HOW TO PROTECT HYPERTROPHIED MYOCARDIUM - A PROSPECTIVE CLINICAL-TRIAL OF 3 PRESERVATION TECHNIQUES

Protection of the hypertrophied myocardium during heart surgery is sti ll a controversial matter We prospectively studied 3 currently availab le preservation techniques in 60 patients operated on for isolated aor tic stenosis. Patients were randomly assigned to one of the following groups: CWB: continuous warm blood cardioplegia ICB: intermittent cold blood with warm blood controlled reperfusion Cryst: intermittent cold crystalloid cardioplegia (SLF11, Biosedra Laboratory, Vernon, France) . All groups were matched for age, ejection fraction, NYHA class, aort ic valve surface, and operative risk score. There were no deaths. No s tatistically significant difference was found among the groups in term s of ventilatory support time, ICU stay time, hospitalization or atria l fibrillation occurrence. Blood gases in the coronary sinus at the ti me of clamp release showed deep acidosis with crystalloid cardioplegia (pH = 7.11 vs 7.39 far CWB and 7.38 for UCB, p < 0.0001) associated w ith a higher lactate production than in the other groups (1.3 mmol vs 0.5 for CWB and 0.58 for ICB, p < 0.0001). Acidosis was corrected at t he end of bypass with no significant differences among groups. CK-MB s amples were taken on arrival in ICU, then 6 and 24 hours later. These samples showed much higher levels with cold blood (H6: 70 mcg/l vs 33 for CWB and 45 for Cryst, p = 0.0019). Although the 3 types of cardiop legia may be safely used for isolated aortic stenosis surgery continuo us warm blood cardioplegia appears to be the best choice.