Myocardial Ischemia Identified With Dobutamine Stress Instantaneous Wave-Free Ratio for Anomalous Aortic Origin of the Right Coronary Artery

A 59-year-old woman with asymptomatic premature ventricular contractions (PVCs) underwent further investigation. Coronary computed tomography showed an anomalous aortic origin of the right coronary artery (RCA) with a slit-like orifice and acute-angle take-off from the left sinus of Valsalva (Figure A–C). Although non-invasive stress tests showed no myocardial ischemia, coronary angiography revealed significant RCA ostial stenosis (Figure D,E). Intravascular ultrasound demonstrated an oval deformity exacerbated during systole by lateral compression (Figure F). The baseline instantaneous wave-free ratio (iFR) was 1.02, but dobutamine stress (up to 2.4 mg/min) reduced the iFR to 0.32, confirming ischemia (Figure G,H). Despite no clear symptoms, but based on the dobutamine stress iFR and high-risk anatomic features, the RCA was relocated to the right sinus of Valsalva (Figure I,J). The postoperative course was favorable, although there was no significant change in PVC frequency, suggesting they were not due to ischemia caused by anomalous aortic origin of the coronary artery (AAOCA).

Figure.

(A–C) Coronary computed tomography shows anomalous aortic origin of the right coronary artery (RCA) with interarterial course, acute-angle take-off, and slit-like ostium from the left sinus of Valsalva. (D,E) Coronary angiography shows proximal narrowing of the RCA. (F) Intravascular ultrasound show the oval deformity caused by extravascular lateral compression (Supplementary Movie). (G) Baseline instantaneous wave-free ratio (iFR) and (H) after dobutamine infusion. (I) Intraoperative findings. The RCA is running externally to the aortic wall. (J) After the coronary reconstruction. Ao, aorta; LCA, left coronary artery; PA, pulmonary artery.

This case highlights the complexity of managing AAOCA, especially in asymptomatic patients. Surgical revascularization is often considered for both symptomatic and asymptomatic AAOCA patients with myocardial ischemia or high-risk anatomic features.¹ The optimal ischemia assessment technique in AAOCA patients remains unclear, but dobutamine stress iFR may be useful for assessing ischemia caused by dynamic obstruction.

Disclosures

The authors have no conflicts of interest regarding this report.

Supplementary Files

Supplementary Movie. RCA IVUS.

Please find supplementary file(s);

https://doi.org/10.1253/circj.CJ-24-0598

Reference

• 1.   Baumgartner H, De Backer J, Babu-Narayan SV, Budts W, Chessa M, Diller GP, et al. 2020 ESC guidelines for the management of adult congenital heart disease. Eur Heart J 2021; 42: 563–645.