Elsevier

European Journal of Radiology

Volume 81, Issue 11, November 2012, Pages 3294-3299
European Journal of Radiology

Benefit of combining quantitative cardiac CT parameters with troponin I for predicting right ventricular dysfunction and adverse clinical events in patients with acute pulmonary embolism

https://doi.org/10.1016/j.ejrad.2012.06.023Get rights and content

Abstract

Objective

To prospectively evaluate the diagnostic accuracy of quantitative cardiac CT parameters alone and in combination with troponin I for the assessment of right ventricular dysfunction (RVD) and adverse clinical events in patients with acute pulmonary embolism (PE).

Materials and results

This prospective study had institutional review board approval and was HIPAA compliant. In total 83 patients with confirmed PE underwent echocardiography and troponin I serum level measurements within 24 h. Three established cardiac CT measurements for the assessment of RVD were obtained (RV/LVaxial, RV/LV4-CH, and RV/LVvolume). CT measurements and troponin I serum levels were correlated with RVD found on echocardiography and adverse clinical events according to Management Strategies and Prognosis in Pulmonary Embolism Trial-3 (MAPPET-3 criteria. 31 of 83 patients with PE had RVD on echocardiography and 39 of 83 patients had adverse clinical events. A RV/LVvolume ratio > 1.43 showed the highest area under the curve (AUC) (0.65) for the prediction of adverse clinical events when compared to RV/LVaxial, RV/LV4Ch and troponin I. The AUC for the detection of RVD of RV/LVaxial, RV/LV4Ch, RV/LVvolume, and troponin I were 0.86, 0.86, 0.92, and 0.69, respectively. Combination of RV/LVaxial, RV/LV4Ch, RV/LVvolume with troponin I increased the AUC to 0.87, 0.87 and 0.93, respectively.

Conclusion

A combination of cardiac CT parameters and troponin I measurements improves the diagnostic accuracy for detecting RVD and predicting adverse clinical events if compared to either test alone.

Introduction

Acute pulmonary embolism (PE) is a common disease with a variable prognosis which ranges from incidental clinical unimportant small embolism to massive embolism with sudden death. Thus, risk stratification relies on early detection of right ventricular dysfunction (RVD) in order to identify normotensive high-risk patients who might benefit from more aggressive therapies, such as thrombolysis or embolectomy [1]. For this purpose echocardiography is considered to be the clinical reference standard. However, recently a multitude of recent studies have evaluated promising morphometric parameters from pulmonary CT angiography (CTPA) for predicting adverse outcomes or early death in patients with acute PE [2], [3], [4], [5], [6].

Beyond imaging signs, troponin I has been proposed as a predictor of clinical outcome in patients with acute PE [7]. Several meta-analyses have demonstrated an association between elevated serum levels of troponin and RVD or adverse clinical events in patients with acute PE (specificity 77–90% and sensitivity 23–100%) [8], [9]. Given the wide range in specificity it has been suggested that a combination of troponin with right ventricular (RV) function or size measurements may have an advantage for identifying normotensive, high-risk PE patients when compared to a single test alone [10], [11].

Therefore, the objective of this study was, to prospectively evaluate the accuracy of quantitative cardiac CT parameters and troponin I serum levels, alone and in combination, for predicting RVD and adverse clinical events in patients with acute PE.

Section snippets

Study population

This study was part of a larger investigation evaluating the accuracy of quantitative CTPA parameters and cardiac biomarkers for predicting RVD in patients treated for PE at the University medical center Mannheim. Initial results of this investigation have been previously published by Henzler et al. [10]. However, the publication by Henzler et al. only looked at presents of RVD as a potential outcome parameter. More importantly from a clinical prospective, is patient outcome in terms of

Results

Patient characteristics, diagnostic findings, co-morbidities and outcome are summarized in Table 1. Echocardiography revealed RVD in 31/83 patients (37%) of whom 17 (55%) were classified as severe and 14 (45%) as moderate.

Discussion

Meta-analysis of normotensive patients with PE revealed that echocardiographically assessed RVD is associated with an increased risk for short-term mortality whereas patients with no evidence of RVD on echocardiography have excellent outcomes [16]. These findings are in accordance to those found in the present study in which the OR of echocardiographically assessed RVD for predicting adverse clinical events was 5.9, indicating that RVD is an important risk factor. Further when looking at the

Study limitations

The present study has several limitations, which have to be considered. First, patients with other underlying disease that may have led to an increase in serum troponin I levels were not excluded. Second, we based our observations on routine CTPA techniques rather than ECG-synchronized scan protocols. Non-ECG synchronized CT has some potential limitations for measuring ventricular chamber size, because the images are not acquired during a specific phases of the cardiac cycle. However, it has

Conflict of interest

All authors have no conflict of interest to disclose.

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