Evaluation of the evidence on the HeartMate II® and HeartWare® ventricular assist devices for the treatment of chronic end-stage heart failure

Heart failure is a complex syndrome that arises when the heart is incapable of pumping enough blood to respond to the metabolic needs of the body. Heart failure is often caused by defective contraction and relaxation of the myocardium, accompanied by elevated cardiac filling pressure. It represents the final stage of a number of cardiovascular diseases. Characterized by limitation in activities of daily living and progressive exhaustion at rest, heart failure is a disabling and life-threatening condition. Severe heart failure, defined as class IV using the functional classification scheme of the New York Heart Association (NYHA), is associated with a 1-year mortality of about 50%. 

Heart failure is a major public health problem, associated with high rates of morbidity and mortality. It is estimated that more than 80,000 people are affected in Quebec, and the incidence of heart failure is expected to increase as a result of ageing of the population. More than 75% of patients suffering from heart failure in Quebec use hospital-based services. Approximately 8,500 people are hospitalized each year; about 85% of these patients are 66 years or older. More than 900 people die from heart failure annually in Quebec. 

End-stage chronic heart failure is characterized by advanced modifications of the cardiac system, marked symptoms at rest, and is refractory to medical and surgical treatment. Cardiac transplantation is the treatment of choice for most cases of end-stage chronic heart failure. However, access to cardiac transplantation remains relatively limited due to strict eligibility criteria and a lack of donor organs. 

An implantable ventricular assist device (VAD) is a technology that has been offered in Canada since 1986 and for which demand continues to grow. A VAD increases cardiac output by reducing the work of the failing heart. It is thus used to improve the chances that a patient survives until receipt of a donor heart (or, occasionally, until recuperation of cardiac function) or for long-term treatment in the case of temporary or permanent ineligibility for heart transplantation. In the past decade, VAD technology has evolved, in order to reduce the number of moving parts and device size and to increase durability; thus, newer “continuous-flow” devices have taken the place of pulsatile-flow VADs.