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