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Clinical research into mechanical circulatory support systems dates back to the 1960s, with the first reported successful human implantation of a left ventricular assist device (LVAD) for postoperative heart failure, in a 37-year-old woman with aortic insufficiency and mitral stenosis.1 Early ventricular assist devices were typically extracorporeal pumps. In general, only short-term use was clinically feasible; the duration of support was limited by the high risk of thrombosis, bleeding, infection, and device malfunction.
Investigators during the 1970s and 1980s focused their efforts on the development of implantable pulsatile pumps to reduce some of the risks associated with the external machines.2 In 2001, one of these devices, the HeartMate VE, although it was large and noisy, was shown to be associated with a rate of survival at 1 year that was higher than that with medical management alone among patients with end-stage heart failure.3
The risk of adverse events remained high with these early LVADs. Although the risk of infection was decreased with implantable devices, it was not fully resolved, since each such pump required an external drive line for its operation, which created a point of entry for bacterial migration. Thromboembolism remained an issue, and the anticoagulation to reduce the risk of thromboembolism increased the risk of bleeding. These pulsatile pumps required considerable mechanical energy and incorporated inflow and outflow valves, resulting in a substantial risk of device failure over time.
Implantable small rotary (continuous-flow) blood pumps have revolutionized mechanical circulatory support since the first human implantation in 1998.4 They are noiseless, which is an important feature for patients’ quality of life. The subsequent evolution of magnetic levitation in...