TY - JOUR
T1 - The Implementation of an Adjustable Afterload Module for Ex Situ Heart Perfusion
AU - Gellner, Bryan
AU - Xin, Liming
AU - Ribeiro, Roberto Vanin Pinto
AU - Bissoondath, Ved
AU - Lu, Pengzhou
AU - Adamson, Mitchell B.
AU - Yu, Frank
AU - Paradiso, Emanuela
AU - Zu, Jean
AU - Simmons, Craig A.
AU - Badiwala, Mitesh V.
N1 - Publisher Copyright:
© 2019, Biomedical Engineering Society.
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Purpose: Windkessel impedance analysis has proven to be an effective technique for instituting artificial afterload on ex situ hearts. Traditional fixed parameter afterload modules, however, are unable to handle the changing contractile conditions associated with prolonged ex situ heart perfusion. In this paper, an adjustable afterload module is described comprising of three fully adjustable sub-components: a systemic resistor, a proximal resistor and a compliance chamber. Methods: Using a centrifugal pump, the systemic resistor and compliance chamber were subjected to testing across their operating ranges, whereby the predictability of resistance and compliance values was evaluated. The components were then assembled, and the full module tested on three separate porcine hearts perfused for 6 h with success defined by the ability to maintain physiological systolic and diastolic aortic pressures across flow rate variability. Results: For both the systemic resistor and compliance chamber, experimental measurements agreed with their theoretical equivalents, with coefficients of determination of 0.99 and 0.97 for the systemic resistor and compliance chamber, respectively. During ex situ perfusion, overall 95% confidence intervals demonstrate that physiological systolic (95–96.21 mmHg) and diastolic (26.8–28.8 mmHg) pressures were successfully maintained, despite large variability in aortic flow. Left ventricular contractile parameters, were found to be in line with those in previous studies, suggesting the afterload module has no detrimental impact on functional preservation. Conclusions: We conclude that due to the demonstrable control of our afterload module, we can maintain physiological aortic pressures in a passive afterload working mode across prolonged perfusion periods, enabling effective perfusion regardless of contractile performance.
AB - Purpose: Windkessel impedance analysis has proven to be an effective technique for instituting artificial afterload on ex situ hearts. Traditional fixed parameter afterload modules, however, are unable to handle the changing contractile conditions associated with prolonged ex situ heart perfusion. In this paper, an adjustable afterload module is described comprising of three fully adjustable sub-components: a systemic resistor, a proximal resistor and a compliance chamber. Methods: Using a centrifugal pump, the systemic resistor and compliance chamber were subjected to testing across their operating ranges, whereby the predictability of resistance and compliance values was evaluated. The components were then assembled, and the full module tested on three separate porcine hearts perfused for 6 h with success defined by the ability to maintain physiological systolic and diastolic aortic pressures across flow rate variability. Results: For both the systemic resistor and compliance chamber, experimental measurements agreed with their theoretical equivalents, with coefficients of determination of 0.99 and 0.97 for the systemic resistor and compliance chamber, respectively. During ex situ perfusion, overall 95% confidence intervals demonstrate that physiological systolic (95–96.21 mmHg) and diastolic (26.8–28.8 mmHg) pressures were successfully maintained, despite large variability in aortic flow. Left ventricular contractile parameters, were found to be in line with those in previous studies, suggesting the afterload module has no detrimental impact on functional preservation. Conclusions: We conclude that due to the demonstrable control of our afterload module, we can maintain physiological aortic pressures in a passive afterload working mode across prolonged perfusion periods, enabling effective perfusion regardless of contractile performance.
KW - Afterload
KW - Ex Vivo heart perfusion
KW - Ex situ heart perfusion
KW - Heart preservation
KW - Heart transplantation
KW - Perfusion
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U2 - 10.1007/s13239-019-00447-w
DO - 10.1007/s13239-019-00447-w
M3 - Article
C2 - 31797263
AN - SCOPUS:85075992999
SN - 1869-408X
VL - 11
SP - 96
EP - 110
JO - Cardiovascular Engineering and Technology
JF - Cardiovascular Engineering and Technology
IS - 1
ER -