Thrombin formation capacity in patients with two different left-ventricular assist devices and after heart transplantation

A. Schlagenhauf1, U. Geisen2, K. Brehm2, G. Trummer2, F. Beyersdorf2, M. Berchtold-Herz2, B. Zieger2 (1Graz, Austria, 2Freiburg, Germany)

Acquired problems and alterations of coagulation
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: Implantation of a left ventricular assist device (LVAD) is associated with the risk for thrombotic and bleeding events that are caused by preactivation on artificial surfaces and changes in hemodynamics. Almost all LVAD patients are diagnosed with acquired von Willebrand syndrome. Additionally, substantial contact activation might lead to clotting factor consumption. The new HeartMate III (HMIII) is a left ventricular assist device featuring several design-improvements over its predecessor (HMII) that hopefully ameliorates bleeding symptoms. We aimed to evaluate the risk of bleeding in patients under HMII and HMIII support compared to patients with heart transplants using Calibrated Automated Thrombography.

Methods: Thrombin generation traces were obtained from patients with HM II- (N=14), HM III-implants (N=12), and heart transplants (N=8). Additionally, INR, aPTT, antithrombin, prothrombin fragments 1+2, and D-dimer were recorded.

Results: The endogenous thrombin potential and peak thrombin generation was significantly higher in HM III patients compared to HM II patients (P<0.05). Interestingly, the endogenous thrombin potential and peak thrombin generation did not differ between HM III patients and heart transplant patients, but HM II patients exhibited a significantly lower endogenous thrombin potential and peak thrombin generation than heart transplant patients (P<0.05). D-dimer was significantly higher in all LVAD patients (HM II and HM III) compared to heart transplant patients (P<0.001). INR, aPTT, antithrombin, and prothrombin fragments 1+2 were comparable.

Conclusion: Increased D-dimer in HMII as well as in HM III patients hint to a clotting factor consumption after LVAD implantation. However, a consequent impact on thrombin formation capacity was only observed in patients with HM II implants. Patients with HM III implants exhibited less impairment of thrombin formation capacity which may result in reduced bleeding tendency.