Subtypes of acute aortic dissection

Background. This series consists of a 12-year experience with a policy of identifying and replacing the aortic segment containing the primary intimal tear for repair of acute aortic dissection. Methods. Patients with type A dissection underwent urgent surgery. Patients with type B dissection were referred for surgery based on selective criteria, including aortic dilatation greater than 5 cm. A classification system for acute dissection is described that specifies the site of intimal tear while retaining the clinical relevance of the Stanford system. Results. Of 168 acute dissections, 139 were type A and 29 were type B. The site of intimal tear was as follows: ascending aorta, 83 cases; arch, 32 cases; descending aorta, 29 cases; multiple tears, 11 cases (10 included arch tears); no tear (intramural hematoma), 6 cases; not noted, 7 cases. Only 60% of acute type A dissections arose from solitary intimal tears in the ascending aorta, whereas 30% had arch tears. Hospital mortality for type A dissection was 13.7% (18.8% for arch tears, NS) and 0% for type B. False lumen patency was 57.1% for type A dissection and 18.8% for type B dissection ( p = 0.002), yet survival was similar for these groups. Ten-year survival for type A dissection with arch tear (0.51 ± 0.12) was lower than 10-year survival for type A dissection with ascending tear (0.74 ± 0.05; p = 0.77), and significantly lower than for type A dissection with descending tear (0.88 ± 0.12; p = 0.029). Conclusions. Systematic resection of the primary tear yielded similar hospital mortality, 5-year survival, and aorta-related event-free survival rates for subtypes of acute type A dissection. Excellent results were obtained with a selective approach to type B dissection.