Anatomic spectrum of left coronary artery anomalies and associated mechanisms of coronary insufficiency.

This is a novel re-appraisal of an understudied and misunderstood group of important coronary anomalies. The general name of the group is "anomalous origin of the left coronary artery," but several additional details should be included in this group of anomalies and the explanation of their pathophysiology. The most lethal form in young athletes or military recruits features intramural aortic proximal course. This comprehensive review is based on a large experience at a dedicated center for coronary artery anomalies, using evolving knowledge (over 20 years) while employing prospective and disciplined programs of evaluation and treatment, according to the nature and severity of each anomaly. The most common pathogenic mechanism of coronary dysfunction relates to intramural coronary course, with or without ectopic origin, leading to variable lateral compression and stenosis inside the aortic tunica media; this compression is present at rest and worsens with exertion. We propose that such variable and dynamic stenoses can be best studied by examining their specific anatomy and clinical presentation, stress testing, and, most importantly, in vivo evaluation by intravascular ultrasonography. Such methods should be used to support individual risk evaluation and selection among treatment options.