Disappearance of aortic intramural hematoma and its significance to the prognosis

Background-An aortic intramural hematoma (IMH) is a form of aortic dissecti on (AD). IMHs regress with time or completely disappear in some patients, w hereas they progress to overt AD in other patients. The purpose of the pres ent study was to investigate how IMHs change serially during a follow-up pe riod. Methods and Results-We analyzed 44 consecutive medically treated patients w ith IMHs, in whom transesophageal echocardiography (TEE) was performed seri ally at both I and 6 months after the onset. After TEE, the patients were f ollowed with interviews (mean follow-up 1552+/-539 days). IMHs disappeared at 6 months in 21 patients (48%) (disappearance group), whereas IMHs were s till demonstrated at 6 months in 20 patients (45%) (persistent group); in t he 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 occur red until 6 months. The disappearance group was younger than the persistent group (64+/-11 versus 72+/-8 years, P<0.01), and the maximum diameter of t he aorta was smaller in the disappearance group than in the persistent grou p (33+/-5 versus 42+/-7 mm, P<0.01). During the long-term follow-up, overt AD occurred at 7 and 11 months in 2 patients, and progressive aortic dilata tion that required surgical treatment occurred at 12 and 24 months in of th e persistent group patients, whereas neither overt AD nor progressive aorti c dilatation occurred in the disappearance group. In the patients in whom o vert AD occurred, the maximal aortic diameter was >45 mill and an IMH was d emonstrated at 1 month. On the other hand, those with a maximal aortic diam eter of <45 mm or a disappeared IMH, did not have overt AD. Conclusion-IMHs disappear ed until month in 18% and until 6 months in 48% o f 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.