HIGH PREVALENCE OF TYPE III ARCH CONFIGURATION IN PATIENTS WITH TYPE B AORTIC DISSECTION

Introduction - Patients with Type B aortic dissection (TBD) in whom the proximal entry tear is located within 2 cm from the left subclavian (i.e. in Zone 3 for TEVAR) have been reported to have a worse prognosis suggesting the presence of an anatomic risk factor (1). We previously showed that in Type III arches, Zone 3 is associated with a consistent pattern of severe angulation and tortuosity (2), and higher pulsatile forces (3). Our aim was to investigate the prevalence of Type III arch configuration in TBD patients.
Methods - We retrospectively reviewed 61 cases of TBD in whom CT images were available. Exclusion criteria were previous arch surgery and bovine arches. Forty-seven suitable cases were stratified according to Aortic Arch Classification. A literature review was conducted to assess the prevalence of Type III arch in non TBD and non aneurysmatic patients. A total of 2357 cases were collected from 7 studies.
Results - TBD cases presented a 72.3% (34/47) prevalence of Type III arch compared to 19.5% (459/2357) in controls (P<.0001). In all Type III TBD cases, the proximal entry tear was located in Zone 3. TBD patients were significantly younger than controls (65.25±13 vs mean pooled age 69.8± 9.1) (P=.0013).
Conclusion - Our data indicate an association between Type III arch configuration and the occurrence of TBD. Such association appears even more relevant when considering the younger age of TBD patients, being Type III arch more common in the elderly. These findings warrant further studies to disclose the potential role of Type III arch configuration as an anatomic risk factor for TBD.