Preservation of myocardial energy-rich phosphates by retrograde application of Bretschneider cardioplegia during aortocoronary bypass surgery

The efficacy of myocardial protection obtained by antegrade applicationof a cardioplegic solution was compared with that obtained by retrogradeapplication via the coronary sinus. Myocardial preservation was assessedusing biochemical parameters, i.e. tissue content of lactate, creatinephosphate, nucleotides, nucleosides and hypoxanthine. Nineteen patientsundergoing routine aortocoronary bypass surgery were randomly allocated toa study group. During cardiac arrest induced by antegrade Bretschneidercardioplegia, myocardial tissue content of creatine phosphate dropped to52% of its pre-ischemic value and degradation of nucleotides occurred,characterized mainly by an accumulation of adenosine. Retrogradecardioplegia prevented this catabolism of energy-rich phosphates completelyduring ischemic cardiac arrest and is therefore considered to be superiorto antegrade cardioplegia.