title: Systematic review: endoscopic and imaging-based techniques in the assessment of portal haemodynamics and the risk of variceal bleeding.
abstract: BACKGROUND
  Invasive measurement of the hepatic venous pressure gradient (HVPG) is regarded as the gold standard for risk stratification and the evaluation of pharmaceutical agents in patients with portal hypertension.
  
  
  OBJECTIVE
  To review the techniques for endoscopic and imaging-based assessment of portal haemodynamics, with particular emphasis on trials where the results were compared with HVPG or direct portal pressure measurement.
  
  
  METHODS
  Systematic search of the MEDLINE electronic database with keywords: portal hypertension, variceal bleeding, variceal pressure, endoscopic ultrasound, Doppler ultrasonography, magnetic resonance angiography, CT angiography, hepatic venous pressure gradient.
  
  
  RESULTS
  Computed tomography angiography and endoscopic ultrasound (EUS) have been both employed for the diagnosis of complications of portal hypertension and for the evaluation of the efficacy of endoscopic therapy. Colour Doppler ultrasonography and magnetic resonance angiography has given discrepant results. Endoscopic variceal pressure measurements either alone or combined with simultaneous EUS, correlate well with HVPG and risk of variceal bleeding and have a low interobserver variability.
  
  
  CONCLUSIONS
  Endoscopic and imaging-based measurements of portal haemodynamics provide an alternate means for the assessment of complications of portal hypertension. Further studies are required to validate their use in risk stratification and the evaluation of drug therapies in patients with portal hypertension.
authors.affiliation: Department of Gastroenterology, University College London Hospitals NHS Foundation Trust, UK.
authors.forename: S N
authors.initials: SN
authors.lastname: Sgouros
authors.forename: K V
authors.initials: KV
authors.lastname: Vasiliadis
authors.forename: S P
authors.initials: SP
authors.lastname: Pereira
mesh_terms: D004724:Endoscopy / Q000379:methods; D004932:Esophageal and Gastric Varices; D006471:Gastrointestinal Hemorrhage; D006801:Humans; D006975:Hypertension, Portal / Q000150:complications* / Q000175:diagnosis; D018810:Magnetic Resonance Angiography / Q000379:methods; D017082:Portal Pressure; D011168:Portal System; D012307:Risk Factors; D018608:Ultrasonography, Doppler / Q000379:methods