Acute pulmonary embolism: mortality prediction by the 2014 European Society of Cardiology risk stratification model

To the Editor:

I eagerly read the recent article by Becattini et al. [1] entitled “Acute pulmonary embolism: mortality prediction by the 2014 European Society of Cardiology risk stratification model”. Those authors compared the prognosis of acute pulmonary thromboembolism in 906 patients according to the European Society of Cardiology (ESC) guidelines published in 2008 and 2014.

I would like to draw attention to a point in table 2 of the article. The authors reported that 59 patients were positive for troponin in the group composed of 196 patients with low risk levels. The 2014 ESC guidelines recommend that patients in Pulmonary Embolism Severity Index (PESI) class I–II or with a Simplified PESI score of 0, and elevated cardiac biomarkers or signs of right ventricular dysfunction (RVD) on imaging tests should also be classified into the intermediate–low-risk category [2]. Thus, ∼30% of patients in this group were classified incorrectly. These 59 patients with low–intermediate risk group, when added to the total number of patients, will make 392, of whom 151 will be troponin positive. Thus, 30-day mortality will be decreased to 5.1% instead of 6% in this group (20 out of 392). However, there will be no significant difference in mortality between low risk and intermediate–high risk (5.1% versus 7%, p=0.16).

In my opinion, another contradiction in the increase in troponin level in 59 of the 196 low-risk patients (increased by 30%). In this study, mortality was one (0.5%) patient in the low-risk group. May be misclassified one patient who did in low risk group if had high troponin level this patient? Mortality rate is 10% in patients with high troponin levels [3], so among 59 patients with positive troponin (which are classified as low risk) 5–6 patients would be expected to die.

Another problem is that of the 59 patients who will be classified as intermediate–high risk in the case of the presence of RVD on echocardiography or computed tomography. As a result, patients with increased levels of troponin alone should be in intermediate risk groups according to the ESC 2014 guidelines.