Morphometry and topography of the coronary ostia in the European bison

Coronary vessels have been widely studied in many species of domestic and wild mammals. However, there are no available literature reports describing the morphology and morphometry of the coronary ostia of the European bison (Bison bonasus). The aim of this study was to measure the area of the coronary ostia and assess their localisation in the coronary sinuses of the aortic root in the European bison.

The study material comprised 27 hearts from European bison of both sexes (16 males and 11 females), from 3 months to 26 years old, inhabiting the Bialowieza Forest (Bialowieza National Park, Poland). The animals were divided into two age groups: ≤ 5 years (group I) and > 5 years (group II).

In all the studied European bison, the aortic valve consisted of three semilunar leaflets, left, right and septal. The ostia of both coronary arteries were located beneath the sinotubular junction. The dimensions of the left coronary ostium were larger than those of the right coronary ostium. They were longer by on average 4.5 mm (95% confidence interval [CI] 3.5-5.6 mm), they were wider by on average 1.6 mm (95% CI 1.0-2.2 mm) and they had a larger area by on average 31.6 mm2 (95% CI 22.7-40.5 mm2). This was evident both in young and in adult bison. After adjusting for age, there were no differences in the ostia dimensions between males and females. There were no differences in the structure of the left and right coronary arteries in nine animals. In the remaining 18 animals, there were variations in the morphology of the coronary ostia or additional ostia.

Because of the anatomical similarity between the European bison and other ruminants, the results of this study can be applied to the other species including endangered ones.