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Clin. Cardiol. 23, 125–126 (2000)
Virginia P. Carangal, M.D., and Gregory J. Dehmer, M.D.
Cardiac Catheterization Laboratory, University of North Carolina Hospitals, Chapel Hill, North Carolina, USA
A 55-year-old woman presented with exertional chest pain. Her exercise test was abnormal, and cardiac catheterization and coronary angiography showed normal left ventricular function with an 80% stenosis in the mid-left anterior descending artery. There was no angiographic evidence of coronary atherosclerosis in either the right or circumflex artery. Contrast injection into the left coronary artery suggested arterial continuity between the distal portion of the circumflex artery and the right coronary artery (Fig. 1). This was confirmed during angiography of the right coronary artery (Fig. 2). A stent was placed to treat the stenosis in the left anterior descending artery and her symptoms resolved.
| Fig. 1 Coronary angiogram of the left coronary artery in a left anterior oblique view with cranial angulation. The posterior descending artery (PDA) and left anterior descending artery (LAD) are identified. The communicating artery (c) is seen in the atrioventricular groove beyond the origin of the PDA. |
| Fig. 2 Coronary angiogram of the right coronary artery in a left anterior oblique view with cranial angulation. This image was recorded at the same angulation as the image in Figure 1, but at a smaller magnification to allow visualization of the entire coronary circulation. Note the catheter positioned in the right coronary artery. Forceful injection of contrast into the right coronary artery filled the entire left coronary system with reflux of the contrast into the aorta from the left main artery. |
Intercoronary artery continuity or "coronary arcade" is a rare variant of the coronary circulation. Arterial continuities exist in other areas such as the superficial volar arch of the hand, intestinal branches of the superior mesenteric artery, and the circle of Willis. Two types of intercoronary arterial connections have been described: communication between the circumflex and the right coronary arteries in the posterior atrioventricular groove (as in this patient) and communication between the left anterior descending and posterior descending arteries in the distal interventricular groove. Intercoronary arterial connections are distinct from coronary collaterals and occur in the absence of obstructive coronary artery disease. Compared with collaterals, these connections are larger in diameter (>= 1 mm), extramural, and straight. Furthermore, the structure of an intercoronary arterial connection is typical of an epicardial coronary artery with a well-defined muscular layer. Collateral vessels resemble arterioles with an endothelium supported by poorly organized collagen and muscle fibers. Intercoronary arterial continuities are thought to arise from a communication between the left anterior embryonic plexus and the right posterior embryonic plexus. Their true prevalence is unknown but we identified only two cases (0.02%) among the last 9,726 coronary angiograms performed at our institution. Large coronary connections have no functional significance except for their potential role in protecting the myocardium should significant atherosclerosis develop in either of the parent arteries.
Reference
Address for reprints:
Gregory J. Dehmer, M.D.
Cardiac Catheterization Laboratory, Room 2227
UNC Hospitals
101 Manning Drive
Chapel Hill, NC 27154, USA
Received: April 5, 1999
Accepted with revision: May 12, 1999