Always think of the right ventricle, even in “low-risk” pulmonary embolism

Patients with pulmonary embolism (PE) represent a prognostically heterogeneous patient population. Therefore, the current European Society of Cardiology (ESC) guidelines recommend risk stratification to guide risk-adjusted management [1]. Since no individual clinical, imaging or laboratory finding has been shown to predict risk of an adverse in-hospital outcome with adequate sensitivity and specificity to justify treatment decisions numerous studies have investigated combination models for an optimised risk classification [2, 3]. Despite considerable progress made in the identification of intermediate-high-risk patients who might benefit from reperfusion therapy, there is an ongoing discussion whether patients classified as low-risk based on clinical parameters (such as the simplified pulmonary embolism severity index (sPESI) or the Hestia criteria) should undergo imaging or laboratory testing for right ventricular (RV) function. The ESC guidelines do not provide a clear recommendation, but suggest that “patients with a sPESI of 0 points and elevated cardiac biomarkers or signs of RV dysfunction on imaging test should be classified into the intermediate-low-risk category” and thus are not candidates for home treatment [1]. There are strong arguments for and against routine imaging or laboratory testing for RV function in low-risk patients: opponents argue that routine testing has not been shown to have therapeutic implications, is time- and cost-intensive, and does not provide additive prognostic information since the risk of adverse events is low per se in patients identified by the sPESI or the Hestia criteria. The study by Côté et al. [4] published in this issue of the European Respiratory Journal appears to support, at least in part, this notion. This pooled analysis of three prospective cohorts, namely the Prognostic Factors for Pulmonary Embolism (PREP) study, the PROgnosTic valuE of Computed Tomography scan in haemodynamically stable patients with acute symptomatic pulmonary embolism (PROTECT) study and a French prospective single-centre registry, confirms that the risk of PE-related adverse events and all-cause mortality during the first 30 days was low (0.77% and 0.39%, respectively) in 779 PE patients without relevant comorbidities (no cancer, cardiopulmonary disease and age ≤80 years) and stable vital signs on admission (normal systolic blood pressure, heart rate and oxygen saturation) [4]. In this context, it should be remembered that the 30-day mortality rate was 1.0% in 305 “low-risk” patients of the sPESI derivation cohort and 1.1% in 2569 patients of the sPESI validation cohort [5]. RV dilation on MDCT is of prognostic relevance in apparently healthy and stable patients with pulmonary embolism