Alterations of arterial morphology in patients with aberrant subclavian artery and type B dissection and its association with dissection

The arterial morphology in patients with aberrant subclavian artery (ASA) and its association with type B aortic dissection are important for treatment and prevention. In the present study, we examined the arterial morphology of ASA patients with type B dissection and evaluated its association with type B dissection in vivo. Patients with aortic dissection who had undergone computed tomography angiography were screened for the presence of ASA and type B dissection from January 2011 to May 2021. The angles of ascending aorta, aortic arch, and aortic deviation and the diameters of the ascending aorta, aortic arch, ASA ostium, and middle ASA segment were measured on the computed tomography angiography scans of the ASA patients with type B dissection (group 1; n = 16), clinically matched counterparts without type B dissection (group 2; n = 32), and patients with clinically matched type B dissection without ASA (group 3, n = 32). The correlation between ASA morphology and type B dissection was analyzed using variance analysis or the Wallis H test. Compared with group 2, group 1 had a sharper ascending aortic angle (131.5° ± 13.7° vs 148.1° ± 7.8°; P = .001), a larger aortic deviation angle in plane 2 (28.2° ± 6.0° vs 22.1° ±7.2°; P = .005) and plane 3 (26.4° ±7.3° vs 21.8° ± 6.3°; P = .028). Similarly, group 1 had a greater diameter in the ascending aorta and aortic arch and the ostium and middle of the ASA (38.3 ± 4.1 mm vs 33.6 ± 4.5 mm [P = .001]; 34.0 ± 9.3 mm vs 26.2 ± 2.9 mm [P = .004]; 20.3 ± 9.3 mm vs 14.0 ± 3.2 mm [P = .018]; 10.8 ± 2.3 mm vs 9.0 ± 1.5 mm [P = .002], respectively), without a significant difference in the aortic arch angle. Compared with group 3, group 1 had a sharper ascending aortic angle (131.5° ± 13.7° vs 142.5° ± 11.7°; P = .026) and smaller aortic deviation angle in plane 1 (21.7° ± 6.2° vs 28.9° ± 6.2°; P = .04) and plane 3 (26.4° ± 7.3° vs 21.8° ± 6.3°; P = .007), although with no significant differences in the aortic arch angle, aortic deviation angle in plane 2, and ascending aortic diameter. The diameters of the ostium and middle segment of the ASA and ascending aorta and the angles of the ascending aorta and aortic deviation are potential risk factors for type B dissection in patients with ASA, which could provide new insights into the mechanism of type B dissection in patients with ASA.