Diastolic dysfunction in septic shock is an independent predictor of elevated B-type natriuretic peptide and hospital mortality

Abstract

Introduction: Diastolic dysfunction as demonstrated by tissue Doppler imaging (TDI), particularly E/E' (peak early diastolic transmitral/peak early diastolic mitral annular velocity) is common in critical illness. In septic shock, the prognostic value of TDI is undefined. This study sought to evaluate and compare the prognostic significance of TDI and cardiac biomarkers (B-type natriuretic peptide (BNP); N-terminal proBNP (NTproBNP); troponin T (TnT)) in septic shock. The contribution of fluid management and diastolic dysfunction to elevation of BNP was also evaluated. Methods: Twenty-one consecutive adult patients from a multidisciplinary ICU underwent transthoracic echocardiography and blood collection within 72 hours of developing septic shock. Results: The mean +/- SD APACHE III score was 80.1 +/- 23.8. Hospital mortality was 29%. E/E' was significantly higher in hospital nonsurvivors (15.32 +/- 2.74, survivors 9.05 +/- 2.75; P = 0.0002). Areas under ROC curves were E/E' 0.94, TnT 0.86, BNP 0.78 and NTproBNP 0.67. An E/E' threshold of 14.5 offered 100% sensitivity and 83% specificity. Adjustment for APACHE III, cardiac disease, fluid balance and grade of diastolic function, demonstrated E/E' as an independent predictor of hospital mortality (P = 0.019). Multiple linear regression incorporating APACHE III, gender, cardiac disease, fluid balance, noradrenaline dose, C-reactive protein, ejection fraction and diastolic dysfunction yielded APACHE III (P = 0.033), fluid balance (P = 0.001) and diastolic dysfunction (P = 0.009) as independent predictors of lnBNP. Conclusions: E/E' is an independent predictor of hospital survival in septic shock. It offers better discrimination between survivors and nonsurvivors than cardiac biomarkers. Fluid balance and diastolic dysfunction were independent predictors of BNP concentration in septic shock.