System and method for retaining vaso-occlusive devices within an aneurysm

#The present invention relates generally to vaso-occlusion, and more particularly to systems and methods for retaining vaso-occlusive devices within an aneurysm.

#Different implantable medical devices have been developed for treating a number of ailments associated with body lumens. In particular, occlusive devices are useful in filling vascular or other body spaces. Some body spaces, such as vascular aneurysms, are formed due to a weakening in the wall of an artery. Often these aneurysms are the site of internal bleeding and stroke. A variety of different embolic agents are known to be, at least arguably, suitable for treatment of these anomalies. These treatments are commonly known as “artificial vasoocclusion.”

#Over the past few years, advancements in the artificial occlusion of vessels and aneurysms have included the delivery and implantation of metal coils as vaso-occlusive devices. Implantable metal coils that are useful as artificial occlusion devices in vasculature lumens or aneurysms are herein referred to as “vaso-occlusive coils.” Vaso-occlusive coils are generally constructed of a wire, usually made of a metal or metal alloy that is wound to a helix. The vaso-occlusive coil assumes an irregular shape upon discharge of the device from the distal end of the catheter. A variety of vaso-occlusive coils are known. For instance, U.S. Pat. No. 4,994,069, issued to Ritchart et al., shows a flexible, preferably coiled, wire for use in small vessel vaso-occlusion. Unlike vaso-occlusive coils used prior to that time, Ritchart et al. teach a coil that is fairly soft and is delivered to the site using a pusher within a catheter lumen. Upon discharge from the delivery catheter, the coil may undertake any number of random or regular configurations used to fill the site.

#In order to better appreciate how the above-recited and other advantages and objects of the present inventions are obtained, a more particular description of the present inventions briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

#FIG. 1 is an illustration of a vaso-occlusive device constructed in accordance with a preferred embodiment of the present inventions, wherein the vaso-occlusive device is shown fully deployed within an aneurysm;

#FIGS. 2(a) and 2(b) illustrate one preferred method of manufacturing the vaso-occlusive device of FIG. 1 in accordance with the present inventions;

#Turning to FIG. 1, a vaso-occlusive element 10 constructed in accordance with a preferred embodiment of the present invention is shown completely deployed within an aneurysm 40 of a blood vessel 60. The aneurysm 40 is shown with an oppositely disposed neck 70 and dome 45. When deployed in its secondary shape, i.e., its deployed shape, the vaso-occlusive element 10 generally includes a central tubular element 15 and proximal 20 and distal 30 ends that are flared open into “umbrella” shapes. As illustrated, the flared opened ends 20/30 advantageously conform to the shape of the aneurysm 40. The diameter of the proximal end 20 of the vaso-occlusive element 10 is larger than the neck 70, and thus the proximal end 20 may completely cover the neck 70.

#As will be described in further detail below, the vaso-occlusive element 10 is manufactured from a relatively dense braid. In this manner, the proximal end 20 may densely cover the neck 70 and function as a retainer. Thus, finer vaso-occlusive devices, such as vaso-occlusive coils or embolic liquids, may effectively be retained within the aneurysm 40, or at the least, the likelihood of these devices migrating out from the aneurysm 40 is minimized. Further, as can be appreciated by one of ordinary skill in the art, the relatively dense coverage of the proximal end 20 allows the vaso-occlusive element 10 itself to function as a vaso-occlusive device. The flared open distal end 30 is placed adjacent the dome 45 of the aneurysm 40 and allows the element 10 to safely conform to the shape of the dome 45. This allows for the distal end 30 to function as an anchor and secure itself within the aneurysm 40 without the need to conform to the entire shape of the aneurysm 40. Thus, the element 10 may conform to a large variety of shapes and sizes of aneurysms 40 since the element 10 need only be secured within the aneurysm 40 by conforming the flared open distal end 30 to the dome 45.

#Turning to FIGS. 2(a)-(b), one preferred method of manufacturing the vaso-occlusive device 10 will now be described. First, a braided tubular element 1 is constructed by braiding multiple fine wires 2 together. The tubular element 1 may also be formed of wires with varying diameters braided together. It may be desirable to use a larger number of wires 2 when forming the tubular element 1, resulting in a relatively dense braid, which provides denser coverage within the aneurysm 40. Optionally, the tubular element 1 may be radiopaque. One method involves braiding a radiopaque fiber, such as platinum, Pt, or gold, Au, into the tubular element 1. Another method involves plating or coating the tubular element 1 with radiopaque material. Additionally, one or more radiopaque markers may be added to the tubular element 1.