Cellular/intercellular interrelations in various parts of aorta after reconstructive treatment of aortic stenosis in infants

Aim. The article focuses on the evaluation of cellular/intercellular relationships in various parts of the aorta after reconstructive treatment of aortic stenosis in infants. Methods. Medical histories and protocols of autopsies of three newborns were studied after surgical treatment of aortic coarctation. The operations were performed in children at 8th, 10th and 15th day after birth. In two cases, resection of the aortic lumen narrowing, botulinum duct ligation and formation of a direct aortic anastomosis were performed. In one observation, a closed balloon dilatation of the aorta in the area of constriction was used. When performing autopsy, the size of the heart, the perimeter of the aorta at the surgical sites and various parts of the aorta were examined. The fragments of the wall of the aortic sections were cut out and fixed in 10% neutral formalin. Histologic sections were prepared in a conventional way followed by staining them with hematoxylin-eosin or picrofuxin by Van Gieson, while elastic fibers were stained with rezorcin-fuchsin by Hotchkiss and Periodic acid-Schiff (PAS) in order to detect mucopolysaccharides. Results. Cellular/intercellular relationships in various parts of the aorta following aortic coarctation in infants have some morphological features. Morphometric examination of the heart and aorta showed a significant increase in the volume and mass of the heart compared with the normal values due to myocardial hypertrophy of the right and left ventricles of the heart. An uneven narrowing of the aortic lumens was most pronounced in the arch and isthmus as compared to the ascending and thoracic parts of aorta. Morphological examination of the aortic wall in the constriction zones demonstrated the presence of coagulation necrosis, lysis of elastic, collagen fibers with surrounding hyperplasia of smooth myocytes, newly formed thin-walled capillary vessels. Outside the coarctation zone, the most significant changes characterized by the development of hypoelastosis, non-uniform accumulation of acid mucopolysaccharides were observed in the walls of the arch and the ascending aorta. Conclusion. In infants with coarctation of the aorta, dilatation of the ascending aorta with compensatory hypertrophy of the heart is observed, and a muscle-fibrous tissue, rich in smooth myocytes and newly formed thin-walled vessels, tends to develop in stenotic zones. The risk of restenosis development is believed to depend on the prevalence and severity of proliferative processes of the cellular elements of the aorta, which allows us to consider early surgical interventions to prevent irreversible destructive changes as justifiable.