Update on the Therapeutic Strategy of Type B Aortic Dissection

Abstract

Stanford type B aortic dissection (TBAD) is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute TBAD unless they have fatal complications. Although patients with uncomplicated TBAD have relatively low early mortality, aorta-related adverse events during the chronic phase worsen the long-term clinical outcome. Recent advances in thoracic endovascular aortic repair (TEVAR) can improve clinical outcomes in patients with both complicated and uncomplicated TBAD. According to present guidelines, complicated TBAD patients are recommended for TEVAR. However, the indication in uncomplicated TBAD remains controversial. Recent results of randomized trials, which compared the clinical outcome in patients treated with optimal medical therapy and those treated with TEVAR, suggest that preemptive TEVAR should be considered in uncomplicated TBAD with suitable aortic anatomy. However, these trials failed to show improvement in early mortality in patients treated with TEVAR compared with patients treated with optimal medical therapy, which suggest the importance of patient selection for TEVAR. Several clinical and imaging-related risk factors have been shown to be associated with early disease progression. Preemptive TEVAR might be beneficial and should be considered for high-risk patients with uncomplicated TBAD. However, an interdisciplinary consensus has not been established for the definition of patients at high-risk of TBAD, and it should be confirmed by experts including physicians, radiologists, interventionalists, and vascular surgeons. This review summarizes the current understanding of the therapeutic strategy in patients with TBAD based on evidence and expert consensus.

Keywords: Acute aortic dissection; Management; Medical therapy; Surgery; TEVAR.

Fig. 1.

Variations of Stanford type B aortic dissection A: Classic aortic dissection or communicating aortic dissection. Apparent longitudinal blood flow is observed in the false lumen. B: Ulcer-like projection develops during clinical course in patients with aortic IMH. In the JCS guideline, this type is designated as ULP-type dissection. C and D: IMH or non-communicating dissection. In C, the patient has thrombosed false lumen and tear but without blood flow. In D, the patient has thrombosed false lumen without tear nor blood flow. ULP, ulcer-like projection; IMH, intramural hematoma.

Fig. 2.

Successful preemptive TEVAR in a patient with uncomplicated TBAD A 35-year-old man with classic aortic dissection. A: Axial and sagittal views on CTA imaging at onset, showing a maximum aortic diameter of 34 mm. B: Axial and sagittal views on CTA imaging at 3 months follow-up revealed significant aortic dilatation, showing a maximum aortic diameter of 40 mm. The patient underwent preemptive TEVAR. C: At 2 years after TEVAR, axial and sagittal views on CTA imaging showed favorable aortic remodeling with expansion of the true lumen.

Fig. 3.

Aortic enlargement of sac formation in a patient with TBAD A: A 60-year-old woman with sac formation in the false lumen. Left and right panels show sagittal image at onset and enlargement of the false lumen, respectively. B: Possible explanation of why partial thrombosis of the false lumen leads to aortic dilatation⁴⁹⁾.