The present invention relates to apparatus and methods for retrieving a vascular device, such as a filter, from within a vessel. More particularly, the present invention provides apparatus useful for retrieving a vascular filter used to prevent embolization associated with diagnostic or therapeutic interventional procedures, thrombectomy and embolectomy.
Percutaneous interventional procedures to treat occlusive vascular disease, such as angioplasty, atherectomy, and stenting, often dislodge material from the vessel walls. This dislodged material, known as emboli, enters the bloodstream and may be large enough to occlude smaller downstream vessels, potentially blocking blood flow to tissue. The resulting ischemia poses a serious threat to the health or life of a patient if the blockage occurs in critical tissue, such as the heart, lungs, or brain.
The deployment of stents and stent-grafts to treat vascular disease, such as aneurysms, involves the introduction of foreign objects into the bloodstream, and also may result in the formation of clots or release of emboli. Such particulate matter, if released into the bloodstream, also may cause infarction or stroke.
Numerous blood filters are known that are designed to capture material liberated from vessel walls during the treatment of vascular disease. Such treatment procedures, such as angioplasty, atherectomy and stenting, typically involve transluminally inserting an interventional device to the treatment site along a guidewire. Upon completion of the procedure, the interventional device is removed from the patient""s blood vessel, and a retrieval mechanism, such as a sheath, is advanced along the guidewire in order to retrieve the blood filter.
One drawback associated with using a sheath to retrieve a filter is that the retrieval process requires two steps: (1) the interventional device (e.g., angioplasty catheter) must be removed and (2) the retrieval sheath must then be advanced along the guidewire to retrieve the filter. This additional exchange adds time to the length of the procedure, involves introduction of an additional element (the retrieval catheter) into the patient""s vasculature, and enhances the risk of dislodging the filter and permitting emboli to escape therefrom.
Moreover, as the retrieval sheath is advanced along the guidewire, its distal end may become entangled with a stent disposed within the patient""s vessel. If, for example, a stent has been deployed, the distal end of the retrieval sheath may inadvertently engage a stent strut, preventing further advancement of the retrieval sheath within the vessel, or even possibly causing vessel dissection.
One disadvantage associated with attempting to retrieve a vascular filter using the guidewire lumen of an interventional device, such as an angioplasty catheter, is that the diameters of such lumens are typically quite small, e.g., 0.014 inch. Accordingly, it is not possible to retrieve previously known vascular filters using the guidewire lumens of most interventional devices.
In view of the foregoing, it would be desirable to provide improved apparatus and methods that streamline retrieval of a vascular filter.
It further would be desirable to provide improved apparatus and methods that facilitate retrieval of a vascular filter, with reduced risk of entangling a retrieval sheath in a deployed stent.
In view of the foregoing, it is an object of the present invention to provide improved apparatus and methods that streamline retrieval of a vascular filter.
It is another object of the present invention to provide improved apparatus and methods that facilitate retrieval of a vascular filter, with reduced risk of entangling a retrieval sheath in a deployed stent.
These and other objects of the present invention are accomplished by providing a retrieval apparatus that reduces the time and effort required to retrieve a vascular filter from a patient""s vessel.
In one preferred embodiment, the present invention includes a retrieval adapter having a proximal end configured to be fitted to the end of an interventional device, such as an angioplasty catheter, and a radially expandable distal end. Upon completion of an interventional procedure such as angioplasty, the balloon of the angioplasty catheter is deflated and the angioplasty catheter then is advanced along the guidewire until the adapter captures the vascular filter.
Alternatively, upon completion of the interventional procedure, the guidewire and attached vascular filter may be withdrawn proximally until the vascular filter engages and is caused to be collapsed by the adapter. Once the vascular filter is collapsed, the vascular filter is partially withdrawn within the adapter, and the vascular filter, adapter, interventional device and guidewire are all removed from the vessel. This streamlined procedure provides a substantial improvement over previously known systems, which typically require exchanging the interventional device for a retrieval sheath before retrieving the vascular filter from the treatment site.
In another embodiment, the retrieval adapter of the present invention may be loaded directly onto the guidewire having the vascular filter so that the adapter is delivered to a treatment site concurrently with the filter. After completion of a diagnostic or therapeutic procedure involving an interventional device, such as an angioplasty catheter, the interventional device is advanced along the guidewire. As the distal end of the interventional device moves distally, it abuts against the adapter and urges the adapter into contact with the filter, thereby causing the adapter to collapse and capture the vascular filter. Alternatively, as for the previous embodiment, the interventional device may be held stationary and the vascular filter and adapter retracted proximally.
In yet another embodiment, the present invention includes a retrieval catheter having proximal and distal ends. The proximal end of the catheter is loaded onto the distal end of an interventional device, and that assemblage then is loaded onto the guidewire having the vascular filter. After completion of a diagnostic or therapeutic procedure, such as stent deployment, the retrieval catheter is advanced over the working element of the interventional device (e.g., the deflated balloon) and the vascular filter. Alternatively, the retrieval catheter may be held stationary and the vascular filter and guidewire retracted proximally to collapse and capture the filter in the retrieval sheath.