Low profile vascular filter system

ES 2 386 348 T3

DESCRIPTION

Small bore vascular filter system.

The present invention relates to the treatment of vascular diseases, and more particularly to a vascular filter system for use in medical procedures.

In percutaneous transluminal coronary angioplasty (PTCA), stents and atherectomy are therapeutic medical procedures used to increase blood flow through the coronary arteries. These procedures can often be performed as alternatives to coronary bypass surgery. Percutaneous transluminal angioplasty (PTA) and the use of stents can often be performed as alternatives to carotid endarterectomy and femoral-popliteal bypass procedures. In PTCA or PTA procedures, the angioplasty balloon is inflated within the stenosed vessel, at the location of an occlusion, to shear and rupture the vessel wall components to obtain an enlarged lumen. In the use of stents, an endoluminal prosthesis is implanted in the vessel to maintain patency after the procedure. In an atherectomy, a rotating blade is used to shear plaque from the arterial wall.

One of the potential complications associated with all of these techniques is the accidental displacement of plaque, a thrombus, or other particulate embolic materials generated during manipulation of the vessel, thereby potentially causing occlusion of the narrower downstream vessels and ischemia or infarct of the organ irrigated by the vessel. Such embolisms can be extremely dangerous for the patient, and can result in a myocardial infarction, stroke, or limb ischemia. In 1995, Waksman et al. reported that distal embolization is common after directional atherectomy in coronary arteries and saphenous vein grafts. See Waksman et al., American Heart Journal 129 (3): 430-5 (1995). This study found that distal embolization occurs in 28% (31 of 111) of patients who undergo atherectomy. In January 1999, Jordan, Jr. et al. reported that treatment of carotid stenosis using percutaneous angioplasty with a stenting procedure is associated with more than eight times the microembolism rate seen using a carotid endarterectomy. See Jordan, Jr. et al., Cardiovascular Surgery 7 (1): 33-8 (1999). Microembolisms, as detected by transcranial Doppler monitoring in this study, have been shown to be a potential cause of stroke. Embolic materials include calcium, intimal debris, atheromatous plaque, and thrombi.

To initiate these procedures, a guidewire must first be introduced into the lumen of the vessel to serve as a conduit for other interventional devices, such as angioplasty balloons and stent delivery systems. This guidewire must be advanced to a position beyond the location of the occlusion. Guide wires must be able to traverse tortuous pathways within the body, consisting of curves, loops, and branches. For this reason, guidewires need to be flexible, but they should also be rigid enough to serve as conduits for other devices. In addition, they must be "torsional" to facilitate directional changes as they are guided into position.

Guide wires are well known in the art, and are typically made of stainless steel, tantalum, or other suitable materials, in a variety of different designs. For example, US-4545390 and US4619274 disclose guidewires in which the distal segment is tapered for greater flexibility. The tapered section may be surrounded by a coil of wire, typically a platinum coil, which provides increased resistance to buckling and kink ability. Another design is identified in US-5095915, in which the distal segment is encased in a polymeric sleeve with axially spaced grooves to provide flexibility.

Vascular filters are well known in the art, especially vena cava filters, as disclosed in US-4727873 and US-4688553. There is also a substantial body of medical literature describing various designs of vascular filters and reporting the results of clinical and experimental use thereof. See, for example, the article by Eichelter and Schenk, entitled "Prophylaxis of Pulmonary Embolism", Archives of Surgery, vol. 97 (August 1968). See also the article by Greenfield, et al., Entitled "A New Intracaval Filter Permitting Continued Flow and Resolution of Emboli", Surgery, vol. 73, no.4 (1973).

Vascular filters are often used during a postoperative period, when there is a perceived risk that a patient will encounter a pulmonary embolism as a result of perioperatively generated clots. A pulmonary embolism is a serious and potentially fatal condition that occurs when these clots travel to the lungs. Therefore, the filter is placed in the vena cava to capture and trap clots before they can reach the lungs.

Many of the prior art vascular filters are designed to be permanently placed in the venous system of the patient, so that even after the need for the filter has passed, the filter remains in place for the life of the patient. US-3952747 discloses a stainless steel filtration device that is permanently implanted transvenously within the inferior vena cava. This device is intended to treat a recurrent pulmonary embolism. It is often considered

ES 2 386 348 T3 is medically undesirable, but permanent implantation is performed since filters are implanted in patients in response to life-threatening situations.

To avoid permanent implantation whenever possible, it is highly desirable to provide an apparatus and method to prevent embolization associated with angioplasty, stenting, and other procedures. In particular, it is desirable to provide a device that can be temporarily placed within the vascular system to collect and retrieve plaque, a thrombus, and other particulate embolic materials that have been displaced during angioplasty, stenting, or other procedures. Such a device is removed at the end of the procedure. US-6179861 and US-6001118 disclose guide wire based filters in which the filter resembles a windsock and is supported by one or more articulated support rings. Documents US-5814064 and US-5827324 disclose filter devices based on guide wires, in which the filter is expanded to a predetermined diameter by the introduction of a fluid or a gas. US-6168604 and US-6152946 disclose guide wire based filters, in which the filter diameter is controlled by advancing and retracting a sheath over the filter component.

US-A-2001/0012951 discloses a thrombus filter apparatus comprising a guide wire with a filter element. The guide wire is free to rotate or translate while the filter element remains stationary.

A common concern with these devices is that the filter is attached to the guidewire, which increases the gauge or diameter of the guidewire, making it difficult to push and track these devices through the vasculature. to reach the treatment site. A related concern commonly encountered with these devices is that if the filter becomes clogged with thrombi, such that distal perfusion is no longer possible, the filter must be removed and replaced, thereby losing the position of the guide wire.

Existing guidewire-based tilting filters do not address the clinical problems of poor ability to push and be tracked through the vasculature, and loss of guidewire position after removal of permanently attached filters to the guide wires.

The present invention provides a vascular filter system that can be used to address the clinical problems of poor pushability and traceability through the vasculature, and loss of guidewire position after removal. of the filters permanently attached to the guidewire, as briefly described above.

An object of the present invention is to provide a vascular filter that is positioned on a guidewire after the distal end of the guidewire has crossed the lesion and is in position beyond an occlusion in a lumen of a vessel. Therefore, the present invention enables the physician to successfully reach the treatment site with a reduced caliber device. Thus, the present invention provides a filter to capture particulate embolic materials that can be released during the procedure, while also allowing perfusion of distal vessels. A further objective of the present invention is to provide a vascular filter that is recoverable while maintaining the position of the guide wire.

The present invention relates to a small caliber vascular filter system for use in percutaneous angioplasty and stent use, and substantially reduces the risk of distal embolization during interventional procedures. The Small Bore Vascular Filter System is designed to address the clinical problems of poor pushability and traceability through the vasculature, and loss of guidewire position after removal of filters. based on guide wires. The small gauge vascular filter system comprises a guidewire having proximal and distal markers, and a filter delivery and deployment system disposed coaxially around the guidewire. The filter delivery and deployment system comprises an inner member and an outer member, with a filter removably attached near the distal end of the inner member, and basket-type proximal and distal sleeves attached near the proximal and distal ends of the filter. The small-bore vascular system also comprises a retrieval catheter that can be arranged coaxially around the guidewire and filter.

The filter system of the present invention comprises a guidewire having proximal and distal markers; a filter delivery and deployment system comprising an inner member and an outer member, with a filter removably attached near the distal end of the inner member; basket-type proximal and distal sleeves attached near the proximal and distal ends of the filter; and a retrieval catheter that can be arranged coaxially around the guidewire and filter. The reduced gauge guidewire of the present invention, comprising proximal and distal markers near its distal end, but without an attached filter, is used to access the surgical site. If the anatomy is tortuous, such that access would be difficult if not impossible with a fixed filter, access can still be achieved with this reduced gauge guidewire. Then, the filter delivery and deployment system, comprising an inner member and an outer member, is introduced with the filter removably attached to the inner member of the filter delivery and deployment system. The outer member folds and constricts the filter, allowing it to achieve a first smaller diameter. The filter of the present invention comprises basket-type proximal and distal sleeves. The basket-type distal sleeve is sized to successfully mount over the proximal marker on the guidewire, but not the distal marker, so that the 3

ES 2 386 348 T3 filter is placed between these two markers. Then, the outer member of the filter delivery and deployment system is retracted to supply the filter. The inner member is then removed, and the filter remains positioned on the guidewire, between the proximal and distal markers. The filter captures particulate embolic materials during the procedure. The retrieval catheter is then used to retrieve the filter and guidewire, if the procedure has been completed. If the procedure has not been completed, but the filter is full and prevents distal perfusion, the filter alone can be removed so that the position of the guidewire is not lost, and the remainder of the procedure can be completed.

In one aspect, the present invention is directed to a small gauge vascular filter system comprising a guidewire having proximal and distal markers. The small gauge vascular filter system further comprises a filter delivery and deployment system disposed coaxially around the guidewire, the filter delivery and deployment system comprising an inner member and an outer member, a filter removably attached near the distal end of the inner member, and proximal and distal basket-type sleeves attached near the proximal and distal ends of the filter. The small gauge vascular filter system further comprises a retrieval catheter that can be arranged coaxially around the guidewire and filter. The retrieval catheter is used to fold the filter, and to remove the filter and guidewire from the vessel lumen.

In another aspect, the present invention is directed to a small gauge vascular filter system comprising a guidewire having proximal and distal markers. The small gauge vascular filter system further comprises a filter delivery and deployment system arranged coaxially around the guidewire, the filter delivery and deployment system comprising an inner member and an outer member, a filter removably attached near the distal end of the inner member, and proximal and distal basket-type sleeves attached near the proximal and distal ends of the filter. The small gauge vascular filter system further comprises a retrieval catheter that can be arranged coaxially around the guidewire and filter. The retrieval catheter is used to fold the filter, to remove the filter from the guidewire, and to remove the filter from the lumen of the vessel. In this way, the position of the guide wire is maintained, to complete the interventional procedure.

An advantage of the present invention is that the filter is delivered to the guidewire after the reduced gauge guidewire has been used to gain access to the intervention site, thereby facilitating access to the site through tortuous anatomy. Another advantage of the present invention is that a filled filter can be folded and retrieved without removing the guidewire, thereby allowing the operator to maintain the position of the guidewire if the intervention procedure has not been completed.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 illustrates an enlarged cross-sectional view of an exemplary embodiment of the reduced-bore vascular filter system, with the filter in the collapsed position, in accordance with the present invention.

Figure 2 illustrates an enlarged, partial, cross-sectional view of an exemplary embodiment of the filter of the reduced-bore vascular filter system, with the filter in the open position, in accordance with the present invention.

Figure 3 illustrates an enlarged, partial, cross-sectional view of an exemplary embodiment of the guide wire of the small gauge vascular filter system in accordance with the present invention.

Figure 4 illustrates an enlarged, partial, cross-sectional view of an exemplary embodiment of the filter and guidewire of the reduced-gauge vascular filter system, with the filter in the open position, in accordance with the present invention.

Figure 5 illustrates an enlarged, partial, simplified, cross-sectional view of an exemplary embodiment of the basket-type proximal sleeve and proximal marker of the reduced-bore vascular filter system in accordance with the present invention.

Figure 6 illustrates an enlarged, partial, cross-sectional view of an exemplary embodiment of the retrieval catheter of the small bore vascular filter system in accordance with the present invention.

With reference to the drawings, Figure 1 illustrates an exemplary embodiment of the small bore vascular filter system in accordance with the present invention. In this exemplary embodiment, the small gauge vascular filter system comprises a guidewire 7, and a filter delivery and deployment system 12, arranged coaxially around the guidewire 7. The filter deployment and delivery system 12 comprises an outer member 13 and an inner member 15, the outer member 13 being arranged coaxially around the inner member 15, and the inner member 15 being arranged coaxially around the inner member 15. guidewire 7. Inner member 15 comprises a filter 1, removably attached near the distal end of inner member 15. The filter 1 is folded into the distal end of the outer member 13, and is constrained by it.

ES 2 386 348 T3

As illustrated in Figure 2, the filter 1, in the exemplary embodiment, comprises a proximal basket-type sleeve 2 and a distal basket-type sleeve 6, and a plurality of struts 3 therebetween to form a support structure of the filter membrane. The filter 1 further comprises at least one marker 4 fixed to at least one strap 3. The filter 1 further comprises a permeable filter membrane 5 attached near the distal basket-type sleeve 6 and attached to the plurality of tie rods 3, as illustrated in Figure 2. The filter 1 has a first smaller diameter for delivery. , as illustrated in Figure 1, and a second larger diameter for deployment, as illustrated in Figure 2.

As illustrated in Figure 3, the reduced gauge vascular filter system in this exemplary embodiment comprises a guidewire 7, having a flexible tip 11, a distal marker 10, and a proximal marker 9. These markers 10, 9 serve two purposes. First, markers 10, 9 identify the future location of filter 1, under fluoroscopy, after guide wire 7, without filter 1, has been inserted into the lumen. Second, as illustrated in Figure 4, the distal marker 10 serves as a stop for the basket-type distal sleeve 6 after the filter has been placed on the guide wire 7. The basket-type distal sleeve 6 has a diameter greater than the maximum diameter of the proximal marker 9, but not greater than the maximum diameter of the distal marker 10. The basket-type proximal sleeve 2 has a diameter that is not greater than the maximum diameter of the proximal marker 9. Consequently, the filter can be positioned between the distal marker 10 and the proximal marker 9, as illustrated in Figure 4.

Figure 5 illustrates another exemplary embodiment of the present invention, in which the basket-type proximal sleeve 2 and a modified proximal marker 9a lock together to minimize longitudinal movement of the device while still allowing rotational movement of the device. The modified proximal marker 9a comprises a protruding rib 9b that engages in a groove 9c in the basket-like proximal sleeve 2. This can minimize movement of the filter 1 within the lumen, thereby avoiding potential vessel damage and / or accidental release of particulate embolic material.

As illustrated in Figure 6, the exemplary embodiment of the present invention further comprises a retrieval catheter 16. Retrieval catheter 16 can be arranged coaxially around guidewire 7 (Figure 1). The distal end 20 of the retrieval catheter 16 has a larger diameter than the body of the retrieval catheter 16. The distal end 20 of the retrieval catheter 16 can be inserted over the filter 1 (Figure 1) to capture and collapse the filter 1, and to remove the filter 1 from the lumen.

As illustrated in Figures 1, 2, 3, 4, and 6, the Small Gauge Vascular Filter System can be used to introduce a reduced gauge guidewire into the lumen of a vessel, followed by delivery and deployment of a filter to capture particulate embolic materials released during the procedure. The guidewire and / or filter can then be retrieved and removed from the lumen. As illustrated in Figure 3, guidewire 7 can be introduced into the lumen of a vessel through a femoral access. Guide wire 7, with a flexible tip 11, is placed beyond an occlusion in a vessel, with the distal marker 10 and proximal marker 9 identifying the future position of the filter under fluoroscopy. Then, as illustrated in Figure 1, the filter delivery and deployment system can be introduced through guide wire 7 and advanced through the lumen of the vessel. Filter 1 is removably attached near the distal end of inner member 15, and filter 1 assumes a first smaller diameter when folded and constricted at the distal end of outer member 13. As illustrated in Figure 4, the basket-like distal sleeve 10 is advanced over the proximal marker 9, but not over the distal marker 10. In the exemplary embodiment, the distal marker 10 abuts to prevent the filter 1 advance distally. Filter 1 is now in position between proximal marker 9 and distal marker 10, and outer member 13 can be retracted to allow filter 1 to reach its second largest diameter. The inner member 15 can also be retracted, and the filter 1 remains in position on the guidewire. At this point, additional interventional devices, such as balloon catheters and stent delivery systems, can be advanced over the guidewire to complete the interventional procedure. The filter remains in position capturing particulate embolic materials. Then, as illustrated in Figure 6, retrieval catheter 16 can be advanced over guidewire 7 to fold and retrieve filter 1. If filter 1 has already filled with particulate embolic materials, and the procedure is not completed. has completed, the retrieval catheter can retrieve the filter 1 on its own, and allow the guidewire 7 to remain in position for the remainder of the procedure.

Guidewire 7 can be made of any number of suitable materials, and can preferably be made of stainless steel or a nickel-titanium alloy. The straps 3 of the filter can be made of any number of suitable materials, and are preferably made of a nickel-titanium alloy. The filter markers 4 can be made of any number of suitable materials and are preferably made of a radiopaque material such as gold, platinum, tantalum, niobium, molybdenum, rhodium, palladium, silver, hafnium, tungsten or iridium. The proximal marker 9 and the distal marker 10 on the guidewire 7 can be made of any number of suitable materials and are preferably made of radiopaque materials such as gold, platinum, tantalum, niobium, molybdenum, rhodium, palladium, silver, hafnium, tungsten or iridium. The basket-type proximal sleeve 2 and the basket-type distal sleeve 6 of the filter 1 may be made of any number of suitable materials and are preferably made of radiopaque materials such as gold, platinum, tantalum, niobium, molybdenum, rhodium, palladium, silver, hafnium, tungsten, or iridium. Filter 1 can also

ES 2 386 348 T3 comprise coatings or any other suitable means to improve the radiopacity of the device. The permeable filter membrane 5 can be made of any number of suitable materials and is preferably made of a flexible polymeric material with elastomeric properties including polyurethane, polyethylene or a copolymer thereof, as well as combinations thereof. The permeable filter membrane 5 may comprise any number and configurations of apertures / holes, and preferably comprises apertures / holes in which the hole size is between about twenty and about three hundred microns in diameter. The holes / openings can be created by any suitable means and preferably can be created by laser drilling. In alternative embodiments, the filter membrane 5 may comprise a porous material rather than fabricated openings / holes. The outer member 13 and the retrieval catheter 16 can be made of any number of suitable materials, and are preferably made of a polymeric material. The inner member 15 can be made of any number of suitable materials and is preferably made of a polymeric or metallic material. The filter 1 may be removably attached to the inner member 15 by any suitable means and, preferably, may be attached by means of a friction fit or a releasable latch. The permeable membrane 5 of the filter may be attached to the struts 3 by any suitable means and preferably it may be attached by a bonding or welding process. The tie rods 3 may be attached to the basket-type sleeves 2, 6 by any suitable means and, preferably, they may be attached by a joining or welding process. The filter markers 4 may be attached to the struts by any suitable means and are preferably attached to the struts by a bonding or welding process. The distal guidewire marker 10 and proximal guidewire marker 9 may be attached to the guidewire by any suitable means and are preferably attached to the guidewire by a bonding or welding procedure.