Natural History and Impact of Thoracic Endovascular Stent-Grafting on Type B Intramural Hematoma: A World of Caution

Objectives: Intramural hematoma (IMH) is characterized by an unpredictable natural history. Thoracic endovascular aortic repair (TEVAR) has increasingly been employed as treatment with limited midterm outcomes reported. Methods: To better characterize the natural history of type B IMH and TEVAR outcomes, we reviewed our institutional experience. Data were collected prospectively, and patients followed in a dedicated aortic clinic. Results: Since 2001, 40 patients were treated for type B IMH without focal intimal disruption (FID) on initial computed tomography (CT). All patients were initially treated with optimal blood pressure management, pain control, and control CT within 5 to 7 days. Fourteen patients had TEVAR during the index hospitalization due to the presence of a new FID with progression of the IMH thickness or persistent symptoms. Of the remaining 26 patients, 16 required late TEVAR at a mean of 41.3 ± 112.2 months for type B dissection, new FID, or pseudoaneurysm formation. The remaining 10 patients had complete resolution of the IMH on optimal medical therapy (OMT) alone. Patients in the early TEVAR group developed a significantly higher rate of complication than patients treated in the chronic TEVAR phase (78% vs 38%; P = .003). Patients treated with early and late TEVAR had a 5-year survival of 100% and 64.9%, respectively. Clinical Impact Favorable outcomes can be achieved with OMT and TEVAR for patients with type B IMH. The TEVAR performed in the acute setting carries a substantial risk of complications, emphasizing the need to optimize the timing of TEVAR and adapt stent-graft design to the pathophysiology of IMH.