Myocardial Injury in Critically Ill Patients with Community-acquired Pneumonia: A Cohort Study

Abstract

Rationale: Myocardial injury, as reflected by elevated cardiac troponin levels in plasma, is common in patients with community-acquired pneumonia (CAP), but its temporal dynamics and etiology remain unknown. Objectives: Our aim was to determine the incidence of troponin release in patients with CAP and identify risk factors that may point to underlying etiologic mechanisms. Methods: We included consecutive patients admitted with severe CAP to two intensive care units in the Netherlands between 2011 and 2015. High-sensitivity cardiac troponin I was measured daily during the first week. We used multivariable linear regression to identify variables associated with troponin release on admission, and we used mixed-effects regression to model the daily rise and fall of troponin levels over time. Results: Of 200 eligible patients, 179 were included, yielding 792 observation days. A total of 152 (85%) patients developed raised troponin levels greater than 26 ng/L. Baseline factors independently associated with troponin release included coronary artery disease (176% increase; 95% confidence interval [CI], 11–589), smoking (248% increase; 95% CI, 33–809), and higher Acute Physiology and Chronic Health Evaluation IV score (2% increase; 95% CI, 0.8–3.3), whereas Staphylococcus aureus as a causative pathogen was protective (70% reduction; 95% CI, 18–89). Time-dependent risk factors independently associated with daily increase in troponin concentrations included reduced platelet count (2.3% increase; 95% CI, 0.6–4), tachycardia (1.5% increase; 95% CI, 0.1–2.9), hypotension (6.2% increase; 95% CI, 2.1–10.6), dobutamine use (44% increase; 95% CI, 12–85), prothrombin time (8.2% increase; 95% CI, 0.2–16.9), white cell count (1.7% increase; 95% CI, 0–3.5), and fever (22.7% increase; 95% CI, 0.1–49.6). Conclusions: Cardiac injury develops in a majority of patients with severe CAP. Myocardial oxygen supply–demand mismatch and activated inflammation/coagulation are associated with this injury.