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

Kommerell 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.

This 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.

A 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.

In 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.