Radial PCI Benefits Seen in Real-world Analysis, Mirroring RCTs

LONG BEACH, CA—Compared with femoral access, the use of radial in PCI procedures is associated with less in-hospital mortality, major access-site bleeding, and other major vascular complications, but also a higher risk of ischemic stroke, according to an analysis of the National Cardiovascular Data Registry (NCDR)’s CathPCI Registry.

“We've seen over the past decade a substantial change in how PCI are performed in the US, with radial access becoming the dominant approach,” noted Reza Fazel, MD (Beth Israel Deaconess Medical Center, Boston, MA), in his presentation here at SCAI 2024. The real-world data confirm the benefits and safety that have been seen in RCTs, he added.

The analysis also lends more support to other contemporary studies demonstrating that radial PCI continues to increase in the United States after years of lagging behind the rest of the world. The American College of Cardiology/American Heart Association guidelines for coronary revascularization now emphasize a radial-first approach in line with what has been recommended in Europe for many years.

To TCTMD, Fazel said while the analysis wasn’t designed to understand what’s behind the increase in the radial approach, the arrival of RCT data showing better outcomes than with femoral access “likely has been a factor for certain people in moving towards using radial access more.”

Panelist Ian C. Gilchrist, MD (Penn State Health Milton S. Hershey Medical Center, Hershey, PA), a longtime radial proponent, said he was glad to see that “it's true that this does appear to be a better approach, a generational change in how we go about invasive procedures.”

Still, he said it’s disappointing that the US still hasn’t caught up with the rest of the world in adoption of radial access, noting that the NCDR data show significant interoperator variability. Gilchrist said that alone speaks to the fact that “it's not just a small core of patients that need to be done femorally, but rather there's operators that just won't convert and there's some that have only mildly, tepidly converted.”

NCDR Data Show Gradient of Benefit

The analysis included 6,658,479 PCI procedures performed between 2013 and 2022. Approximately 40% of all procedures were performed radially, which the authors said represents a 2.8-fold increase over the past decade (P < 0.001). The increase in use of radial access was seen in STEMI, NSTE ACS, and non-ACS procedures, as well as in all geographic regions.

In instrumental variable analysis, radial access was associated with a lower frequency of adverse events, with the exception of stroke.

CathPCI Registry, 2013-2022: Outcomes by Access Route

Analysis with a falsification endpoint of gastrointestinal or genitourinary bleeding showed no difference between radial and femoral patients (P = 0.89), which Fazel said supports the lack of residual confounding.

There was a gradient of benefit across presentations, with STEMI patients reaping the greatest gains from radial access in terms of bleeding reduction and survival, but also having a slightly higher risk of stroke compared with femoral patients.

In the non-ACS group, radial access was not associated with a survival benefit, but there was an advantage over femoral access for major access-site bleeding and other vascular complications. The inclusion of these patients as part of the real-world analysis is novel, Fazel noted, since non-ACS patients were not part of any RCTs that compared radial and femoral PCI approaches.

There's operators that just won't convert and there's some that have only mildly, tepidly converted. Ian Gilchrist

In a press conference prior to his presentation, Fazel said the increased risk of stroke, which he called “small, but real,” has not been seen in any of the major RCTs.

“There’s been signals of this that haven’t achieved statistical significance in trials,” he added. To power a trial to detect a difference, he estimated that 300,000 patients would need to be enrolled. Among the largest trials to date of radial versus femoral access, MATRIX, at 8,404 patients, showed no difference between groups in rates of stroke.

Fazel added that there is clinical plausibility for the higher stroke risk with radial access due to manipulation of catheters in the innominate artery. Data from the British Cardiovascular Intervention Society registry confirm this with a suggestion that left radial access may be associated with less of a stroke risk than right radial access, he continued, possibly due to more favorable vascular anatomy.

Gilchrist said the stroke risk is an area that can be improved upon.

“We are passing wires and equipment right past the carotid and other things,” he noted. “I think an acknowledgment that that's a danger zone, if you go through that area, may prompt people to [be more careful].”