Shunt for redistributing atrial blood volume

Abstract

A shunt for regulating blood pressure between a patient's left atrium and right atrium comprises an anchor comprising a neck region, first and second end regions, and a conduit affixed with the anchor that formed of a biocompatible material that is resistant to transmural and translation tissue ingrowth and that reduces a risk of paradoxical embolism.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation application of U.S. application Ser. No. 15 / 449,834, filed Mar. 3, 2017, now U.S. Pat. No. 10,076,403, the entire contents of which are incorporated by reference herein.FIELD OF THE INVENTION[0002]This application generally relates to percutaneously placed implants and methods for redistributing blood from one cardiac chamber to another to address pathologies such as heart failure (HF), myocardial infarction (MI) and pulmonary arterial hypertension (PAH).BACKGROUND OF THE INVENTION[0003]Heart failure is the physiological state in which cardiac output is insufficient to meet the needs of the body or to do so only at a higher filing pressure. There are many underlying causes of HF, including myocardial infarction, coronary artery disease, valvular disease, hypertension, and myocarditis. Chronic heart failure is associated with neurohormonal activation and alterations in autonomic control. Although these co...

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Benefits of technology

[0070]In view of the foregoing drawbacks of previously-known interatrial shunts, a shunt constructed in accordance with the principles of the present invention provides a more durable configuration that maintains luminal patency for extended periods of time. The inventive shunt further enables redistribution of interatrial blood volumes and pressure imbalances while reducing a risk of paradoxical embolism caused by emboli moving through the shunt from the right to left atria.

[0071]Shunts constructed in accordance with the principles of the present invention also provide greater safety by enhancing long-term patency and reducing the risk of pannus formation after a prolonged period of implantation by reducing the impact of the manner in which the shunt is implanted in the interatrial septum.

[0072]In accordance with the principles of the present invention, shunts having an anchor and conduct are provided for redistributing atrial blood volumes, in which the shunt dimensions, contours and materials maintain long-term patency while reducing the risk of paradoxical embolism. It is hypothesized that such shunt designs will provide reductions in left atrial pressure, relieve pulmonary congestion, and lower pulmonary artery pressure, among other benefits. The inventive devices are configured for implantation through the atrial septum, and preferably through the fossa ovalis.

[0073]In particular, shunts designed in accordance with the principles of the present invention are designed to control LAP by transferring a small portion of the blood normally flowing from the left atrium to the left ventricle and diverting it instead to the right atrium, thereby modestly reducing LV end-diastolic filling volume. When the LAP is elevated, the LV operates on a steeper portion of its diastolic compliance curve. Accordingly, even a modest reduction in LV end-diastolic volume leads to a substantial fall in LV end-diastolic pressure. That reduction causes a commensurate reduction in upstream filling pressures including LAP, pulmonary venous pressure, and pulmonary artery pressure. The anticipated clinical result of these pressure reductions is expected to relieve or even prevent pulmonary congestive symptoms. At smaller interatrial gradients with less shunting, the effect on LV volume and filling pressures becomes progressively smaller until it is negligible. As interatrial shunting primarily affects LV filling and not afterload, beneficial effects on lowering end-diastolic pressure are expected, regardless of LV systolic function, for patients with heart failure associated with reduced ejection fraction (HFrEF) and patients with heart failure and preserved ejection fraction (HFpEF).

[0078]In one aspect of the present invention, a device for regulating blood distribution between a patient's left atrium and right atrium comprises an anchor having a neck region joining first and second end regions, the neck region configured to engage the fossa ovalis of the patient's atrial septum; and a conduit affixed to the anchor so that the conduit extends into the right atrium by a distance selected to reduce the risk of paradoxical embolism. The conduit preferably comprises a biocompatible material that limits (or inhibits excessive) tissue ingrowth into the lumen of the conduit. The anchor and conduit are configured to accommodate endothelial or neointima layer growth up to a thickness of about 0.6 mm or less, so as to render such material inert, inhibit hyperplasia, and substantially inhibit obstruction of the flow path through the device.

[0082]Subjects with a variety of heart pathologies may be treated with, and may benefit from, the inventive device. For example, subjects with heart failure and pulmonary congestion, reducing the left atrial pressure and left ventricular end diastolic pressure may provide a variety of benefits, including but not limited to decreasing pulmonary congestion; decreasing pulmonary artery pressure; increasing ejection fraction; increasing fractional shortening; and decreasing left ventricle internal diameter in systole. Other heart pathologies that may be treated include myocardial infarction, which may be treated by deploying the device during a period immediately following the myocardial infarction, e.g., within six months after the myocardial infarction, or within two weeks following the myocardial infarction, to reduce myocardial remodeling.

Problems solved by technology

Accordingly, even a modest reduction in LV end-diastolic volume leads to a substantial fall in LV end-diastolic pressure.

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