Acute type A intramural hematoma: analysis of current management strategy.

Background: Management of acute type A intramural hematoma (IMH) remains controversial, varying from immediate surgery to medical management only. Conversion to typical dissection remains a concern. We analyzed our experience managing acute type A IMH.
Methods and Results: Between October 1999 and May 2008, 251 patients with acute type A aortic dissection were treated, including 36 (14.3%) with type A IMH. Seven IMH patients (19%) were repaired immediately, 28 (80%) managed initially with optimal medical management and eventual repair and 1 (3%) with medical management only. End points analyzed were early mortality and conversion to typical dissection (flow in the false lumen of the ascending aorta). Time (hours) from onset of symptoms defined initiation of IMH. Early mortality for acute type A IMH was 8.3% (3/36): 14.3% (1/7) with immediate repair and 7.1% (2/28) when optimal medical management with eventual repair was undertaken (P=0.69). The 1 medically managed Asian patient survived with resolution of the IMH. Conversion to type A IMH to typical dissection occurred in 33% (12/36) of cases. No conversions were observed within 72 hours. Aortic diameter did not predict conversion. In actuarial analysis among the initially medically managed group with eventual repair, the hazard conversion to typical dissection increased significantly at 8 days from the onset of symptoms (P<0.05).
Conclusions: Despite optimal medical management, conversion of type A IMH to typical dissection still remains a concern, with the most significant risk beyond 8 days. In our patient population, timely surgical repair is recommended.