Thrombus was confirmed through the evaluation of the returned device.The pump was returned assembled with the driveline cut approximately 2 inches from the pump housing and the severed distal end portions, measuring approximately 15 inches and 22.5 inches in length, were also returned.The sealed inflow conduit, the sealed outflow graft, and the sealed outflow graft bend relief were not returned.The outflow elbow was returned attached to the pump outlet port.Examination of the pump blood-contacting surface found a denatured ring of tissue-like thrombus adhered to the inlet bearing ball.The tissue showed laminated layering, indicating that the thrombus formed over an undetermined period of time.Examination of the proximal side of the outlet stator revealed a dark, denatured deposition occluding the outlet stator.Its areas of denaturation as well as the contact marks observed at the distal end of the rotor, suggest that it was present for an undetermined period of time while the pump was supporting the patient.Although a root cause for the development of the depositions could not conclusively be determined through this evaluation, they could have contributed to the patient's elevated lactate dehydrogenase levels and reported pump power elevation.Upon removal of the observed depositions, the device was cleaned.The disassembled pump¿s bearings, rotor, and blood-contacting surfaces were then examined under a microscope and no anomalies were observed.Electrical continuity testing of the driveline did not reveal any discontinuities or shorts.The pump was reassembled and functionally tested under normal operating conditions using a mock circulatory loop.The data retrieved from that testing revealed normal pump power consumption and pressure values, comparable to what was recorded during the manufacturing process and the device functioned as intended.Device thrombosis and hemolysis are listed in the instructions for use as potential adverse events that may be associated with the use of the heartmate ii left ventricular assist system.A review of the device history records revealed no deviations from manufacturing or quality assurance specifications.The manufacturer is closing the file on this event.
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