Predictors of residual pulmonary vascular obstruction after pulmonary embolism: Results from a prospective cohort study

Background: We aimed to determine the prevalence of residual pulmonary vascular obstruction (RPVO) after symptomatic pulmonary embolism (PE) and to identify risk factors for RPVO. Methods: On the basis of a prospective cohort of patients with a documented symptomatic venous throm-boembolism, we included patients who had an acute PE and underwent a ventilation/perfusion lung scan at 3 to 24 months during the follow-up after PE. RPVO score was assessed for each patient. Initial pulmonary vascular obstruction at PE diagnosis was also assessed when available. Univariable and multivariable analyses were performed with preselected data to identify predictors for persistent defect defined as RPVO >= 5%. Results: Among the 537 included patients, 278 (51.8%) had RPVO >= 5%, and 191 (35.6%) had RPVO >= 10%. In primary multivariate analysis on overall population, age >= 65 years (odds ratio [OR] 2.25, 95% CI, 1.45-3.52) and chronic respiratory failure (OR 3.19, 95% CI, 1.22-10.04) were independent predictors of RPVO >= 5%. In secondary multivariate analysis restricted to 256 patients with available initial pulmonary vascular obstruction score at index PE (IPVO), age >= 65 years (OR 2.78, 95% CI, 1.41-5.53), unprovoked PE (OR 2.11, 95% CI, 1.11-4.07) and IPVO >= 20% (OR 2.94, 95% CI, 1.68-5.20) were found to be independent risk factors for RVPO >= 5%. Conclusion: In this selected population of patients with an acute PE, age >= 65 years, unprovoked PE and IPVO >= 20% at PE diagnosis appeared to be risk factors for residual pulmonary vascular obstruction measured at three to 24 months.