Effects on coronary endothelial function of the Cohn stabilizer for beating heart bypass operations

Background. The effects of different stabilizing methods for minimally invasive beating heart coronary artery bypass grafts (CABG) on coronary endothelial function are unknown. Methods. We compared the effects on endothelial function of the Cohn stabilizer (used with proximal snaring by Retract-o-tape silicone air cushion) and a coronary shunt (CTS flow coil shunt) on an in vivo model of beating heart CABG. The two techniques were applied for 15 minutes on porcine epicardial coronary arteries. Control rings were taken from the same coronary artery. Endothelial function of control and instrumented arterial rings was studied in organ chamber experiments. Evaluation of endothelial coverage was performed with silver nitrate staining. Results. Endothelium-dependent relaxation to serotonin and bradykinin was significantly decreased in the shunt group compared to control, Cohn stabilizer, and snare groups. There were no significant differences in the endothelium-independent relaxation to sodium nitroprusside between groups. Conclusions. Greater endothelium-dependent relaxation with the Cohn stabilizer suggests better preservation of endothelial coverage at the site of application and reduced propensity for coronary spasm and later development of intimal hyperplasia. (Ann Thorac Surg 2000;70:1111-4) (C) 2000 by The Society of Thoracic Surgeons.