Background: In vitro studies suggested that circulating inflammatory cytokines cause septic myocardial dysfunction. However, no in vivo clinical study has investigated whether serum inflammatory cytokine concentrations correlate with septic myocardial dysfunction.
Methods: Repeated echocardiograms and concurrent serum inflammatory cytokines (IL-1β, IL-6, IL-8, IL-10, IL-18, tumor necrosis factor-α, and monocyte chemoattractant protein-1) and cardiac biomarkers (high-sensitivity [hs] troponin-T and N-terminal pro-B-type natriuretic peptide [NT-proBNP]) were examined in 105 patients with severe sepsis and septic shock. Cytokines and biomarkers were tested for correlations with systolic and diastolic dysfunction, sepsis severity, and mortality.
Results: Systolic dysfunction defined as reduced left ventricular ejection fraction (LVEF) < 50% or < 55% and diastolic dysfunction defined as e'-wave < 8 cm/s on tissue-Doppler imaging (TDI) or E/e'-ratio were found in 13 (12%), 24 (23%), 53 (50%), and 26 (25%) patients, respectively. Forty-four patients (42%) died in-hospital. All cytokines, except IL-1, correlated with Sequential Organ Failure Assessment and APACHE (Acute Physiology and Chronic Health Evaluation) II scores, and all cytokines predicted mortality. IL-10 and IL-18 independently predicted mortality among cytokines (OR = 3.1 and 28.3, P = .006 and < 0.0001). However, none of the cytokines correlated with LVEF, end-diastolic volume index (EDVI), stroke-volume index (SVI), or s'-wave and e'-wave velocities on TDI (Pearson linear and Spearman rank [ρ] nonlinear correlations). Similarly, no differences were found in cytokine concentrations between patients dichotomized to high vs low LVEF, EDVI, SVI, s'-wave, or e'-wave (Mann-Whitney U tests). In contrast, NT-proBNP strongly correlated with both reduced LVEF and reduced e'-wave velocity, and hs-troponin-T correlated mainly with reduced e'-wave.
Conclusions: Unlike cardiac biomarkers, none of the measured inflammatory cytokines correlates with systolic or diastolic myocardial dysfunction in severe sepsis or septic shock.