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

Background. The effects of different stabilizing methods for minimally inva sive beating heart coronary artery bypass grafts (CABG) on coronary endothe lial function are unknown. Methods. We compared the effects on endothelial function of the Cohn stabil izer (used with proximal snaring by Retract-o-tape silicone air cushion) an d a coronary shunt (CTS flow coil shunt) on an in vivo model of beating hea rt CABG. The two techniques were applied for 15 minutes on porcine epicardi al coronary arteries. Control rings were taken from the same coronary arter y. Endothelial function of control and instrumented arterial rings was stud ied in organ chamber experiments. Evaluation of endothelial coverage was pe rformed with silver nitrate staining. Results. Endothelium-dependent relaxation to serotonin and bradykinin was s ignificantly decreased in the shunt group compared to control, Cohn stabili zer, and snare groups. There were no significant differences in the endothe lium-independent relaxation to sodium nitroprusside between groups. Conclusions. Greater endothelium-dependent relaxation with the Cohn stabili zer suggests better preservation of endothelial coverage at the site of app lication and reduced propensity for coronary spasm and later development of intimal hyperplasia. (Ann Thorac Surg 2000;70:1111-4) (C) 2000 by The Soci ety of Thoracic Surgeons.