The left ventricular assist device (LVAD) has rapidly been incorporated into the management of patients with advanced heart failure.  In response to an internal audit demonstrating a rapid increase in the incidence of pump thrombosis following implantation of HeartMate II LVADs, the authors pooled data from additional centers to investigate this trend.  The resultant retrospective analysis of 895 HeartMate II LVADs implanted in 837 patients identified 72 confirmed pump thrombosis in 66 patients and an additional 36 suspected thrombosis. Starting in the spring of 2011, the incidence of thrombosis at 3 months from implant rose from 2.2% to 8.4% by early 2013.  Levels of LDH and in particular a doubling in levels in the previous week were highly predictive of thrombosis.  Thrombosis was associated with substantial morbidity and mortality with 11 patients receiving urgent transplantation and a further 20 requiring pump replacement.  Mortality in those not undergoing a surgical procedure was 48.2% in the following 6 months. 

Conclusions

The incidence of thrombosis in the HeartMate II LVAD device has increased dramatically since early 2011 and is associated with substantial morbidity and mortality.  Of note, anticoagulation protocols changed during the course of this analysis, but continued inquiry is required to understand the underlying cause of these findings.  This study speaks to the importance of real-world surveillance of device therapies to continually ensure their optimal use and safety for patient benefit.

 Summarized by Steven M. Bradley and Hussain Contractor

•  Starling RC, Moazami N, Silvestry SC, Ewald G, Rogers JG, Milano CA, Rame JE, Acker MA, Blackstone EH, Ehrlinger J, Thuita L, Mountis MM, Soltesz EG, Lytle BW, Smedira NG. Unexpected abrupt increase in left ventricular assist device thrombosis. N Engl J Med. 2014 Jan 2;370(1):33-40.