Inadvertent Anastomosis of Internal Mammary Artery to Great Cardiac Vein

Abstract

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A 68-year-old man underwent successful 3-vessel coronary artery bypass grafting (CABG): a left internal mammary artery (LIMA) was anastomosed end to side to a large diagonal branch of the left anterior descending coronary artery (LAD) and was then skipped to the distal LAD; and saphenous vein grafts (SVGs) were anastomosed to the circumflex and right coronary arteries. He returned to his cardiologist 2 years later, complaining of new-onset angina. Repeat coronary angiography revealed patent SVGs and a patent LIMA to the 1st diagonal branch of the LAD. However, there was an obvious inadvertent insertion of the LIMA skip graft into the great cardiac vein, instead of the distal LAD (Figs. 1 and 2). The patient underwent successful placement of a drug-eluting stent at the native proximal LAD lesion (Fig. 3). This resulted in a “flush” occlusion of the grafted large 1st diagonal branch. The patient remained free of angina at the 12-month clinical follow-up.

Fig. 1. Cineangiogram in right anterior oblique caudal view shows the insertion of the left internal mammary artery skip graft into the great cardiac vein (arrow indicates anastomotic site). Drainage of contrast medium into the coronary sinus can be seen.

LAD = left anterior descending

Real-time motion image is available at www.texasheart.org/journal.

Fig. 2. Cineangiogram in anteroposterior cranial view shows the native left anterior descending coronary artery (LAD)–diagonal system before percutaneous coronary intervention at the proximal LAD. The left main coronary artery (LMCA) is apparent, as is the saphenous vein graft (SVG) that supplies the 1st obtuse marginal branch (OM1) of the left circumflex coronary artery (LCx). The LCx–OM1 fills retrograde from the native left coronary injection. In addition, outlined faintly is the left internal mammary artery (LIMA) skip graft (seen prominently in Fig. 1), which is anastomosed to the great cardiac vein.

Real-time motion image is available at www.texasheart.org/journal.

Fig. 3. Cineangiogram in anteroposterior cranial projection shows the left anterior descending coronary artery (LAD) after stenting. In comparing this image with Figure 2, note the absence of the 1st diagonal branch after stenting of the proximal LAD.

LMCA = left main coronary artery

Comment

Since the first use of saphenous vein CABG by René Favaloro in 1968, at least 20 cases of acquired aortocoronary fistula to cardiac veins have been described in the medical literature, and most of these have involved the use of SVGs.¹ Although iatrogenic aortocoronary fistula is an extremely rare sequela to CABG, the use of cardioplegia during CABG may make it difficult for the surgeon to differentiate between an intramyocardial portion of the LAD and an adjacent, sclerotic great cardiac vein in an area of epicardial fat. Clinical clues regarding the possibility of an aortocoronary fistula are the presence of heart failure without an obvious cause (especially right-heart failure consequent to substantial left-to-right shunting), new-onset angina pectoris or the persistence of old angina after CABG, or new continuous precordial murmur after CABG.² Diagnosis is usually made using cineangiography. However, the ever-increasing use of multidetector computed tomographic coronary angiography should enable easy, noninvasive, and accurate identification of the fistulous pathway. Although a conservative approach has been advocated for asymptomatic patients,² there is no consensus on how to treat this rare condition in symptomatic patients. The traditional surgical approach has been fistula closure and repeat bypass grafting of the culprit vessel, but there have been case reports of successful percutaneous fistula occlusion by embolization of coils or detachable balloons.^3,4 Recently, Sheiban and colleagues⁵ successfully treated an inadvertent end-to-side anastomosis of a LIMA to the great cardiac vein with percutaneous retrograde coronary sinus catheterization and covered-stent deployment at the anastomotic site.