Changes in aortic growth rate and factors influencing aneurysmal dilatation after uncomplicated acute type B aortic dissection

Abstract OBJECTIVES The aim of this study was to evaluate changes in aortic growth rate and factors influencing aneurysmal dilatation after uncomplicated acute type B aortic dissection (ABAD). METHODS Medically treated patients with uncomplicated ABAD between September 2004 and January 2020 were retrospectively reviewed. Diameters of 6 different sites in the descending aorta were measured and aortic growth rate was calculated according to the time interval. Factors associated with aneurysmal changes were also investigated. RESULTS This study enrolled a total of 105 patients who underwent >2 serial computed tomography with a mean follow-up duration of 35.4 (12.1–77.4) months. The mean overall growth rates of the proximal descending thoracic aorta (DTA), mid-DTA, distal DTA, proximal abdominal aorta, maximal DTA and maximal abdominal aorta were 0.6 (1.9), 2.9 (5.2), 2.1 (4.0), 1.2 (2.2), 3.3 (5.6) and 1.4 (2.5) mm/year, respectively. The growth rate was higher at the early stage. It decreased over time. Growth rates of proximal DTA, mid-DTA, distal DTA, proximal abdominal aorta, maximal DTA, and maximal abdominal aorta within 3 months after dissection were 1.3 (9.6), 12.6 (18.2), 7.6 (11.7), 5.9 (7.5), 16.7 (19.8) and 6.8 (8.9) mm/year, respectively. More than 2 years later, they were 0.2 (0.6), 1.6 (1.6), 1.2 (1.3), 0.9 (1.4), 1.7 (1.9) and 1.2 (1.7) mm/year, respectively. Factors associated with aneurysmal changes after uncomplicated ABAD included an elliptical true lumen (odds ratio = 3.16; 95% confidence interval: 1.19–8.41; P = 0.021) and a proximal entry >10 mm (odds ratio = 3.08; 95% confidence interval: 1.09–8.69; P = 0.034) on initial computed tomography imaging. CONCLUSIONS The aortic growth rate was higher immediately after uncomplicated ABAD but declined eventually. Patients with an elliptical true lumen and a large proximal entry might be good candidates for early endovascular intervention after uncomplicated ABAD.