A rare V-shaped course variant of the posterior right diagonal artery: a case description and literature analysis

Coronary artery anomalies were found in 1,686 patients (1.3% incidence) undergoing coronary arteriography at the Cleveland Clinic Foundation from 1960 to 1988. Of the 1,686 patients, 1,461 (87%) had anomalies of origin and distribution, and 225 (13%) had coronary artery fistulae. Most coronary anomalies did not result in signs, symptoms, or complications, and usually were discovered as incidental findings at the time of catheterization. Eighty-one percent were "benign" anomalies: 1) separate origin of the left anterior descending and circumflex from the left sinus of Valsalva; 2) ectopic origin of the circumflex from the right sinus of Valsalva; 3) ectopic coronary origin from the posterior sinus of Valsalva; 4) anomalous coronary origin from the ascending aorta; 5) absent circumflex; 6) intercoronary communications; and 7) small coronary artery fistulae. Other anomalies may be associated with potentially serious sequelae such as angina pectoris, myocardial infarction, syncope, cardiac arrhythmias, congestive heart failure, or sudden death. Potentially serious anomalies include: 1) ectopic coronary origin from the pulmonary artery; 2) ectopic coronary origin from the opposite aortic sinus; 3) single coronary artery; and 4) large coronary fistulae. Coronary artery anomalies require accurate recognition, and at times, surgical correction.

Twenty-three cases of an anatomic variant of the left anterior descending artery (LAD) are described. This variant is termed "dual LAD" and consists of two branches which supply the usual distribution of the LAD. One branch (short LAD) terminates in the proximal aspect of the anterior interventricular sulcus (AIVS). A second, longer branch has a variable course outside the AIVS and returns to the AIVS distally. The long LAD arose from the LAD proper in 21 cases and from the RCA in two cases. The initial course of the long LAD was on the epicardial surface of the left ventricle (17 cases), right ventricle (three cases), or within the interventricular septum (three cases). Recognition of these variants is important for correct surgical identification of the short and long LADs.