Retrograde versus antegrade cardioplegia: Impact on right ventricular function

Abstract

Retrograde cardioplegia administered through the coronary sinus has several documented advantages over antegrade cardioplegia but has been thought to provide inadequate right ventricular myocardial protection. We prospectively compared the effects of retrograde and antegrade cardioplegia on right ventricular performance in patients undergoing myocardial revascularization. Two groups of similar age, extent of disease, and preoperative left ventricular ejection fraction received retrograde (n = 16) or antegrade (n = 14) crystalloid cardioplegia. A right ventricular rapid-response thermistor catheter, previously developed and validated in our institution, was used to measure right atrial pressure, pulmonary artery pressure, right ventricular ejection fraction, end-diastolic volume index, and stroke volume index before bypass (baseline) and at several intervals after bypass. There were no differences in cross-clamp time, heart rate, cardiac enzymes, inotrope requirements, or arrhythmias between the two groups. Right ventricular parameters were equivalent in both groups at all time intervals except 30 minutes after bypass, at which time right ventricular end-diastolic volume index was lower (80 ± 6 versus 93 ± 6 mL/m2; p < 0.05) and right ventricular stroke volume index was higher (35 ± 3 versus 29 ± 2 mL/m2, p < 0.05) in the retrograde group compared with the antegrade group, indicating better right ventricular function with retrograde cardioplegia early after bypass. In both groups, right ventricular end-diastolic volume index was higher than baseline (p < 0.05) during the first 4 hours after bypass. No other important differences were found. At 24 hours after bypass, right ventricular end-diastolic volume index remained higher than baseline with both antegrade and retrograde cardioplegia, suggesting continued impaired right ventricular performance in both groups. Except for a minor advantage of retrograde cardioplegia early after bypass, these results suggest that right ventricular protection during myocardial revascularization is similar with retrograde and antegrade cardioplegia. © 1992.