Anomalous origin of the coronary artery arising from the opposite sinus: prevalence and outcomes in patients undergoing coronary CTA

Abstract

Aims: The impact of coronary computed tomographic angiography (CTA) on management of anomalous origin of the coronary artery arising from the opposite sinus (ACAOS) remains uncertain. We examined the prevalence, anatomical characterization, and outcomes of ACAOS patients undergoing CTA.

Methods and results: Among 5991 patients referred for CTA at two tertiary hospitals between January 2004 and June 2014, we identified 103 patients (1.7% prevalence) with 110 ACAOS vessels. Mean age was 52 years (range 5-83, 63% male), with 55% previously known ACAOS and 45% discovered on CTA. ACAOS subtypes included: 39% interarterial (n = 40 anomalous right coronary artery, n = 3 anomalous left coronary artery), 38% retroaortic, 15% subpulmonic, 5% prepulmonic, and 2% other. ACAOS patients were assessed for symptoms, ischaemic test results, revascularization, all-cause or cardiovascular (CV) death, and myocardial infarction. CTAs were reviewed for ACAOS course, take-off height and angle, length and severity of proximal narrowing, intramural course, and obstructive coronary artery disease (CAD). In follow-up (median 5.8 years), there were 20 surgical revascularizations and 3 CV deaths. After adjusting for obstructive CAD (n = 21/103, 20%), variables associated with ACAOS revascularization included the following: CV symptoms, proximal vessel narrowing ≥50%, length of narrowing >5.4 mm, and an interarterial course.

Conclusion: The prevalence of ACAOS on CTA was 1.7%, including 45% of cases discovered incidentally. CTA provided excellent characterization of ACAOS features associated with coronary revascularization, including the length and severity of proximal vessel narrowing.

Keywords: anomalous coronary artery; coronary computed tomographic angiography; prognosis; revascularization; sudden cardiac death.

Figure 1

Distinguishing a subpulmonic vs. interarterial course. (Left panel) Three-dimensional volume rendering (top) and multiplanar image reconstruction (bottom) demonstrating an anomalous left main (LM) coronary artery arising from the right coronary cusp and following a subpulmonic course below the pulmonic valve (PV). (Right panel) Three-dimensional volume rendering (top) and multiplanar image reconstruction (bottom) demonstrating an anomalous left main coronary artery (ALCA) with an interarterial course above the pulmonic valve. ALCA, interarterial anomalous left main coronary artery; Ao, aorta; LM, left main coronary artery; PA, pulmonary artery; PV, pulmonic valve; RV, right ventricle.

Figure 2

Study design. ACAOS, anomalous origin of the coronary artery arising from the opposite sinus; CTA, computed tomographic angiography.

Figure 3

(A) CTA-identified ACAOS features. Lumen diameters obtained in double oblique view, taking the maximum and minimum diameters of the vessel at the most narrowed proximal location and the distal reference using the smallest available slice thickness (0.5–0.625 mm isotropic resolution). *Centreline length of vessel narrowing shown in double oblique and curved multiplanar views extending from (a) ACAOS vessel take-off to (b) normal calibre distal reference. ACAOS, anomalous origin of the coronary artery arising from the opposite cusp. (B) Intramural location and take-off angles obtained in multiplanar axial reconstructions at the level of the ACAOS ostium using the smallest available slice thickness (0.5–0.625 mm). Vessel take-off level (above/below commissure) shown in 3D reformatted image.

Figure 4

Example of ACAOS take-off above the aortic valve commissure. Post-mortem autopsy study of patient who died from idiopathic pulmonary fibrosis while awaiting lung transplant. Autopsy demonstrates an interarterial ARCA with separate take-off from the left coronary cusp above the aortic valve commissure. Image courtesy of Dr Robert Padera (Department of Pathology, Brigham and Women's Hospital, Boston, MA).

Figure 5

ACAOS course subtype stratified by the prevalence of CTA-identified ostia type. Note the most common take-off of an interarterial ARCA is a separate ostia. *Note here that numbers do not add to 100% given indeterminate take-offs resulting from a bioprosthetic valve limiting take-off visualization in one patient with interarterial ARCA, and misalignment artefact in one patient with a retroaortic left circumflex. Subtype images obtained by multiplanar axial reconstructions at the level of the ACAOS ostium using the smallest available slice thickness (0.5–0.625 mm).

Figure 6

Prevalence of ACAOS subtypes on coronary CTA. The number of ACAOS vessels by subtype, and per-vessel prevalence. Most common subtypes were interarterial RCA (n = 40) and retroaortic LCX (n = 38). *Other ACAOS include retrocardiac LCX (n = 1) and RCA arising from the non-coronary cusp with an otherwise normal course (n = 1). ACAOS, anomalous origin of the coronary artery arising from the opposite sinus; CTA, computed tomographic angiography; LAD, left anterior descending; LCX, left circumflex; RCA, right coronary artery.

Figure 7

Outcomes of ACAOS patients following CTA. ACAOS, anomalous origin of the coronary artery arising from the opposite sinus; CABG, coronary artery bypass grafting; CAD, coronary artery disease; LAD, left anterior descending; LCX, left circumflex; RCA, right coronary artery.