Acute Type B Aortic Dissection in the Absence of Aortic Dilatation

Study Questions:

What are the characteristics of acute type B aortic dissection (ABAD) patients who present with a descending thoracic aortic diameter <3.5 cm?


The investigators categorized 613 ABAD patients enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2009 according to the aortic diameter <3.5 cm (group 1) and ≥3.5 cm (group 2). Demographics, clinical presentation, management, and outcomes of the two groups were compared. The χ2 test was used for comparing categorical variables between patients with an aortic diameter <3.5 cm and ≥3.5 cm; the Student t-test was used for comparing continuous variables between both diameter groups.


Overall, 21.2% (n = 130) had an aortic diameter <3.5 cm. Patients in group 1 were younger (60.5 vs. 64.0 years; p = 0.015) and more frequently female (50.8% vs. 28.6%; p < 0.001). They presented more often with diabetes (10.9% vs. 5.9%; p = 0.050), history of catheterization (17.0% vs. 6.7%; p = 0.001), and coronary artery bypass grafting (9.7% vs. 3.4%; p = 0.004). Marfan syndrome was equally distributed in the two groups. The overall in-hospital mortality did not differ between groups 1 and 2 (7.6% vs. 10.1%; p = 0.39).


The authors concluded that about one-fifth of ABAD patients do not present with any aortic dilatation, and are more frequently females and younger.


In this study, one hypothesis for the increased proportion of females among ABAD patients with a normal aortic diameter could be that the female aorta may dissect at a smaller diameter, because a 3 cm aortic diameter may be considerably increased compared with the normal aortic measurements in females. Additional research is needed to explore the molecular and genetic predisposition of these patients.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Vascular Medicine, Aortic Surgery, Cardiac Surgery and CHD and Pediatrics, Congenital Heart Disease, CHD and Pediatrics and Interventions, CHD and Pediatrics and Prevention, CHD and Pediatrics and Quality Improvement, Interventions and Structural Heart Disease, Interventions and Vascular Medicine

Keywords: Aortic Aneurysm, Thoracic, Hospital Mortality, Demography, Dilatation, Registries, Catheterization, Marfan Syndrome, Genetic Predisposition to Disease, Coronary Artery Bypass, Diabetes Mellitus

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