Different remodeling of descending thoracic aorta after acute event in aortic intramural hemorrhage versus aortic dissection

The natural healing process of medically treated aortic dissection (AD) and aortic intramural hemorrhage (AIH) developed in the descending thoracic ao rta was compared to test the hypothesis that absence of intimal tear and fl ow communication in AIH may have different impact on the remodeling of the affected aorta after the acute event. In 25 patients with AD and 20 with AI H involving distal descending thoracic aorta stabilized with medical treatm ent, follow-up (mean 9 months) transesophageal echocardiography was perform ed-to measure the maximal dimensions of aorta, true lumen, false lumen in A D, and-abnormal wall thickening in BIH, The sex ratio, prevalence of hypert ension, baseline maximal dimension, and longitudinal extent of the affected aorta did not show any significant difference in bath group;. Patients wit h AIH were older than those with AD (63 +/- 10 vs 50 +/- 9, p <0.01). Disap pearance of abnormal wall thickening with complete restoration of the aorta occurred in 70% (14 of 20) patients with AlH, which was significantly more frequent than in AD (8%, p <0.01). In AD, progressive dilatation of the ao rta with continuous flow communication in the false lumen resulted in large r dimension of the aorta than in AIH (44 +/- 13: vs 35 +/- 7 mm, p <0.01). Absence of persistent flow communication resulted in a favorable remodeling process in AlH affecting distal descending aorta. This finding, along with different mean age in AlH and AD, may suggest that AlH is not lust a precu rsor of overt AD but a distinct disease entity with different pathophysiolo gy. (C) 1999 by Excerpta Medical, Inc.