The OregonHeart Total Artificial Heart: Design and Performance on a Mock Circulatory Loop

Abstract

Widespread use of heart transplantation is limited by the scarcity of donor organs. Total artificial heart (TAH) development has been pursued to address this shortage, especially to treat patients who require biventricular support. We have developed a novel TAH that utilizes a continuously spinning rotor that shuttles between two positions to provide pulsatile, alternating blood flow to the systemic and pulmonary circulations without artificial valves. Flow rates and pressures generated by the TAH are controlled by adjusting rotor speed, cycle frequency, and the proportion of each cycle spent pumping to either circulation. To validate the design, a TAH prototype was placed in a mock circulatory loop that simulates vascular resistance, pressure, and compliance in normal and pathophysiologic conditions. At a systemic blood pressure of 120/80 mm Hg, nominal TAH output was 7.4 L/min with instantaneous flows reaching 17 L/min. Pulmonary artery, and left and right atrial pressures were all maintained within normal ranges. To simulate implant into a patient with severe pulmonary hypertension, the pulmonary vascular resistance of the mock loop was increased to 7.5 Wood units. By increasing pump speed to the pulmonary circulation, cardiac output could be maintained at 7.4 L/min as mean pulmonary artery pressure increased to 56 mm Hg while systemic blood pressures remained normal. This in vitro testing of a novel, shuttling TAH demonstrated that cardiac output could be maintained across a range of pathophysiologic conditions including pulmonary hypertension. These experiments serve as a proof-of-concept for the design, which has proceeded to in vivo testing.

Interagency registry for mechanically assisted circulatory support report on the total artificial heart

“…44 The BiVACOR TAH is a design using magnetic levitation technology that can generate continuous or pulsatile flow. 45 The quest for a long-term heart replacement continues with designs in the form of the ReinHeart TAH, 46 CCFTAH, 47 OregonHeart TAH, 48 Helical Flow TAH, 49 and a hybrid CF-TAH. 50 The concept of a bioartificial TAH has also been proposed.…”

Characterization of a pulsatile rotary total artificial heart

“…The second‐generation TAH retains many of the design elements of the first‐generation TAH 13 (Figure 1). Briefly, a single continuously spinning rotor in a polished titanium housing shuttles between the left and right positions.…”

“…The first‐generation (OregonHeart) TAH utilizes a rotary pump that inherently produces pulsatile flow using a single rotor with a unique shuttling action. The hemodynamic performance of the first‐generation TAH has been previously described 13 . Bench testing of this first‐generation TAH demonstrated proof‐of‐concept that sufficient cardiac output could be maintained across a range of physiologic and pathophysiologic conditions while providing pulsatile flow with a single shuttling rotor.…”

Intrinsic Heart Regeneration in Adult Vertebrates May be Strictly Limited to Low‐Metabolic Ectotherms

“…The engineering approach is fundamentally different in that it aims at replacing damaged tissues with mechanical or artificial elements, producing functional artificial components outside the body to be transplanted into patients. Examples of this tactic include endeavors like mechanical hearts, [29][30][31] repopulating decellularized hearts with stem cells [32,33] and 3D bioprinting of entire organs. [34] These strategies have, however, not yet been successful in producing a fully functional and/or maintenance free heart.…”