Maximum aortic diameter as a simple predictor of acute type B aortic dissection.

Received June 7, 2007; accepted for publication September 18, 2007 Address reprint requests to Shigeyuki Sasaki, MD, PhD: Division of Medical Science, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsu-cho, Ishikari, Hokkaido 061 –0293, Japan. Objectives: To identify the most prognostic predictor of Stanford type B aortic dissection at admission. Patients and Methods: Forty-three patients with Stanford type B aortic dissection were divided into two groups: (1) those who developed dissection-related events later (EV group: n = 18), including the need for surgery (n = 12), rupture (n = 1), dissection-related death (n = 5), and aortic enlargement ≥5 mm in diameter per year (n = 15); (2) those without later events (NoEV group: n = 25). Clinical features, aortic diameters, and blood flow status were compared. Results: The maximum aortic diameter at admission was 41.5 ± 1.7 mm for the EV group, which was significantly greater than the NoEV group (34.4 ± 0.9 mm, p <0.001). A maximum aortic diameter ≥40 mm was found in 11 patients (61%) of the EV group, whereas this maximum was found in 4 (16%) of the NoEV group (p = 0.004). A patent false lumen at admission was found in all patients of the EV group and in 17 (68%) of the NoEV group (p = 0.013). Other factors were not significant. A Cox hazard analysis indicated a maximum aortic diameter ≥40 mm as a significant predictor for dissection-related events (hazard ratio 3.13, p = 0.032). The presence of a patent false lumen did not reach a statistical significance. Conclusion: Our results indicated that a maximum aortic diameter ≥40 mm at admission was the most prognostic factor for developing late dissection-related events, rather than the presence of a patent false lumen. (Ann Thorac Cardiovasc Surg 2008; 14: 303–310)