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 ±â€…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 ±â€…3.1 versus 9.0 ±â€…6.5 mm Hg, P  = 0.22), left ventricular systolic pressures (44.3 ±â€…7.2 versus 39.1 ±â€…9.0 mm Hg, P  = 0.13), mean aortic pressures (30.9 ±â€…5.8 versus 28.1 ±â€…8.1 mm Hg, P  = 0.37), and coronary resistance (0.174 ±â€…0.046 versus 0.173 ±â€…0.066 mL/min/g, P  = 0.90). There were also no significant differences between lactate (2.4 ±â€…0.5 versus 2.6 ±â€…0.4 mmol/L, P  = 0.17) and glucose (173 ±â€…75 versus 156 ±â€…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.