Clinical Analysis of Acute Type A Intramural Hematoma: Comparison Between Two Different Pathophysiological Types

Background Type A intramural hematoma (IMH) has two different etiologies, which are rupture of vasa vasorum and penetrating atherosclerotic ulcer (PAU); however, it is difficult to know which is the initiating event. Methods Between January 1993 and August 2004, 28 patients of acute type A IMH were treated in our department and were divided into two groups, 20 patients with IMH probably caused by rupture of vasa vasorum (non-PAU group) and 8 patients with IMH probably caused by PAU (PAU group), according to pathologic specimen and atherosclerotic findings on computed tomography. Background factors, radiographic findings, and prognosis were analyzed retrospectively. Results Surgery was performed in 15 patients (75%) in non–PAU group and 4 patients (50%) in PAU group during the first admission. Late progression was noted in 3 patients, and operation was required. Finally, operation was performed in 22 patients (78.6%). The history of myocardial infarction (p = 0.026) and chronic renal failure (p = 0.026) were more associated with PAU group than with non-PAU group. Ascending aortic diameter at the onset was significantly larger in non-PAU group (50.3 ± 6.6 mm) than in PAU group (43.9 ± 9.0 mm; p = 0.046), and there were significantly more ulcer lesions in PAU group (1.9 ± 0.4) than in non-PAU group (1.1 ± 0.4; p = 0.0004). There was no significant difference in long-term survival rates between them. Conclusions The PAU group patients have more coexisting atherosclerotic diseases and multiple aortic ulcer lesions with significantly mild ascending aortic dilatation compared with non-PAU group patients.