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?
Methods:
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.
Results:
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).
Conclusions:
The authors concluded that about one-fifth of ABAD patients do not present with any aortic dilatation, and are more frequently females and younger.
Perspective:
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.
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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