Background: Aortic intramural hematoma (IMH) is a variant of overt aortic dissection. The predictors of progression of IMH to dissection and rupture are still unknown, and strategies for management are not established.
Methods and results: A multicenter study was conducted comprising 66 patients with IMH and hospital admission <or=48 hours after onset of initial symptoms. Among these, progression to aortic dissection or rupture occurred in 30 (45%) and death occurred in 13 (20%) patients within 30 days. Late progression was noted in 14 (21%) and death in 11 (17%) patients, yielding a 1-, 2-, and 5-year survival of 76%, 73%, and 43%, respectively. In a set of 9 variables, multivariate analysis identified IMH location in the ascending aorta (type A; P=0.02) and moderately ectatic aortic diameters (49+/-13 mm with progression versus 57+/-16 mm without progression; P=0.03) as independent predictors of early progression. In type A IMH, early mortality was 8% with swift surgery versus 55% without surgery (P=0.004). The risk of late progression of IMH was independently associated with age at index diagnosis (P=0.01) and absence of beta-blocker therapy during follow-up (P=0.03). Kaplan-Meier analysis confirmed improved 1-year survival of IMH with beta-blocker therapy (95% versus 67% without beta-blockers; P=0.004).
Conclusions: Regardless of aortic diameter, IMH of the ascending aorta (type A) is at high risk for early progression, and, thus, undelayed surgical repair should be performed. Moreover, oral beta-blocker therapy may improve long-term prognosis of IMH independent of anatomical location.