Ultra-low fractional area coverage flow diverter for treating aneurysms and vascular diseases

Abstract

The various embodiments described herein include methods for fabricating thin- film flow diversion apparatuses. In one aspect, a method includes: (1) creating a plurality of trenches using photolithography and deep reactive ion etching on a substrate; (2) depositing a metal sacrificial layer on the substrate; (3) forming a Nitinol layer with a plurality of fenestrations by depositing Nitinol on the metal sacrificial layer; (4) forming a thin-film of Nitinol by removing the metal sacrificial layer; (5) crystallizing the thin-film of Nitinol; and (6) elongating the thin-film of Nitinol.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a 35 U.S.C. §111(a) continuation of PCT international application number PCT / US2011 / 037988 filed on May 25, 2011, incorporated herein by reference in its entirety, which is a nonprovisional of U.S. provisional patent application No. 61 / 348,239, filed on May 25, 2010, incorporated herein by reference in its entirety. Priority is claimed to each of the foregoing applications.[0002]The above-referenced PCT international application was published as PCT International Publication No. WO 2011 / 150118 on Dec. 1, 2011 and republished on Apr. 5, 2012, and is incorporated herein by reference in its entirety.[0003]This application is related to PCT International Application No. PCT / US2010 / 026430 filed on Mar. 5, 2010, published on Sep. 10, 2010 as PCT International Publication No. WO 2010 / 102254, and republished on Jan. 20, 2011, incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR D...

AI Technical Summary

Benefits of technology

[0019]An aspect of the present invention is patterning of thin films, and in particular construction of vascular flow diversion devices for various vascular diseases including but not limited to treating aneurysms and other applications. The devices of the present invention are configured to be extremely low profile and are covered with the minimal amount of blood contacting material. The thin-film manufacturing processes of the present invention allow for production of ultra-low profile and hyperelastic structures (e.g. >400% elongation). These hyperelastic properties allows for the creation of self expanding vascular flow diversion devices, and in particular delivery of the material on a self expanding platform without folding of the material. In vitro and in vivo experiments show flow diversion devices manufactured with the micro-machined thin-film of the present invention, along with a stent or support structure, do not generate thrombosis in the arteries less than 5 mm and provide adequate and rapid flow diversion without production of intimal hyperplasia or vascular stenosis.

[0020]Simulated blood studies have shown that the thin-film structures of the present invention are capable of reducing the intra-aneurismal flow velocity and vorticity greater than 90% in a pseudo-aneurysm, even though the coverage area was less than ˜10%.

Problems solved by technology

Conventional stent structures do not provide sufficient flow diversion to treat aneurysms.

PTFE, Dacron and other polymer structures are fabricated in such a fashion that it is extremely difficult to precisely control the porosity to a tolerance of 1 micron.

Even in cases where porosity can macroscopically be controlled in these materials, specific shapes and distributions cannot be generated precisely.

For example, it is highly difficult, if not impossible, to specifically fabricate a circular or diamond shape pattern that is regular and repeating into structures comprising these materials.

This increases the size of any flow diversion device without providing significant benefit in regards to the thickness direction.

However, this procedure requires a craniotomy (an opening in the skull) and is not always applicable depending on the aneurysm size, location, and complexity.

While coils are beneficial, they can only be used for aneurysms with “necks” narrow enough to hold coils in the aneurysm.

This procedure is complicated (it involves two types of devices: a stent and multiple coils), sometimes does not produce aneurysm occlusion, and is limited by the physical size of the stent's delivery system.

While they can wall off aneurysms by circumferentially covering the wall of an artery, they have been far too bulky for use as neurovascular stents or in other flow diversion vascular systems requiring a low profile.

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