Hemodynamic and Metabolic Changes During Exercise in Calves With Total Artificial Hearts of Different Sizes yet Similar Output

Abstract

To evaluate the effects of downsizing of the total artificial heart (TAH), we compared the anaerobic threshold (AT) values in calves with two different types of TAH (Cleveland Clinic-Nimbus TAH and the downsized MagScrew TAH). Exercise studies were performed using a treadmill in 12 calves. During the exercise, parameters to obtain the AT were measured. To evaluate the determinants of the AT, a linear regression analysis was performed between AT and potential variables. AT values from 29 studies revealed no significant differences between the two different TAHs, with no significant differences in hemodynamic or oxygen metabolic parameters. AT values correlated well with pump flow/body weight (Q) multiplied by the hemoglobin level, regardless of the TAH used. In conclusion, downsizing of the original TAH design did not reduce AT without any significant differences in hemodynamic or oxygen metabolic parameters during exercise in calves.

An innovative, sensorless, pulsatile, continuous-flow total artificial heart: Device design and initial in vitro study

“…We have also drawn on 20 years of experience in pulsatile TAH design incorporating basic design requirements for providing systemic flows, implantability, and inherent passive balancing of the left and right flows 17-35. The CFTAH design, however, is extremely innovative, exploring radical new concepts in TAH design in the use of a speed modulated, single shaft, dual centrifugal pump without the use of valves and sensors for control, which greatly decreases the pump size and improves system reliability.…”

Artificial Organs 2007: A Year in Review

“…Keiji Kamohara et al. (37) of the Cleveland Clinic (Cleveland, OH, USA) evaluated the effects of downsizing of the TAH and compared the anaerobic threshold (AT) values in calves with two different types of TAH (Cleveland Clinic‐Nimbus TAH and the downsized MagScrew TAH). AT values from 29 studies revealed no significant differences between the two different TAHs, with no significant differences in hemodynamic or oxygen metabolic parameters.…”