Coronary–Coronary Bypass with Patency Validated by 64-Slice Multidetector Computed Tomography

A 43-year-old woman with a history of ischemic heart disease presented for surgical revascularization of the left anterior descending coronary artery (LAD). Both the length of the stenosis and its intramyocardial location precluded percutaneous intervention. The mid LAD was embedded deep in the myocardium and was stenosed throughout its intramyocardial course (Fig. 1). During surgery, the left internal mammary artery (LIMA) was dissected in a standard manner, but the unfavorable position of the heart in the chest cavity prevented the pedicled LIMA from reaching the target LAD. Even skeletonization of the LIMA and division of the pleura failed to provide adequate length for an in situ graft. The LIMA was then used as a free graft, with proximal anastomosis to the ascending aorta. This maneuver still produced insufficient length for safe construction of a distal anastomosis. The only remaining option was to create an LAD-to-LAD bypass with a free LIMA graft. Nine months after the operation, a follow-up 64-slice multidetector computed tomogram showed a patent graft (Fig. 2).

Fig. 1 Preoperative coronary angiogram (left anterior oblique view) shows tight stenosis (arrow) of the left anterior descending coronary artery in its intramyocardial segment.

Fig. 2 Computed tomographic angiogram 9 months after the operation shows native stenosed left anterior descending coronary artery (black arrow) and a patent left internal mammary artery graft (white arrow). The proximal and distal anastomoses of the coronary–coronary bypass are indicated by white arrowheads.

Comment

Coronary–coronary bypass was first described by Rowland and Grooters.¹ The indication was a porcelain aorta, and the great saphenous vein served as a graft. Common indications for coronary–coronary bypass are a porcelain aorta, stenosis or occlusion of the subclavian artery, insufficient graft length, an arterial conduit-sparing procedure, or harvest-related injury of the internal mammary arteries.² The target artery for coronary–coronary bypass is usually the right coronary artery, but the coronary–coronary bypass technique can also be used for LAD revascularization. The primary difficulty in using coronary–coronary bypass is the progression of atherosclerosis in the proximal portion of the vessel that is to be bypassed. In our patient, the absence of atherosclerotic changes in the left main stem and proximal LAD favored coronary–coronary bypass. To evaluate the patency of the graft after the operation, we used 64-multislice computed tomographic angiography. Because the patient was symptom-free, a patent graft was expected. The use of this technique to evaluate graft patency after coronary revascularization has been validated: Tochii and colleagues³ reported 100% sensitivity, 96.5% specificity, 83.3% positive predictive value, 100% negative predictive value, and 97% diagnostic accuracy for this imaging method. The procedure is far better tolerated by patients than is heart catheterization, and it is associated with fewer complications.