Effect of coronary artery occlusion on myocardial protection by retroperfusion of cardioplegic solutions.
Coronary artery stenoses impede delivery of cardioplegic solutions infused through the aortic root. Therefore, the efficacy of retroperfusion of cardioplegic solution through the coronary sinus was assessed in dogs subjected to cold, potassium cardioplegic arrest. Group I (N = 15) had the left anterior descending (LAD) coronary artery occluded throughout ischemia while Group II (N = 15) had a patent LAD. Transmural biopsies of both the left ventricular (LV) apex and right ventricle (RV) were assayed for adenosine triphosphate (ATP) and creatine phosphate (CP). Regional wall temperatures were sequentially monitored. The time from aortic cross-clamping to electrical arrest varied widely, but the mean arrest time of each group was similar (174 +/- 22 vs 175 +/- 28 sec). (table; see text) Comparable depletion of ATP stores (vs preischemia) occurred in each ventricle regardless of coronary artery patency. Similarly, CP stores were depleted 60-72% (P less than 0.01) during ischemia. Mean temperatures during arrest of the RV and LV (17.2-19.5 degrees C) did not differ and were not affected by LAD occlusion. Coronary venous resistance remained constant with repetitive infusions. These data suggest that myocardial protection with coronary sinus retroperfusion is independent of arterial patency, but is suboptimal, perhaps due to the prolonged time needed to induce ventricular arrest.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001831:Body Temperature; D003331:Coronary Vessels / Q000503:physiopathology*; D004285:Dogs; D006324:Heart Arrest, Induced / Q000379:methods*; D010477:Perfusion / Q000379:methods*
D000255:Adenosine Triphosphate