[The plasma level of an inactive moiety of B-type natriuretic peptide precursor as a predictor of cardiac function during operations under extracorporeal circulation]

Ventricular cardiomyocytes secrete brain natriuretuc peptide (BNP) and an inactive moiety of its precursor (nt-proBNP). It is recommended the blood level of the latter should be monitored to ascertain the severity of myocardial lesion. This investigation was undertaken to study the diagnostic and prognostic value of a substantial increase in blood nt-proBNP levels (600 pg/ml or more) in patients operated on under extracorporeal circulation. Thirty-eight patients operated on for coronary heart disease were examined. Before surgery, the plasma concentration of nt-proBNP had been determined by electrochemiluminescence (Elescys, Roche). According to plasma nt-proBNP levels, the patients were divided into 2 groups: 1) 24 patients with nt-proBNP levels of less than 600 pg/ml; 2) 14 patients with its levels of 600 pg/ml or more. Group 1 patients showed signs of diastolic dysfunction of the right ventricle: the lower ratio of its early to atrial filling linear velocity integrals and the increased end-diastolic volume index. In the postperfusion period, nt-proBNP is a significant independent predictor of left ventricular function. The patients with the baseline nt-proBNP levels of above 600 pg/ml were found to have decreases in ejection fraction of the left ventricle and in its pump ratio along with elevated pulmonary wedge pressure.