Type:
Educational Exhibit
Keywords:
Not applicable, Dilatation, Stents, Diagnostic procedure, CT-Angiography, CT, Interventional vascular, Arteries / Aorta, Anatomy, Vascular
Authors:
S. Schiro', I. Paladini, A. Andreone, E. Epifani, C. Marcato, N. Sverzellati; Parma/IT
DOI:
10.26044/ecr2020/C-09792
Background
Kommerell’s Diverticulum (KD) is a congenital aortic variant. It’s a persistent remnant of the fourth primitive dorsal aortic arch, from which an aberrant subclavian artery arises either in a left or right aortic arch [1, 2]. Aberrant subclavian artery is found in the 1% of population and KD is present in about 60% of cases [3].
There are two different types of KD:
- type I in a left sided aortic arch with a right aberrant subclavian artery (Fig.2A)
- type II in a right sided aortic arch with a left aberrant subclavian artery (Fig.2B)
Clinical presentation
KD is primarily asymptomatic but may present with dysphagia, chest pain and blood pressure difference in the upper limbs (subclavian steal syndrome). Symptoms are mainly associated to aneurysmal dilatation, atheromatous process that leads to rigidity of the vascular wall, narrowing of esophagus and trachea space due to co-existing aberrant artery.
The abrupt reduction in caliber between the wide diverticulum and the normal-sized subclavian artery causes considerable alteration in the pattern of blood flow, resulting in jet, wave, and eddy currents that predispose to post-stenotic dilatation, thrombosis, and perforation. This mechanism triggered by the presence of cystic medial necrosis in the diverticulum wall can lead to aortic dissection or rupture [4].
Imaging Findings
KD is seen as a bulging at the origin of the aberrant subclavian artery on Angio-CT. Type I KD presents usually a conical shape, while Type II KD is usually larger and rounded. Moreover, KD should be distinguish from its mimics such as saccular aneurysm of the thoracic aorta, dilatated KD and ductus diverticulum. A useful distinguishing feature from KD, is that Kommerell aneurysms have the typical imaging features of atherosclerotic aneurysms, including calcified plaque and mural thrombus, whereas plaque and thrombus is not commonly seen in uncomplicated Kommerell diverticula and ductus diverticula [2].
How to measure:
- According to Ota. et al: the maximum distance from the diverticulum wall adjacent to the trachea to the opposite aortic wall (descending aorta) [5] Fig.3
- According to Idrees et al: at the cross-sectional diameter from opposite aortic wall to the tip of KD and at the level of origin of the aberrant subclavian artery from the arch [6] Fig.4
Treatment
Treatment is mandatory when symptomatic, when asymptomatic yet the diverticulum orifice exceeds 30 mm and/or the diameter of the descending aorta adjacent to the diverticulum exceeds 50 mm, it should be treated.
Treatment options include:
- open surgical aortic repair
- total endovascular aortic repair