EDITORIAL/REVIEW Retrograde Coronary Sinus Versus Antegrade Cardioplegic Perfusion: A Review

-----------------------------------.... Retrograde coronary sinus perfusion may provide equal if not better myocardial protection than antegrade cardioplegia during certain heart surgeries. The coronary venous system can be divided into the greater and lesser systems and veno-venous and arterio-venous anastomoses. Venous drainage varies greatly and retrograde coronary sinus perfusion depends on this variation. Antegrade cardioplegia is effective in some severely obstructed vasculature due to collaterals but generally these are insufficient and areas of the heart remain unprotected. The coronary venous system is a low pressure system unaffected by atherosclerosis. Great care must be taken to avoid overpressurization. Because direct cannulation can be difficult, Fabiani created a technique whereby the right heart is pressurized causing backflow into the sinus. Diehl combined this right heart approach with a dose of antegrade cardioplegia to stop the heart quickly. Investigators have compared retrograde coronary sinus perfusion to antegrade cardioplegia using infrared myocardial thermography, microsphere injection, and crystalloid and perfluorocarbon cardioplegia. Retrograde coronary sinus perfusion remains a viable alternative to antegrade cardioplegia for various cardiac conditions and its application may increase as investigators improve and simplify the technique. lntroductio"------------------Myocardial preservation during cardiac surgery is essential for the success of the procedure. While delivery of cold cardioplegia via the aortic root may be the best method of myocardial protection in normal coronary vasculature (1), retrograde coronary sinus perfusion (RCSP) may provide equal if not superior protection (1,2,3,4) during surgery for aortic valves, severe coronary artery disease, and "redo" coronary artery bypass grafts (CABG). I. Anatomy The coronary venous system can be divided into three systems Address correspondence to: David A. James, CCP, 6218 West Shores Rd., Orange Park, FL 32073 Volume 21, Number 4, Winter 1989 (5). The greater system (Figure 1) is composed of those vessels that drain into the coronary sinus: 1. Anterior descending coronary vein 2. Posterior left ventricular vein 3. The oblique vein of Marshall 4. Middle cardiac vein 5. Small cardiac vein All of these veins form the great cardiac vein which becomes the coronary sinus. The great and middle cardiac veins along with the posterior left ventricular veins have unicuspid or bicuspid valves whereas the oblique vein of Marshall does not (6). The lesser system is composed of those vessels that drain directly into the right atrium. Included is a small but important venous system called the Thebesian veins that drain into the lumens of the heart and tend to be dense in the right atrium (5). The third venous system consists of all the veno-venous and arterio-venous anastomoses that interconnect these systems. Myocardial venous drainage is extremely variant to the extent that only 21% of studied coronary sinuses follow the described drainage patterns (5). RCSP is dependent on this variation of the coronary venous system and the extent of veno-venous and arterio-venous conduits to protect the right heart because of the lack of drainage into the coronary sinus from that area. II. History As early as 1898 Pratt (7) believed that the heart could be nourished by the Thebesian and coronary veins. Beck followed in the 1940's with an attempt to arterialize the coronary sinus of patients with coronary artery disease (8). The degree of difficulty of the two-stage procedure and a high mortality rate caused the technique to be abandoned. Eckstein (9) in 1953 and others (10, 11, 12) demonstrated that the coronary sinus was unable to deliver the normal oxygen demand requirements of the beating myocardium but could sustain a beating heart for short periods. The interest in RCSP declined as antegrade cardioplegia (AC) evolved into a simple and effective means of delivering cardioplegia. With the success of cardiac surgery, the population of cardiac patients with diffuse coronary disease grew. A new generation of "redo" (second and third operation) patients also appeared. The inadequacy of regional myocardial protection by antegrade The Journal of Extra-Corporeal Technology 13 1--------; ......... 2------+-~..-~ 3 ------J_.