Effects of metabolic stimulation on cardiac allograft recovery

Background. We previously demonstrated that continuous perfusion of cardiac allografts during hypothermic storage with donor blood harvested at the ti me of organ retrieval improves myocardial recovery after transplantation. H owever, myocardial metabolism and function remain depressed compared to bas e line values. This study evaluated the use of a continuous infusion of don or blood enhanced with insulin to augment aerobic myocardial metabolism dur ing and after hypothermic storage. Methods. Yorkshire pigs (45 to 50 kg) were used to perform 14 orthotopic ca rdiac transplants using either continuous perfusion with donor blood (blood group, n = 7) or perfusion with donor blood enhanced with 10 IU/L insulin (insulin group, n = 7). After heparinization, hypothermic (4 degreesC) card ioplegic arrest, and donor heart extraction, donor blood (2844 +/- 210 mL) was harvested in both groups and perfused at room temperature (20 degreesC) at a pressure of 60 mm Hg for 3 hours. Blood cardioplegia was delivered af ter each anastomosis in both groups and arterial and coronary sinus blood s amples were obtained to examine myocardial metabolism. A Millar micromanome ter was used to measure left ventricular developed pressure and the rate-pr essure product at varying preloads. Results. There were no differences in either myocardial lactate or acid rel ease between the two groups. Hearts in the insulin group displayed higher m yocardial oxygen extraction than those in the blood group. The recovery of developed pressure was higher in the insulin group compared to the blood gr oup (91% +/- 19% vs 73% +/- 2%, p = 0.04). Conclusions. In this model, continuous perfusion of cardiac allografts with donor blood and insulin preserves myocardial metabolism during hypothermic storage and improves metabolic and functional recovery after orthotopic ca rdiac transplantation. (Ann Thorac Surg 2001;71:219-25) (C) 2001 by The Soc iety of Thoracic Surgeons.