Protection of the right ventricle: comparison of retrograde with antegrade cardioplegia

Abstract

The adequacy of right ventricular (RV) preservation and cooling with retrograde cardioplegia has been questioned. We compared the effects of retrograde with antegrade cardioplegia on the recovery ventricular function inpatients undergoing coronary artery surgery. Two groups of similar age, left ventricular function and extent of disease received either retrograde (RC) or antegrade (AC) multidose cold-blood cardioplegia. A right ventricular rapid-response catheter measured right ventricular haemodynamics before and after bypass. Needle thermistors recorded intramyocardial temperatures in the right ventricular free wall, the left ventricular free wall and the septum. There were no differences in bypass times, ischaemic times, inotrope requirements or arrhythmia frequency between the 2 groups. RV haemodynamics were similar in both groups before bypass. Immediately after bypass the RV end diastolic volume index was lower in the retrograde group than in the antegrade group, and RV ejection fraction was higher. This indicates better RV preservation with retrograde cardioplegia early after bypass. By 30 min after bypass all haemodynamic variables had returned to baseline values in both groups. Retrograde cardioplegia provided effective cooling in all areas of the heart. The mean time to achieve electromechanical quiescence was longer with retrograde cardioplegia, and a larger total volume of cardioplegia was required. Except for a minor advantage for RC soom after bypass, this study suggests that RV protection during coronary artery surgery is the same whether retrograde or antegrade cardioplegia is used. The time taken o achieve diastolic arrest with retrograde cardioplegia may presuade surgeons that combination of antegrade and retrograde cardioplegia remains the most satisfactory technique.