Prognostic role of embolic burden assessed at computed tomography angiography in patients with acute pulmonary embolism : systematic review and meta-analysis

Summary: Background: In patients with acute pulmonary embolism (PE), risk stratification is indicated for tailoring of both diagnostic strategies and acute treatment. Whether embolic burden assessed at computed tomography (CT) angiography has a role in risk stratification in these patients is debated. Objective: To systematically review and perform a meta-analysis to evaluate the role of CT-assessed burden associated with embolic obstruction and embolic localization in the prognostic stratification of patients with acute PE. Methods: We performed a systematic search in EMBASE and MEDLINE up until 30 June 2013. Studies reporting on the 30-day outcome of patients with confirmed PE and CT-assessed embolic burden were included. The study outcome was death. Results: Thirty studies reporting on the prognostic value of CT-assessed embolic burden met the inclusion criteria for this systematic review; of these, 19 were included in the meta-analysis. Five studies (2215 patients) were included in the analysis of localization: an association between embolus localization in the central arteries and 30-day mortality was found after heterogeneity was resolved (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.29-3.89, I2 = 0%). No correlation was observed between obstruction index (according to the Qanadli scoring system) and 30-day mortality after heterogeneity was reduced (16 studies, 3884 patients, OR 1.22, 95% CI 0.99-1.51, I2 = 27%). Conclusion: Localization of emboli assessed at CT angiography can be used for risk stratification in patients with acute PE. Moreover, no correlation was observed between obstruction index and prognosis.