Assessment of the intramural segment of interarterial anomalous coronary arteries originating from the opposite sinus of Valsalva on CT angiography

Abstract

\n \n \n Of the coronary anomaly variants, an anomalous coronary artery originating from the opposite sinus (AAOCA) with an interarterial course poses the highest the risk of sudden cardiac death. Assessment of high risk anatomical characteristics can be done with Computed Tomography Angiography (CTA). High risk features are a slit-like ostium, acute angle take-off, proximal narrowing and an intramural course. For an intramural course no clear-cut CT parameters exist.\n \n \n \n To deduct new CTA criteria to identify an intramural course as well as the length of the intramural segment based on peroperative findings.\n \n \n \n Twenty patients were included that received unroofing surgery of the right or left AAOCA between 2010 and 2019. All patients had a pre-operative CTA (0.5–1mm slice-thickness) performed. The presence of the intramural segment was measured peroperatively by the surgeon and used as indicator for CTA evaluation. Using multiplanar reconstructions, CTA images were rotated perpendicular to the horizontal plane of the aortic valve annulus and AAOCA to assess the distance between the aortic and AAOCA lumen and the shape of the AAOCA. This was done at every 2mm for the length of the intramural course as described by the surgeon (Figure 1).\n \n \n \n Analysis of 20 patients (40% male, AAORCA n=17, age at diagnosis AAOCA 45.6±10.5 years), showed a mean intramural length of 11.5±2.4mm at surgery. The median distance between the aortic and AAOCA lumen was 0.76mm (IQR 0.72–0.97mm) for the intramural segment. At the distal end of the intramural part (indicated by no. 5 in Figure 1), the mean distance was 1.20mm±0.27mm. The median ratio between the antero-posterior and transverse diameter of the AAOCA lumen at the distal end of the intramural part was 0.94 (IQR 0.88–0.99). Along the intramural part (Figure 1, no. 1–4) this ratio was 0.56mm±0.11mm, indicating a more flattened ostial shape along the course of the vessel.\n \n \n \n Results indicate that an aortic to AAOCA lumen distance of ≤0.76mm on CTA is suggestive of an intramural course. A distance between the aorta and AAOCA of ≥1.2mm combined with an antero-posterior to transverse diameter ratio of 0.94 of the AAOCA indicates that the intramural trajectory has ended.\n \n \n \n Type of funding sources: None.\n