Dual Circulation Assessment, Low Volume Each Do a Disservice to Radial Access
ORLANDO, FL—Operators looking to improve patient outcomes and contemporize their practices should let go of outdated patient assessments and assumptions about radial access and move toward increasing their volume, researchers told an audience today at SCAI 2016.
Christopher Pyne, MD (Lahey Hospital and Medical Center, Burlington, MA), sought to dissuade colleagues who still put value in dual circulation testing of the hand before radial PCI.
“It’s important . . . to understand that there is no evidence of a positive or negative predictive value of circulation screening for postprocedural hand ischemia,” he said.
Pyne told the audience that “if you cling to dual circulation testing” and “if you are going to do it you should probably be doing it with oximetry and plethysmography,” because only about 1.5% of patients will fail it as opposed to 6% who will fail a visual Allen’s test.
The 2010 First International Transradial Practice Survey showed that worldwide, 60-70% of patients were getting some form of dual circulation assessment, with the United States leading the way with the highest rates at over 90%, Pyne said. Even in Japan, which had the lowest rate, more than half of patients were still being tested.
But circulation in the hand is complex and cadaver studies have shown diverse anatomic variability from one individual to another, Pyne noted. Additionally, studies have repeatedly shown no real value of the Allen’s test as a corollary to artery patency and distribution of blood flow. Even among patients with clearly abnormal Allen’s results, the literature shows few cases of ischemic injury to the hand, he reiterated.
‘Waste of Time’
The RADAR trial was the first to look specifically at this issue and “is the trial that has given most of us the confidence to move away from dual circulation assessment,” Pyne said. The results showed that thumb capillary lactate levels and hand discomfort was equivalent between patients with normal, intermediate, or abnormal Allen’s test results. In fact, Pyne said the vast majority of hand ischemia is likely due to embolic phenomenon, vasospasm, local thrombosis, or compartment syndrome.
In his own informal survey this year of eight high-radial-volume hospitals, he found that four had completely abandoned circulation assessment—including one that reported not performing them at all in the last two decades—with none of the hospitals reporting a single known ischemic hand complication. Only one of those hospitals reported routinely using it, and the other three reported that while they use it, the results are typically ignored or for research only.
Panelist Sunil V. Rao, MD (Duke University Medical Center, Durham, NC), asked Pyne what, if any, utility there is for those still using dual assessment. Pyne said the most logical reason—and probably the only one—would be as a baseline to evaluate whether hemostasis is being achieved after radial access.
James Nolan, MD (University Hospitals of North Midlands, Stoke-on-Trent, Stafford, England), was far more blunt. “I haven’t personally done an Allen’s test in the last 15 years,” he said. “I think it’s a useless, meaningless waste of time.”
Mortality Improves, but Only With High Volume
Nolan continued his strong comments in a presentation on whether radial access should only be used in high-volume centers. Both the RIVAL and MATRIX trials have shown that hospital radial volume and operator volume exert significant influence on the outcomes of MACE and major bleeding for radial versus femoral access. In both trials, higher volumes were associated with approximately 50% reductions in bleeding, while low- and intermediate-volume centers demonstrated no impact of a radial strategy on outcomes compared with femoral.
Nolan showed similarly consistent data from his own soon-to-be published study looking at the effect of operator radial practice on 30-day mortality compared with a femoral approach in 164,359 procedures performed in the United Kingdom. The study found that as an operator’s radial proportion increases, mortality decreases about 6% for every 10% volume increase.
“It doesn’t become significant until you do about 30 to 40% of your procedures radially,” he said, adding that the study also found that for the highest volume operators, mortality improves by about 50% compared with doing the same procedure femorally.
The learning curve is the most likely mechanistic explanation for this effect, Nolan said, although contemporary studies show a shorter learning curve than in prior decades. Nevertheless, he said low-volume operators and centers “are likely to still be on their learning curve, and it’s very difficult for learning-curve operators to reproduce the results of experts in radial, not surprisingly.”
Importantly, Nolan said data also suggest that higher-volume operators are more willing than those at lower volumes to perform radial PCI in complex patients with the highest bleeding risk, likely providing an explanation for why high-volume operators demonstrate a greater impact on outcomes than lower-volume operators.
“Radial access is better for your patients, but only if you switch to a high-volume radial practice,” he commented. “It’s a powerful reason to move your interventional practice to mostly radial access.”
Time, Effort Combat Femoral Skill Decline
Moderator Sanjit Jolly, MD (McMaster University, Hamilton, Canada), asked Nolan his feelings on the suggestion that high-volume radial operators are worse at femoral procedures and that this difference explains the discrepancy between radial and femoral outcomes in the RIVAL and MATRIX trials.
Nolan noted that in his own practice his volume of femoral cases is quite low and the mortality rate is high, but explained that those cases are all severely ill patients, which is likely the case for many high-volume radial operators.
An audience member expressed concern about losing experience in femoral technique by shifting to a 100% radial practice.
“You always have to do some femoral procedures,” Nolan said. “But when I do a femoral case I keep them in recovery for 4 hours. I don’t let them out of my sight. I use ultrasound guidance, I use radiologic screening; I try to do a very good femoral procedure. You can do femoral procedures very well, even if you are a low-volume operator, if you put the time and effort in to doing them.”
Jolly then pondered why there is so much continued resistance to radial access.
Nolan suggested that operators who still persist in doing mostly femoral cases are primarily older and set in their ways. “The data on radial access is not going to get any better than this,” he said. “It is absolutely consistent across multiple randomized trials and observational registries. If you don’t understand and believe that data, nobody anywhere in the world will change your mind.”
- Pyne and Nolan report no relevant conflicts of interest.
Pyne C. Role of testing for dual circulation of the hand before radial access. Presented at: SCAI 2016; May 5, 2016; Orlando, FL.
Nolan J. Should radial approach only be used in high volume radial centers? Presented at: SCAI 2016; May 5, 2016; Orlando, FL.