RESUMO
OBJECTIVES: 1. Identify clinical, biochemical and inflammatory predictors of allograft ischemic injury in clinical heart transplantation. 2. Evaluate the impact of high dose insulin (GIK) on allograft metabolism during blood cardioplegia and post-ischemic injury. DESIGN: A clinical, prospective, randomized open trial comprising 25 consecutive heart transplantations at a university hospital. Ischemic injury was evaluated from plasma levels of creatine kinase isoenzyme MB (CK-MB). Blood cardioplegic arterial and coronary sinus concentrations of C3a, IL-6, substrates, amino acids and blood gases were measured at the end of the implantation period, prior to reperfusion. Twelve patients received high dose insulin with glucose, potassium and amino acids. RESULTS: CK-MB increased from 1.9 +/- 0.2 to 161 +/- 13 microg/l (range 47-293 microg/l). The peak level of CK-MB correlated with donor age (r = 0.48, p = 0.02) and implantation time (r = 0.53, p = 0.02); and with recipient plasma IL-6 (r = 0.56, p = 0.02), allograft oxygen extraction (r = 0.56, p = 0.02), lactate release (r = 0.47, p = 0.02) and allograft arterial-coronary sinus (cs) pH (r = 0.47, p = 0.02) all during final cardioplegia before reperfusion. Seventy-two percent of the variance of CK-MB was explained by a model which included donor age, art-cs pH difference and arterial IL-6. In contrast, CK-MB was unrelated to total ischemic time (r = -0.17, p = 0.38). Insulin infusion had no effect on myocardial substrates during cardioplegia, or on post-ischemic CK-MB. CONCLUSION: Donor age, duration and quality of the implantation period are significant predictors of allograft ischemic injury in heart transplantation. High dose insulin had no detectable effects on allograft metabolism during cardioplegia, or on subsequent ischemic injury.