Prevalence of type III arch configuration in patients with type B aortic dissection

OBJECTIVES: Type III aortic arch configuration consistently presents anatomical and biomechanical characteristics which have been associated with an increased risk of type B aortic dissection (TBD). Our aim was to investigate the prevalence of type III arch in patients with TBD and type B intramural haematoma (IMH-B). METHODS: A multicentre retrospective analysis was performed on patients with TBD and IMH-B observed between 2002 and 2017. The computed tomographic images were reviewed to identify the type of aortic arch. Exclusion criteria included previous arch surgery, presence of aortic dissection or aneurysm proximal to the left subclavian artery and bovine arches. An ad hoc systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to assess the prevalence of type III arch in non-TBD and non-aneurysmal patients. RESULTS: Two hundred and sixty-one patients with TBD/IMH-B were found to be suitable for the study and were stratified according to aortic arch classification. The ad hoc literature search provided 10 relevant articles, from which a total of 7983 control cases were retrieved. TBD/IMH-B patients were significantly younger than controls [64.3, standard error: 0.74 (62.84-65.76) vs mean pooled age 70.5, standard error: 0.40 (69.71-71.28)]. Patients with TBD/IMH-B presented with a significantly higher prevalence of type III arch [41.0% (107/261) (35.2-47.1)] than controls [16% (1241/7983) (10-22)]. CONCLUSIONS: Our data indicate an association between type III arch configuration and the occurrence of TBD/IMH-B. These findings warrant further studies to disclose the potential role of type III arch configuration as an anatomical risk factor for TBD/IMH-B.