A novel nonlinear afterload for ex vivo heart evaluation: Porcine experimental results. Issue 9 (20th May 2022)

• Record Type: Journal Article
• Authors: Pigot, Henry; Soltesz, Kristian; Paskevicius, Audrius; Liao, Qiuming; Sjöberg, Trygve; Steen, Stig
• Is Part Of: Artificial organs. Volume 46:Issue 9(2022)
• Page Start: 1794
• Page End: 1803
• Publication Date: 2022-05-20
• Subjects: cardiac afterload -- ex vivo heart evaluation -- functional evaluation -- heart perfusion -- heart transplantation -- working heart; Artificial organs -- Periodicals; 617.956
• DOI: 10.1111/aor.14307
• Languages: English
• ISSNs: 0160-564X

Abstract

Abstract: Background: Existing working heart models for ex vivo functional evaluation of donor hearts often use cardiac afterloads made up of discrete resistive and compliant elements. This approach limits the practicality of independently controlling systolic and diastolic aortic pressure to safely test the heart under multiple loading conditions. We present and investigate a novel afterload concept designed to enable such control. Methods: Six ∼70 kg pig hearts were evaluated in vivo, then ex vivo in left‐ventricular working mode using the presented afterload. Both in vivo and ex vivo, the hearts were evaluated at two exertion levels: at rest and following a 20 μg adrenaline bolus, while measuring aortic pressure and flow, left ventricular pressure and volume, and left atrial pressure. Results: The afterload gave aortic pressure waveforms that matched the general shape of the in vivo measurements. A wide range of physiological systolic pressures (93 to 160 mm Hg) and diastolic pressures (73 to 113 mm Hg) were generated by the afterload. Conclusions: With the presented afterload concept, multiple physiological loading conditions could be tested ex vivo, and compared with the corresponding in vivo data. An additional control loop from the set pressure limits to the measured systolic and diastolic aortic pressure is proposed to address discrepancies observed between the set limits and the measured pressures. Abstract : An adaptive cardiac afterload concept is presented for ex vivo heart evaluation that aims to provide safe adjustment of systolic and diastolic pressures to test hearts under a variety of loading conditions. The afterload was tested with six porcine hearts and the results were compared to corresponding in vivo hemodynamic measurements. Across all individuals, the afterload gave physiological systolic and diastolic aortic pressures, and aortic pressure waveforms that matched the general shape of the in vivo measurements.