Ventricular assist devices for advanced heart failure

Abstract

The limited number of donor organs for orthotopic heart transplantation has boosted interest in alternative therapies, including mechanical circulatory support. Ventricular assist devices (VADs) were developed in the 1960s to help patients who could not be weaned from cardiopulmonary bypass following cardiac surgery. Since then, attention has focused on creating a safe, durable, and hemodynamically effective device for the patient with advanced heart failure. Durable LVADs were initially developed as destination therapy (DT) for patients not eligible for heart transplantation. But safety and performance concerns led the FDA to restrict use to patients who were eligible for a transplant-bringing about the concept of "bridge to transplantation (BTT)." Durable, smaller, and totally implantable devices were developed, permitting an enhanced quality of life. The American Heart Association (AHA) guidelines recommend continuous flow pump device (CF-LVAD) implantation as BTT for patients awaiting heart transplantation who have become refractory to medical therapy. Besides DT and BTT, VADs are used as a "bridge to decision" (BTD) or "bridge to recovery" (BTR). During acute illness, many patients fall into a gray zone with a clinical status that improves over time and with the potential of listing for transplantation. These patients are frequently designated as BTD and may be supported by percutaneous temporary VADs or extracorporeal membrane oxygenation (ECMO). With increasing therapy options, patients benefit from decisions made by an experienced multidisciplinary team. This chapter describes the expanding use of ventricular assist devices for treating advanced heart failure, including the rationale, evolution of device technology, patient selection criteria, complications (gastrointestinal bleeding, pump thrombosis, stroke, aortic valve insufficiency, right ventricular failure), description of the INTERMACS scale, and corresponding recommendations for device support. VAD therapy in well-selected patients provides a superior survival benefit but still has the risk of complications. The use of VADs for destination therapy will continue to increase and likely will become a primary therapy for end-stage heart failure. Engineering initiatives will focus on developing an internal battery-powered generator and strategies to decrease thrombotic and bleeding complications.