Systems and methods for making encapsulated hourglass shaped stents

Abstract

Systems and methods for the manufacture of an hourglass shaped stent-graft assembly comprising an hourglass shaped stent, graft layers, and an assembly mandrel having an hourglass shaped mandrel portion. Hourglass shaped stent may have superelastic and self-expanding properties. Hourglass shaped stent may be encapsulated using hourglass shaped mandrel assembly coupled to a dilatation mandrel used for depositing graft layers upon hourglass shaped mandrel assembly. Hourglass shaped mandrel assembly may have removably coupled conical portions. The stent-graft assembly may be compressed and heated to form a monolithic layer of biocompatible material. Encapsulated hourglass shaped stents may be used to treat subjects suffering from heart failure by implanting the encapsulated stent securely in the atrial septum to allow blood flow from the left atrium to the right atrium when blood pressure in the left atrium exceeds that on the right atrium. The encapsulated stents may also be used to treat pulmonary hypertension.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application No. 62 / 343,658, filed May 31, 2016, the entire contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]This application relates to systems and methods for the manufacture of hourglass or “diabolo” shaped encapsulated stents for treating congestive heart failure and other disorders treated with encapsulated hourglass shaped stents.BACKGROUND[0003]Heart failure is the physiological state in which cardiac output is insufficient to meet the needs of the body and the lungs. Congestive Heart Failure (CHF) occurs when cardiac output is relatively low due to reduced contractility or heart muscle thickening or stiffness. There are many possible underlying causes of CHF, including myocardial infarction, coronary artery disease, valvular disease, and myocarditis.[0004]CHF is associated with neurohormonal activation and alterations in autonomic control....

AI Technical Summary

Benefits of technology

The present invention provides systems and methods for making encapsulated stent-grafts that can be used to treat CHF and other conditions benefited by encapsulated stents. The new systems and methods involve making hourglass shaped stents using a mandrel assembly and compressing the stent-graft assembly against the mandrel to form the encapsulated stent-graft. The new methods also involve using a balloon catheter to inflate the stent-graft and control the pressure within the balloon to achieve the desired adhesion and inter-nodal-distance of the graft material. The new systems and methods provide improved encapsulated stent-grafts that can better treat CHF and other conditions.

Problems solved by technology

Heart failure is the physiological state in which cardiac output is insufficient to meet the needs of the body and the lungs.

However, the larger volume of blood also stretches the heart muscle, enlarging the heart chambers, particularly the ventricles.

At a certain amount of stretching, the hearts contractions become weakened, and the heart failure worsens.

In low ejection fraction (EF) heart failure, high pressures in the heart result from the body's attempt to maintain the high pressures needed for adequate peripheral perfusion.

However, the heart weakens as a result of the high pressures, aggravating the disorder.

Pressure in the left atrium may exceed 25 mmHg, at which stage, fluids from the blood flowing through the pulmonary circulatory system flow out of the interstitial spaces and into the alveoli, causing pulmonary edema and lung congestion.

This stiffness may impede blood from filling the heart, and produce backup into the lungs, which may result in pulmonary venous hypertension and lung edema.

However, pharmacological approaches are not always successful, as some people may be resistant or experience significant side effects

Such mechanical devices enable propulsion of significant volumes of blood (liters / min), but are limited by a need for a power supply, relatively large pumps, and the risk of hemolysis, thrombus formation, and infection.

However these approaches are highly invasive and have the general risks associated with highly invasive surgical procedures.

However, Dobak states that a valved design may not be optimal due to a risk of blood stasis and thrombus formation on the valve, and that valves can also damage blood components due to turbulent flow effects.

Dobak does not provide any specific guidance on how to avoid such problems.

While Banas describes a method for encapsulating a cylindrical stent, the method in Banas does not describe encapsulation of an hourglass shaped stent intended for treatment of CHF.

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