Thorac Cardiovasc Surg 2014; 62 - SC157
DOI: 10.1055/s-0034-1367418

Platelet function in patients with left ventricular assist devices

M. Baghai 1, C. Heilmann 1, L. Nakamura 2, U. Geisen 3, M. Berchthold-Herz 1, G. Trummer 1, B. Zieger 2, F. Beyersdorf 1
  • 1Heart Center Freiburg University, Department of Cardiovascular Surgery, Freiburg, Germany
  • 2University Medical Center Freiburg, Department of Paediatrics and Adolescent Medicine, Freiburg, Germany
  • 3University Medical Center Freiburg, Institute of Clinical Chemistry and Laboratory Medicine, Freiburg, Germany

Objectives: Unexplained bleeding events are a severe complication in patients with left ventricular assist devices (LVAD). Platelet dysfunction may contribute to bleeding tendencies. However, comprising data of platelet function in LVAD patients with regards to bleeding events are scarce. In specific, previous publications did not employ LVAD patients without implanted device but different patients for controls.

Methods: We analysed 39 patients with a HeartMate II: in a native state (n = 19: before implantation, n = 11, after explantation, n = 8), in an early postoperative (≤14 day, n = 28) and in a late postoperative state (≥30 days, n = 30). Data of at least two time points were available for each patient. Platelet function was measured via Born's aggregometry (collagen 2 µg/ml, ristocetin 1.2 mg/ml, ADP 4µmol/l, epinephrine 8 µmol/ml) in percent of normal values. Overall mean values were classified into four categories: normal, ≥70%, and mild, 50-69%, medium, 30-49%, or severe dysfunction, ≤29%. Additionally, bleeding events after LVAD implantation were recorded in all patients.

Results: Platelet dysfunction was detectable in 18 of 19 patients without LVAD (7 mild, 9 medium, 2 severe) and in all patients following LVAD implantation (early: 8 mild, 11 medium, 9 severe; late: 9 mild, 16 medium, 5 severe). According to this classification, platelet function did not change over the course of the study (native-early, p = 0.27, n = 14; early-late, p = 0.17, n = 21). Bleeding events occurred in 17 of 39 patients (44%) in the early and in 25 of 33 patients (64%) in the late period. Reexplorations were necessary in 9 of them early and in 9 patients late.

Conclusions: According to our data, platelet aggregation values are most often impaired in LVAD patients even without implanted LVAD and do not change after LVAD implantation. A possible contribution of platelet dysfunction to the occurrence of bleeding events in LVAD patients remains to be elucidated.