Purpose or Case Report: A vascular ring is a rare congenital anomaly encircling the trachea and esophagus by vascular structures, which may not be patent. One common form is a right aortic arch with aberrant left subclavian artery (RAA-ALSA), often arising from a diverticulum of Kommerell (DoK) and completed by a left ductus or ligamentum arteriosum. The DoK, an embryonic remnant of the left dorsal arch, may further compress the airway and esophagus. The aim of this study is to compare DoK morphology across intracardiac anatomic variants in RAA–ALSA patients, hypothesizing that intracardiac lesions altering fetal ductal flow impact DoK size, with right-obstructive lesions yielding a smaller DoK and left-obstructive lesions a larger DoK.
Methods & Materials: This is a single-center retrospective cohort study of patients with RAA-ALSA who underwent CT or cardiovascular MRI between 2003 and 2023 before repair. Patients were classified into four groups: normal intracardiac anatomy, right-obstructive lesions, left-obstructive lesions, and other congenital heart disease (CHD). The following parameters were measured using the double oblique technique on multiplanar reformatting: DoK diameter and distance from the tip of DoK to the aortic wall (DAW) both indexed to body surface area (BSA), DoK angle from the aortic arch, and thoracic inlet index. Groups were compared using Fisher Exact and Kruskal-Wallis tests with post-hoc analyses comparing CHD subgroups to normal anatomy.
Results: Among 237 patients, 179 (75.5%) had normal intracardiac anatomy, 8 (3.4%) right-obstructive, 5 (2.1%) left-obstructive, and 45 (19.0%) other CHD. The median age at imaging was 3.8 years (IQR 0.6-11.2); 63.3% underwent CT, and 36.7% cardiac MR. Indexed DoK diameter was significantly smaller in right-obstructive lesions (median 9.49mm/m2) and larger in left-obstructive lesions (34.17 mm/m2) compared to the normal group (14.20 mm/m2). Left-obstructive lesions also exhibited greater indexed DoK-to-aortic wall distance, more obtuse DoK angles, and smaller thoracic inlet indices relative to the normal group.
Conclusions: In patients with RAA-ALSA vascular rings, right-obstructive CHD is associated with a smaller DoK, while left-obstructive CHD is associated with a larger DoK, supporting the hypothesis that altered fetal ductal flow influences DoK size. Further investigation is warranted to determine the differences in symptomatology and outcomes among vascular ring patients with and without intracardiac anomalies.