ORIGINAL INVESTIGATIONS: Different Clinical Features of Aortic Intramural Hematoma Versus Dissection Involving the Descending Thoracic Aorta

Background: Although indicators of surgical and medical treatment have been applied to patients with typical dissection (AD) of the descending thoracic aorta, the natural history of descending aortic intramural hematoma (AIH) is not yet clearly known. Objective: The goal of this study was to test the hypothesis that the absence of flow communication through the intimal tear in AIH involving the descending aorta has a different clinical course compared with AD. Methods: We prospectively evaluated clinical and echocardiographic data between AD (76 patients) and AIH (27 patients) of the descending thoracic aorta. Results: Patients had no differences In age, gender, or clinical presentation. The development of pleural effussion or periaortic hematoma was more frequent in patients with AIH than it was in patients with AD. AIH and AD had same predictors of complications at follow-up: aortic diameter (>5 cm) at diagnosis and persistent back pain. Although medical treatment was selected in the same proportion between groups, surgical treatment was more frequently selected in AD (39% vs. 22%, p < 0.01). AD patients who received surgical treatment had higher mortality than those with AIH (36% vs. 17%, p < 0.01). There was no difference in mortality between patients who received medical treatment (15% in AD vs 14% in AIH, p = 0.7). In follow-up imaging studies of 23 patients with AIH,6 patients (25%) showed complete resolution and 6 patients (25%) increased the descending aortic diameter. Typical AD developed in 3 patients (13%). A three-year survival rate did not show significant difference (82 ± 6% in AIH vs 75 ± 7% in AD, p = 0.37). Conclusion: AIH of the descending thoracic aorta have relatively frequent complications at follow-up including dissection and aneurysm formation. Medical treatment with very close imaging follow-up and timed elective surgery in cases with complications allow better management for patients with AIH of the descending thoracic aorta.