Coronary flow reserve is associated with tissue ischemia and is an additive predictor of intensive care unit mortality to traditional risk scores in septic shock

Background Reduced coronary velocity flow reserve (CFR) is associated with poor outcome in patients with cardiovascular disease. We investigated whether CFR is associated with tissue ischemia and acidosis, impaired myocardial deformation and adverse outcome in patients with septic shock. Methods In 70 mechanically-ventilated patients with septic shock, we examined: a) S′ and E′ mitral annular velocities using tissue Doppler imaging (TDI), b) CFR of the left anterior descending artery after adenosine infusion using transesophageal Doppler echocardiography and c) lactate, pyruvate and glycerol in tissue by means of a microdialysis (MD) catheter inserted into the subcutaneous adipose tissue as markers of tissue ischemia and acidosis. SOFA and APACHE II prognostic scores and mortality in the intensive care unit (ICU) were recorded. Results Reduced CFR, S′ and E′ as well as increased E/E′ correlated with increased SOFA, APACHE II and MD lactate to pyruvate ratio (p < 0.05 for all correlations). Impaired TDI markers also correlated with increased MD glycerol (p < 0.05). Reduced CFR correlated with decreased E′ (p < 0.05). CFR was 1.8 ± 0.42 in non-survivors (n = 34) versus 2.08 ± 0.44 in survivors (p = 0.007). A CFR < 1.90 predicted mortality with sensitivity of 70% and specificity of 69% (area under the curve 77%; p = 0.003). CFR had an additive value to APACHE (chi-square change: 4.358, p = 0.03) and SOFA (chi-square change: 3.692, p = 0.04) for the prediction of mortality. Conclusion Tissue ischemia and acidosis is a common pathophysiological link between decreased CFR and impaired LV myocardial deformation in septic shock. CFR is an additive predictor of ICU mortality to traditional risk scores in septic shock.