Anomalous coronary artery arising from the opposite sinus: descriptive features and pathophysiologic mechanisms, as documented by intravascular ultrasonography.

BACKGROUND: Anomalous coronary artery originating from the opposite sinus of Valsalva (ACAOS) can cause syncope, myocardial infarction, and sudden death in the absence of critical, fixed stenosis. In the following cases, intravascular ultrasonography (IVUS) was used to document the functional anatomy in ACAOS. This application has not been previously reported in the literature. METHODS AND
RESULTS: In four patients with symptomatic ACAOS and IVUS, the anomalous vessels had a tangential proximal course, and a proximal intramural tract of variable length had fixed lateral compression that worsened during systole. By pressure wire, no significant gradient was present at baseline or after adenosine administration. Ergonovine provocation elicited no spasticity of proximal ectopic segments. Dobutamine, atropine, and rapid saline infusion provoked no symptoms or angiographic changes but did provoke subtle IVUS changes. To correlate these changes with the prognosis, further longitudinal evaluation, involving larger series, will be required.
CONCLUSION: IVUS and pressure-wire methods may be valuable for subclassifying ACAOS and other coronary anomalies in terms of their pathophysiologic repercussions and for substantiating individual indications for treatment. To establish definitive recommendations and protocols, a larger study will be required.