The correlation between elevated cardiac troponin I and pulmonary artery obstruction index in ED patients with pulmonary embolism

Received 14 October 2007; received in revised form 24 March 2008; accepted 24 March 2008.

Abstract

Objectives

The aim of this study is to investigate the correlation between cardiac troponin I (cTnI) values and the pulmonary artery obstruction index assessed with spiral computed tomography (CT) scan in emergency department (ED) patients with pulmonary embolism (PE).

Methods

This is a retrospective cohort study of all 179 ED patients diagnosed with PE between December 2004 and January 2007. Study population consisted of 104 (58.1%) of 179 patients with PE in whom both cTnI was measured and a contemporaneously performed CT scan was available for review. In these patients, the levels of cTnI measured in the ED were correlated with the degree of pulmonary vascular obstruction determined by applying the modified Computed Tomography Obstruction Index to the spiral CT scan performed in the ED.

Results

Troponin values were elevated in 20 (19.2%) of 104 patients (95% confidence interval [CI], 11.6-26.8) with a mean cTnI concentration of 0.38 ± 0.44 μg/L. Elevated cTnI value had a significant correlation with main pulmonary arteries involvement using the modified Computed Tomography Obstruction Index score (P = .0001). Elevated ED cTnI value had 53.8% (95% CI, 37.6-66) sensitivity and 92.3% (95% CI, 87-96.4) specificity, 70% (95% CI, 49-86) PPV, and 85.7% (95% CI, 80.7-90) NPV for predicting main pulmonary artery obstruction on CT. Increased cTnI values were highly correlated to intensive care unit admission of patients with PE (RR, 12.83; 95% CI, 3.87-42.4).

Conclusions

Measuring cTnI value might be considered in ED patients who are suspected of having PE. Elevated cTnI should raise the clinician's concern for the possibility of central pulmonary vascular obstruction.

a Department of Emergency Medicine, The George Washington University, Washington, DC 20037, USA

b Department of Radiology, The George Washington University, Washington, DC 20037, USA

c School of Public Health and Health Services, The George Washington University, Washington, DC 20037, USA

Corresponding author. Tel.: +1 202 741 2911; fax: +1 202 741 2921.

The study was presented as an oral presentation at the SAEM 2007 Annual Meeting on May 16 to 19, Chicago.

The abstract was presented at the Ninth Annual SAEM Mid-Atlantic Regional Research Forum in November 2006 at the George Town University.

A full report on the presentation has been published on the ACEP NEWS vol.26, no. 10, October 2007, page 10.

PII: S0735-6757(08)00246-5

doi:10.1016/j.ajem.2008.03.033

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