Incomplete myocardial reperfusion despite a patent coronary bypass: a generally unrecognized shortcoming of the surgical approach to coronary artery disease.

When assessing a coronary artery bypass graft, the patency rate is virtually the sole criterion of success. However, this fails to identify grafts which are patent by incompletely reperfuse the diseased vessel. Angiograms of 82 patients with 172 bypassed coronary arteries confirmed patency in 126 (73%); however, in 30 reperfusion was incomplete though the graft was patent, making the rate of complete reperfusion only 56% (96/172). Causes included localized narrowings in the region of the anastomosis [9], significant narrowing along the graft [6], pre-existing additional stenoses in the native vessel, remote from the anastomosis and the lesion [7], stenoses not present preoperatively but seen postoperatively in the native vessel, remote from the anastomosis and original lesion [6], and separate obstructions of unbypassed branches [2]. While incomplete reperfusion is often unavoidable and is certainly preferable to total occlusion, evaluation based purely on patency rates is misleading, since it overlooks the fact that a significant proportion of patent grafts will not totally reperfuse the diseased vessel.