Wells Score and Poor Outcomes Among Adult Patients With Subsegmental Pulmonary Embolism

Abstract

Introduction: Since the introduction of computed tomography pulmonary angiography, isolated subsegmental pulmonary embolism has become a commonly recognized clinical problem, but its clinical relevance remains unclear. The objective of the present study was to evaluate the extent to which the simplified Wells score discriminates between patients with varying levels of risk of complications after presenting with subsegmental pulmonary embolism. Materials and Methods: Retrospective cohort study. Patients included had subsegmental pulmonary embolism (1 or multiple emboli limited to subsegmental arteries). Primary explanatory variable was the simplified Wells score, categorized as high (>4) or low (≤4). The primary outcome was time to death or new venous thromboembolism. Kaplan-Meier techniques and Cox regression analysis were used to compare the survival experience of patients with high versus low Wells score with and without adjustment for active malignancy, age, Charlson score, previous venous thromboembolism, and previous major surgery in the last 30 days. Main Results: Seventy-nine patients with subsegmental pulmonary embolism were included. Patients with a high Wells score had a 4-fold increased risk of the composite outcome (hazard ratio = 4.2, 95% confidence interval [CI] = 2.0-8.9, P < .001). Other covariates significantly associated with increased risk in univariate analyses included active malignancy, a low serum albumin, and an increased Charlson score. In multivariate Cox regression analyses adjusting for these other factors, a high Wells score remained significant (hazard ratio 5.5, 95% CI 2.4-12.6, P < .001). Conclusion: High Wells score is associated with death or new venous thromboembolism during follow-up among patients with subsegmental pulmonary embolism. Clinical trial registration: ClinicalTrials.gov number, NCT01372514.