Variant of the left coronary artery with an unusual origin and course: Anatomic and postmortem angiographic findings

This study demonstrates anatomic and postmortem angiographic findings characterizing the origin of the left coronary (LC) artery arising in common trunk with the right coronary (RC) artery from the right aortic sinus and its course via the ventricular septum (VS) to the left heart. This anomaly was a single finding observed among 388 angiographies and 60 corrosion castings. The course of the LC was divided in four segments. The first three form a curve that is upward concave. Large branches to the septomarginal trabecula (ST), VS, diagonals (DS), and the small anterior interventricular (anterior descending) artery originated from the outer part of this curve. In the anteroposterior x-ray, the above curve resembles a deep-bottom pot with a handle corresponding to the fourth segment. In the right anterior oblique, the first and second segments form a large erect angle. The third segment occupies the lower part of the absent proximal anterior interventricular artery, and the fourth crosses the outflow tract and the first segment in the middle. The course of these four segments of LC resembles the shape of the number 6. These findings are important for interpreting coronary angiographies in patients with this anomaly. (C) 1998 Wiley-Liss, Inc.