Performance of 4 clinical decision rules in the diagnostic management of acute pulmonary embolism::A Prospective cohort study

Background: Several clinical decision rules (CDRs) are available to exclude acute pulmonary embolism (PE), but they have not been directly compared. Objective: To directly compare the performance of 4 CDRs (Wells rule, revised Geneva score, simplified Wells rule, and simplified revised Geneva score) in combination with D-dimer testing to exclude PE. Design: Prospective cohort study. Setting: 7 hospitals in the Netherlands. Patients: 807 consecutive patients with suspected acute PE. Intervention: The clinical probability of PE was assessed by using a computer program that calculated all CDRs and indicated the next diagnostic step. Results of the CDRs and D-dimer tests guided clinical care. Measurements: Results of the CDRs were compared with the prevalence of PE identified by computed tomography or venous thromboembolism at 3-month follow-up. Results: Prevalence of PE was 23%. The proportion of patients categorized as PE-unlikely ranged from 62% (simplified Wells rule) to 72% (Wells rule). Combined with a normal D-dimer result, the CDRs excluded PE in 22% to 24% of patients. The total failure rates of the CDR and D-dimer combinations were similar (1 failure, 0.5% to 0.6% [upper-limit 95% CI, 2.9% to 3.1%]). Even though 30% of patients had discordant CDR outcomes, PE was not detected in any patient with discordant CDRs and a normal D-dimer result. Limitation: Management was based on a combination of decision rules and D-dimer testing rather than only 1 CDR combined with D-dimer testing. Conclusion: All 4 CDRs show similar performance for exclusion of acute PE in combination with a normal D-dimer result. This prospective validation indicates that the simplified scores may be used in clinical practice. Primary Funding Source: Academic Medical Center, VU University Medical Center, Rijnstate Hospital, Leiden University Medical Center, Maastricht University Medical Center, Erasmus Medical Center, and Maasstad Hospital. © 2011 American College of Physicians