Correlation of Pre-Explant Lactate Dehydrogenase Concentrations and Findings During Post-Explant Pump Analysis of the HeartMate II Left Ventricular Assist Device

Background Analyses of the HeartMate II left ventricular assist device are routinely performed after explant if returned to the manufacturer. Findings from manufacturer-reported pump analyses have not been correlated with pre-explant serum lactate dehydrogenase (LDH) values. Methods Between May 2004 and December 2014, 502 patients underwent primary HeartMate II implantation. Seventy pumps were explanted in 58 patients and returned to the manufacturer for pump analysis: 51 (73%) for suspected pump thrombosis, 12 (17%) for device-related infection, and 7 (13%) for percutaneous lead fracture. Median time from implant to explant was 12.4 months (range, 1 to 57 months). Results Pump thrombus was confirmed in 53 of 70 pumps (76%). Stratified by major clinical indications for explant of suspected pump thrombus or infection and lead fracture, the presence of pump thrombus was identified in 47 of 51 (92%) and 6 of 19 (32%), respectively. The median of 1) all LDH values, 2) maximum LDH values, and 3) interval change in LDH between 6 and 2 months before device explant were 1,061, 1,940, and −27 IU/L with thrombus present and 533, 504, and 13 IU/L in the absence of thrombus. Density estimation of LDH concentrations identified that a LDH value of 1,155 IU/L in the 6 months preceding pump thrombus had a 78% sensitivity and 90% specificity for findings of pump thrombus at the time of pump analysis. Conclusions Pre-explant LDH concentrations significantly correlated with findings on manufacture-performed pump analysis. These data validate LDH surveillance as an important clinical tool for identification of pump thrombus.