Radial Access for Angiography and PCI on the Rise in US

Uptake of transradial cardiac catheterization and PCI is on the rise in the United States, an increase driven not only by younger operators entering practice with a strong radial background but also by older operators switching over from femoral access, a contemporary analysis from the Veterans Affairs (VA) healthcare system shows.

The study, published March 11, 2022, in Circulation: Cardiovascular Quality and Outcomes, found that nearly all operators performing procedures in 2018 were choosing radial access at least some of the time.  

“This likely means that most hospitals have figured out the equipment and training piece needed to allow their teams to use radial access,” lead investigator Jacob A. Doll, MD (VA Puget Sound Healthcare System, Seattle, WA), told TCTMD. “But we still see a huge spectrum in the frequency of radial access used by individual operators. I think there’s still a lot of work to be done to help people become more comfortable with radial and to use it for more-complex procedures.”

For Doll, implementing appropriate systems and providing access to training and education, as opposed to operator proficiency, are the critical pieces necessary to facilitate a radial-first approach.

Data from several randomized trials have shown that transradial coronary angiography and PCI is associated with better clinical outcomes, particularly reduced risk of bleeding, plus improved patient comfort and lower costs compared with transfemoral procedures. Compared with European and Asian countries, as well as Canada, the US has historically lagged behind in terms of radial access, however, although much of that data is older. In the latest American College of Cardiology/American Heart Association guidelines for coronary revascularization, a radial-first approach is now emphasized, just as it has been for many years by the European Society of Cardiology.

“Our hypothesis was that we had caught up somewhat to Europe, although we weren’t quite sure,” said Doll. “We were also interested in how that increase in radial was happening. Specifically, we weren’t quite sure if it was happening with people new to interventional cardiology, those coming out of training as radial operators, or if it was people who were traditionally femoral operators changing their practice.”

Going Radial at Least Once in 2018

Within the VA Clinical Assessment, Reporting, and Tracking (CART) program with complete data on access site, there were 253,179 diagnostic angiograms and 93,614 PCIs performed between 2011 and 2018. Overall, 159,699 angiograms were done with femoral access and 93,480 via the radial artery. With PCI, 65,227 and 28,387 cases were done with transfemoral and transradial access, respectively.

Between 2011 and 2018, the rate of radial access for diagnostic angiograms increased steadily from 17.5% to 60.4% (P < 0.01) and from 14.0% to 51.8% for PCI procedures (P < 0.01). Researchers also assigned operators to a cohort based on the year they first performed cardiac catheterization. This analysis showed that each yearly cohort entered with higher usage of radial access than the preceding cohort. With operators from 2011 as the comparator, all subsequent yearly cohorts had higher rates of radial-access diagnostic angiography and PCI.

The fact that people who started out with no or minimal radial access are now doing 50% of more their cases with radial indicates to me that this is a technique available to everyone. Jacob A. Doll

In 2018, the last year of the study, 332 operators performed more than 28,000 procedures, and nearly all operators went with radial access at least once. Additionally, 41% used the radial artery for 75% or more of their cases, while 25% went with radial access in fewer than 25% of their procedures.

The results also indicate that uptake increased among experienced operators. For those who entered practice in 2011 when radial-access rates were low, 164 operators were still working in 2018. Of those, 51 were classified as high radial users (≥ 75% of cases), 59 were moderate users (26% to 74% of cases), and 54 were low users (≤ 25% of cases).

“The fact that people who started out with no or minimal radial access are now doing 50% of more their cases with radial indicates to me that this is a technique available to everyone,” said Doll. “If we can provide people with enough support, everyone can make the transition.” Previous studies have shown that operators overcome the learning curve with transradial percutaneous coronary interventions in roughly 30 to 50 cases.     

Reduction in Bleeding With Femoral Access

With coronary angiography, the adjusted rate of bleeding with radial access declined from 2.4% in 2011 to 1.3% in 2018 and, with femoral procedures, from 2.4% to 1.4% during the same time period. With PCI, the adjusted rates of bleeding declined modestly, down from 2.4% in 2011 to 2.1% in 2018 with radial-access PCI and from 3.5% to 2.7% with transfemoral PCI.

“Bleeding for femoral access appears to be going down,” said Doll. “I think the results highlight a real success in our field, which is recognizing bleeding complications as important for patient outcomes and really focusing on driving those complications down whether radial or femoral access is used. I do think that if patients are going to receive femoral access, ensuring that we provide that as safely as possible is important. Our data would indicate that’s probably occurring.” 

The predicted risk of bleeding, calculated from clinical and presentation variables, was significantly higher for patients treated with femoral access. This risk-treatment paradox, which has been shown in previous studies, suggests there is still an opportunity to benefit some of the highest-risk patients undergoing cardiac catheterization and PCI, say researchers.

To TCTMD, Doll said there are ways to eliminate or reduce the existing paradox. First is helping operators to become more comfortable performing radial access in high-bleeding-risk procedures. Many of the variables that place patients at higher risk, such as older age, complex coronary artery disease, or STEMI presentation, can make cases more technically challenging and some operators may reflexively perform the procedure via the femoral artery. He added that models for predicting the risk of bleeding could be improved, which would help spur the switch to radial access.

“I think if we could potentially identify for operators those at highest bleeding risk, it would help them consider radial access, even if that may be a more technically challenging procedure,” said Doll.