Performance of four clinical decision rules in the diagnostic management of acute pulmonary embolism; The prometheus diagnostic accuracy study

Background: Several clinical decision rules (CDRs) are available for the exclusion of acute pulmonary embolism (PE) but not directly compared. This prospective multicenter study directly compared the performance of four CDRs (Wells rule, revised Geneva score, simplified Wells rule and simplified revised Geneva score) in excluding PE in combination with D-dimer testing. Methods: The clinical probability of PE was assessed using a computer program, which calculated all CDRs and indicated the next diagnostic step. Clinical care was guided by the results of the CDRs and D-dimer results. A 'PE unlikely' result according to all CDRs in combination with a normal D-dimer result excluded PE, while patients with 'PE likely' according to at least one of the CDRs or an abnormal D-dimer result underwent CT-scanning. CDRs results were compared with PE prevalence indentified by CT-scanning or venous thromboembolism during 3-month follow-up. Results: Eight hundred and seven consecutive patients with suspected acute PE were included and PE prevalence was 23%. The number of patients categorized as 'PE unlikely' ranged from 62% (simplified Wells rule) to 72% (Wells rule). Combined with a normal D-dimer level, the CDRs excluded PE in 22-24% of patients. The total failure rates of the CDR-D-dimer combinations were similar (one failure, 0.5-0.6%, upper 95% CI 2.9-3.1%). Despite 30% of the patients had discordant CDR outcomes, PE was missed in none of the patients with discordant CDRs and a normal D-dimer result. Conclusions: All four CDRs show similar performance for exclusion of acute PE in combination with a normal D-dimer level. This prospective validation indicates that the simplified scores may be used in clinical practice