Fibrin clot permeability (Ks) in patients on left ventricular assist device

Abstract

Background Patients on left ventricular assist devices (LVAD) are prone to excessive hemostasis disturbances due to permanent contact of artificial pump surfaces with blood components. Aims We aimed to investigate if fibrin clot permeability is altered in patients on long-term continuous flow LVAD therapy and if the clot permeability is associated with clinical characteristics and adverse events. Methods We investigated 85 end-stage heart failure patients (90.6% men, age 48.6–63.8 years) scheduled for continuous flow long-term LVAD support according to current clinical indications. The patients were assessed periodically: prior to LVAD implantation (T1), 3–6 months (T2) after LVAD implantation, 6–12 months after (T3) and then every 6 months. We tested the first three blood samples (T1-T3) and the last available blood sample (T4), but no longer than 5 years after LVAD implantation. We assessed hemostasis parameters changes during the study period. Results MACCE occurred in 36.5% patients, bleeding events in 25.9%, NACE in 62.4%; 31.7% patients died, and 17.6% underwent transplantation. We observed a decrease in fibrin clot permeability (Ks) between T1, T2, T3 and T4 time periods; P < 0.01 for each comparison. Fibrin clot permeability was negatively correlated with fibrinogen concentration: r = 0.51, P < 0.001, factor VIII activity r=-0.42, P < 0.001. Discrepancies in Ks were observed between patients with MACCE, bleeding, and NACE, and patients without adverse events. Ks showed a constant trend towards normalization (P < 0.01) only in patients without adverse events. Conclusions Adverse events such as MACCE, NACE, and bleeding may be associated with inappropriate fibrin clot structure.