Higher Volume and Proportion of Transradial Cases Linked with Lower Mortality


To get the biggest bang for their dollar, operators need to not only increase the total number of PCIs they perform, but also increase the proportion of cases they tackle via the radial artery.

The Take Home. Higher Volume and Proportion of Transradial Cases Linked with Lower Mortality

In a new analysis, investigators report that two key operator-level variables—procedural volume and percentage of cases performed transradially—were associated with mortality among patients undergoing PCI. 

“One of the problems is that while people are increasingly recognizing that radial is associated with better outcomes, they might think, well, if I do 20% or 30% of my cases radial, then that’s OK,” senior investigator Mamas Mamas, BMBCh, DPhil (University of Keele, Stoke-on-Trent, England), told TCTMD. “What our paper shows is that to really get the benefit, you need to be doing a high proportion of your cases radially. If you’re doing anything less than 30% or 40% of your cases radially, you won’t see any benefit. You have to be much higher than that.”

The bottom line, he said, is that if operators are going to switch from transfemoral access, they really need to commit to the procedure. The greater the proportion of cases performed radially, the greater the reduction in adverse clinical outcomes, such as mortality at 30 days, said Mamas.

Given the overall clinical benefit observed in this study, as well as multiple randomized trials, Matthew Cavender, MD (Brigham and Women’s Hospital, Boston, MA) and Prashant Kaul, MD (University of North Carolina at Chapel Hill), who wrote an editorial accompanying the study, say transradial access should be the default strategy in patients undergoing cardiac catheterization.

In Europe, for example, the “radial-first” approach is a class IA recommendation in patients with ACS undergoing coronary angiography and PCI, they report. In the United States, operators are increasingly going radial—there was a 13-fold increase in use between 2007 and 2013—but more than 80% of cases are still performed via the femoral artery.

Now that the benefits of transradial access over transfemoral “should no longer be in question,” Cavender and Kaul wonder whether it is time for labs, hospital systems, and professional societies to make transradial access a “quality metric” of care and to institute a benchmark for the proportion of cases to be done via the radial artery. If transradial access became a quality indicator, it might increase utilization across the United States, they say.

The study and editorial were published online May 9, 2016, ahead of print in Circulation: Cardiovascular Interventions.

RIVAL Hints at Impact of Radial Volume

Explaining the rationale for the analysis, Mamas noted that in the RIVAL study—a trial comparing radial and femoral access in patients with ACS undergoing PCI—there was a suggestion that procedural radial volumes had an impact on outcomes. In a subgroup analysis of that study, the primary composite endpoint of death, MI, stroke, or non-CABG-related major bleeding at 30 days was reduced at high-volume radial PCI centers but not at those considered intermediate- or low-volume sites. Other US studies have suggested a relationship between transradial PCI volumes and outcomes.

Using data from the British Cardiovascular Intervention Society (BCIS), the researchers identified 164,395 procedures performed between 2012 and 2013 within the National Health Service in England and Wales. Overall, the proportion of PCIs performed transradially increased from 60% in early 2012 to 70% in late 2013.

The proportion of cases performed via the radial artery increased as operator volume increased. For example, among low-volume operators (performing one to 123 cases annually), there was a roughly even split between cases done via the femoral and radial arteries. However, among the high-volume operators (performing 238-658 cases annually), nearly 75% of cases were performed transradially. The proportion of cases performed transradially was also significantly higher at higher-volume PCI centers.

Overall, PCI performed via the radial artery was associated with a 39% lower risk of death at 30 days compared with transfemoral PCI (OR 0.61; 95% CI 0.55-0.68).

In examining the relationship between operator/hospital volumes and outcomes, only the operator’s total volume of PCI cases performed annually and the operator’s proportion of cases performed transradially were associated with reductions in 30-day mortality. For every extra 100 procedures performed by the operators, the risk of death at 30 days declined an additional 11% among patients treated transradially. For every 10% increase in the proportion of cases performed via the radial artery, there was a 6% reduction in risk of death at 30 days.

“The key thing is that the proportion is independent of the volume,” said Mamas. “Even when you adjust for the difference in the volume between operators, there still seems to be a very strong signal that the proportion of cases done with the radial approach impacts outcomes.”

‘I Can’t Remember the Last Femoral Case’

Overall, Mamas said that if operators are performing less than 40% of their cases via the radial artery, there doesn’t appear to be an improvement in clinical outcomes. For operators who perform a large percentage of their cases radially, even increasing the proportion further can have an impact as there did not appear to be ceiling in which the interaction diminished.

Prior to the study, Mamas said he did approximately 85% of his cases via the radial artery. “Now, I can’t remember the last femoral case,” he said. “I’m really trying everything possible to stick to radial, whereas perhaps, before, in the most challenging cases, I wouldn’t have. These data show the benefit continues to increase, even above 90%. That to me is a very strong message for changing one’s practice.”

Mamas said it’s not uncommon for operators, when they begin the shift to transradial access, to opt for the transfemoral route in complex patients. However, in doing so, operators might be avoiding the patients who stand to benefit the most.

“If you’re only doing simple cases in young, relatively fit men coming for elective PCI, those are low-risk bleeding patients,” he said. “Switching to radial PCI in those sorts of patients, you’re not going to get much of a benefit. In the high-risk bleeding cases—the elderly, frail ladies coming in with acute coronary syndrome—those patients have the most to benefit from switching to radial.”

In their editorial, Cavender and Kaul make a similar argument, noting that as operators gain proficiency with transradial access, the patients in whom they’re comfortable using it expands to higher-risk patients. Many of these high-risk acute coronary syndrome patients are also being treated with potent antiplatelet therapy and anticoagulants, so a strategy designed to “avoid bleeding in those patients who are at the highest risk of adverse events and death may be the key factor that is driving the benefit of transradial access.”

One of the interesting aspects of the analysis is that there are few UK operators on the fence between transfemoral and transradial PCI. Mamas said the data suggests UK interventional cardiologists are either high-volume transfemoral or transradial operators, with few individuals in between. Physicians sticking to transfemoral access are typically low-volume interventionalists, he added.

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Michael O’Riordan is the Associate Managing Editor for TCTMD and a Senior Journalist. He completed his undergraduate degrees at Queen’s…

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  • Hulme W, Sperrin M, Rushton H, et al. Is there a relationship of operator and center volume with access site-related outcomes? Circ Cardiovasc Interv. 2016;9:e003333.

  • Cavender MA, Kaul P. Is it time for radial access to become a quality metric for percutaneous coronary intervention? Circ Cardiovasc Interv. 2016;9:003881.

  • Mamas, Cavender, and Kaul report no relevant conflicts of interest.