Bench-to-bedside review: Significance and interpretation of elevated troponin in septic patients

Because no bedside method is currently available to evaluate myocardial contractility independent of loading conditions, a biological marker that could detect myocardial dysfunction in the early stage of severe sepsis would be a helpful tool in the management of septic patients. Clinical and experimental studies have reported that plasma cardiac troponin levels are increased in sepsis and could indicate myocardial dysfunction and poor outcome. The high prevalence of elevated levels of cardiac troponins in sepsis raises the question of what mechanism results in their release into the circulation. Apart from focal ischemia, several factors may contribute to the microinjury and minimal myocardial cell damage in the setting of septic shock. A possible direct cardiac myocytotoxic effect of endotoxins, cytokines or reactive oxygen radicals induced by the infectious process and produced by activated neutrophils, macrophages and endothelial cells has been postulated. The presence of microvascular failure and regional wall motion abnormalities, which are frequently observed in positive-troponin patients, also suggest ventricular wall strain and cardiac cell necrosis. Altogether, the available studies support the contention that cardiac troponin release is a valuable marker of myocardial injury in patients with septic shock.