Comparison of retrograde versus antegrade cold blood cardioplegia: randomized trial in elective coronary artery bypass patients

Objective: Myocardial areas distal to complete coronary artery occlusion are poorly protected by antegrade cardioplegia. Hence, retrograde cardioplegia becomes an important adjunct in myocardial protection. An aim of the study was to compare both methods prospectively. Methods: 158 coronary artery bypass grafting (CABG) patients were randomly assigned to two groups according to myocardial protection technique: 89 patients to group 1-retrograde cold blood cardioplegia (RCBC); and 69 patients to group 2-antegrade cold blood cardioplegia (ACBC). Preoperative parameters were similar but cross-clamp time and volume of cardioplegia needed were higher in the retrograde group. The results were assessed on the basis of: (I) clinical outcome; (2) ECG and enzymatic parameters of ischemia; (3) assessment of early systolic function by means of cardiac output (CO), stroke work index (SWI), left ventricular stroke work index (LVSWI) and right ventricular stroke work index (RVSWI) taken before, and 1 and 5 h after coming off bypass; (4) late systolic and diastolic function by echo assessment of segmental contractility of 17 segments and indexes of peak transmitral flow (TMI) taken 7 days and 6 months after operation. Results: Ischemic events, inotropes and ventricular fibrillation on reperfusion were significantly more frequent in the antegrade group. Sinus rhythm at an early stage postoperatively was found more frequently in the retrograde group. All these parameters became comparable 24 h after operation. Early myocardial recovery was better in the retrograde group where intraoperative improvement in CO and SWI was significant. At the same time, SWI decreased significantly in the antegrade group. RVSWI changes were similar in both groups. There were no differences in mortality and perioperative MI. Late myocardial performance by segmental contractility and diastolic transmitral flow were similar in both groups. Conclusions: Retrograde continuous blood cardioplegia reduces ischemic injury and permits better early recovery of myocardial function. There is no difference, however, regarding long-term assessment of myocardial recovery.