SCAI Experts Update Transradial Guidance

It’s time to revisit “best practices” for transradial procedures, say experts from the Society for Cardiovascular Angiography and Interventions (SCAI). With 6 years of additional data to inform their advice, a newly updated consensus statement recommends the use of ultrasound to guide vascular access, suggests the ulnar artery may be a reasonable alternative access site, and discourages noninvasive testing of hand circulation prior to interventions.

Since the last consensus statement was published in 2013, use of the radial artery for coronary interventions has increased dramatically, said lead author Adhir Shroff, MD (University of Illinois at Chicago). “With that, there's a lot more people practicing radial access and then there've been a lot more studies published that have helped to define best practices,” he told TCTMD. “We wanted to take the opportunity to summarize some of those areas for clinicians.”

The first major issue to be addressed in the document, published online last week in Catheterization and Cardiovascular Interventions, was the use of ultrasound to ease transradial procedures, Shroff said. “Ultrasound is really an important tool to be incorporated into radial access. I think we really wanted to highlight at least the data that's been out there that's helped to show the benefits of improving time-to-access and your likelihood of having successful access.”

Specifically, the writing committee suggests that all transradial operators should “develop proficiency with ultrasound guidance to facilitate forearm vascular access” and that “real-time ultrasound guidance should be available and used when difficulty with radial access is encountered or expected.”

To tell people to do a technique in a different manner is a little more personal than telling people you need to give these kinds of medications for this condition. Adhir Shroff

Next, many studies have come out in recent years showing the potential of ulnar artery access should the radial artery be unavailable or the risk of complications high, said Shroff. Data have shown better outcomes with radial over ulnar access, but “it's still better than transfemoral,” he said, noting that ultrasound use is especially important when attempting ulnar access to “make sure they have a direct picture of the artery and you don't have any nerve damage.”

Ultimately, the document’s co-authors advise radial access in “most situations” but say “the ulnar artery may be a reasonable alternate access site when the risks of radial access failure or complication are high.” Also, “the ipsilateral ulnar artery may be a reasonable secondary access site after failed radial access; however, the data are limited,” they observe, adding that there is limited evidence to support ulnar artery use over contralateral radial or transfemoral access following radial artery occlusion.

One thing that’s no longer recommended is the use of noninvasive testing prior to radial access. Many operators used to perform routine collateral testing to help document ulnar artery patency, but a recent study showed that this strategy did not help predict patients with complications.

“Actually, you can potentially harm somebody,” Shroff said. “If you have an abnormal test and you decide to go femoral access, you might have a higher chance of a complication based on you not doing radial access.”

The recommendation in the current paper is that routine collateral testing “should not be used as a triage tool for access site selection.” However, the SCAI document adds, it might be useful postprocedure to identify radial artery occlusion and assessing the adequacy of hemostasis techniques.

Open Questions

Much remains unknown regarding transradial access, said Shroff, who identified the effectiveness and safety of distal radial—or so-called snuffbox—access and the optimal heparin dose as open questions.

There are “very little data to support or reject the use of distal radial access over radial access,” he said, acknowledging that this technique has been popularized by operators presenting cases on social media.

By summarizing these topics and what is available in the literature, Shroff said he hopes this document will “help stimulate the clinical research community to design trials to address these questions, so that in our next update we can have more clinical trial data from which to make further recommendations.”

Additionally, while this update did specifically endorse transradial access for primary PCI, Shroff said he’d like to see this come to pass in the future. “We're behind some of our European colleagues,” he said. “In Europe, they have a class I recommendation for these patients to obtain radial access and we really wanted to try to say that in this document as well. However, we received some . . . pushback from some leadership that it may be a little too aggressive in this statement for an American audience. But I do think that's something we need to continue to discuss in the next few years and . . . help define that further.”

The nitty gritty of this document aside, Shroff pointed to the fact that transradial operators generally aren’t adhering to as many of the best practices as they should be, according to a 2018 survey of more than 1,000 interventionalists. “We want to encourage operators to follow these best practices,” he said, noting that guidance about technique is not always as well received as clinical advice.

“People think that the way they do things is the right way and it's the best way based on their experience,” Shroff said. “To tell people to do a technique in a different manner is a little more personal than telling people you need to give these kinds of medications for this condition. . . . There's a lot of best practices put out about medication prescription or diagnostic studies or modalities or when to use an echo but not necessarily about how you actually perform the echo or how you perform a nuclear medicine stress test.” Still, he said, “we're optimistic.”