Radiation Exposure and Arterial Access Site
What is the difference in radiation exposure between transradial access and transfemoral access for diagnostic coronary angiograms and percutaneous coronary interventions (PCIs)?
The investigators performed 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 randomized controlled trials (RCTs) that compared radiation parameters in relation to access site, published from January 1, 1989, to June 3, 2014. Three investigators independently sorted the potentially relevant studies, and two others extracted data. They 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. The authors used both fixed-effects and random-effects models with inverse variance weighting for the main analyses, and did confirmatory analyses for observational studies.
Of 1,252 records identified, the authors obtained data from 24 published RCTs for 19,328 patients. The 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 minute, 95% confidence interval [CI], 0.84-1.24; p < 0.0001) and PCI (1.15 minute, 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•cm2, 95% CI, -0.10 to 3.55; p = 0.06), and significantly higher kerma-area product for PCI (0.55 Gy•cm2, 95% CI, 0.08-1.02; p = 0•02). Mean operator radiation doses for PCI with basic protection were 107 μSv (standard deviation 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 minutes in 1996 to about 30 seconds in 2014 (p < 0.0001). In observational studies, differences and effect sizes remained consistent with RCTs.
The authors concluded that transradial access was associated with a significant increase in radiation exposure compared with transfemoral access.
This meta-analysis reports that transradial access was associated with a small, but statistically significant increase in radiation exposure in both diagnostic and interventional procedures, compared with transfemoral access. While the clinical significance of this radiation increase is uncertain at this point, it should be part of the informed consent and decision-making process for patients undergoing angiography. Meanwhile, clinicians and institutions should ensure that adequate measures are taken to continually minimize radiation exposure by enhancing training and adhering to the ALARA (as low a radiation as allowable) principle.
Keywords: Coronary Angiography, Diagnostic Imaging, Fluoroscopy, Percutaneous Coronary Intervention, Radiation Dosage
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