Risk evaluation of type B aortic dissection. Importance for treatment of acute aortic syndrome

Acute aortic syndrome (AAS) is a modern term used to describe interrelated emergency aortic conditions with similar clinical characteristics and challenges including aortic dissection, intramural hematoma (IMH) and penetrating aortic ulcer (PAU). Population-based studies suggest that the incidence of aortic dissection ranges from 2.6 to 3.5 cases per 100,000 inhabitants per year; hypertension and a variety of genetic disorders with altered connective tissue are the most prevalent risk conditions. In general, open surgical repair is recommended when dissection involves the ascending aorta, whereas medical management and endovascular stent graft repair is the best option when the ascending aorta is spared. Pathological conditions involving the aortic arch may be treated using a hybrid approach combining debranching of supra-aortic vessels and stent graft placement. Stent graft-induced remodeling of a dissected aorta seems to have long-term benefits in complicated and so-called uncomplicated type B dissections as almost every case reveals a risk profile and one in eight patients diagnosed with acute type B aortic dissection has either an IMH or a PAU. Pain is the most commonly presenting symptom of AAS and should prompt immediate attention including diagnostic imaging modalities, such as multislice computed tomography, transesophageal ultrasound and magnetic resonance imaging. A specific therapeutic approach is necessary for IMH and PAU because without treatment they have a very poor outcome, are unpredictable in evolution and can be more severe than acute aortic dissection. All patients must receive the best medical treatment available at admission. High-risk but asymptomatic patients with IMH and PAU can probably be monitored without interventions. All symptomatic patients will need treatment. In many of these patients a direct surgical approach is often prohibitive due to age and multiple comorbidities. Endovascular treatment offers superior results and is becoming a recognized indication for such patients. Irrespective of the treatment modality close surveillance is mandatory in order to monitor disease progression.