the treatment is not successful.

There are several limitations to these BGCs that limit their usefulness. The small size of the balloon requires the use of a high concentration of contrast in the inflation medium to aid in visualization which can be difficult to inflate and deflate with, at least partially due to relatively high viscosity of such contrast. In other words, inflation and deflation times can be long, and deflation can be difficult which can prolong the total duration of the procedure. The overall size (e.g., width) and stiffness of the conventional BGC allows advancement into the ICA but no further. More distal advancement that is closer to the point of occlusion would be beneficial but is not possible with these BGCs. Obtaining occlusion with a balloon more distally is complicated by attempting to inflate a balloon in the M1 segment of the middle cerebral artery (MCA), which can have catastrophic consequences if not performed delicately to prevent vessel injury. Access through the radial artery instead of the femoral artery could result in a reduced risk of injury, but BGCs are too large for use in the radial artery unless they are used without an introducer sheath—an omission that can lead to complications.

In one embodiment, a catheter device can comprise a catheter including a longitudinal lumen and having a proximal end and a distal end. In one aspect, the distal end is capable of insertion into at least the internal carotid artery. In another aspect, the distal end is sized and designed to allow insertion into vessels smaller than the ICA. In another aspect, the catheter device can include an occlusion balloon connected to the distal end and operable to occlude blood flow in a blood vessel by inflation and deflation using a pressurization fluid.

In another aspect, the catheter device can include a pressure sensor associated with the distal end and operable to measure blood pressure data from at least one of a downstream and upstream location of the occlusion balloon and transmit the blood pressure data to a controller. In yet another aspect, the controller can be operable to receive the blood pressure data from the pressure sensor, generate inflation control information based on the blood pressure data, and transmit the inflation control information to the occlusion balloon. In one aspect, the occlusion balloon can be operable to inflate or deflate based on the inflation control information by changing a selected volume of the pressurization fluid within the occlusion balloon.

In another embodiment, a method of using a catheter device to treat cerebral thrombectomy in a subject can comprise inserting a catheter device into a cerebral vasculature of a subject such that a distal end of the catheter device is adjacent a patient thrombus. In one aspect, the method can comprise measuring blood pressure data using a pressure sensor located at least at one of a downstream and upstream position of an occlusion balloon of the catheter device. In another aspect, the method can comprise inflating or deflating the occlusion balloon based on the blood pressure data to achieve a desired degree of occlusion.

The catheter device disclosed herein can include several components (e.g., an intermediate aspiration catheter, a retrievable stent, and occlusive balloons). One balloon can inflate around the distal end of the aspiration catheter to occlude flow where the thrombectomy is performed. At an end of the retrievable stent, another balloon can inflate on the inside of the stent. These two balloons can remain inflated as the system is pulled from the patient's body to perform the thrombectomy. The clot being removed can be trapped between the balloons.

To provide safety, blood flow and pressure sensors can be embedded in the devices (both the catheter and retrievable stent) to sense when blood flow halts due to balloon occlusion. The balloon can be inflated by a closed system that stops inflation when a safe and effective amount of inflation is achieved. This system can prevent unsafe overinflation of the balloons to prevent damage to the vessel. Additionally, this can be a dynamic device that maintains optimum inflation throughout the pull so that the balloon volumes change to match the change in vessel caliber as the devices are removed from the patient. Similarly, the device can dynamically and actively maintain safe inflation during use which can include shifting of the device relative to vessel walls. For example, during use the device may shift upstream or downstream slightly where vessel elasticity and/or vessel inner diameter increases or decreases. The device can provide for active and dynamic adjustment of inflation to compensate for a loss of flow blockage or an undesirable increase in pressure against vessel walls.

These properties (sensing of blood flow and pressure, and dynamic inflation of one or more balloons) can provide flow arrest at the site of the clot and allow the clot to be trapped between balloons in addition to the standard approach of retrieving the clot with a combination of a retrievable stent and aspiration. This approach can provide additional benefits in the intracranial circulation because of the real-time feedback used to maintain balloon inflation to a safe and occlusive degree. With this general invention background, the following discussion presents specific examples which further illustrate these concepts.

In one embodiment, as illustrated inFIG.1, the catheter device100can include an occlusion balloon120b, one or more pressure sensors110a,110b, and a controller150electrically coupled155to the catheter101. In one aspect, the catheter device100can include a longitudinal lumen104having a proximal end104aand a distal end104b. Note that the proximal end104aμlustrated is truncated and extends from the target location to the insertion point (seeFIG.2). An optional catheter106can be inserted along the vessel pathway separately or contemporaneously with the longitudinal lumen104. The guide wire106can further optionally include an inflation lumen to facilitate inflation of a second occlusion balloon (as more fully described inFIG.3A). In one aspect, the distal end104bcan be capable of insertion into at least the internal carotid artery, and in some cases into vessels smaller than the ICA. As a general guideline, an outer diameter of the longitudinal lumen104can be from 1 mm to 3 mm, often from 1 mm to 2 mm, and in some cases 1.8 mm to 1.9 mm. Further, the guide wire can generally have an outer diameter of 0.5 to 2 mm, and in some cases 0.5 mm to 1.6 mm. Similarly, the catheter and lumen can be formed of a material and of dimensions to allow sufficient flexibility to avoid damage to ICA and smaller vessels.

In another aspect, the occlusion balloon120bcan be connected to the distal end104bof the guide wire and operable to occlude blood flow in a blood vessel102(contained by vessel walls102aand102b) by inflation and deflation using a pressurization fluid. The occlusion balloon can be connected to the lumen as an integrated part of the lumen, or attached to an outer surface of the lumen. In one example, the occlusion balloon can be formed from a resilient polymer bladder. For example, the resilient bladder can be glued, crimped or otherwise secured to the outer surface. Corresponding pressurization fluid holes can be located on the lumen and within the bladder to allow pressurization fluid to be introduced or withdrawn from the bladder.

In another aspect, the pressure sensor110bcan be associated with the distal end104band operable to measure blood pressure data from at least one of a downstream103band upstream103alocation of the occlusion balloon120band transmit the blood pressure data to a controller150. Pressure sensors can be fully or at least partially embedded in a wall of the lumen, or attached to an outer surface of the lumen.

In yet another aspect, the controller150can be operable to receive the blood pressure data from the one or more pressure sensors110a,110b, generate inflation control information based on the blood pressure data, transmit the inflation control information to a pressurization fluid source where a pump, valve or other flow control mechanism can be used to introduce additional fluid to the occlusion balloon120bor to remove fluid from the occlusion balloon120b. In one more aspect, the occlusion balloon120bcan be operable to inflate or deflate based on the inflation control information by changing a selected volume of the pressurization fluid within the occlusion balloon120b. Any suitable pressurization fluid can be used such as, but not limited to, saline solution, CO2, and the like. In one example, the fluid can be a saline solution.

In another embodiment, a method of using the catheter device100to treat cerebral thrombectomy in a subject can comprise inserting a catheter device100into a cerebral vasculature of a subject such that a distal end104bof the catheter device100is adjacent a patient thrombus105. In one aspect, the method can comprise measuring blood pressure data using one or more pressure sensors110a,110blocated at least at one of a downstream103band upstream position103aof an occlusion balloon120aof the catheter device100. In another aspect, the method can comprise inflating or deflating the occlusion balloon120abased on the blood pressure data to achieve a desired degree of occlusion.

As one example method, a guide catheter having an optional balloon on the tip can be oriented in an extracranial location and is intended to remain stationary. The guide catheter balloon can be inflated and a catheter device as described herein can be advanced to the clot. Alternatively, the guide catheter balloon can be omitted in favor of the occlusion balloon of the catheter device100. Optionally, a second microcatheter can also be used to pass the clot and then deploy a stentriever. The distal access with a balloon on the catheter device100and the dynamic inflation can safely maintain flow arrest throughout the procedure of withdrawing the catheters to remove the clot.

In another alternative, the method can include inflation of a balloon on a microcatheter distal to the thrombus. For example,FIG.3aμlustrates such an alternative as occlusion balloon320b. The balloon can then be inflated dynamically to maintain proper inflation to withdraw and pull the clot together with the balloon until reaching a larger catheter.

Catheter Device

Many balloon-guide catheters lack a physical mechanism to prevent fragments of clots from moving deeper into the vasculature during a cerebral thrombectomy procedure. These clot fragments can block small vessels in the brain leading to further brain injury. The use of a distal balloon can enhance clot capture by preventing fragments from passing the balloon. Further, the placement of one or more pressure sensors at the one or more balloons (e.g., proximal and distal balloons) at the site of the clot can provide real-time blood flow analysis, data on balloon vessel occlusion, and data on vascular stability. In conjunction with the pressure sensor feedback system, the one or more balloons can modulate inflation-deflation settings according to the blood pressure-flow profile. This can provide a consistent seal as a clinician retracts the clot from small cerebral arteries to vessels of larger diameter (e.g., common carotid artery). For example, vessels having an inner diameter less than about 6 mm and in some cases less than 4 mm can be reached without damage. Advantageously, the catheter device can reach vessels having an inner diameter of less than 5 mm, in some cases less than 4 mm, other cases 3 mm, and most often not less than 2 mm.

In one embodiment, as generally illustrated inFIG.2, a catheter device system200can include a catheter device210that can provide dynamic automated changes in balloon inflation based on feedback that is generated from a controller220through adjustment of pressurization fluid volumes from a fluid source240. The balloon can be positioned using either radial250aor femoral arterial access in a subject250. In addition to housing the balloon, the catheter device210can also allow for access of the cervicocerebal arteries for performance of angiography and mechanical thrombectomy. For radial access250a, the catheter device210can also measure markers of perfusion to prevent ischemia to the upper extremity. For example, a waveform of the vessel pressure tracing can be analyzed. A tardus parvus waveform on the downstream transducer would indicate upstream occlusion. This can be compared with an upstream sensor in the brachial artery. If there is increased resistive index or waveform findings of “knocking” or “stump-thump,” occlusion of the supply to the upper extremity can be suspected. Absence of such findings would provide increased confidence that there is preserved flow via collaterals in the ulnar artery. The catheter device210can remain in place following removal of endovascular hardware used for angiography and mechanical thrombectomy. Regardless, radial pressure sensors can be oriented to be adjacent the radial artery and the brachial arteries. As a general guideline, such sensors can be oriented about 20 cm and 40 cm from a hub (e.g. bifurcated luer hub) at a proximal end of the catheter device. A hydrophilic coating can be provided along an entire length of an exterior surface of the longitudinal lumen. In another example, a transition zone location can be varied based on whether the catheter device is intended to femoral or radial access. Transition zones are located at an interface between the occlusion balloon and the lumen.

The catheter device210can be safely positioned in the anterior or posterior circulation. It can be safely used via a radial approach250a, with balloon deflation commensurate with safe removal through the upper extremity without damaging corresponding arteries. The catheter device210can have sensors distal to the balloon to allow for inflation without using contrast agent. Instead, a practitioner can view the distal blood pressure waveform pulsatility change of the subject250on a display230as the balloon is inflated.

In one example, an intermediate catheter with embedded pressure sensors can be oriented distal and proximal to an occlusion balloon. The occlusion balloon can inflate sufficiently to provide protective occlusion and to effectively perform mechanical thrombectomy. The balloon can be inflated and deflated automatically, based on algorithms responding to arterial waveforms, allowing for dynamic adjustment of inflation to maintain optimal stasis of blood-flow as the catheter and balloon passes through arterial segments with variable diameter. As an example, a specific volume of saline can be delivered to both the distal and proximal balloon based on information gathered by the pressure sensors, one located downstream and one upstream of the clot site. This technology can enhance margins for clot retrieval, increase access at distal occlusion sites with better ease and safety, and minimize thrombus fragmentation. Although exact dimensions can vary, the distal pressure sensor or sensors can generally be placed within about 0 mm to 1 cm, and most often 0.2 mm to 1 cm, of an adjacent surface of the nearest occlusion balloon.

In another embodiment, as illustrated inFIG.3a, a catheter device300acan comprise a longitudinal lumen304having a proximal end304aand a distal end304b. In one optional aspect, the catheter device300acan be inserted through an optional guide catheter306. In one aspect, the distal end304bcan be capable of insertion into at least the internal carotid artery.

The catheter device30acan have various properties to allow insertion into the narrower and more fragile cerebral vasculature. A catheter having excessive stiffness, although suitable with some contrast agents with a high viscosity, can prevent access to the cerebral vasculature. To allow access to the cerebral vasculature, the diameter of the lumen304can be reduced and the use of contrast agent can be avoided using one or more pressure sensors310a,310bto provide dynamic inflation and deflation of one or more occlusion balloons320a,320b. Notably, at least one pressure sensor310acan be oriented on the guide wire306proximal and adjacent to the balloon320a. Although exact dimensions may vary the pressure sensors can be within about 10 mm, and often within about 5 mm of a nearest surface of the occlusion balloon.

In one example, the catheter300acan include a longitudinal lumen304of any suitable aspiration catheter. The catheter300acan comprise a longitudinal lumen304used to extract a thrombus by connecting the longitudinal lumen304to a syringe or other extraction volume on negative pressure for aspiration. The catheter300acan comprise additional concentric lumens such as a lumen for a guidewire, a microcatheter, a stent retriever, a suction source, and any other suitable tools.

In some cases, the catheter300acan have a variable stiffness along a portion of a length of the catheter300a. For example, the variable stiffness can include a catheter tip304cstiffness that is less than a catheter shaft stiffness. In this manner, a proximal portion of the catheter can be stiffer than a distal portion so as to facilitate insertion along an entire vascular pathway to the target cerebral tissue.

The catheter device300acan be a sterile single-use device comprising any suitable material. A suitable material for the catheter300acan have various biological properties including but not limited to: biocompatibility (e.g., does not produce an inflammatory response when in contact with blood vessels), non-thrombogenicity (e.g., coating with a non-thrombogenic material such as heparin), non-mutagenic, non-toxic, biofilm resistant, microbial resistant, compliance, conformability, the like, or a combination thereof.

A suitable material for the catheter300acan have various physical properties including but not limited to: a suitable tensile strength sufficient to withstand applied torque used in a inserting the catheter300ato a thrombus location (torque control can be provided with a double-stranded steel braid), compression resistance to maintain a suitable shape (e.g., a high modulus and kink resistance), adequate flexibility to maneuver through blood vessels (a suitable modulus at the distal end to achieve a greater flexibility compared to the proximal end), a low coefficient of friction to allow movement of the catheter300athrough the vasculature, radiopaque properties, the like, or a combination thereof.

The variability of the stiffness of the catheter300acan be achieved by bonding sections of different moduli together. In one example, the stiffness of the proximal end can range from about 100,000 psi to about 300,000 psi. In another example, the stiffness of the distal end can range from about 100 psi to about 5,000 psi. In another example, the stiffness of the distal end can range from about 100 psi to about 1,000 psi. In another example, the stiffness of the distal end can range from about 100 psi to about 500 psi.

In one more example, the catheter300acan have various chemical properties, e.g., the catheter300acan comprise a material that satisfies United States Pharmacopeia (USP) Class VI classifications. The catheter can be sterilized using various methods such as ethylene oxide (EtO), Sterrad, Steris System 1, Cidex OPA processes, the like, or a combination thereof. The material for the catheter300acan accept a suitable coating to prevent microbial growth or thrombus-generation.

In one example, the material for the catheter300acan comprise, but is not limited to, one or more of: polyurethanes (e.g., polyester-based polyurethanes, polyether-based polyurethanes, poly-carbonate-based polyurethanes having a suitable durometer, e.g., 75 Shore A to 75 Shore D, or thermoplastic polyurethanes, or the like), polyamides (e.g., nylon 11, nylon 12, or the like), fluoropolymers (e.g., polytetrafluorethylene (PTFE)), polyolefins, PVC, polyimides, polyetheretherketone (PEEK), the like, or a combination thereof. In one example, the catheter300acan comprise a hydrophilic coating. Suitable hydrophilic coatings can include but are not limited to: polyethylene terephthalate (PET), PTFE, polyethylene (PE), the like, or a combination thereof.

In one aspect, the distal end304bis capable of insertion into at least one of the anterior cerebral arteries, anterior communicating arteries, and the middle cerebral arteries. Further, the distal end can be capable of insertion into one or more of the internal carotid arteries, anterior cerebral arteries, middle cerebral arteries, vertebral arteries, basilar arteries, posterior cerebral arteries, and their branches. In one example, the catheter300acan have a usable length for a procedure of from about 50 cm to about 150 cm. In one example, the usable length for a procedure can be from about 120 cm to about 145. In another example, the usable length for a procedure can be from about 130 cm to about 135 cm. In another example, the usable length for a procedure can be about 132 cm.

In one example, the inner and outer diameter of the catheter300acan be selected to provide access to at least one of the anterior cerebral arteries, anterior communicating arteries, and the middle cerebral arteries. In one example, the inner diameter of the catheter can be about 1.37 mm (e.g., about 4 in French Gauge), and the outer diameter can be about 1.78 mm (e.g., about 5 in French Gauge). As a general guideline, the outer diameter of the catheter at the distal end can be from 0.9 mm to 2.2 mm, and most often 1 mm to 1.9 mm.

In one aspect, the catheter can comprise a soft radiopaque tip that facilitates vessel engagement and catheter placement into at least one of the anterior cerebral arteries, anterior communicating arteries, and the middle cerebral arteries. The smaller diameter of the catheter300aand the variable stiffness with the softer tip304ccan allow the catheter300ato be used for radial access. In one aspect, the catheter300acan be adapted for radial access and can further comprise a radial pressure sensor oriented along a radial portion of the longitudinal lumen304. In one aspect, a catheter300afor use through the radial artery can use dynamic inflation and deflation of the occlusion balloon and by including inflation and deflation lumens that are reduced in size to allow for radial access. The radial pressure sensor can provide dynamic feedback including radial blood pressure data to a controller that can adjust the inflation or deflation of one or more occlusion balloons as the catheter is inserted throughout the radial vasculature.

In one aspect, the catheter device300can comprise an occlusion balloon320bconnected to the distal end304b. In one example, the occlusion balloon320bcan be operable to occlude blood flow in a blood vessel302by inflation and deflation using a pressurization fluid.

In one example, the occlusion material can be formed of a material used for compliant balloons that can be inflated by volume not pressure. In one example, the one or more occlusion balloons320a,320bcan comprise any suitable material for insertion into a cerebral artery including but not limited to: polyurethane, silicone, the like, or a combination thereof.

In one aspect, the one or more occlusion balloons320a,320bcan be operable to inflate via injection of a selected volume of pressurization fluid into the occlusion balloon320a,320bor deflate via removal of at least a portion of the selected volume from the occlusion balloon320a,320b. In one example, the selected volume of pressurization fluid can be an amount of from about 1 μl to about 50 μl. In another example, the selected volume of pressurization fluid can be an amount of from about 1 μl to about 10 μl. In another example, the selected volume of pressurization fluid can be an amount of from about 1 μl to about 5 μl. In another aspect, the selected volume of pressurization fluid for insertion into the one or more occlusion balloons can be provided by the inflation control information received from a controller350. In one aspect, an electronic syringe pump can be configured to provide the selected volume of pressurization fluid for insertion into the one or more occlusion balloons320a,320b. Due to the particularly fragile cerebral vasculature the dynamic volume control of the occlusion balloons can have a high precision and low volumetric variability. In one example, adjustments to occlusion volume can be controlled to within 0.05 μl to 5 μl and most often 1 μL to 3 μl.

In another example, the pressurization fluid can comprise a viscosity of from about 0.5 centipoise (cP) and 1.5 cP, and in some cases less than 1.4 cP, at STP. In one example, the pressurization fluid can have an osmolarity of from about 270 mOsm/L to about 330 mOsm/L. In another example, the saline can have a pH of from about 7.0 to about 7.5. In one example, the pressurization fluid can be saline. In one example, the saline can have a sodium chloride concentration of about 0.9% w/v.

In another aspect, the pressurization fluid can be a suitable liquid that is substantially free of contrast agent. A contrast agent can include any suitable agent that can be used to temporarily change the way x-rays, computed tomography (CT), magnetic resonance (MR) imaging, and ultrasound interact with the body. In one example, contrast agents can include but are not limited to: iodine-based and barium sulfate compounds used in x-ray and CT imaging exams; gadolinium; the like; or a combination thereof. Thus, the pressurization fluid can advantageously be a saline solution or CO2, for example. In another aspect, the one or more occlusion balloons320a,320bcan be configured to dynamically adjust balloon inflation or deflation to maintain occlusion during movement of the catheter300ain the blood vessel302based on feedback from the one or more pressure sensors310a,310b. Dynamic inflation of the one or more balloons320a,320bcan maintain sufficient occlusion without damaging the vessel walls302a,302b. For example, the diameter of the vasculature can change from a radial access position to an internal carotid artery to an anterior cerebral artery, or a middle cerebral artery, or a posterior cerebral artery. The diameter of the vasculature can also change within a specific cerebral artery. For example, the diameter of the middle cerebral artery can vary between different segments such as M1, M2, M3, and M4. The one or more occlusion balloons320a,320bcan inflate in response to changing diametric vascular dimensions as the catheter is moved into or out of the cerebral arteries. In one aspect, dynamic adjustment of the occlusion balloons320a,320bcan maintain sufficient occlusion without using a contrast agent to visualize occlusion. Using a catheter300awithout contrast agent allows for a reduction in the diameter of the catheter300aand the stiffness of the distal end304bto provide enhanced access into the cerebral vasculature (e.g., the anterior cerebral artery, or the middle cerebral artery, or the posterior cerebral artery).

In another example, the occlusion balloons320a,320bcan be configured to have a degree of flexibility sufficient to be responsive to inflation and deflation adjustments in a selected time period without causing damage to tissue as the occlusion balloons320a,320bare moved through the cerebral vasculature. In one aspect, the occlusion balloon can be sufficiently responsive to inflation and deflation adjustments when the occlusion balloon can complete an inflation or deflation event within a selected time period, wherein the inflation or deflation event is the total time to complete inflation or deflation after receiving inflation control information from a controller. In one example, the selected time period can be less than one or more of: 10 ms, 5 ms, 1 ms, 100 μs, 50 μs, 10 μs, 1 μs, or a combination thereof.

In one aspect, the catheter device300can a pressure sensor310bassociated with the distal end304band operable to measure blood pressure data from at least one of a downstream and upstream location of the occlusion balloon320b. In another aspect, the pressure sensor304bcan be operable to measure blood pressure data from at least one of a downstream305band upstream305alocation of the blood clot305.

Although other pressure sensors can be suitable, the one or more pressure sensors310a,310bcan most often be one of two different types: (i) an optical fiber based pressure sensor, or (ii) solid-state pressure sensors. In one example, the one or more pressure sensors310a,310bcan be solid state pressure sensors. In one example, the one or more pressure sensors310a,310bcan be an IntraSense® SMI-1B-48-150-BAUU pressure sensor having a pressure range of from about 460 mmHg to about 1260 mmHg, a sensor size of about 1 French, and pressure sensitivity of about 5 uV/V/mmHg. In another example, the one or more pressure sensors310a,310bcan be a obtained from a different commercial vendors (e.g., Millar®).

In one aspect, the one or more pressure sensors310a,310bcan be operable to measure blood pressure data within a margin of error of less than at least one of 2 mmHg, 1 mmHg, 0.5 mmHg, the like, or a combination thereof. In another aspect, the one or more pressure sensors310a,310bcan be operable to provide blood pressure data, blood flow information, or blood pressure waveform pulsatility to a controller via microwires embedded in the catheter300a. In another aspect, the one or more pressure sensors310a,310bcan be operable to measure blood pressure waveform pulsatility. In one example, the “waveform pulsatility” can be based on the pulsatility index (PI) as calculated the difference between the peak systolic velocity and the end diastolic volume divided by the mean flow velocity during the cardiac cycle. In one example, the PI of a cerebral artery (e.g., MCA) can be measured using Trans Cranial Doppler (TCD). As used herein, “blood flow information” can be blood perfusion (e.g., the volume of blood flowing through a certain mass (or volume) or tissue per unit time, with units of mL/(mL*min). As used herein, blood pressure can include the systolic blood pressure, the diastolic blood pressure, the like, or a combination thereof.

In another aspect, one or more of blood pressure data, blood flow information, or blood pressure waveform pulsatility can be transmitted to a controller350via a wireless or wired connection355. In one example, the controller350can be operable to receive one or more of blood pressure data, blood flow information, or blood pressure waveform pulsatility from the one or more pressure sensors310a,310b. In one aspect, the controller350can be operable to generate inflation control information based on one or more of blood pressure data, blood flow information, or blood pressure waveform pulsatility. In one aspect, the controller can be operable to transmit the inflation control information to the occlusion balloon320b. As used herein, “inflation control information” refers to a control signal from the controller that regulates the inflation or deflation of the one or more occlusion balloons320a,320b. In one aspect, the one or more occlusion balloons320a,320bcan be operable to inflate or deflate based on the inflation control information by changing a selected volume of the pressurization fluid within the one or more occlusion balloons320a,320b. In another aspect, the inflation control information can be at the controller from one or more of the blood pressure data, the blood flow information, or blood pressure waveform pulsatility using a pressure-tracing algorithm. As one specific example, development of a tardus parvus waveform during the procedure can indicate successful occlusion. This can involve a prolonged systolic upslope, a rounded peak, and a prolonged return to diastolic pressure.

In another example, the blood clot can be captured via a stent retriever or via aspiration. In one embodiment, as illustrated inFIG.3b, the catheter device300bcan further comprise a stent retriever330oriented within the lumen and deployable to capture and remove a blood clot305. In another embodiment, as illustrated inFIG.3c, the catheter device300ccan further comprise a suction source370fluidly connected375to the lumen304and configured to remove debris from a blood clot305via aspiration.

In one embodiment, as illustrated inFIG.3d, the catheter device300dcan comprise a proximal occlusion balloon320aoriented adjacent the distal end304b. In some cases, as illustrated inFIG.3a, the catheter device300acan comprise both a distal occlusion balloon320boriented at the distal end304band a proximal occlusion balloon320aoriented adjacent the distal end304b. In one aspect, the distal occlusion balloon304bcan be operable to prevent downstream305bpassage of fragmented blood clots that break off from the blood clot305.

In another embodiment, as illustrated inFIG.3e, the catheter device300ecan further comprise an outer catheter380. In this example, the outer catheter can be a guide catheter that can have a diameter that is operable for access outside of the cerebral arteries and the inner catheter can be configured for access to the cerebral arteries as discussed herein.

In one embodiment, as depicted inFIG.4, functionality400for adjustment of balloon inflation or deflation to maintain balloon occlusion during movement of the catheter in the blood vessel can include a start operation402or an activation operation. Another operation can include measuring blood pressure data, at one or more pressure sensors, from a downstream or upstream location of a blood clot or of an occlusion balloon, as shown in in operation404. Another operation can include transmitting, from the pressure sensor, the blood pressure data to a controller, as shown in operation406. Another operation can include receiving, at a controller, blood pressure data from the pressure sensor, as shown in operation408. Another operation can include generating control information at the controller based on blood pressure data received from the one or more pressure sensors, as shown in operation410. Another operation can include transmitting the control information from the controller to a suitable flow control device for delivering or withdrawing pressurization fluid from the occlusion balloon, as shown in operation412. Another operation can include inflating or deflating the occlusion balloon based on the inflation control information received from the controller, as shown in operation414. After the occlusion balloon has been inflated or deflated, the restart operation416can loop back to operation404. In one example, the blood pressure data and the blood flow information collected from the one or more pressure sensors can be displayed on a graphical user interface that can be electrically connected to the controller.

FIG.5illustrates a general computing system or device500that can be employed in the present technology. The computing system500can include a processor502in communication with a memory504. The memory504can include any device, combination of devices, circuitry, and the like that is capable of storing, accessing, organizing, and/or retrieving data. Non-limiting examples include SANs (Storage Area Network), cloud storage networks, volatile or non-volatile RAM, phase change memory, optical media, hard-drive type media, and the like, including combinations thereof.

The computing system or device500additionally includes a local communication interface518for connectivity506between the various components of the system. For example, the local communication interface can be a local data bus and/or any related address or control busses as may be desired.

The computing system or device500can also include an I/O (input/output) interface508for controlling the I/O functions of the system, as well as for I/O connectivity to devices outside of the computing system500. A network interface516can also be included for network connectivity. The network interface510can control network communications both within the system and outside of the system. The network interface can include a wired interface, a wireless interface, a Bluetooth interface, optical interface, and the like, including appropriate combinations thereof. Furthermore, the computing system500can additionally include a user interface512, a display device540, as well as various other components that would be beneficial for such a system.

The processor502can be a single or multiple processors, and the memory504can be a single or multiple memories. The local communication interface518can be used as a pathway to facilitate communication between any of a single processor, multiple processors, a single memory, multiple memories, the various interfaces, and the like, in any useful combination.

FIG.6also provides an illustration of a microphone and one or more speakers that can be used for audio input and output from the wireless device. The display screen can be a liquid crystal display (LCD) screen, or other type of display screen such as an organic light emitting diode (OLED) display. The display screen can be configured as a touch screen. The touch screen can use capacitive, resistive, or another type of touch screen technology. An application processor and a graphics processor can be coupled to internal memory to provide processing and display capabilities. A non-volatile memory port can also be used to provide data input/output options to a user. The non-volatile memory port can also be used to expand the memory capabilities of the wireless device. A keyboard can be integrated with the wireless device or wirelessly connected to the wireless device to provide additional user input. A virtual keyboard can also be provided using the touch screen.

Various techniques, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, compact disc-read-only memory (CD-ROMs), hard drives, non-transitory computer readable storage medium, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. Circuitry can include hardware, firmware, program code, executable code, computer instructions, and/or software. A non-transitory computer readable storage medium can be a computer readable storage medium that does not include signal. In the case of program code execution on programmable computers, the computing device can include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements can be a random-access memory (RAM), erasable programmable read only memory (EPROM), flash drive, optical drive, magnetic hard drive, solid state drive, or other medium for storing electronic data. The low energy fixed location node, wireless device, and location server can also include a transceiver module (i.e., transceiver), a counter module (i.e., counter), a processing module (i.e., processor), and/or a clock module (i.e., clock) or timer module (i.e., timer). One or more programs that can implement or utilize the various techniques described herein can use an application programming interface (API), reusable controls, and the like. Such programs can be implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language can be a compiled or interpreted language, and combined with hardware implementations.

As used herein, the term processor can include general purpose processors, specialized processors such as VLSI, FPGAs, or other types of specialized processors, as well as base band processors used in transceivers to send, receive, and process wireless communications.

In one example, multiple hardware circuits or multiple processors can be used to implement the functional units described in this specification. For example, a first hardware circuit or a first processor can be used to perform processing operations and a second hardware circuit or a second processor (e.g., a transceiver or a baseband processor) can be used to communicate with other entities. The first hardware circuit and the second hardware circuit can be incorporated into a single hardware circuit, or alternatively, the first hardware circuit and the second hardware circuit can be separate hardware circuits.

Modules can also be implemented in software for execution by various types of processors. An identified module of executable code can, for instance, comprise one or more physical or logical blocks of computer instructions, which can, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together but can comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.

Indeed, a module of executable code can be a single instruction, or many instructions, and can even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data can be identified and illustrated herein within modules and can be embodied in any suitable form and organized within any suitable type of data structure. The operational data can be collected as a single data set or can be distributed over different locations including over different storage devices, and can exist, at least partially, merely as electronic signals on a system or network. The modules can be passive or active, including agents operable to perform desired functions.

Methods of Using the Catheter Device

Disclosed herein is a neurovascular mechanical thrombectomy device that can be used in the treatment of acute ischemic stroke. The device can be delivered into the neuro-vasculature with an endovascular approach. The thrombus can be mechanically removed to restore blood flow in the neuro-vasculature.

In one embodiment, as illustrated inFIG.7, a method700of using a catheter device to treat cerebral thrombectomy in a subject can comprise inserting a catheter device into a cerebral vasculature of a subject such that a distal end of the catheter device is adjacent a patient thrombus, as shown in block710. The method can further comprise measuring blood pressure data using a pressure sensor located at least at one of a downstream and upstream position of an occlusion balloon of the catheter device, as shown in block720. The method can further comprise inflating or deflating the occlusion balloon based on the blood pressure data to achieve a desired degree of occlusion, as shown in block730.

In another aspect, the method can comprise dynamically adjusting a balloon inflation or deflation to maintain occlusion during movement of the catheter in the cerebral vasculature based on feedback from the pressure sensor. In another aspect, the method can comprise providing the catheter with a variable stiffness to allow insertion into the cerebral vasculature of the subject. In another aspect, the method can comprise providing the catheter with a size allowing radial access to the subject. In another aspect, the method can comprise removing the thrombus from the subject. In another aspect, the method can comprise generating inflation control information from the blood pressure data and pressure-tracing algorithms to adjust the inflation or deflation of the occlusion balloon. In another aspect, the method can comprise measuring blood pressure waveform pulsatility and blood flow information using the pressure sensor.

EXAMPLES

The following examples are provided to promote a more clear understanding of certain embodiments of the present disclosure, and are in no way meant as a limitation thereon.

Example 1: Generated Pressures of a Catheter Device

A catheter device disclosed herein can have a balloon-rated burst pressure of >600 PSI. For a provided flow rate, the generated pressures are provided in Table 1.

TABLE 1Generated Pressures at Given Flow RatemL/s4681015psi111190278369599Kg/cm2813202642

Example 2: Use of a Catheter Device for Treatment of Acute Ischemic Stroke

The radial artery is punctured with a sharp hollow needle. A guidewire is advanced through the lumen of the needle and the needle is withdrawn. A sheath is passed into the blood vessel using the guidewire. An outer catheter380is used to introduce the catheter device300einto the radial artery. The catheter device300ecan be guided to the cerebral artery to a location of a thrombus305without the use of a contrast agent. The pressures sensors310aand310bprovide real-time blood pressure data to a controller350.

The controller generates inflation control information and signals the occlusion balloon320ato inflate when the degree of occlusion resulting from occlusion balloon320aor320bis below a selected level of occlusion and to deflate when the degree of occlusion resulting from occlusion balloon320aor320bis above a selected level of occlusion that may cause injury to the vessel walls302a,302b.

Once the catheter device is adjacent the thrombus305, a suction source can be used to aspirate the thrombus. The thrombus305can be prevented from fragmentation and downstream passage via occlusion balloon320b. The degree of downstream blood flow can be reduced using occlusion balloon320a. A stent retriever330can also be used to retrieve the thrombus from the cerebral artery.

After the procedure has been completed, the catheter device can be removed from the cerebral artery through the radial access by suitable inflation and deflation of the occlusion balloons320a,320bbased on inflation control information from the controller350.

The foregoing detailed description describes the disclosure with reference to specific exemplary embodiments. However, it will be appreciated that various modifications and changes can be made without departing from the scope of the present disclosure as set forth in the appended claims. The detailed description and accompanying drawings are to be regarded as merely illustrative, rather than as restrictive, and all such modifications or changes, if any, are intended to fall within the scope of the present disclosure as described and set forth herein.