Abstract:
Modular systems comprising a cannula and at least one clip-on access port adjacent to a distal end of the cannula to provide insertion of one or more therapeutic or diagnostic devices into a vessel or cardiac tissue through a single incision site. The access port can be removably attached to a distal region of the cannula in a fixed orientation or in any desired orientation. The devices can be operated in combination or independently. The systems can be employed to provide multiple therapies, including blood perfusion, filtration, aspiration, vessel occlusion, atherectomy, and endoscopic devices. Methods of using the system for vessel cannulation are also disclosed herein.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a modular system for introducing therapeutic or diagnostic devices, such as a blood filter, occluder, atherectomy device, stents, angiographic catheters, and pressure monitors to a vessel or cardiac tissue. More particularly, the system delivers the devices independently or in combination through a single incision on the vessel or cardiac tissue via one or more removably attached access ports and lumens. 
     BACKGROUND OF THE INVENTION 
     During various cardiothoracic, pulmonary, and vascular surgeries, including coronary artery bypass grafting, heart valve repair or replacement, atrial or ventricular septal defect repair, angioplasty, atherectomy, aneurysm repair, and pulmonary thrombectomy, cannulation of a patient&#39;s vessel(s) are often required to provide vascular access for delivery of various diagnostic and therapeutic devices. In a conventional approach, separate incisions are needed for introduction of each medical device. For example, during coronary artery bypass grafting (CABG) surgeries, cardiopulmonary bypass is established by cannulation of the aorta to provide circulatory isolation of the heart and coronary blood vessels. Two incisions on the aorta may be required, i.e., one for insertion of the arterial cannula and another for insertion of a balloon occluder to provide coronary isolation from the peripheral vascular system. When cardiac arrest is desired, a third incision may be required on the aorta to introduce a catheter for delivering cardioplegic solution to the coronary arteries. Additional incisions may be required for insertion of other devices, such as a blood filter, pressure monitor, or atherectomy device. Once the incisions are made on the aorta, the devices often remain in the aorta throughout the entire procedure despite only being used intermittently, e.g., the cardioplegia catheter. 
     Due to significant mortality and morbidity associated with conventional CABG surgeries from the use of cardiopulmonary bypass for circulatory support and the traditional method of access by median sternotomy, minimally invasive concepts recently have been adopted to make cardiothoracic procedures less invasive. Minimally invasive alternatives include the minimally invasive direct CABG procedure in which the operation is performed through minimal access incisions, eliminating cardiopulmonary bypass. The second alternative is to perform the procedure through minimal access incisions, and cardiopulmonary support is instituted through an extra thoracic approach, i.e., the port access approach. The third alternative is to perform the procedure on a beating heart which allows greater access for more extensive revascularization, i.e., the “off pump” sternotomy approach. In any of the minimally invasive alternatives, the space allowed for multiple instrumentation and device insertion is limited. 
     The disadvantages associated with the conventional or minimally invasive approach are that (1) by having multiple devices inserted in the aorta, the space available for the surgeon to perform procedures is limited, and (2) the aorta is traumatized as a result of multiple incisions, which may result in aortic dissection, aortic wall hematoma, and/or embolization of calcium plaque from the aortic wall. The greater the aortic trauma, the higher the perioperative morbidity a patient will endure. 
     New devices or systems are therefore needed which provide access to a patient&#39;s vessel and introduction of multiple diagnostic and therapeutic devices during cardiovascular procedures, thereby minimizing crowding caused by the multiple device insertions and trauma to the vessel wall. 
     SUMMARY OF THE INVENTION 
     The methods and systems of the present invention provide means of introducing a combination of multiple devices or instruments into a vessel through a single incision site, thereby reducing the number of incisions on the vessel and minimizing space crowding during vascular surgeries. More particularly, various devices and instruments can be inserted into the vessel through one or multiple lumens and access ports which are removably attached to a cannula in the modular access port systems, thereby minimizing the trauma of exchanging devices through the vessel wall. The methods and systems can be used in conventional or minimally invasive surgeries to provide any combination of the following functions: perfusion, drug delivery, fluid infusion, vessel occlusion, filtration, aspiration, blood sampling, venting, fluid diversion, venous return in cardiopulmonary bypass, atherectomy, fluid pumping, suturing, stapling, collagen or fibrin delivery, placement of pacing leads, use of angiographic catheters, angioplasty catheters, valvuloplasty catheters, electrode catheters, sizing tools, internal vessel segregating or isolating dams, endoscopic cameras, pressure monitors, shunts, stents, grafts, stent/grafts, vessel surfacing modalities, radioactive isotopes, graft delivery, and endoscopic devices. For example, devices traditionally introduced through the femoral artery (i.e., stents, atherectomy catheters, or angioplasty catheters) can also be introduced directly into the aorta, if deemed advantageous or beneficial to the patient. 
     In a first embodiment, the cannula has a lumen communicating between a proximal end and a distal end. The distal end is adapted for perfusion of blood, i.e. for use as an arterial cannula or venous return cannula in cardiopulmonary bypass. The proximal end is adapted for attachment to a bypass-oxygenator machine. A clip-on access port is removably attached to a distal region of the cannula. The access port has a lumen extending from a proximal end to a distal end. The proximal end of the port is adapted to receive medical devices. In certain embodiments, the access port can be attached to any standard arterial or venous cannula in any orientation. In other embodiments, the access port is attached to the cannula only in one orientation to ensure a desired relationship between the cannula and the access port. 
     In another embodiment, a second access port is removably mounted to the distal region of the cannula adjacent to the first access port, such that the ports are arranged at the vertices of a triangle. Having the triangular arrangement may be preferred in minimally invasive procedures where surgical space is limited. Alternatively, the second port is removably mounted to the first port, such that the ports and the cannula are arranged in a linear configuration. A hemostatic valve may be included in the lumen of either or both of the access ports. The distal ends of the cannula and/or the access ports may include a suture flange for securing the system onto the vessel. 
     In a first method to provide insertion of medical devices and cannulation of a vessel or cardiac tissue, the access port is attached adjacent the distal region of the cannula. The distal ends of the cannula and the access ports are inserted through an incision on the vascular or cardiac tissue. For example, to provide arterial cannulation for cardiopulmonary bypass, the cannula is inserted through an incision on the aorta. A medical device, such as a cardioplegia catheter, can be inserted through the proximal end of the access port and deployed in the aorta. When cardioplegia is no longer required, the catheter can be removed from the access port and another medical device, such as a pressure monitor can be inserted into the aorta through the port. In this way, the cannula system allows exchange of multiple devices through the access port without requiring additional incision. 
     In another method, when deployment of multiple medical devices into a vessel or cardiac tissue is necessary, a second access port can be attached to either the cannula or the first access port prior to inserting the cannula into the vascular tissue. For example, during arterial cannulation for cardiopulmonary bypass, a blood filter may be inserted through the first access port, and an occlusion catheter having a balloon occluder may be inserted through the second port into the aorta The blood filter is expanded to entrap embolic materials, calcium, myocardial tissue debris, or atheromatous plague, which arise as a result of introducing instrumentation or manipulating tissue during surgery. The balloon occluder is expanded to provide circulatory isolation of the coronary vessels from the peripheral vascular system. The proximal end of the cannula is attached to a bypass-oxygenator machine to deliver oxygenated blood to the aorta. After the cardiopulmonary bypass is established, a surgical procedure can be performed on the heart and/or aorta. 
     Alternatively, the blood filter and the occlusion catheter can be inserted sequentially through the access ports into the aorta. After completion of the surgical procedure, one or both devices can be removed from the access ports. In situations where continuation of the cardiopulmonary bypass is desired post-operatively due to a patient&#39;s low cardiac output state, the blood filter may be removed, leaving the occlusion catheter and the cannula in the aorta. In this manner, multiple therapies and procedures are employed in combination or independently of each other. 
     It will be understood that there are several advantages to using the clip-on access port(s) disclosed herein for delivering medical therapies. For example, the access port(s) (1) permit a combination of therapies to be employed through only one incision site, thereby minimizing trauma to the vessel wall, (2) allow multiple devices to be operated in combination or independently, (3) reduce the number of devices used concomitantly, thereby minimizing crowding in the surgical field, (4) can be employed in a variety of cardiac or vascular surgeries, (5) can be used in minimally invasive procedures, (6) can be easily mounted to a standard arterial or venous cannula and thereafter removed, and (7) can be mounted to a modified cannula, such that the port is attached to the cannula in only one orientation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A depicts an oblique view of an embodiment of a clip-on access port according to the present invention. 
     FIG. 1B depicts a lateral view of the clip-on access port of FIG.  1 A. 
     FIG. 1C depicts an embodiment of a cannula adapted for insertion into a vein or artery. 
     FIG. 1D depicts a spatial relationship between the access port of FIG.  1 B and cannula of FIG.  1 C. 
     FIG. 1E depicts the access port of FIG. 1B attached to the cannula of FIG.  1 C. 
     FIG. 1F depicts a blood filter inserted through the access port of FIG.  1 E. 
     FIG. 1G depicts a distal view of the blood filter of FIG.  1 F. 
     FIG. 2A depicts an oblique view of another embodiment of the clip-on access port. 
     FIG. 2B depicts a lateral view of the access port of FIG.  2 A. 
     FIG. 2C depicts another embodiment of the cannula having a mounting mechanism at its distal region. 
     FIG. 2D depicts the access port of FIG. 2B attached to the distal region of the cannula of FIG. 2C in a predetermined orientation. 
     FIG. 3A depicts an obturator adapted for insertion into the access port of FIG.  1 A. 
     FIG. 3B depicts a lateral view of the obturator of FIG.  3 A. 
     FIG. 3C depicts the access port of FIG. 3A having the obturator of FIG. 3B inserted through its lumen. 
     FIG. 4 depicts a cannula with a second port adjacent the distal end of the cannula and adjacent the first port, wherein the ports and the distal end of the cannula are arranged substantially in a line. 
     FIG. 4A depicts a cross-section of the cannula of FIG.  4  through section line A—A. 
     FIG. 5 depicts a cannula with a second port adjacent the distal end of the cannula and adjacent the first port, wherein the ports are arranged at the vertices of a triangle. 
     FIG. 5A depicts a cross-section of the cannula of FIG.  5  through section line A—A. 
    
    
     DETAILED DESCRIPTION 
     In a first embodiment, a clip-on access port for deployment of medical devices, including a blood filter, a balloon occluder, a pressure monitor, an endoscope, a windsock filter, a flow director, an atherectomy catheter, an aspiration/suction catheter, a cardioplegia catheter, a coronary stent, a graft, and a perfusion catheter, in a vessel or cardiac tissue is provided as depicted in FIGS. 1A and 1B. The access port comprises proximal end  10 , distal end  15 , and lumen  20 . Proximal end  10 , which may include a hemostatic valve, is adapted to receive a medical device. Attachment mechanism  25 , shown as a plurality of opposed clips, is mounted on distal region  22  of the access port. The attachment mechanism is adapted to be removably attached to a distal region of a cannula. Flange  30  may be included adjacent the distal end of the access port. First and second aligning members  26 , which are mounted on distal region  22 , can engage a suture flange on the cannula. Flange  30  and aligning members  26  fit to ensure proper circumferential alignment and coupling between the access port and a cannula. 
     The access port described above can be removably attached to a standard arterial or venous cannula shown in FIG.  1 C. The cannula has proximal end  35 , distal end  40 , and lumen  44 . Suture flange  45  may be slideably mounted on distal region  49  of the cannula for securing the cannula onto the vascular tissue. Lumen  44  is adapted to receive oxygenated or deoxygenated blood. Proximal end  35  is adapted for attachment to a bypass-oxygenator machine. 
     In use for cardiopulmonary bypass, for example, the access port is attached to distal region  49  of the cannula through attachment mechanism  25  in any preferred orientation as depicted in FIGS. 1D and 1E. In certain embodiments, the alignment will be fixed by a complementary fit between the clip-on port and the cannula, as by the engagement of opposing flat surfaces (e.g., aligning members  26  of the access port engages suture flange  45  of the cannula, and flange  30  of the access port engages distal region  41  of the cannula). After the access port is secured onto the cannula, distal end  40  of the cannula is inserted through an incision on the aortic wall into the ascending aorta. Various medical devices can then be inserted through proximal end  10  and passed through distal port  15  of the access port to deploy in the aorta. 
     In FIGS. 1F and 1G, a blood filter device carrying filter  50  is inserted into proximal end  10  of the access port. The filter device includes plunger  55 , which upon activation deploys filter  50  through port  15  of the access port. Filter  50  is shown in an expanded state. The reader is referred to  Barbut  et al., U.S. Pat. No. 5,769,816,  Maahs,  U.S. Pat. No. 5,846,260,  Tsugita  et al., U.S. Pat. No. 5,911,734, and  Barbut  et al., U.S. Pat. No. 5,662,671 (all of which are expressly incorporated herein by reference in their entirety), for a detailed description of the design and construction of blood filter devices. During cardiopulmonary bypass, oxygenated blood will be delivered to the aorta from proximal end  35 , lumen  44  and distal port  40  of the cannula. Proximal end  35  is attached to a bypass-oxygenator machine  100  through connector  99 . Expanded filter  50  captures embolic material, such as calcium deposits, atheromatous plaque, myocardial tissue debris, and thrombi, generated during cardiac surgery. Alternatively device  55  can be any of a balloon occluder, pressure monitor, endoscope, atherectomy device, aspirator, drug delivery catheter, blood-sampling device, valvuloplasty catheter, electrode catheter, segregating or isolating dams, endoscopic camera, or stent, graft, shunt, and perfusion catheters. 
     In certain embodiments, a second access port can be attached to the first access port or the cannula to provide deployment of other medical devices. For example, a catheter with a balloon occluder can be inserted into the second access port to provide circulatory isolation of the coronary and peripheral arteries. The catheter can also deliver carioplegia solution to arrest the heart. Alternatively, multiple ports will be bonded to form a single clip-on unit. In this way, the cannula system allows delivery of multiple medical therapies to the aorta through one incision, thereby minimizing trauma to the aortic wall. 
     FIGS. 2A and 2B depict another embodiment of the access port, which comprises proximal end  10 , distal end  15 , and lumen  20 . Proximal end  10 , which includes hemostatic valve  90 , is adapted to receive a medical device. Attachment mechanism  25 , mounted on distal region  22  of the access port, is adapted to engage a distal region of the cannula in a specific orientation. Extension member  30  is mounted on distal end  15  of the access port to ensure proper attachment to a cannula. In an alternative embodiment, the access port may include a second port  80  adjacent the first port, including proximal opening  81 , lumen  82 , and distal port  83 . 
     Another embodiment of the cannula, which is modified to accommodate the attachment of the access port, is shown in FIG.  2 C. The cannula has proximal end  35 , distal end  40 , and lumen  44 . Suture flange  45  may be slideably mounted on distal region  49  of the cannula for securing the cannula onto the vascular tissue. Lumen  44  is adapted to receive oxygenated or deoxygenated blood. Proximal end  35  is adapted for attachment to a bypass-oxygenator machine. Housing  60 , which provides a complementary fit for the attachment mechanism of the access port, is mounted on distal region  49  of the cannula. 
     In use, the access port is attached to distal region  49  of the cannula through engaging attachment mechanism  25  with housing  60  in a fixed orientation as depicted in FIG.  2 D. After the access port is secured onto the cannula, distal end  40  of the cannula is inserted through the vascular or cardiac tissue of interest. Sutures can be placed on suture flange  45  to secure the cannula onto the vascular tissue. Various medical devices can then be deployed by inserting through proximal end  10  and passing through distal port  15  of the access port. Having the access port attached to the cannula in one orientation may be preferred in situations where a specific direction of medical device deployment is required. 
     In certain embodiments, the access port includes an obturator adapted for insertion in proximal end  10  and lumen  20  of the access port as depicted in FIGS. 3A,  3 B, and  3 C. The obturator has proximal end  61 , body  62 , and distal end  63 . Proximal end  61  includes releasable engaging mechanism  66  (snap cap), depicted as a latch in FIGS. 3A and 3B. Gripping members  70  are mounted proximal to the engaging mechanism  66  on opposite sides of the obturator. The engaging mechanism is operated by depressing the gripping members radially inward for insertion into the access port. Proximal end  61  also includes porous plug  75 , which allows passage of air or gas, but not fluid or blood. Body  62  of the obturator has longitudinal grooves  77 , which communicate with porous plug  75  and provide passage for air or gas. 
     In use, the obturator is inserted through proximal end  10  and lumen  20  of the access port as depicted in FIG.  3 C. Distal end  63  of the obturator protrudes distal to port  15 . The access port is then clipped onto a cannula and inserted into a vascular structure of interest. When the access port is not in use, the obturator can remain inserted to prevent back flow of blood or fluid. Porous plug  75  allows venting of air or gas and not blood or fluid. When insertion of a medical device is desired, the obturator is removed by depressing gripping members  70  radially inward to release engaging members  66  from proximal end  10  of the access port, and withdrawing the obturator from the access port. 
     The length of the cannula will generally be between 10 and 60 centimeters, more preferably approximately 20 to 35 centimeters, more preferably approximately 30 centimeters. The inner diameter of the cannula will generally be between 0.5 and 1.5 centimeters, preferably approximately 1.0 centimeters. The length of the clip-on access port will generally be between 2.0 and 10.0 centimeters, preferably approximately 6.0 centimeters. The inner diameter of the lumen of the access port will generally be between 0.2 and 1.2 centimeters, preferably approximately 0.6 centimeters. The foregoing ranges are set forth solely for the purpose of illustrating typical device dimensions. The actual dimensions of a device constructed according to the principles of the present invention may obviously vary outside of the listed ranges without departing from those basic principles. 
     Thus, while the invention has been described in connection with what is presently considered to be the most practical embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.