In Vitro Hemolytic Performance of the Novel Realheart Total Artificial Heart Versus Syn <scp>C</scp> ardia Total Artificial Heart With Human Blood

BACKGROUND: The SynCardia Total Artificial Heart (TAH) is FDA-approved for bridge to transplantation and has been implanted in over 2000 patients. While hemolysis has been reported postimplantation, no published in vitro test data assess hemolysis or hematology. The Realheart TAH is a novel four-chamber pulsatile positive displacement TAH which mimics the natural heart's atrioventricular plane movement for physiological flow patterns and gentle blood handling. This study evaluates in vitro hemolytic performance of the SynCardia TAH against a newer prototype of the Realheart TAH, V11.2, using human blood. METHODS: Hemolysis testing followed ASTM standards, F1830-97 and F1841-97 (2017) using pooled human whole blood diluted to a hematocrit of 30% ± 2%. The targeted flow and pressure head were 5 ± 0.25 L/min and 100 mmHg, respectively. Hematology parameters were analyzed, plasma free hemoglobin (pfHb) was measured, and milligram normalized index of hemolysis (mgNIH) and modified index of hemolysis (MIH) were calculated. Statistical analyses were performed. RESULTS: Mean mgNIH (n = 6) were 18.11 ± 3.53 mg/100 L for V11.2 and 37.15 ± 12.42 mg/100 L for SynCardia (p < 0.05), a 2.05-fold increase in SynCardia TAH. MIH values were 1.69 ± 0.31 for V11.2 and 3.67 ± 1.29 for SynCardia (p < 0.05). Compared with the static control, SynCardia significantly reduced erythrocyte and increased platelet counts, effects not observed with the V11.2, whereas V11.2 significantly reduced leukocyte counts relative to the control. CONCLUSION: Realheart TAH V11.2 exhibited significantly lower hemolysis than SynCardia TAH in a modified systemic circulation test rig, indicating better hemocompatibility.