Regarding the fact that the insertion of a PAC is an invasive procedure without proven survival benefit, and a comprehensive echocardiographic study requires a high degree of training and sometimes is not available within 24 h, a biomarker accurately detecting myocardial dysfunction and providing prognostic information in patients with sepsis would be of paramount interest.
Cardiac troponins are regulatory proteins of the thin actin filaments of the cardiac muscle. Myocardial cell injury results in the release of cardiac troponin I (cTnI) and cardiac troponin T (cTnT), which differ from troponin isoforms of the skeletal muscle, and thus are highly sensitive and specific biomarkers of myocardial damage.’ The measurement of cTnI and cTnT levels in blood is standard for diagnosis and risk stratification in patients with ACS. The currently employed tests use monoclonal antibodies against several different epitopes of the cTnI and cTnT molecules.
Cardiac troponin levels start to rise 3 to 4 h after the onset of myocardial infarction and also, presumably, other causes of myocardial damage, respectively, and remain elevated for 4 to 10 days. Due to their widespread use, raised levels of cardiac troponins have been found in patients with many conditions other than myocardial ischemia due to flow-limiting coronary artery disease (CAD) including pulmonary embolism, renal failure, and sepsis. Among unselected critically ill patients, 15.3% (32 of 209 patients; cTnI cutoff, > 3.6 Mg/L), 15.8% (41 of 260 patients; cTnI cutoff, > 1.5 Mg/L), and 25% (53 of 213 patients; cTnI cutoff, > 0.4 Mg/L) had elevated cTnI levels. Patients with raised troponin levels included those with acute myocardial infarction and those with troponin level elevation due to conditions other than myocardial infarction. Mortality among troponin-positive patients was higher compared to that among troponin-negative patients, irrespective of the cause of troponin posi-tivity.> Patients with elevated troponin levels were more likely to be hypotensive, needed more therapy with vasoactive agents, received mechanical ventilation more often, and had longer stays in the ICU.