Is Treatment of LVAD Thrombosis with rTPA a True Alternative to Pump Exchange?

Objectives: Pump thrombosis is a complication of LVAD (left ventricular assist device) therapy. Surgical pump exchange as well as medical therapy are associated with considerable mortality and morbidity. We investigated the patients we treated with recombinant tissue plasminogen activator (rTPA) for mortality, complications and recurrence.

Methods: All patients who underwent medical treatment of pump thrombosis with rTPA over a period of 4 years were retrospectively identified and analyzed.

Results: 44 patients on LVAD therapy (HVAD, HeartWare) were followed up for 388 ± 359 (1–1,185) days after implantation. We identified 26 events suggestive of pump thrombosis and finally analyzed 22 cases in which both HVAD flow curves and laboratory parameters were indicative of pump thrombosis. These events occurred in 10 patients (90% male, age at LVAD implantation 53.5 ± 16.9 (23.8–73.4) years) after 359 ± 251 (11–854) days of support. rTPA was used in 20 (90.9%) cases and administered via a venous access in 19 (95.00%) and directly into the left ventricle in 1 (5%) case. 18 cases occurred in patients who were on oral anticoagulation at the time of diagnosis, and 4 cases occurred in patients on i.v. heparin. Those on oral anticoagulation were immediately put on i.v. heparin. In 2 cases, thrombosis resolved during administration of i.v. UFH. In the remaining 20 cases, the first dose of rTPA was administered at an INR of 2.22 ± 0.73 (1.08–3.90), a PTT of 52.46 ± 12.55 (30–81) s, a platelet count of 173.15 ± 69.03 (77–366)/nL and fibrinogen of 370.25 ± 132.95 (199–704) mg/dL. Resolution of thrombosis was achieved in 19 (95%) cases including 3 patients where resolution was followed by fatal complications. Treatment failure with a fatal outcome occurred in 1 case. Further stratification of the resolved cases showed that resolution with neither complications nor recurrence was rare (n = 3). Rethrombosis occurred in eight, nonfatal complications in one, and both nonfatal complications and rethrombosis in four.

Thus, recurrence occurred in 75% of those who survived thrombolytic treatment. Anticoagulation issues as possible causes of re-thrombosis were identified in 5 (33.3%) of the recurrent cases.

Conclusions: Thrombolytic treatment of LVAD thrombosis is associated with substantial morbidity, mortality and recurrence rates and should not be the first line of treatment in patients eligible for pump exchange.

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