Fibrinolytic activation during long-term support with the HeartMate II left ventricular assist device

Abstract

Human physiologic responses to pulsatile left ventricular assist devices (LVADs) are well understood; responses to the newer continuous flow pumps are not. Therefore, we evaluated the long-term effects of continuous flow LVAD support on fibrinolytic activation. Twelve recipients of an axial flow LVAD as destination therapy were assessed for fibrinolytic activation at 1, 3, 6, 9, and 12 months postimplantation. The fibrinolytic response and changes were assessed in terms of fibrinogen, D-dimer, plasma free hemoglobin, international normalized ratio (INR), and red blood cell (RBC) sedimentation rate. Bleeding and thromboembolic events were recorded. All fibrinolytic response parameters were elevated at baseline; mean RBC sedimentation rate was 51.8 mm/h, mean D-dimer was 3.95 nmol/L, and the mean fibrinogen was 356 mg/dl. The D-dimer and fibrinogen levels increased after LVAD implantation but returned to near-normal levels by 12 months. Red blood cell sedimentation rates increased indicating ongoing inflammation. Plasma free hemoglobin values decreased and remained low, an indicator of low shear rates and hemolysis. Three nonfatal bleeding events but no thromboembolic events were observed. Fibrinolytic responses initially increase after LVAD implantation but then gradually normalize.