ИСТИНА

Objective. The assessment of changes in the parameters of local hemodynamics in patients with symptomatic occlusions of the internal carotid artery (ICA) and moyamoya disease after bypass surgery. Background: Occlusions of the ICA and moyamoya disease are common causes of stroke due to perfusion deficit. Surgical revascularization is an effective treatment for these patients. To create a well-functioning bypass, it is very important to understand the processes of local hemodynamics. Methods: Study included 112 patients who underwent surgical treatment in Burdenko Center of Neurosurgery from 1999 to 2020. Among them, there were 105 patients with occlusions of the ICA and 7 patients with moyamoya disease. In all patients during the main stage of bypass surgery local hemodynamic parameters were studied using methods of intraoperative contact Doppler ultrasonography (89 patients - 72%) and flowmetry (56 cases - 50%). In 33 cases (29%) both methods were used. In 42 cases we studied the impact of CT-perfusion measured mean transit time (MTT) values on local hemodynamic parameters. Measurements of local hemodynamic parameters, including blood flow values and flow direction in recipient artery proximally and distally to anastomosis, were made before and after cerebral revascularization. Results: The study revealed that patients with occlusions of the ICA (105 patients) in all cases had distal direction of blood flow before the bypass. In patients with moyamoya disease proximal direction of blood flow was seen more often (5 from 7 cases – 71%). Values of blood flow in cortical vessels significantly differed depending on the severity of perfusion deficit. Local hemodynamics in recipient artery after revascularization significantly depended on the ability of bypass to reverse the blood flow in the proximal cortical artery. Change in the direction of blood flow was observed in 86 cases (77%). Possible mechanism of local blood flow alteration after bypass surgery was studied. Conclusions: Knowledge of initial parameters of hemodynamics and their changes after the revascularization play important role for the correct technique of the surgery, the further functioning of the bypass, and as a result, the improvement of the clinical symptoms.