Long-Term Outcome of Type B Aortic Intramural Hematoma: Comparison With Classic Aortic Dissection Treated by the Same Therapeutic Strategy

Background The long-term clinical course and therapeutic strategy of patients with type B aortic intramural hematoma (IMH) are not completely known. The purpose of this study was to clarify long-term prognosis of patients with type B IMH by comparison with type B classic aortic dissection (AD). Methods Clinical data were compared retrospectively between 37 patients with acute type B IMH (IMH group) and 69 patients with acute type B AD (AD group). Our therapeutic strategy for all patients was medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression. Results Initially, medical therapy was selected for 104 of 106 (98%) patients. In two patients of the AD group, immediate surgical treatment was performed because of aortic rupture. As for complications, no significant difference was seen between the two groups. There was no significant difference in the incidence of the total number of deaths; early death, late death, or causes of deaths. The actuarial survival rates for the IMH group at 1, 2, 5, and 10 years were 97 ± 3, 97 ± 3, 85 ± 9, and 85 ± 9%, respectively; the values were 96 ± 1, 96 ± 1, 89 ± 4, and 71 ± 9%, for the AD group. The actuarial survival rates of the two groups were not significantly different from each other (p = 0.398). Conclusions Patients with type B IMH have similar long-term prognosis to patients with type B AD. Medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression can be a rational therapeutic strategy in patients with type B IMH.