Early assessment of outcome in cardiogenic shock: Relevance of plasma N-terminal pro-B-type natriuretic peptide and interleukin-6 levels

Objective: Plasma N-terminal pro-B-type natriuretic peptide (Nt-pro-BNP) levels are frequently elevated in critically ill patients and are associated with an increased mortality. In this study, we determined Nt-pro-BNP levels in patients with cardiogenic shock (CS) and evaluated its association with clinical and hemodynamic parameters and 30-day mortality. Design: Retrospective study. Setting: Two, eight-bed intensive care units at a university and a community hospital. Patients. Retrospective study on stored plasma samples of 58 patients with CS, obtained at admission to the intensive care unit. Interventions: None. Measurements and Main Results: Massively elevated Nt-pro-BNP concentrations showed no significant association with duration of shock, total Sequential Organ Failure Assessment score, or invasive hemodynamic parameters at the time of blood sampling but a significant association with estimated glomerular filtration rate (p < 0.001), C-reactive protein (p = 0.03), age (p = 0.005), and body weight (p = 0.03). Both in univariate and multivariate survival analyses, Nt-pro-BNP levels above the median (>12,782 pg/mL) were significant predictors of 30-day mortality (p < 0.001) and showed a complementary role with inter-leukin (IL)-6 in predicting outcome. Patients with IL-6 >195 pg/mL and Nt-pro-BNP above the median value had the highest 30-day mortality (93.7%), whereas patients with lower IL-6 levels together with lower Nt-pro-BNP levels had significantly better survival (mortality rate 26.3%). Among patients who had acute myocardial infarction, those with Nt-pro-BNP concentrations above the median level showed a highly impaired clinical course even if coronary revascularization was successful (30-day mortality 90.9% vs. 29.4%, p = 0.001), whereas survival of patients with unsuccessful revascularization did not differ significantly with respect to the median of Nt-pro-BNP (30-day survival rate 81.8% vs. 75.0%, p = 0.71). Conclusion: The massive elevations of Nt-pro-BNP observed in the early phase of CS seem to be independent of ventricular performance. Nt-pro-BNP levels are nevertheless predictive of 30-day survival in patients with CS especially in those with successful revascularization and might be used in combination with IL-6 for estimation of outcome early on. (Crit Care Med 2009; 37:1837-1844)