Cardiac troponin I levels in acute pulmonary embolism

Abstract

Objective: Estimation of individual risk and choice of initial therapeutic approach for patients with pulmonary embolism (PE) remains controversial. The three key components for risk stratification in PE are clinical evaluation, cardiac biomarkers and assessment of right ventricular size and function. The aim of this study was to assess the ability of admission troponin I (TnI) levels to predict short-term mortality and complicated clinical course in patients with PE.

Methods: We performed a retrospective analysis of 100 consecutive patients admitted with a diagnosis of PE between January 2004 and November 2007. Patients in whom the diagnosis was confirmed by spiral computed tomography, ventilation perfusion scan, pulmonary angiography or echocardiography and with serum TnI measurement in the first 24 hours of hospital stay were selected. The study population (n = 62) was divided into two groups according to the presence or absence of elevated TnI levels (TnI > or = 0.10 ng/ml). Clinical characteristics, electrocardiographic and echocardiographic signs of right ventricular dysfunction (RVD), brain natriuretic peptide (BNP) levels, in-hospital mortality and the composite endpoint of complicated PE (defined as the presence of at least one of the following: in-hospital death, cardiogenic shock, need for mechanical ventilation or inotropic support) were compared between groups.

Results: Thirty-seven patients (59.7%) had elevated TnI levels (Tpos) and 25 (40.3%) had normal levels (Tneg). The two groups were not significantly different (p = NS) in age (66.2 vs. 71 years), gender (female 70.3 vs. 60.0%), clinical presentation or length of hospital stay (14.7 vs. 18.1 days). Tpos patients had a higher prevalence of electrocardiographic signs of RVD (78.4 vs. 40.0%, p < 0.01). Echocardiographic RVD was also more common in the Tpos group but the difference did not reach statistical significance (56.0% vs. 27.3%, p = NS). Elevated serum TnI was significantly associated with complicated in-hospital clinical course (complicated PE: 29.7% in the Tpos group vs. 4.0% in the Tneg group (adjusted OR = 9.08; 95% CI 1.07-77.4; p = 0.044). In-hospital mortality was 8.1%, with a strong trend for higher mortality in the Tpos group (13.5% vs. 0%, p = 0.055).

Conclusions: Elevated TnI levels are associated with higher risk for in-hospital mortality and complicated clinical course. Additional studies are needed to assess whether troponin levels, alone or in conjunction with other tests, can be used to guide therapeutic strategy and improve the prognosis of patients with PE.