Anatomy of the coronary arteries and localization of coronary atherosclerosis in siblings with coronary heart disease

There is no doubt that there is a similar genetic predisposition in close relatives to the development of cardiovascular disease, while the features of coronary anatomy and possible commonality of pathological process in close relatives remain beyond research interest. 
Aim. To study the anatomy of the coronary arteries, the nature and severity of coronary lesion in pairs of male siblings suffering from coronary artery disease, in comparison with control pairs of patients who are not closely related. 
Materials and methods. This retrospective study included 87 male patients. The main group (58 patients or 29 couples) consisted of siblings with a horizontal hereditary burden for coronary artery disease. The control subgroup included 29 big brothers of the main group and another 29 patients who unrelated to them. To assess the degree of anatomy identity of the coronary bed in pairs of patients, we used a comparative characteristic of 25 segments of the coronary arteries (SyntaxScore). If there was similarity in anatomy and in the severity of the atherosclerotic process, each segment was assigned one point. In terms of the ratio of the total scores to the total number of segments (n=25), each pair of patients was assigned anatomical and atherosclerotic identity indexes. 
Results. According to the results of the study, the average indices of anatomical and atherosclerotic identity indexes were significantly higher in pairs of sibs compared to control pairs of patients (0.92 versus 0.88, p=0.008 and 0.92 versus 0.76, p0.001 respectively). When analyzing atherosclerotic lesions of the coronary arteries in pairs of sibs, a statistically significant coincidence of lesions in a number of segments of the coronary arteries was revealed, with the highest agreement in the left main coronary artery (=0.869, p0.001) and in the proximal segments of the main branches of the coronary arteries: left anterior descending artery (=0.786, p0.001) and right coronary artery (=0.812, p0.001). In the group of control pairs, such regularities were not revealed. 
Conclusion. In siblings with horizontal hereditary burden for coronary artery disease along the sibling line, the average anatomical and atherosclerotic identity indexes are significantly higher compared to control pairs. In pairs of siblings, there is the highest and most reliable probability of developing coronary atherosclerosis in the left main coronary artery and in the proximal segments of the left anterior descending artery and right coronary artery.