Twenty-four-hour Normothermic Ex Vivo Heart Perfusion With Low Flow Functional Assessment in an Adult Porcine Model

Abstract

Background. Cold static storage and normothermic ex vivo heart perfusion are routinely limited to 6 h. This report describes intermittent left atrial (LA) perfusion that allows cardiac functional assessment in a working heart mode. Methods. Using our adult porcine model, general anesthesia was induced and a complete cardiectomy was performed following cardioplegic arrest. Back-table instrumentation was completed and normothermic ex vivo heart perfusion (NEHP) was initiated in a nonworking heart mode (Langendorff). After 1 h of resuscitation and recovery, LA perfusion was initiated and the heart was transitioned to a coronary flow-only working heart mode for 30 min. Baseline working heart parameters were documented and the heart was returned to nonworking mode. Working heart assessments were performed for 30 min every 6 h for 24 h. Results. Twenty-four-hour NEHP on 9 consecutive hearts (280 ± 42.1 g) was successful and no significant differences were found between working heart parameters at baseline and after 24 h of perfusion. There was no difference between initial and final measurements of LA mean pressures (5.0 ± 3.1 versus 9.0 ± 6.5 mm Hg, P = 0.22), left ventricular systolic pressures (44.3 ± 7.2 versus 39.1 ± 9.0 mm Hg, P = 0.13), mean aortic pressures (30.9 ± 5.8 versus 28.1 ± 8.1 mm Hg, P = 0.37), and coronary resistance (0.174 ± 0.046 versus 0.173 ± 0.066 mL/min/g, P = 0.90). There were also no significant differences between lactate (2.4 ± 0.5 versus 2.6 ± 0.4 mmol/L, P = 0.17) and glucose (173 ± 75 versus 156 ± 70 mg/dL, P = 0.37). Conclusions. A novel model using intermittent LA perfusion to create a coronary flow-only working heart mode for assessment of ex vivo cardiac function has been successfully developed.