2011 Volume 49 Issue 6 Pages 918-924
A durability test of the implantable Left Ventricular Assist System EVAHEART was conducted to demonstrate that the EVAHEART Blood Pump can be run for 2 years without failing. This testing was useful to indicate potential for BTT and possibly DT applications. We developed a custom durability test mock circulation loop which generates a pulsatile flow simulating the native left ventricle. This mock circulation loop includes components which mimic the left ventricle (LV chamber) and compliance in the aorta (aortic column), and a loop which connects the blood pump to both the LV chamber (inlet) and the aortic column (outlet). The LV chamber has two one-way valves and a linear motor connected to a rolling seal, allowing it to generate pulsatile flow. The blood pump speed was tuned to achieve clinically relevant flow, based on the need to supplement a failing heart. The simulated heart rate (stroke rate of the linear actuator) cycled through 3 different settings each day to simulate changes in patient activity level. The sample size for the durability test was set to 18, and the test duration was 2 years. During the test, no critical blood pump failures were observed. There were no indications of significant decrease in pump performance or seal performance. Furthermore, no symptoms of failure, such as abnormal wear, were observed. In conclusion, the durability test successfully demonstrated that the EVAHEART Blood Pump achieved component reliability at a minimum of 90% reliability and 88% confidence interval over a mission life of two years.
