Wells clinical prediction rule and pulmonary embolism rule out criteria (PERC) in preventing over investigation of pulmonary embolism in emergency departments

Background: Depending on the worse outcomes of missed diagnosis of pulmonary embolism (PE), unnecessary diagnostic tests are usually ordered to most of the patients with dyspnea or pleuritic chest pain. Aims: To identify rates and causes of overinvestigation for PE in our emergency department (ED) and to search whether it was possible to reduce this overinvestigation by using Wells score and Pulmonary Embolism Rule Out Criteria (PERC) in daily practice. Methods: A retrospective observational cohort study performed in an ED of a tertiary care university hospital. 108 patients, who had diagnotic tests with the suspicion of PE, were included in the study. Results: Among the whole study group, 53(49%) were diagnosed as PE (+) and overdiagnosis was present in 55 (51%) patients i.e., PE (-).The sensitivity of high Wells score was 43%, specificity 78%, positive predictive value 66% and negative predictive value 59% for PE diagnosis. PERC criteria found to be negative (when all of the 8 criteria were fulfilled) in only 5 (5%) patients. The sensitivity of the test was 98%, specificity 7%, positive predictive value %50, negative predictive value %80.When individual parameters of PERC were evaluated solely for the exclusion of PE; no leg swelling and no previous DVT or PE history were found significantly negatively correlated with the diagnosis of PE (p=0.001, r= -0.325 and p= 0.013, r= -0.214 respectively) Conclusion: Over investigation of PE in EDs still remains as an important problem. In order to prevent this, the clinical prediction rules must be developed further or may be used in combination.