title: Effect of radial versus femoral access on radiation dose and the importance of procedural volume: a substudy of the multicenter randomized RIVAL trial.
abstract: OBJECTIVE
  The authors sought to compare the radiation dose between radial and femoral access.
  
  
  BACKGROUND
  Small trials have shown an increase in the radiation dose with radial compared with femoral access, but many were performed during the operators' learning curve of radial access.
  
  
  METHODS
  Patients were randomized to radial or femoral access, as a part of the RIVAL (RadIal Vs. femorAL) trial (N = 7,021). Fluoroscopy time was prospectively collected in 5740 patients and radiation dose quantified as air kerma in 1,445 patients and dose-area product (DAP) in 2,255 patients.
  
  
  RESULTS
  Median fluoroscopy time was higher with radial versus femoral access (9.3 vs. 8.0 min, p < 0.001). Median air kerma was nominally higher with radial versus femoral access (1,046 vs. 930 mGy, respectively, p = 0.051). Median DAP was not different between radial and femoral access (52.8 Gy-cm(2) vs. 51.2 Gy·cm(2), p = 0.83). When results are stratified according to procedural volume, air kerma was increased only in the lowest tertile of radial volume centers (low 1,425 vs. 1,045 mGy, p = 0.002; middle 987 vs. 958 mGy, p = 0.597; high 652 vs. 621 mGy, p = 0.403, interaction p = 0.026). Multivariable regression showed procedural volume was the greatest independent predictor of lower air kerma dose (ratio of geometric means 0.55; 95% confidence interval 0.49 to 0.61 for highest-volume radial centers).
  
  
  CONCLUSIONS
  Radiation dose as measured by air kerma was nominally higher with radial versus femoral access, but differences were present only in lower-volume centers and operators. High-volume centers have the lowest radiation dose irrespective of which access site approach that they use. (A Trial of Trans-radial Versus Trans-femoral Percutaneous Coronary Intervention (PCI) Access Site Approach in Patients With Unstable Angina or Myocardial Infarction Managed With an Invasive Strategy [RIVAL]; NCT01014273).
authors.affiliation: Department of Medicine, McMaster University and Population Health Research Institute, Hamilton Health Sciences, Hamilton, Ontario, Canada. sanjit.jolly@phri.ca
authors.forename: Sanjit S
authors.initials: SS
authors.lastname: Jolly
authors.forename: John
authors.initials: J
authors.lastname: Cairns
authors.forename: Kari
authors.initials: K
authors.lastname: Niemela
authors.forename: Philippe Gabriel
authors.initials: PG
authors.lastname: Steg
authors.forename: Madhu K
authors.initials: MK
authors.lastname: Natarajan
authors.forename: Asim N
authors.initials: AN
authors.lastname: Cheema
authors.forename: Sunil V
authors.initials: SV
authors.lastname: Rao
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Cantor
authors.forename: Vladimír
authors.initials: V
authors.lastname: Džavík
authors.forename: Andrzej
authors.initials: A
authors.lastname: Budaj
authors.forename: Tej
authors.initials: T
authors.lastname: Sheth
authors.forename: Vicent
authors.initials: V
authors.lastname: Valentin
authors.forename: Anthony
authors.initials: A
authors.lastname: Fung
authors.forename: Petr
authors.initials: P
authors.lastname: Widimsky
authors.forename: Emile
authors.initials: E
authors.lastname: Ferrari
authors.forename: Peggy
authors.initials: P
authors.lastname: Gao
authors.forename: Barbara
authors.initials: B
authors.lastname: Jedrzejowski
authors.forename: Shamir R
authors.initials: SR
authors.lastname: Mehta
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000000981:diagnostic imaging / Q000628:therapy*; D002983:Clinical Competence; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging*; D005471:Fluoroscopy; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D059032:Learning Curve; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D011446:Prospective Studies; D017534:Radial Artery / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011834:Radiation Monitoring; D015641:Radiography, Interventional / Q000379:methods*; D013997:Time Factors