Elsevier

The Lancet

Volume 386, Issue 10009, 28 November–4 December 2015, Pages 2192-2203
The Lancet

Articles
Radiation exposure in relation to the arterial access site used for diagnostic coronary angiography and percutaneous coronary intervention: a systematic review and meta-analysis

https://doi.org/10.1016/S0140-6736(15)00305-0Get rights and content

Summary

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.

Findings

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·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 (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.

Interpretation

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.

Funding

None.

Introduction

Transradial access for diagnostic coronary angiography and percutaneous coronary intervention (PCI) is gaining popularity worldwide because of its proven advantages over the more traditional transfemoral access route, including reduced risk of complications associated with the access site and bleeding, improved patient comfort, early ambulation, and cost savings.1, 2, 3, 4 Moreover, in patients undergoing primary PCI for ST-elevation myocardial infarction, transradial access has been associated with a significant reduction in mortality and better net clinical benefits compared with transfemoral access.2, 5, 6 In a large meta-analysis of more than 760 000 patients, we noted that, compared with transfemoral access, transradial access was associated with a 78% reduction in bleeding (odds ratio [OR] 0·22, 95% credible interval [CrI] 0·16–0·29) and 80% reduction in transfusions (OR 0·20, 95% CrI 0·11–0·32). Overall, mortality was also reduced by 44% with transradial access (OR 0·56, 95% CrI 0·45–0·67).4 Despite these important advantages for patients, concerns about increased radiation exposure for both patient and operators have partly contributed to the slow uptake of transradial access in clinical practice, especially in the USA.7 Several observational studies and a few randomised trials have compared radiation exposure between transradial access and transfemoral access. Although the findings from some studies suggest that radiation exposure might be increased with transradial access, whether this is a real effect is unclear, because of the many limitations of observational data and the potential effect of the learning curve and operator proficiency. A large multicentre survey of more than 50 000 patients8 even reported that the radial route was associated with lower doses of radiation than the femoral route. So far, only one large-scale randomised trial has compared radiation exposure between the radial and femoral approaches.1 Despite this study, no global quantitative assessment of radiation exposure based on access site is available. Although data have accumulated since the inception of transradial access in 1989, the question of whether transradial access constitutes a real radiation hazard or not remains unanswered.

We therefore did a systematic review and meta-analysis with the aim of gathering data from all available randomised controlled trials and observational studies comparing radiation exposure between transradial access and transfemoral access, and assessing whether transradial access is associated with higher radiation exposure, using fluoroscopy time as a surrogate estimate of patient and operator radiation exposure, the kerma-area product as an estimate of patient exposure, and recorded operator dosimetry.

Section snippets

Search strategy and selection criteria

We did this systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement9 and followed a strict protocol (available on request).

We searched scientific literature databases for RCTs comparing transradial access and transfemoral access in terms of radiation exposure to the patient. We did a systematic search of PubMed, Embase, and the Cochrane Library, using various combinations of keywords such as “(trans)-radial”,

Results

From an initial screen of 1265 records, we reviewed and included 24 RCTs undertaken between 1995 and 2014 in our meta-analysis, which included data for 19 328 patients in 11 countries (figure 1). 18 studies were single-centred, and six were multicentred (table 1). Most of the studies were small—only four enrolled more than 1000 patients. The level of operator skill was heterogeneous across the 24 trials, with some trials done by highly experienced radial operators, but others only required that

Discussion

Although observational and randomised data for radiation dosimetry in cardiac catheterisation have been accumulating since 1989, whether transradial access is associated with a clinically significant increase in patient and operator radiation exposure compared with transfemoral access is unclear. Radiation exposure in interventional cardiology is of the utmost importance, because low but frequent doses of ionising radiation can cause effects including skin injuries, premature cataract

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