Has the Incidence of Pump Thrombosis and Stroke in Patients with a HeartMate II Increased over Time?

Abstract

Purpose Whether there has been a change in the incidence of pump thrombosis and thromboembolic complications with the HM2 following approval and changes made in the inflow and outflow grafts is unknown. We sought to evaluate if the incidence of these events had changed during these 2 time periods. Methods and Materials A retrospective review of all patients receiving HMII at a single center was undertaken to identify incidences of pump thrombosis and stroke. The incidence was evaluated at the 2 time periods following approval (2008) and following changes made to the grafts (2011). Results 235 patients (mean age of 53.9 +/− 14 years) underwent implantation of a HMII from January 2006 to April 2012. Suspected pump thrombosis occurred in 6.0% of patients, which was verified in 4.7%. The risk of pump thrombosis trended higher in the post-2011 era (HR 3.88, 95% CI 0.97-15.52, P=0.056). A recent therapeutic INR was not protective against pump thrombosis (HR 1.05, 95% CI 0.89-1.23). Stroke occurred in 4.7% of patients, occurring with similar frequency before and after February 2008 and April 2011. A recent therapeutic INR (HR 0.04, 95% CI 0-0.74) and a higher proportion of therapeutic INR measurements (HR 0.11, 95% CI 0.02-0.67) were protective against stroke (P Conclusions The incidence of pump thrombosis and stroke does not appear to have increased during the 2 time periods although there is a trend towards more frequent pump thrombosis in the post-2011 era. The relative contribution of the change in HMII design over patient-related factors can not be ascertained but this warrants a careful evaluation in a larger cohort of patients.