title: Sources of error in intra-arterial pressure measurements across a stenosis.
abstract: OBJECTIVE
  To investigate potential errors associated with different techniques of intra-arterial pressure measurement at angiography.
  
  
  METHODS
  An experimental model of an arterial stenosis was developed. Experiments were performed to assess the relevance of catheter position, catheter direction and catheter type on the recorded intraluminal pressure. Transstenotic pressure gradients were recorded with and without angiographic catheters crossing the stenosis.
  
  
  RESULTS
  At physiological flow rates angiographic catheter type does not influence the recorded pressure. At high flow rates through tight stenoses there is a significant catheter-related difference in recorded pressure adjacent to a stenosis. Downstream pressures may be altered by up to 85 mmHg when standard angiographic catheters are placed across a stenosis.
  
  
  CONCLUSIONS
  The different techniques employed to measure pressure differences across a model stenosis may introduce significant errors up to 85 mmHg. Care must be taken when pressure measurements alone are used to interpret the clinical significance of a stenosis. In low flow conditions there may not be a detectable pressure gradient across a 95% stenosis.
authors.affiliation: Department of Vascular Radiology, St. James's University Hospital, Leeds, U.K.
authors.forename: R G
authors.initials: RG
authors.lastname: McWilliams
authors.forename: I
authors.initials: I
authors.lastname: Robertson
authors.forename: S W
authors.initials: SW
authors.lastname: Smye
authors.forename: L
authors.initials: L
authors.lastname: Wijesinghe
authors.forename: D
authors.initials: D
authors.lastname: Kessel
mesh_terms: D000792:Angiography / Q000295:instrumentation; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation / Q000379:methods*; D002404:Catheterization / Q000295:instrumentation; D003251:Constriction, Pathologic / Q000503:physiopathology; D004867:Equipment Design; D006801:Humans; D008953:Models, Anatomic; D012039:Regional Blood Flow / Q000502:physiology