Conference Coverage

A bovine arch predicts worse outcomes with type B aortic dissections



– The presence of a bovine arch predicts higher mortality in patients with a type B aortic dissection (TBAD), according to a study presented by Jan S. Brunkwall, MD, at a symposium on vascular and endovascular issues sponsored by the Cleveland Clinic Foundation.

Dr. Jan S. Brunkwall

The bovine arch is a congenital interruption in the evolution of the arch, and is a misnomer because it does not actually reflect the arch branching pattern found in cattle. It represents the most common variation of the aortic arch, with a prevalence of 1%-41%, depending on the literature, according to a study published by Dr. Brunkwall, chairman of the department of vascular and endovascular surgery at the University of Cologne (Germany), and his colleagues (Eur J Vasc Endovasc Surg. 2018; 55:385-391).

In order to assess the effect of the bovine arch on survival, Dr. Brunkwall and his colleagues performed a retrospective cohort analysis of patients with TBAD admitted at two centers. CT angiograms (CTAs) of patients referred because of aortic dissection were also reevaluated with regard to the presence of a bovine arch.

A total of 154 patients with TBAD and 168 with type A aortic dissection were assessed, and 110 oncologic patients who had undergone a chest CTA for disease staging during the study period acted as a control group.

There was an overall prevalence of 17.6% for bovine arch variants, with no statistical difference in prevalence between patients with a dissection and those in the control group, or between patients with a type A or type B dissection. However, mortality was 34.5% in patients with TBAD who had a bovine arch versus 16% in patients without a bovine arch. This was a significant difference (P =.04), according to Dr. Brunkwall.

Multivariate analysis showed that the presence of a bovine arch with TBAD was an independent predictor of mortality. “The reason for the high mortality cannot be explained by our data,” said Dr. Brunkwall, “but there has been a suggestion that the shear stress is different and higher in patients with a bovine arch leading to a stiffer aorta and more endothelial damage.”

Dr. Brunkwall reported that he had no disclosures.

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