Effects of biventricular shunt on pump characteristics in a maglev total artificial heart

Abstract

Severe left ventricular failure can progress to right ventricular failure, necessitating alternatives to heart transplantation, such as total artificial heart (TAH) treatment. Conventional TAHs encounter challenges associated with miniaturization and hemocompatibility owing to their reliance on mechanical valves and bearings. A magnetically levitated TAH (IB-Heart) was developed, utilizing a magnetic bearing. The IB-Heart features a distinctive biventricular shunt channel situated between the flow paths of the left and right centrifugal blood pumps, simplifying and miniaturizing its control system. However, the impact of these shunt channels remains underexplored. This study aimed to investigate the effects of shunt flow on pump characteristics and assess the IB-Heart’s potential to regulate flow balance between systemic and pulmonary circulation. At a rotational speed of 2000 rpm and flow rate range of 0–10 L/min, shunt flow exhibited a minor impact, with a 1.4 mmHg (1.3%) effect on pump characteristics. Shunt flow variation of about 0.13 L/min correlated with a 10 mmHg pressure difference between the pumps’ afterload and preload conditions. This variance was linked to changes in the inlet flow rates of the left and right pumps, signifying the ventricular shunt structure’s capacity to mirror the function of an atrial shunt in alleviating pulmonary congestion. The IB-Heart’s ventricular shunt structure enables passive regulation of left-right flow balance. The findings establish a fundamental technical groundwork for the development of IB-Hearts and TAHs with similar shunt structures. The innovative coupling of centrifugal pumps and the resultant effects on flow dynamics contribute to the advancement of TAH technology.

Anatomical and Hemodynamic Characterization of Totally Artificial Hearts

“…In summary, shared characteristics of these TAHs include: 1) All are valveless. OregonHeart, 29 RollingHeart, 30 MagVad TAH, 31 and the centrifugal/axial family of TAHs (Dragon Heart, 32 CFTAH, 33 p-CFTAH, 34 IB-Heart, 35 etc) are also valveless designs. OregonHeart uses a rotor to alternatively shuttle between the systemic and pulmonic positions without the need of valves.…”

“…6) None use continuous flow mechanisms (like the BiVACOR 38 (BiVACOR Inc, Houston TX), CFTAH, 39 Dragon Heart, 32 IB-Heart, 35 or OregonHeart 29 ), pneumatic mechanisms (like the SynCardia 5 and SoftHeart 22 ), or hydraulic mechanisms (like the Aeson 6 and AbioCor 9,10 ). Claw TAH, Beating TAH, and Frankenstein TAH use mechanical mechanisms and could be categorized into the same family of TAHs as the Nimbus, 40 Realheart, 26 and ReinHeart.…”