The Modified or "Button" Bentall is a relatively complex surgical procedure wherein the aortic root is replaced with a graft. This necessitates removing the coronary arteries and re-atttaching them to the aortic graft. Complications can arise particulalry at the sites where the coronary arteries are sewn into the graft, known as the coronary anastamoses. However, this study notes that the incidence of such complications is extremely low.
Ann Thorac Surg. 2003 Jun;75(6):1797-801; discussion 1802. Fate of coronary ostial anastomoses after the modified Bentall procedure. Milano AD1, Pratali S, Mecozzi G, Boraschi P, Braccini G, Magagnini E, Bortolotti U.
CONCLUSIONS: The modified Bentall operation is associated with an extremely low incidence of anastomotic complications particularly at the coronary ostia. More extensive use of new imaging techniques is desirable to assess the true incidence of such complications in patients receiving a composite aortic conduit.