DIPRA Quells Fears Over Distal Radial Cath and Hand Function at 1 Year

PHOENIX, AZ—Patients who undergo cardiac catheterization with distal radial artery access have similar grip strength and other measures of hand function at 1 year as patients who had conventional radial access, according to 1-year data from the DIPRA study presented here at the Society for Cardiovascular Angiography and Interventions (SCAI) 2023 Scientific Sessions.

Distal access—involving puncture of the radial artery distal to the superficial palmar arch—has been shown in some studies to reduce the chances of a radial artery occlusion compared with proximal radial access, although the data are mixed, with the recent DISCO RADIAL trial showing no statistically significant difference in radial artery occlusion rates. When occlusions happen, they compromise the ability to use the radial artery for future percutaneous procedures and CABG.

Sometimes called snuffbox access, the distal radial approach has thus far accumulated less data than proximal radial PCI with regard to long-term impact on hand function, which necessitated the DIPRA study, noted Karim Al-Azizi, MD, (Baylor Scott & White Heart Hospital Plano, TX), during his presentation.

“Distal radial artery access was not associated with an increased risk of hand dysfunction in the short term at 30 days or at 1 year compared to proximal radial artery access,” he said in a late-breaking trial session.

For the primary outcome of the composite of handgrip test, thumb-forefinger pinch test, and a self-reported questionnaire on hand function, there were no differences between the distal and proximal patient groups at 1 year (P = 0.59), Al-Azizi showed.

While there is a learning curve, he said distal radial “is something that we can keep in the toolbox and perhaps actually there is an argument for it in certain patients over proximal.”

Radial pioneer Ian C. Gilchrist, MD (Penn State Health Milton S. Hershey Medical Center, Hershey, PA), who was a panelist, told TCTMD that he doesn’t expect many operators to be swayed to distal access, other than those who are already hard-core radial users.

“I happen to think that we should all be doing safe vascular access where everyone gets ultrasound and you do your best for every patient and every artery,” he said. “I don’t know that I’m intrigued enough at this point to use distal radial as my starting point. I see it as another option in the toolbox, but not an option that nonradial operators are going to take.”

No Differences in Hand Tests

For the single-center DIPRA study, the researchers randomized 300 patients (mean age 66.6 years; 25% female) who were undergoing angiography or PCI from March 2020 to December 2021 to receive distal access or standard proximal access. To be enrolled, patients needed to have a palpable radial artery in the distal position that could accommodate at least a 5-Fr sheath.

Ultrasound-guided access was mandated in the distal radial cohort but was optional for the proximal group. Successful radial access was achieved in 96.7% of the distal group and 98% of the proximal group (P = 0.72), with no differences in rates of bleeding. Radial artery occlusion occurred in one patient in the proximal group and two in the distal group.

The 1-year follow-up consisted of 112 patients randomized to the distal cohort and 104 to the proximal cohort.

Change in hand function from baseline to 1 year was measured with a hand dynamometer to test grip strength and with a pinch dynamometer to measure thumb-forefinger pinch ability. Patients also completed an abbreviated version of the QuickDASH questionnaire, which asks patients to rate their ability to use their hand in various situations.

As with the composite primary outcome, there were no differences between the distal and proximal groups on secondary measures of median change in handgrip strength (P = 0.57), median change in pinch-grip strength (P = 0.66), or median change in QuickDASH scores (P = 0.58).

‘Elegant’ but a Hard Sell

The findings from DIPRA build on those from the multicenter, international RATATOUILLE study, which also used repeated hand function tests and patient questionnaires, that concluded there were no differences at 1 year after a distal radial procedure. However, in that study, patients served as their own controls, with the contralateral hand undergoing all the same tests during follow-up as the hand used in the procedure.   

To TCTMD, Al-Azizi said while RATATOUILLE provided a signal of safety, DIPRA takes it a step further by adding needed head-to-head comparison data with proximal radial access.

The overall message is that in patients who have both palpable radial segments, distal access performs “as good as a proximal radial from a success standpoint, but also from a safety standpoint and up to 1 year. So, I think this is where it complements RATATOUILLE,” he said.

I see it as another option in the toolbox, but not an option that nonradial operators are going to take. Ian C. Gilchrist

Session co-moderator Prashant Kaul, MD (Piedmont Heart Institute, Atlanta, GA), polled the audience after the presentation, asking how many were using a distal radial approach as a default access in their practice. There were no hands raised. Kaul then asked how many were using traditional radial as a default and there was a smattering of hands.

While that lackluster response might suggest otherwise, “after many years of work, based on the NCDR registry, radial access is now 70% of all PCIs in this country, which is a huge change compared to about 5 or 10 years ago,” Kaul said.

Samir Pancholy, MD (Wright Center for Graduate Medical Education, Scranton, PA), another panelist and avid radial operator who spoke with TCTMD about the study, agreed that it would be hard to convince operators who already had to be swayed into using radial access to now try this more difficult form based on the available data, especially when experienced radial operators feel lukewarm about it.

Pancholy added that distal punctures can be more painful for patients, while for operators a commonly encountered barrier to using it in elderly patients is arthritic hands.

“If you try to do a distal radial on an 82-year-old woman with a BMI of less than 30, you’re going to have a more difficult time than regular radial. Yeah, it's a very elegant access site. But is it doable in 99% of cases like regular radial in my hands? I cannot break 90% with distal radial,” he said.