title: Power injection of microcatheters: an in vitro comparison.
abstract: OBJECTIVE
  To determine the tolerance of 0.021-inch and 0.027-inch microcatheters to power injection in an in vitro flow model.
  
  
  METHODS
  Twenty-four microcatheters (0.021-inch, n = 13; 0.027-inch, n = 11) were injected with iothalamate meglumine through a flow model with use of a power injector and high-pressure tubing. Catheters used included Rebar (0.021-inch, n = 4; 0.027-inch, n = 4), Transit (0.021-inch, n = 3; 0.027-inch, n = 3), Renegade (0.021-inch, n = 4; 0.027-inch, n = 4), and Renegade STC-18 (0.021-inch, n = 2) models. Through the 0.021-inch microcatheters, 5-second injections were performed at an initial rate of 0.7 mL/sec. Injection rates were increased by 0.5 mL/sec and the process was repeated until the pressure approached 1,000 psi or catheter breakage occurred. A similar process was repeated for the 0.027-inch catheters starting at a rate of 3.4 mL/sec.
  
  
  RESULTS
  The 0.021-inch catheters were injected 303 times and the 0.027-inch catheters were injected 210 times. Three catheter failures occurred, with all breaks occurring at pressures greater than manufacturer recommendations. The 0.027-inch catheters as a group tolerated significantly higher injection rates than the 0.021-inch catheters. Of the 0.021-inch catheters, the STC-18 also provided superior maximum flow and volume compared with the Renegade catheter. The Rebar catheter tolerated significantly lower maximum injection rates and volumes than the other 0.027-inch catheters.
  
  
  CONCLUSIONS
  The majority of microcatheters can be power-injected in vitro at pressures far greater than manufacturer recommendations. When fractures occur, they are near the hub of the catheter. Significantly greater rates of injection are possible through 0.027-inch catheters.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University Medical Center, 510 South Kingshighway Boulevard, St. Louis, Missouri 63110, USA. brownda@mir.wustl.edu
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Brown
authors.forename: Dimitrios C
authors.initials: DC
authors.lastname: Papadouris
authors.forename: Robert V
authors.initials: RV
authors.lastname: Davis
authors.forename: Suresh
authors.initials: S
authors.lastname: Vedantham
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Pilgram
mesh_terms: D002404:Catheterization / Q000295:instrumentation*; D003287:Contrast Media / Q000008:administration & dosage*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007267:Injections / Q000379:methods*; D007482:Iothalamate Meglumine / Q000008:administration & dosage*; D008422:Materials Testing; D008904:Miniaturization; D011312:Pressure; D013314:Stress, Mechanical
chemical_list: D003287:Contrast Media; D007482:Iothalamate Meglumine