Early postoperative heparinization reduce hemolysis in patients with HeartMate II devices

Hemolysis is closely related with pump thrombosis and thromboembolic events in patients with continuous flow left ventricular assist devices. We retrospectively investigated the impact of early postoperative heparinization on hemolysis in patients with HeartMate II devices. From April 2013 to August 2017, 83 patients (age 45 ± 12 years; 20 females; body surface area 1.6 ± 0.2 m²) underwent HeartMate II implantation. Postoperative heparinization was started when hemostasis was achieved and continued until full warfarinization. Hemolysis was defined in accordance with the Interagency Registry for Mechanically Assisted Circulatory Support definitions. The average support period was 22 ± 14 months. The 6-, 12-, and 24-month freedoms from hemolysis were 72%, 70%, and 67%, respectively. Pump thrombosis developed in five (6%) patients and four (5%) required pump exchanges. Heparin start time was significantly later in patients with hemolysis (43 ± 23 h after implantation) versus those without (29 ± 14 h after implantation; p = 0.01). Receiver operating characteristic analysis determined the cut-off point of heparin start time as 29 h. The patients were divided into the early group (heparin start time < 29 h; n = 29), and the late group (heparin start time > 29 h; n = 54). The respective 6-, 12-, and 24-month freedoms from hemolysis for the early group (86%, 86%, and 86%, respectively) were significantly higher than those for the late group (49%, 47%, and 44%, respectively; p = 0.002). Being in the late group was an independent risk factor for hemolysis (hazard ratio 4.09). Early postoperative heparinization (within 29 h after implantation) reduces hemolysis in patients with HeartMate II devices.