Resistance and tolerance of the myocardium to ischemia

Since 1967, the authors have abandoned coronary perfusion in valve, particularly aortic, surgery. Some of the difficulties encountered during defibrillation at the period where coronary perfusion was always used have dramatically decreased. Extra-corporeal-circulation is now performed under moderate hypothermia--28 to 30 degrees C--which gives excellent myocardial protection for aortic cross clamping time of 30 to 60 minutes. In coronary artery surgery, the same technique is now used, after having wrongly believed previously that coronary perfusion was indicated. In conclusion, we feel that coronary perfusion is not indicated any more but in very exceptional cases.