Flow and Contractile Function of Isolated Hearts After Prolonged Hypothermic Perfusion

Background Normal ionic perfusate containing butanedione monoxime (BDM), a reversible myofilament inhibitor, could be better than either a high potassium (KCl) or a low calcium (CaCl2) perfusate for long-term cardiac preservation. This hypothesis was tested in 70 isolated guinea pig hearts. Methods and Results Three groups time control (8 hours, 370C), cold control (22 hours, 3.80C), and cold+BDM (22 hours) -were perfused with typical Krebs-Ringer solution (2.5 mmol/L CaCl2 and 4.5 mmol/L KCl). Two other groups were cold perfused for 22 hours either with 2.5 mmol/L CaCI2+20 mmol/L KCl (high) or with 0.5 mmol/L CaCl2 (low)+4.5 mmolIL KCl. These changes were maintained from 20 minutes before cold perfusion until 30 minutes after rewarming to 370C. Coronary vasodilator reserve was tested before cold perfusion and 2 hours after warm reperfusion with adenosine (Ade), acetylcholine (Ach, endothelium dependent), and nitroprusside (NP, endothelium independent). Each treatment decreased left ventricular pressure (LVP) by more than 80% before cold perfusion. During warm reperfusion, LVP was lower in cold control (-72+5%), high KCl (-76±4%), and low CaCl2 (-80±4%) groups than in BDM