title: Prognostic role of embolic burden assessed at computed tomography angiography in patients with acute pulmonary embolism: systematic review and meta-analysis.
abstract: 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, I(2)  = 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, I(2)  = 27%).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal and Cardiovascular Medicine - Stroke Unit, University of Perugia, Perugia, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Vedovati
authors.forename: F
authors.initials: F
authors.lastname: Germini
authors.forename: G
authors.initials: G
authors.lastname: Agnelli
authors.forename: C
authors.initials: C
authors.lastname: Becattini
mesh_terms: D000792:Angiography / Q000379:methods*; D006801:Humans; D011379:Prognosis; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: meta-analysis; mortality; prognosis; pulmonary embolism; tomography, X-ray computed