Treatment of thrombus formation associated with the MicroMed DeBakey VAD using recombinant tissue plasminogen activator

Background-The latest generation of left ventricular assist devices consists of nonpulsatile impeller pumps. In these small pumps, thrombus formation inside the device does not lead to thromboembolic end-organ dysfunction but may dramatically impair pump flow. We report on our experience with thrombus-related pump dysfunctions of the MicroMed DeBakey left ventricular assist device and its treatment. Methods-Eight of 22 patients with a MicroMed DeBakey VAD presented with a critically reduced pump flow. In 7 cases, an increased power demand indicative of progressive thrombus formation associated with the device was evident, whereas 1 case presented with thrombus formation within the inflow conduit associated with a very low power demand. Brief spontaneously resolving pump stops had been noted in 6 patients. All 8 patients were treated with 100 mg of recombinant tissue plasminogen activator (rt-PA), administered via an IV line. Results-Rt-PA lysis led to an increase of pump flow along with a reduction of power demand within a short time in all patients. No severe bleeding complications occurred. However. 4 patients experienced transient epistaxis. All patients could be discharged from intensive care immediately after discontinuation of thrombolytic therapy. Conclusion-Rt-PA lysis is a very effective tool for thrombus-related pump dysfunction in patients with impeller pumps, which renders emergency surgical exchange unnecessary in most cases.