Uptake of radial access in the United States: A glass half full?

In the last 25 years, enormous time and effort has been devoted to investigating the impact of arterial access site practice on outcomes after cardiac procedures, triggered by an increasing awareness of the detrimental effects of access site complications and bleeding. A considerable body of research involving randomized trials and very large observational studies confirm that the use of a transradial approach unequivocally decreases these important complications. In high-risk populations, such as patients undergoing primary angioplasty in which these complications can have major deleterious effects, this translates into mortality reduction. As a result of this large body of evidence, transradial access is now the dominant route for cardiac procedures in most of Europe and in many other parts of the world. In the United Kingdom, transradial access is utilized in more than 70% of all percutaneous coronary intervention (PCI) procedures, with the rate rapidly increasing year after year (Figure 1). It seems clear that in the near future, almost all cardiac interventions will be performed transradially in the United Kingdom. In the United States, a very different picture has emerged. Uptake of transradial access has been slow, and the overwhelming majority of cases are still performed transfemorally. It is interesting to consider the response of interventional cardiologists to different data sets. In 2003, Keeley et al published a meta-analysis of a relatively small number of patients involved in multiple, small, randomized trials comparing angioplasty or thrombolysis for the treatment of acute myocardial infarction.1 There was a small mortality reduction associated with primary angioplasty. After this publication, interventional cardiologists enthusiastically advocated a change in practice away from thrombolysis and toward the use of primary angioplasty for acute myocardial infarction. In 2012, we published a meta-analysis of a relatively small number of patients involved in multiple, small, randomized trials comparing radial with femoral access for primary angioplasty.2 Mortality was reduced by almost 50% in the radial access group. This meta-analysis is supported by a large unselected observational study that demonstrates that the results obtained in selected patients enrolled in randomized trials translate into real-world benefits in a large primary angioplasty population.3 These data did not prompt a universally enthusiastic response. Editorials were published arguing against widespread adoption of radial access for primary angioplasty.4 This divergent response to similar data may in part relate to the technical difficulties faced by established femoral operators seeking to change to a radial access–based practice. Rather than ignoring the data supporting radial access, the question has to be: How can we support people who are femoral operators making this sometimes difficult transition? Most of the initial investigators and innovators responsible for developing and validating the transradial technique in the last 25 years have been European. Within the United Kingdom, a small group of motivated interventional cardiologists (who had been trained in high-volume European radial centers) established an interlinked series of training courses and fellowship programs. These served to educate and train the new generation of interventional cardiologists who are now overwhelmingly radial operators. The value of these training programs in changing national practice cannot be underestimated. It is only in recent years that a cohort of similarly well-trained and highly motivated radial operators has emerged in the United States, triggering a rapidly expanding United States–based transradial education program. This is supported by the major role played by United States investigators in the development of the literaUptake of radial access in the United States: A glass half full?