PATHOMORPHOLOGICAL PICTURE OF STRUCTURAL CHANGES OF THE AUTOVENOUS CONDUITS WALLS, DEPENDING ON THE TECHNIQUE OF SAMPLING DURING CORONARY BYPASS SURGERY

Abstract

Coronary bypass surgery as one of the methods of revascularization is the most frequently performed operation in cardiac surgery. The use of internal thoracic arteries and the large
saphenous vein as conduits still remains as the gold standard. Early and long-term results of coronary bypass surgery directly depend on the effectiveness of the conduits functioning. The importance of the internal thoracic artery and its contribution to the results of surgery in coronary surgery can hardly be overestimated. The main disadvantage of autovenous conduits is their dysfunction, which begins to manifest itself from the first year after coronary bypass surgery, and according to the results of some studies, patency in 5 years after the surgery does not exceed 50–60%. This fact dictates the need to search for the causes of dysfunction of autovenous conduits. Venous shunts are in conditions that do not correspond to the original rheology of blood in their lumen, unlike the internal thoracic artery, and are subjected to constant pressure from the aorta. This fact is associated with the rate of dysfunction of the conduit due to the progression of proliferative processes in its wall. Of course, this fact may occur in violation of the patency of venous shunts, but the results of coronary shuntographies performed in the long term after surgery often demonstrate excellent results of the functioning of individual venous conduits. It is known that the capacity of the distal channel is one of the determining factors ensuring the long-term functioning of conduits, but the quality of conduits is also essential. The preservation of the structures of the conduit wall and, in particular, the endothelial layer ensures the constancy of homeostasis inside the vessel lumen and prevent the progression of proliferative processes that can lead to narrowing of the lumen or thrombosis. Prevention of damage to the endothelium of the venous conduit is provided by its sampling in a single block with surrounding tissues, which ensures the safety of the wall structures. The rejection of the technique of forced dilation of the vein`s lumen ensures the safety of the endothelial layer, which is clearly demonstrated by pathomorphological examination. The technique of preparing of venous conduits using the “No-touch” technique in combination with an adequate capacity of the shunted pool can provide freedom from dysfunction by improving the results of myocardial revascularization in a long-term period.