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[Experimental heart transplantation in dogs--preservation of isolated hearts for 36 hours by retrograde coronary sinus microperfusion].

In this study, the method of preserving isolated canine hearts for transplantation was established. The newly-developed method is named retrograde coronary sinus microperfusion technique. Canine hearts were arrested and cooled to 4 degrees C by means of normograde coronary perfusion with Collins' solution containing 10% fluorocarbon (FC) in order to avoid myocardial damage during warm ischemic time. Then, the hearts, immersed in Collins' solution, were retrogradely perfused through a coronary sinus at a rate of 60 ml/hr or 30 ml/hr with above-mentioned solution. After preservation for 36 hours, heterotopic heart transplantation was performed in an abdominal cavity of a recipient dog. The 36 hour-preserved hearts restored their cardiac beat after reperfusion with recipient blood. Histological observation did not show any abnormal findings in these preserved hearts. In order to evaluate the cardiac functions of preserved hearts for 24 to 36 hours, left ventricular end-systolic pressure-volume ratio (Emax) and end-diastolic pressure-volume relation were measured. Both were well restored in 24 hour-preserved hearts. The 36 hour-preserved hearts resulted in Emax within a satisfactory range, while end-diastolic pressure was elevated in all cases. This was markedly impaired with infusion of isoproterenol. These results strongly suggested that transplantation using 24 hour-preserved hearts could be performed well. On the other hand, the 36 hour-preserved hearts were considered to function satisfactorily under careful management after grafting. The retrograde coronary sinus microperfusion method developed here was found to be useful for a distant heart procurement.