Continuous warm blood cardioplegia: A randomized prospective clinical comparison

Abstract

Seventy-eight patients undergoing isolated coronary artery bypass grafting (CABG) were randomized to receive one of two myocardial preservation techniques. Control patients (C) (n=38) had myocardial protection by moderate systemic hypothermia, topical cold saline, and myocardial arrest with antegrade dilute blood/cold potassium cardioplegia with subsequent intermittent retrograde solution every 10–15 minutes during the period of aortic cross-clamping. The experimental group (warm blood, WB) (n=40) had myocardial protection at systemic normothermia, myocardial arrest with antegrade high potassium, and warm blood cardioplegia with subsequent continuous retrograde low potassium warm blood cardioplegia throughout aortic cross-clamping. The two groups were similar preoperatively. After aortic declamping, all WB patients developed a spontaneous rhythm. Only three (7.5%) required intraoperative defibrillation compared with 23 (61%) C patients,p<0.0001. The cross-clamp time per graft was greater with WB,p=0.003. The postoperative need for inotropes, cardiac pacing, incidence of ventricular dysrhythmia, chest tube drainage, and hospital stay did not differ between groups. Perioperative myocardial infarction occurred in 2 WB and 0 C patients (p=0.25). Mortality was not different between groups (WB=1, C=2,p=0.89). It is possible to perform CABG with continuous warm blood cardioplegia with low morbidity and mortality. However, no clear advantage was demonstrated over standard techniques that allow the technical ease of a bloodless field. The metabolic and physiologic significance of spontaneous resumption of sinus rhythm upon aortic declamping remains to be elucidated.