Results of ultrasound flowmetry for coronary artery bypass grafting in high-risk patients

Backgraund. Today ischemic heart disease (CHD) ranks first in the structure of mortality in the Russian Federation. Despite the rapid development of methods for treating coronary artery disease, coronary artery bypass grafting (CABG) remains the gold standard. Currently, intraoperative flowmetry is increasingly used to assess the functional state of coronary bypass grafts and to determine the blood flow velocity in them, which significantly improves the overall quality of the performed surgical intervention [1-3]. Aims: to evaluate the effectiveness of the use of intraoperative ultrasound flowmetry and to reveal the differences in the characteristics of blood flow in coronary bypass grafts in patients with high surgical risk who underwent surgery in conditions of cardiopulmonary bypass and on a beating heart. Materials and methods: In a prospective study conducted in the period from 2017 to 2019, 189 patients of high surgical risk who underwent CABG both under the conditions of cardiopulmonary bypass and on a beating heart were included. Intraoperative ultrasound flowmetry was performed in all patients in both groups. To assess the functional state of the imposed shunts, such indicators as mean volumetric blood flow velocity, pulsation index and diastolic flow were used. Results. When comparing the flowmetric parameters between the groups, no statistically significant differences were found (p>0,05). However, in patients who underwent CABG under the conditions of cardiopulmonary bypass (group 1), there was a longer duration of mechanical ventilation and the need for prolonged mechanical ventilation (27,5±93,7 hours and 17 cases versus 10,2±40 hours and 6 cases in the group with CABG on the beating heart (group 2)). In the majority of patients in group 2, hemodynamics remained stable, cardiotonic support for 24 hours or more was required for 48 (37,5%) patients, while in group 1, 78 (61,3%) patients required cardiotonic support in the early postoperative period (p = 0,0001). The mean time spent in the ICU was 39,9±97,3 and 19,3±36,2 h for groups 1 and 2, respectively (p = 0,0006). In addition, the average blood loss in patients of group 1 exceeded the values of blood loss in group 2 (420±220 ml and 315±245 ml, respectively). The fatal outcome in group 1 was 1,5% (2 patients), caused by ischemic stroke, in group 2 - 1% (1 patient), the cause was multiple organ failure against the background of acute myocardial infarction. Conclusions. Despite the statistically insignificant difference in the obtained flowmetric data in the groups, the very possibility of intraoperative assessment of coronary blood flow using ultrasound flowmetry significantly reduces the risks of postoperative complications associated with the anastomotic technique.