Prognostic Value of Cardiac Biomarkers and Tissue Doppler Echocardiography to Septic Shock Mortality

Introduction: Refractory hypotension and cardiovascular collapse are frequently observed in the terminal phases of septic shock. While impaired systolic function has been identified as the major culprit, the contribution of diastolic dysfunction to cardiovascular morbidity and mortality in septic shock is not fully understood.Objectives: To evaluate the prognostic significance of NTproBNP, Troponin I, and Tissue Doppler echocardiographic variables to septic shock mortality.Methods: Thirty patients with septic shock were enrolled in the study after exclusion of patients with significant heart diseases. Each patient was subjected to the following: Measurement of serum NTproBNP, Troponin I by ELISA technique, and routine echocardiographic study with measuring of LV end-diastolic volume index (LVEDVI), LV end-systolic volume index (LVESVI) and calculation of LV ejection fraction (LVEF) and cardiac output index (COI), LV diastolic function was assessed with measuring of transmitral peak E and A velocities, E/A ratio and E deceleration time. Tissue Doppler echocardiography was performed with measuring of septal mitral annulus peak e , a and s velocities, the E/e was then calculated. All the above measurements were done within 72 hours of development of septic shock.Results: The study population were divided into two groups according to 28th day mortality, group I (survivors, 11 patients, 5 males and 6 females) and group II (non survivors, 19 patients, 8 males and 11 females). No significant difference between groups regarding age and sex distribution, and associated co-morbidities except for the higher incidence of renal diseases in group II. The most common source of sepsis was chest infection and infected surgical wounds in group I, and chest infection followed by abdominal sepsis and infected surgical wounds in group II. 27 patients (85%) had positive culture (9 in group I 18 in group II). The most common organisms were klebseilla in group I (45.4%), and MRSA in group II (31.5%) followed by Klebseilla (26.3%). Serum levels of NT-proBNP were markedly elevated in group II than group I with p 0.004 [median (inter-quartile range): 540 (350- 1040) fmol/L and 180 (61-441) fmol/L, respectively]. Troponin-I was only minimally elevated in group II with non-significant p-value 0.19. According to the echocardiographic variables; lower e velocity and higher E/e were the only predictor factors for mortality with a cut off limit for E/e of 7.6, sensitivity 83%, and specificity of 50% (E/e was 7.8± 1.4 in group I and 11.5±5.0 in group II, p-value: 0.02). None of the other variables showed any relation to mortality.Conclusions: Higher NT-proBNP, lower e velocity and higher E/e were the only predictor factors for mortality in septic shock. Although non-survivors had higher levels of Troponin I, it didn t reach a statistically significant value.