MINI-FOCUS ISSUE : MECHANICAL CIRCULATORY SUPPORT : OPPORTUNITIES AND CHALLENGES Identi fi cation and Management of Pump Thrombus in the HeartWare Left Ventricular Assist Device System A Novel Approach Using Log File Analysis

Fro of Va Au Un sac Ch He He OBJECTIVES The study sought to characterize patterns in the HeartWare (HeartWare Inc., Framingham, Massachusetts) ventricular assist device (HVAD) log files associated with successful medical treatment of device thrombosis. BACKGROUND Device thrombosis is a serious adverse event for mechanical circulatory support devices and is often preceded by increased power consumption. Log files of the pump power are easily accessible on the bedside monitor of HVAD patients and may allow early diagnosis of device thrombosis. Furthermore, analysis of the log files may be able to predict the success rate of thrombolysis or the need for pump exchange. METHODS The log files of 15 ADVANCE trial patients (algorithm derivation cohort) with 16 pump thrombus events treated with tissue plasminogen activator (tPA) were assessed for changes in the absolute and rate of increase in power consumption. Successful thrombolysis was defined as a clinical resolution of pump thrombus including normalization of power consumption and improvement in biochemical markers of hemolysis. Significant differences in log file patterns between successful and unsuccessful thrombolysis treatments were verified in 43 patients with 53 pump thrombus events implanted outside of clinical trials (validation cohort). RESULTS The overall success rate of tPA therapy was 57%. Successful treatments had significantly lower measures of percent of expected power (130.9% vs. 196.1%, p 1⁄4 0.016) and rate of increase in power (0.61 vs. 2.87, p < 0.0001). Medical therapy was successful in 77.7% of the algorithm development cohort and 81.3% of the validation cohort when the rate of power increase and percent of expected power values were <1.25% and 200%, respectively. CONCLUSIONS Log file parameters can potentially predict the likelihood of successful tPA treatments and if validated prospectively, could substantially alter the approach to thrombus management. (J Am Coll Cardiol HF 2015;3:849–56) © 2015 by the American College of Cardiology Foundation. m the *Division of Cardiology, Montefiore Medical Center, Albert Einstein College of Medicine, New York, New York; yDivision Cardiovascular Medicine and Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan; zMedStar Heart and scular Institute, MedStar Washington Hospital Center, Washington, DC; xHeart Lung Clinic, St. Vincent’s Hospital, Sydney, stralia; kDepartment of Surgery, Division of Cardiac Surgery, Center for Medical Physics and Biomedical Engineering, Medical iversity of Vienna, Vienna, Austria; {Heart Failure and Cardiac Transplantation Center, Tufts Medical Center, Boston, Mashusetts; #HeartWare Inc., Framingham, Massachusetts; and the **Department of Cardiology, University of Chicago Medicine, icago, Illinois. Dr. Jordehas served as a consultant andon the advisoryboard forHeartWare Inc., Thoratec Corporation, and Jarvik art Inc. Dr. Aaronson has received research grant support from HeartWare Inc. Dr. Najjar has received research support from artWare Inc.; and has served on the advisory board for HeartWare Inc. and XDx Inc. Dr. Pagani has received research grant support ABBR EV I A T I ON S