Disappearance of Aortic Intramural Hematoma and Its Significance to the Prognosis

Background —An aortic intramural hematoma (IMH) is a form of aortic dissection (AD). IMHs regress with time or completely disappear in some patients, whereas they progress to overt AD in other patients. The purpose of the present study was to investigate how IMHs change serially during a follow-up period. Methods and Results —We analyzed 44 consecutive medically treated patients with IMHs, in whom transesophageal echocardiography (TEE) was performed serially at both 1 and 6 months after the onset. After TEE, the patients were followed with interviews (mean follow-up 1552±539 days). IMHs disappeared at 6 months in 21 patients (48%) (disappearance group), whereas IMHs were still demonstrated at 6 months in 20 patients (45%) (persistent group); in the disappearance group, IMHs disappeared at 1 month in 8 patients (18%). In 3 patients (7%) in whom an IMH was demonstrated at 1 month, overt AD occurred until 6 months. The disappearance group was younger than the persistent group (64±11 versus 72±8 years, P 45 mm and an IMH was demonstrated at 1 month. On the other hand, those with a maximal aortic diameter of <45 mm or a disappeared IMH did not have overt AD. Conclusions —IMHs disappeared until 1 month in 18% and until 6 months in 48% of patients with IMHs. The disappearance of IMHs was related to the maximum diameter of the aorta and age. Both a disappeared IMH and a maximal aortic diameter of <45 mm suggest a good prognosis.