Authors: Hendriksen JMT et al., BMJ 2015 Sep 8; 351:h4438
In the primary care setting, Wells and Geneva rules all performed well.
How accurate are prediction rules, combined with point-of-care D-dimer testing, for ruling out pulmonary embolism (PE) in the primary care setting? In a systematic review followed by a validation study, researchers assessed five rules and specific score thresholds: original Wells (≤4), modified Wells (≤2), simplified Wells (≤1), revised Geneva (≤5), and simplified revised Geneva (≤2). The validation study involved 600 patients with suspected PE in 300 Dutch general practices.
Sensitivities of three Wells rules, combined with point-of-care D-dimer testing, were higher (95%–96%) than sensitivities of the two Geneva rules (88% and 90%). For each rule, specificity was about 50% and positive predictive value was about 20%. Negative predictive values for the Wells rules and Geneva rules were 99% and 97%, respectively. Failure rates ranged from 1.2% for the simplified Wells rule to 3.1% for the simplified revised Geneva rule; this difference was significant. PE eventually was diagnosed in three patients in the validation study who were classified initially as having low probability of PE, regardless of which rule was applied.
This study validated five easy-to-use prediction rules, combined with point-of-care D-dimer testing, to rule out PE in primary care settings. The Wells rules, particularly the simplified Wells rule, performed the best; the simplified Wells rule consists of 1 point each for clinical signs of deep venous thrombosis (DVT), heart rate >100 beats/minute, recent surgery or immobilization, previous PE or DVT, hemoptysis, cancer, and alternative diagnoses less likely than PE. Among the three misclassified validation patients, one was a 75-year-old man with a history of venous thromboembolism, and two were young women who were taking oral contraceptive pills — affirming that prediction rules plus D-dimer testing should not replace good clinical judgment but should supplement it.