Probability scores and diagnostic algorithms in pulmonary embolism: are they followed in clinical practice?

Introduction: Clinical probability scores (CPS) determine the pre-test probability of pulmonary embolism (PE) and assess the need for the tests required in these patients. Our objective is to investigate if PE is diagnosed according to clinical practice guidelines.

Materials and methods: Retrospective study of clinically suspected PE in the emergency department between January 2010 and December 2012. A D-dimer value ≥ 500 ng/ml was considered positive. PE was diagnosed on the basis of the multislice computed tomography angiography and, to a lesser extent, with other imaging techniques. The CPS used was the revised Geneva scoring system.

Results: There was 3,924 cases of suspected PE (56% female). Diagnosis was determined in 360 patients (9.2%) and the incidence was 30.6 cases per 100,000 inhabitants/year. Sensitivity and the negative predictive value of the D-dimer test were 98.7% and 99.2% respectively. CPS was calculated in only 24 cases (0.6%) and diagnostic algorithms were not followed in 2,125 patients (54.2%): in 682 (17.4%) because clinical probability could not be estimated and in 482 (37.6%), 852 (46.4%) and 109 (87.9%) with low, intermediate and high clinical probability, respectively, because the diagnostic algorithms for these probabilities were not applied.

Conclusions: CPS are rarely calculated in the diagnosis of PE and the diagnostic algorithm is rarely used in clinical practice. This may result in procedures with potential significant side effects being unnecessarily performed or to a high risk of underdiagnosis.