In-Situ forming foam for the treatment of vascular dissections
Inventors
Freyman, Toby • MCGILL, MEGHAN
Assignees
Medtronic Inc • Medtronic Vascular Inc • Arsenal Medical Inc
Publication Number
US-10682436-B2
Publication Date
2020-06-16
Expiration Date
2034-03-12
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Abstract
Systems and methods related to polymer foams for the treatment of blood vessel dissections are generally described. Some embodiments relate to compositions and methods for the preparation of polymer foams, and methods for using the polymer foams. The polymer foams can be applied to or within a dissection caused by an intimal tear in a blood vessel, sealing the dissection and preventing further perfusion thereof. In some embodiments, the polymer foam can be formed within a body cavity (i.e., in-situ foam formation). The foam may be used to fill the dissection as a thrombosing agent. In addition, the foam may be used in conjunction with medical devices such as stents, stent-grafts, balloons, and catheters.
Core Innovation
The invention relates to systems and methods for treating blood vessel dissections—such as aortic dissections—using polymer foams that are formed in-situ. The core of the technology involves delivering a fluid prepolymer material into a dissection, such as a false lumen created by an intimal tear, where it reacts in the water-containing environment of the body to generate gas and expand into a foam. The foam fills and seals the dissection by forming a conformal barrier, thereby preventing further blood perfusion into the false lumen.
The method addresses the limitations of conventional treatments like stents or stent grafts, which may not adequately seal the intimal tear or may occlude collateral arteries. The background highlights that existing solutions often require repeated interventions, can block vital branch arteries, or do not provide sufficient sealing—resulting in continued perfusion of false lumens or exposure to other complications.
By forming the foam directly at the target site, whether alone or in conjunction with medical devices such as stents, stent grafts, balloons, or catheters, the invention offers a flexible approach to isolating or filling false lumens. The foam can serve as a thrombosing agent, facilitate sealing of the tear, and provide mechanical stability without necessarily obstructing collateral vessels. The foam’s properties, including biocompatibility, elasticity, and the ability to contain agents like radiopaque materials or procoagulants, further enhance its suitability for intravascular therapy.
Claims Coverage
There are three independent inventive features based on the three independent claims found in the patent.
Treating false lumens using balloon-contained in-situ forming foam
A method involves: - Covering a false lumen adjacent to a true lumen within a patient using a balloon. - Injecting a fluid prepolymer material (comprising a specified polyol composition with amine catalyst, water, surfactant, diluent, and a second composition with multiple isocyanate groups) into or onto the false lumen. - Forming a foam by a water-triggered reaction upon injection, generating gas and cross-linking with 1- to 10-fold expansion, forcing material into interstitial areas of the false lumen. - The reaction proceeds from the outside-in, forming an outer skin that surrounds the foam and promotes resistance to deformation and undesired movement. - The balloon acts to contain the foam within the false lumen and prevent impingement into the true lumen as the foam fills the false lumen.
Treating false lumens using a medical device and in-situ forming foam
A method involves: - Covering the false lumen using a medical device (which may be a graft). - Injecting a fluid prepolymer material (as above, with specific components) into a space between the medical device and the false lumen. - Forming a foam in-situ by a water-triggered reaction, resulting in gas generation, cross-linking, 1- to 10-fold expansion, and forcing the material into the interstitial area. - An outer skin forms from the outside-in, providing resistance to deformation and movement of the foam. - The medical device contains the foam in the false lumen and prevents impingement of the false lumen into the true lumen as the false lumen is filled.
Treating false lumens by directly injecting in-situ forming foam
A method includes: - Injecting a fluid prepolymer material (with specified polyol composition, amine catalyst, water, surfactant, diluent, and an isocyanate composition) directly into the false lumen within a patient. - Forming a foam via a water-triggered reaction that generates gas and initiates cross-linking, causing 1- to 10-fold expansion and filling interstitial spaces in the false lumen. - The reaction proceeds from the outside-in, creating an outer skin around the foam to resist deformation and undesired movement into collateral vessels or outside the false lumen.
The inventive features center on the in-situ formation of polymer foams within false lumens of blood vessels, either with the aid of a balloon, a medical device, or direct injection, utilizing specific prepolymer chemistries and foam formation mechanisms to achieve sealing, containment, and resistance to migration.
Stated Advantages
Foams can be delivered into closed body cavities and create conformal contact with target tissues without requiring specific knowledge of the target site.
The system provides additional flexibility and varied treatment options compared to existing methods for the treatment of vascular dissections.
Use of in-situ forming foam may reduce post-surgical complications and the need for re-interventions by more effectively sealing intimal tears than stents alone.
Foam applied in conjunction with stents may enable endovascular repair in cases where stenting alone is not a viable option due to complicated dissection anatomy.
The foam can be engineered to be biocompatible, biodegradable, elastic, or to support targeted adhesion to tissues, widening its range of use.
The foam creates a seal while minimizing the risk of obstructing collateral branches, reducing the chances of ischemia or paralysis compared to grafted stents.
Porous foam formulations increase surface area, supporting thrombosis and improved outcomes in false lumen occlusion.
Foams can be designed to be soft and compressible to avoid impinging on the true lumen and interfering with physiological functions.
Foam delivery can incorporate radiopaque or other imaging agents to aid visualization during and after deployment.
Documented Applications
Treatment of aortic dissections, including Type A and Type B dissections, by sealing intimal tears and filling or isolating false lumens.
Repair of dissections occurring in other blood vessels such as the carotid artery, vertebral artery, and coronary artery, in conjunction with or as an alternative to stents or grafts.
Use as a thrombosing agent to promote clotting in the false lumen, facilitate thrombosis, and support recovery of the true lumen.
Reinforcement of weak arterial walls or tears by selectively sealing areas of a bare stent without occluding arterial branches.
Filling body cavities created by loss of tissue, including false lumens and other cavities within the body or wounds.
Delivery using endoscopic, open surgical, transcutaneous puncture, or related medical procedures for treating vascular dissections.
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