Prognostic Significance of Elevated Cardiac Troponin-T Levels in Acute Respiratory Distress Syndrome Patients

Matthew B Rivara,Michelle N Gong,Ednan K Bajwa,James L Januzzi,David C Christiani,B Taylor Thompson,Holger K Eltzschig

doi:10.1371/journal.pone.0040515

Abstract

BackgroundElevated levels of biochemical markers of myocardial necrosis have been associated with worsened outcomes in Acute Respiratory Distress Syndrome (ARDS), but there are few prospective data on this relationship. We investigated elevated cardiac troponin T (cTnT) levels and their relationship with outcome in patients with ARDS.MethodsA prospective cohort study of patients with ARDS was conducted at a tertiary-care academic medical center. Patients had blood taken within 48 hours of ARDS onset and assayed for cTnT. Patients were followed for the outcomes of 60-day mortality, number of organ failures, and days free of mechanical ventilation. Echocardiographic and electrocardiographic (ECG) data were analyzed for signs of myocardial ischemia, infarction, or other myocardial dysfunction.Results177 patients were enrolled, 70 of whom died (40%). 119 patients had detectable cTnT levels (67%). Median cTnT level was 0.03 ng/mL, IQR 0–0.10 ng/mL, and levels were higher among non-survivors (P = .008). Increasing cTnT level was significantly associated with increasing mortality (P = .008). The association between increasing cTnT level and mortality remained significant after adjustment in a multivariate model (HRadj = 1.45, 95% CI 1.17–1.81, P = .001). Elevated cTnT level was also associated with increased number of organ failures (P = .002), decreased number of days free of mechanical ventilation (P = .03), echocardiographic wall motion abnormalities (P = 0.001), and severity of tricuspid regurgitation (P = .04). There was no association between ECG findings of myocardial ischemia or infarction and elevated cTnT.ConclusionsElevated cTnT levels are common in patients with ARDS, and are associated with worsened clinical outcomes and certain echocardiographic abnormalities. No association was seen between cTnT levels and ECG evidence of coronary ischemia.

Highlights

The Acute Respiratory Distress Syndrome (ARDS) is marked by considerable cardiovascular strain
Because of the nature of the strong pathophysiologic relationship between coronary artery disease (CAD) and diabetes, we evaluated whether patients with reported diabetes had elevated cardiac troponin T (cTnT) levels despite the absence of known CAD
Mortality Prediction By itself, cTnT level had modest ability to predict mortality, with area under the receiver operator characteristic (ROC) curve of (AUROC) 0.62, and sensitivity 57%, specificity 66%, negative predictive value (NPV) 70%, and positive predictive value (PPV) 52% at the optimal cut-point

Summary

Introduction

The Acute Respiratory Distress Syndrome (ARDS) is marked by considerable cardiovascular strain. Hypoxemia stimulates increased cardiac output, which can result in myocardial strain in the setting of decreased oxygen supply and pulmonary hypertension due to hypoxic pulmonary vasoconstriction, pulmonary endothelial injury, and in situ thrombosis of the pulmonary vasculature [1]. This condition is further exacerbated by pulmonary capillary obliteration and lung fibrosis as the syndrome progresses, as well as by increased intrathoracic pressure from mechanical ventilation [1,2]. We investigated elevated cardiac troponin T (cTnT) levels and their relationship with outcome in patients with ARDS

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Conclusion