Kommerell Diverticulum: Distinctions Between Arch Side and Evaluation of Morphology, Size, And Risk

BackgroundKommerell diverticulum (KD) is a dilated proximal aberrant right or left subclavian artery associated with either right or left aortic arches (RAA-ARSA or LAA-ALSA). Although case series suggest that KD may be a liability for vascular complications, the risk, pattern of dilation throughout the life span, and differences between arch sides are not known.MethodsThis study was a single-center retrospective review of patients of all ages with KD on cross-sectional imaging. Maximal short-axis diameter of KD (KDmax), absolute and indexed to descending aortic diameter (DAo), was correlated with age. Comparisons were made between arch sides. Patients with vascular complications were described.ResultsA total of 104 patients with KD were included: 68 (65%) with RAA-ALSA, 36 (35%) with LAA-ARSA, 43 (41%) asymptomatic. Although KDmax was correlated with age (RAA-ALSA r = 0.84; [P< .0001]; LAA-ARSA r = 0.51 [P = .001]), KDmax indexed to DAo was not (RAA-ALSA r = 0.14 [P = .27]; LAA-ARSA r = −0.22 [P = .21]). Patients with RAA-ALSA had larger KDmax indexed to DAo (1.02 ± 0.20 mm/mm vs 0.89 ± 0.18 mm/mm; P = .002) and more symptoms (75% vs 28%; P < .0001), and they were younger (median, 9.5 years vs 61.7 years; P < .0001). Six patients (58 to 80 years of age) had vascular complications, and all 6 had LAA-ARSA and risk factors for acquired aneurysms.ConclusionsIn older patients, KDmax indexed to DAo was not larger, thus arguing against isolated KD dilation with age. Diverticula from RAA-ALSA and LAA-ARSA demonstrated different phenotypes, a finding suggesting different disease processes and likely different risk. The incidence of vascular complications was lower than in previous reports, and these complications occurred exclusively in patients with LAA-ARSA and aneurysm risk factors. This finding suggests that conservative management of asymptomatic KD is often reasonable, especially in patients with RAA-ALSA.