Natural history and serial morphology of aortic intramural hematoma: A novel variant of aortic dissection

Background Acute aortic dissection is a cardiovascular emergency that requires prompt diagnosis and treatment. Transesophageal echocardiography is the current standard diagnostic imaging modality in many medical centers. Aortic intramural hematoma is a variant of aortic dissection whose natural history and prognosis have not been well studied. We performed transesophageal echocardiography in patients with aortic intramural hematoma to determine the echocardiographic characteristics and echocardiographic evolution of this lesion, impact on patient management, and patient outcome. Methods and Results Twenty-one consecutive patients with aortic intramural hematoma confirmed anatomically (four patients) or with an additional diagnostic imaging technique (17 patients) underwent a transesophageal echocardiographic examination. Fifteen patients with longstanding hypertension had chest or back pain, and the intramural hematoma was visualized in the ascending aorta (n = 4), along the whole aorta (n = 4), in the descending aorta (n = 6), or in the aortic arch (n = 1). The thickening of the aortic wall was crescentic. Patients with ascending aortic intramural hematoma had the following results: two patients died suddenly, three patients underwent surgery because of increased aortic wall thickening (one patient) or secondary intimal tear (two patients), and the remaining three patients had regression of the hematoma. Patients with hematoma confined to the descending aorta and the patient with aortic arch involvement (n = 7) had a different result: one patient died from aortic rupture and the remaining six patients did well. Six patients had a traumatic aortic injury, and the intramural hematoma was located along the descending thoracic aorta. The thickening of the aortic wall was circular in five patients and crescentic in one. Three of these patients had normalized thickness of the aortic wall on follow-up transesophageal echocardiographic studies. The other three patients died from multiorgan system failure. Aortography showed a reduction of the diameter of the aortic lumen in four patients; diameter in the remaining 17 patients was normal. Conclusions Aortic intramural hematoma can be detected and monitored by transesophageal echocardiography but not by aortography. Two types of aortic intramural hematoma can be distinguished: (1) traumatic of good prognosis and (2) nontraumatic, which can be an early stage of the classic aortic dissection, with bad prognosis in cases involving the ascending aorta.