Differential Effects of Single versus Double Aortic Clamping on Myocardial Protection during Coronary Bypass

Abstract

The effects of double ( n = 60, group 1) versus single ( n = 60, group 2) aortic clamping on myocardial function and protection were investigated during coronary artery bypass grafting using a heart-lung pump. In group 1, after opening the cross clamp, proximal anastomosis was completed using side clamps and, in group 2, distal and proximal anastomosis was completed with a single clamp. Cross clamping time in the single-clamp patients (group 2; 77.1 min) was significantly higher than in the double-clamp patients (group 1; 62.9 min). Troponin T was significantly higher in group 2 than in group 1 h and 24 h after surgery. Post-operative left ventricular ejection fraction decreased in both groups, but this was not statistically significant. Post-operative wall motion score index and myocardial performance index increased significantly in both groups compared with the pre-operative level. Overall, the double-clamp technique provided better myocardial protection than the single-clamp technique and neither technique seemed to have a negative impact on the early post-operative global functioning of the left ventricle, however the effect of these techniques on the global functioning of the left ventricle in the late postoperative period needs to be evaluated.