From Rabbit Hearts Coronary Sinus Inverse Filling Myocardial Protection, A Comparative Study

Comparative Study of Myocardial Protective Effectsof Retrograde Coronary Sinus Perfusion Methodson Isolated Rabbit HeartsAbstractObjective:The myocardial protective effects of retrograde normothermic blood perfused beating heart were evaluated on an isolated rabbit heart model, compared with retrograde perfusion with cold crystalloid cardioplegia, cold blood cardioplegia or warm blood cardioplegia.Methods:Isolated rabbit hearts were randomly subjected into four groups:group A received retrograde coronary sinus perfusion with cold crystalloid cardioplegia, group B with cold blood cardioplegia, group C with warm blood cardioplegia, and group D were maintained heart beating by retrograde perfusion with normothermic oxygenated blood. After 60mm retrograde perfusion, the hearts were switched on Langendorff-Neely antegrade perfused working heart model for another 60mm. The heart function, myocardial enzyme leak, myocardial lactate content, intramyocyte free calcium, myocardial membrane ATPase and fluidity were measured and analysed statisticaly.Results:The main results are as followings:1.After retrograde coronary sinus perfusion, recovery of cardiac function, activity of ATPase and fluidity of the myocardial membrane in group D was superior to those of group A, B and C(p<0.0 1). Recovery of group B and C was better than group A(p<0.01).2.The leak of CK, LDH, myocardial content of lactate and MDA, and theintramyocyte calcium followed retrograde perfusion was much lower in group D than those of group A, B and C. The group A was the worst.Conclusion:The isolated retrograde normothermic blood perfused beating heart model was established. Retrograde coronary sinus perfusion was a feasible approach for myocardial protection. Our preliminary results suggested that the myocardial protective effects of retrograde normothermic oxygenated blood perfused beating heart was superior to those perfused with cold crystalloid cardioplegia, cold blood cardioplegia or warm blood cardioplegia. Retrograde perfused beating heart might prevent myocardium from ischemialreperfusion injury by reducing free radical production, ameliating intramyocyte paradoxical calcium accumulation, and maintaining membrane fluidity.