Myocardial protection in diffuse coronary artery disease. Intermittent retrograde cold-blood cardioplegia at systemic normothermia versus intermittent antegrade cold-blood cardioplegia at moderate systemic hypothermia.

In order to determine the comparative merits of antegrade cardioplegia at moderate systemic hypothermia versus retrograde cardioplegia at systemic normothermia, we performed coronary artery bypass grafting using intermittent oxygenated blood cardioplegia in 2 sets of 50 consecutive patients with triple-vessel disease (complete occlusion of 1 coronary artery and greater than 90% narrowing of the other 2, with poor distal runoff). Group 1 had antegrade cardioplegia at moderate systemic hypothermia (28 degrees C). Group 2 had retrograde cardioplegia at systemic normothermia. This resulted in no deaths and in no differences in complication rates. Group 2's postoperative need for inotropic agents or vasodilators was significantly less (epinephrine, p < 0.0009; dopamine, p < 0.002; nitroglycerin, p < 0.001). Elevations of CKMB fraction were significantly more common in Group 1: 46% had CKMB levels greater than 9%, versus 16% of Group 2 patients (p < 0.0001). Intraoperative transesophageal echocardiography was performed in 39 Group-1 patients and in 42 Group-2 patients. Development of a new wall-motion abnormality after bypass was significantly only in Group 1 (p < 0.009, by chi 2 analysis). We conclude that retrograde cardioplegia at normothermia provides myocardial protection that equals or surpasses that of antegrade delivery at moderate systemic hypothermia, while avoiding the possible deleterious side effects of hypothermia.