Arterial wall damage caused by snaring of the coronary arteries during off-pump revascularization

Background: Anastomosis of a saphenous or mammary artery conduit to the cor onary artery requires precise and reproducible microsurgical technique. Ove r the past three decades, the elective induction of cardiac arrest and circ ulatory support have provided the conditions suitable for microsurgical ana stomosis to all coronary vessels. Beating heart coronary grafting was rejuv enated at our center in 1985 as an alternative to cardiopulmonary bypass an d cardioplegic arrest. One of the requirements for off-pump grafting is loc al vascular control of the target vessel and prevention of bleeding into th e field from the open coronary artery. The most common hemostasis technique in use today is the application of circumferential traction sutures and sn ares around the coronary artery. We performed a human cadaver study to eval uate the potential for local trauma to the native coronary artery caused by this method of hemostasis. Methods: Our research team applied both 5-0 polypropylene and 2-0 polyester snares to the proximal and distal right coronary artery (RCA) and left ant erior descending (LAD) in 25 isolated fresh human cadaver hearts. A total o f 100 points of snare application to the native coronary vessels were induc ed and then investigated histologically, with hematoxylin-eosin, Weigert, a nd phosphotungstic hematoxylin staining. Results: The results suggested a direct relationship between the severity o f the arterial lesion induced by the snares and the degree of local atheros clerotic disease in the native coronary artery. Compression and buckling of the elastic lamellae with medial fractures (similar in nature to angioplas ty but directed inward) were seen when snares were applied to a region with marked atherosclerotic disease. Conclusions: The application of snares to the coronary artery proximal and distal to the anastomotic site must be done with caution. In cases of marke d atherosclerotic disease in the underlying coronary artery, a new intimal- medial lesion can occur with indiscriminate application of a tourniquet. Th is phenomenon may account for some of the reported cases of late peri-anast omotic or distal stenoses seen with off-pump coronary artery bypass graftin g and significantly detract from the advantages offered by beating heart su rgery. If one or both snares can be avoided entirely, or applied carefully to disease-free segments of the vessel, this problem may be avoided entirel y.