Informativity of the cardiac biomarker NT-proBNP early after on-pump coronary artery bypass grafting (pilot study)

The objective: to study the relationship between the blood levels of the N-terminal segment of B-type natriuretic peptide precursor (NT-proBNP) and hemodynamic parameters after on-pump ischemic heart disease (IHD) surgeries, and to evaluate the biomarker association with myocardial dysfunction manifestations. Material and methods. The study involved 38 patients aged 55,0±1,5 years with IHD who underwent coronary arteries bypass grafting (CABG). NT-proBNP blood level, pulmonary artery catheterization (PAC) data, and transpesophageal echocardiography (TEE) data were studied within the first hour of admission to the intensive care unit (ICU). Correlation analysis, logistic regression with calculation of odds ratio (OR) and 95% confidence interval (95% CI) and ROC analysis with calculation of area under ROC curve (AUC) were used. Results. In 52.6% of patients, NT-proBNP blood level was normal (179.75 [112.65–237.5] pg/ml), and in 47.4% of patients the biomarker level was increased (615.25 [425.7–1158.0] pg/ml). NT-proBNP blood level was not correlated with PAC data and moderately correlated with TEE parameters. NT-proBNP >366 pg/mL were associated with left ventricular (LV) end-systolic area index (LVESAI) >9 cm2 /m2 (OR1.0032, 95% CI 1.0009–1.0054, p = 0.006, AUC0.847), NTproBNP >440 pg/mL were associated with LV area contraction fraction (LVACF) <40% (OR1.0021, 95% CI 1.0001–1.0042, p = 0.036, AUC0.750) and with LV end-diastolic area index (LVEDAI) >15 cm2 /m2 (OR1.0029, 95% CI 1.0002–1.0055, p = 0.032, AUC0.865). NT-proBNP <272 pg/mL identified patients without postoperative inotropic support (OR0.9973, 95% CI 0.9947–0.9999, p=0.041, AUC0.737), and NT-proBNP >385 pg/mL was a predictor of ICU length of stay >24 hours (OR1.0029, 95% CI 1.0008–1.0050, p = 0.008, AUC0.731). NT-proBNP >505 pg/mL was associated with a vasoactive-inotropic index >10 (OR1.0026, 95% CI 1.0006–1.0046, p = 0.010, AUC0.769), and NT-proBNP >701 pg/mL was a predictor of the refractory heart failure (HF) (OR1.0066, 95% CI 1.0012–1.0120, p = 0.017, AUC0.976). Conclusion. On admission to the ICU, the median NT-proBNP content in patients who underwent on-pump CABG was within the normal range and amounted to 305.0 [176.2–604.5] pg/ml. Biomarker at this stage of treatment moderately correlated with preoperative echocardiographic indices of LV systolic function. In the early period after admission of patients to the ICU, NT-proBNP levels within 366–448 pg/ml are associated with signs of myocardial dysfunction, including LVESAI >9 cm2/m2, LVEDAI >15 cm2/m2, LVACF <40% and ICU length of stay >24 h. NT-proBNP in the range of 505–701 pg/ml were associated with severe postoperative HF clinical sings.