First report of 90-day support of 2 calves with a continuous-flow total artificial heart

Objective: The Cleveland Clinic continuous-flow total artificial heart (CFTAH) is a compact, single-piece, valveless, pulsatile pump providing self-regulated hemodynamic output to left/right circulation. We evaluated chronic in vivo pump performance, physiologic and hemodynamic parameters, and biocompatibility of the CFTAH in a well-established calf model. Methods: CFTAH pumps have been implanted in 17 calves total. Hemodynamic parameters, pump performance, and device-related adverse events were evaluated during studies and at necropsy. Results: In vivo experiments demonstrated good hemodynamic performance (pump flow, 7.3 +/- 0.7 L/min; left atrial pressure, 16 +/- 3 mm Hg; right atrial pressure, 17 +/- 3 mm Hg; right atrial pressure-left atrial pressure difference, 1 +/- 2 mm Hg; mean arterial pressure, 103 +/- 7 mm Hg; arterial pulse pressure, 30 +/- 11 mm Hg; and pulmonary arterial pressure, 34 +/- 5 mm Hg). The CFTAH has operated within design specifications and never failed. With ever-improving pump design, the implants have shown no chronic hemolysis. Three animals with recent CFTAH implantation recovered well, with no postoperative anticoagulation, during planned in vivo durations of 30, 90, and 90 days (last 2 were intended to be 90-day studies). All these longest-surviving cases showed good biocompatibility, with no thromboembolism in organs. Conclusions: The current CFTAH has demonstrated reliable self-regulation of hemodynamic output and acceptable biocompatibility without anticoagulation throughout 90 days of chronic implantation in calves. Meeting these milestones is in accord with our strategy to achieve transfer of this unique technology to human surgical practice, thus filling the urgent need for cardiac replacement devices as destination therapy.