Reduced Flow during Ex-Situ Heart Perfusion Provides Superior Function Preservation and Less Edema Formation

Abstract

PurposeEx-situ heart perfusion (ESHP) allows continuous functional and metabolic resuscitation of donor hearts before transplantation. Evidence indicates that hearts that are perfused under physiologic conditions lose the normal vasomotor tone and fail in a few hours. We aim to evaluate the reduced coronary flow during ex situ heart perfusion on cardiac function and coronary vascular resistance.MethodsPorcine hearts (n=6 each group) were perfused in working mode for 6 hours either by constant diastolic pressure perfusion (40 mmHg) or constant coronary blood flow rate perfusion (500mL/min). Cardiac functional parameters, coronary vascular resistance (CVR) and metabolism were monitored continuously. Myocardial injury parameter of cardiac troponin I and lipid peroxidation marker oxidized low-density lipoprotein were evaluated in the perfusate. These parameters were compared between groups at different time.ResultsCardiac function was better preserved in the flow control group at 5 hours (T5) of perfusion, indicated by higher stroke work and cardiac index (p<0.05, Figure AC). After perfusion the flow control group showed less edema than the pressure control group (p<0.001, Figure B). Both groups have a significant decrease of CVR, with relative higher in the flow control group (p<0.01, Figure D). cTnI was lower in the flow control group starting at T3, indicating less myocardial injury (p<0.05, Figure E). oxLDL increased in both groups, indicating lipid peroxidation formation; the level in the flow control group was significantly lower in comparison to the pressure control group (p<0.01, Figure F), suggesting less oxidative stress in this group.ConclusionReduced coronary flow during ex-situ heart perfusion decreased edema formation, showed less myocardial damage and oxidative stress which may contribute to better cardiac function preservation. The relative higher coronary vascular resistance induced by reduced coronary flow perfusion may help to maintain the cardiac function. Ex-situ heart perfusion (ESHP) allows continuous functional and metabolic resuscitation of donor hearts before transplantation. Evidence indicates that hearts that are perfused under physiologic conditions lose the normal vasomotor tone and fail in a few hours. We aim to evaluate the reduced coronary flow during ex situ heart perfusion on cardiac function and coronary vascular resistance. Porcine hearts (n=6 each group) were perfused in working mode for 6 hours either by constant diastolic pressure perfusion (40 mmHg) or constant coronary blood flow rate perfusion (500mL/min). Cardiac functional parameters, coronary vascular resistance (CVR) and metabolism were monitored continuously. Myocardial injury parameter of cardiac troponin I and lipid peroxidation marker oxidized low-density lipoprotein were evaluated in the perfusate. These parameters were compared between groups at different time. Cardiac function was better preserved in the flow control group at 5 hours (T5) of perfusion, indicated by higher stroke work and cardiac index (p<0.05, Figure AC). After perfusion the flow control group showed less edema than the pressure control group (p<0.001, Figure B). Both groups have a significant decrease of CVR, with relative higher in the flow control group (p<0.01, Figure D). cTnI was lower in the flow control group starting at T3, indicating less myocardial injury (p<0.05, Figure E). oxLDL increased in both groups, indicating lipid peroxidation formation; the level in the flow control group was significantly lower in comparison to the pressure control group (p<0.01, Figure F), suggesting less oxidative stress in this group. Reduced coronary flow during ex-situ heart perfusion decreased edema formation, showed less myocardial damage and oxidative stress which may contribute to better cardiac function preservation. The relative higher coronary vascular resistance induced by reduced coronary flow perfusion may help to maintain the cardiac function.