title: Radiation exposure in relation to the arterial access site used for diagnostic coronary angiography and percutaneous coronary intervention: a systematic review and meta-analysis.
abstract: BACKGROUND
  Transradial access for cardiac catheterisation results in lower bleeding and vascular complications than the traditional transfemoral access route. However, the increased radiation exposure potentially associated with transradial access is a possible drawback of this method. Whether transradial access is associated with a clinically significant increase in radiation exposure that outweighs its benefits is unclear. Our aim was therefore to compare radiation exposure between transradial access and transfemoral access for diagnostic coronary angiograms and percutaneous coronary interventions (PCI).
  
  
  METHODS
  We did a systematic review and meta-analysis of the scientific literature by searching the PubMed, Embase, and Cochrane Library databases with relevant terms, and cross-referencing relevant articles for randomised controlled trials (RCTs) that compared radiation parameters in relation to access site, published from Jan 1, 1989, to June 3, 2014. Three investigators independently sorted the potentially relevant studies, and two others extracted data. We focused on the primary radiation outcomes of fluoroscopy time and kerma-area product, and used meta-regression to assess the changes over time. Secondary outcomes were operator radiation exposure and procedural time. We used both fixed-effects and random-effects models with inverse variance weighting for the main analyses, and we did confirmatory analyses for observational studies.
  
  
  RESULTS
  Of 1252 records identified, we obtained data from 24 published RCTs for 19 328 patients. Our primary analyses showed that transradial access was associated with a small but significant increase in fluoroscopy time for diagnostic coronary angiograms (weighted mean difference [WMD], fixed effect: 1·04 min, 95% CI 0·84-1·24; p<0·0001) and PCI (1·15 min, 95% CI 0·96-1·33; p<0·0001), compared with transfemoral access. Transradial access was also associated with higher kerma-area product for diagnostic coronary angiograms (WMD, fixed effect: 1·72 Gy·cm(2), 95% CI -0·10 to 3·55; p=0·06), and significantly higher kerma-area product for PCI (0·55 Gy·cm(2), 95% CI 0·08-1·02; p=0·02). Mean operator radiation doses for PCI with basic protection were 107 μSv (SD 110) with transradial access and 74 μSv (68) with transfemoral access; with supplementary protection, the doses decreased to 21 μSv (17) with transradial access and 46 μSv (9) with transfemoral. Meta-regression analysis showed that the overall difference in fluoroscopy time between the two procedures has decreased significantly by 75% over the past 20 years from 2 min in 1996 to about 30 s in 2014 (p<0·0001). In observational studies, differences and effect sizes remained consistent with RCTs.
  
  
  CONCLUSIONS
  Transradial access was associated with a small but significant increase in radiation exposure in both diagnostic and interventional procedures compared with transfemoral access. Since differences in radiation exposure narrow over time, the clinical significance of this small increase is uncertain and is unlikely to outweigh the clinical benefits of transradial access.
  
  
  BACKGROUND
  None.
authors.affiliation: Quebec Heart-Lung Institute, Laval University, QC, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Plourde
authors.affiliation: The Wright Center for Graduate Medical Education, The Commonwealth Medical Center, Scranton, PA, USA.
authors.forename: Samir B
authors.initials: SB
authors.lastname: Pancholy
authors.affiliation: University Hospital of North Staffordshire, Stoke-on-Trent, UK.
authors.forename: Jim
authors.initials: J
authors.lastname: Nolan
authors.affiliation: McMaster University and the Population Health Research Institute, Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Sanjit
authors.initials: S
authors.lastname: Jolly
authors.affiliation: The Duke Clinical Research Institute, Duke University, Durham, NC, USA.
authors.forename: Sunil V
authors.initials: SV
authors.lastname: Rao
authors.affiliation: The Wright Center for Graduate Medical Education, The Commonwealth Medical Center, Scranton, PA, USA.
authors.forename: Imdad
authors.initials: I
authors.lastname: Amhed
authors.affiliation: New York University School of Medicine, New York, NY, USA.
authors.forename: Sripal
authors.initials: S
authors.lastname: Bangalore
authors.affiliation: Apex Heart Institute; Department of Cardiology, Sheth VS General Hospital, Ahmedabad, India; Smt NHL Municipal Medical College, Ahmedabad, India.
authors.forename: Tejas
authors.initials: T
authors.lastname: Patel
authors.affiliation: Department of Cardiology-Angiology, Heart & Vascular Center Neu-Bethlehem, Göttingen, Germany.
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Dahm
authors.affiliation: Quebec Heart-Lung Institute, Laval University, QC, Canada; Department of Mechanical Engineering, McGill University, Montreal, QC, Canada. Electronic address: Olivier.Bertrand@criucpq.ulaval.ca.
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Bertrand
mesh_terms: D006328:Cardiac Catheterization; D017023:Coronary Angiography; D005263:Femoral Artery; D006801:Humans; D062645:Percutaneous Coronary Intervention; D017534:Radial Artery; D000069079:Radiation Exposure