A Calf with a Left Aortic Arch and a Right Descending Aorta

Abstract

A left aortic arch with a right descending aorta was observed in a 2-day-old, female Holstein calf. The ascending aorta originated from the right ventricle and continued to the left aortic arch at the left side of the trachea. After diverging from the bicarotid trunk and the left subclavian artery, it turned medially, passed to the right over the trachea and the esophagus, diverged from the aberrant right subclavian artery, and joined the right descending aorta. The trachea and esophagus were compressed by an incomplete vascular ring formed by the ascending aorta, left aortic arch, right descending aorta, and right subclavian artery. The calf also demonstrated other cardiovascular malformations such as situs inmrsus of the atria, straddling of the mitral valve, right-ventricular double outlet, ventricular septal defect, tubular hypoplasia of the aortic isthmus, congenital fistula between the left coronary artery and the left ventricle, and right costocervical venous connection to the left atrium.