[Predictors of early occlusion of coronary bypass grafts in patients with extremely low ejection fraction]

The authors carried out a retrospective study aimed at revealing predictors of early incompetence of coronary bypass grafts in patients with the ejection fraction below 30%. The study included a total of 104 patients presenting with coronary artery disease and the ejection fraction below 30%, who over the period from 2009 to 2016 underwent coronary artery bypass grafting with the use of autovenous and autoarterial conduits. 77 patients endured plasty of an aneurysm of the left ventricle (LV), 89 patients sustained plasty of the valvular apparatus. All patients were subjected to control coronary bypass angiography (CBA) within 12 postoperative months. Thus, we analysed a total of 184 autoarterial and 84 autovenous shunts. The findings of CBA revealed occlusions of 2 (1%) arterial and 10 (11%) venous conduits. Analysing the coronary bypass angiographies of the patients ranked according to the values of the effective stroke volume index demonstrated the following regularity: a decrease in the LV effective stroke volume index of less than 30 ml/m2 was accompanied bу increased incidence of thrombosis of autovenous shunts in the immediate postoperative period. Predictors of early occlusion of coronary bypass grafts were revealed by means of the Cox regression analysis. It was determined that using an autovein increased the risk of occlusion of the shunt by 26%, a decrease in the effective stroke volume index of the left ventricle by 1 ml/m2 increased the risk of early occlusion of coronary bypass grafts by 18%, a decrease in the diameter of the shunted artery by 0.5 mm increased the risk for early occlusion of the shunt by 12%, a decrease in the blood flow velocity (Qmean) by 1 ml/m2 increased the risk for occlusion of the shunt by 10%, a decrease in the peripheral resistance index (RI) by 1 unit elevated the risk of early occlusion of the bypass graft by 12%. Analysing the revealed independent predictors with the help of the neural network method demonstrated that the strongest influence on early incompetence of the coronary bypass graft was exerted by the type of the conduit and effective stroke index.