Large Meta-analysis Confirms Survival, Bleeding Benefits With Radial Access

(UPDATED) Patients with chronic and acute coronary syndromes undergoing angiography or PCI via the radial artery are less likely to die and have a significantly lower risk of major bleeding compared with patients via the femoral approach, according to an updated review and meta-analysis. Moreover, that survival benefit was not entirely dependent on the bleeding reduction, suggesting that other factors may be at play.

Long-time proponents are adamant: it’s time for any holdouts still relying primarily on the transfemoral approach to make the switch once and for all.

“Radial first, that’s the message,” Roxana Mehran, MD (Icahn School of Medicine at Mount Sinai, New York, NY), one of the study’s senior authors, told TCTMD. “Any operator who is not comfortable going with the radial approach should become comfortable with the radial approach. It really is the best way to go. It’s better for the patients, better for their outcomes, and you start to see higher patient satisfaction when they can walk out of the hospital sooner rather than sitting there with a groin complication.”  

To TCTMD, Sunil Rao, MD (Duke University Medical Center/Durham VA Medical Center, NC), a longtime proponent of radial access who wasn’t involved in the meta-analysis, said the reduction in mortality seen here lines up with data from some randomized trials, such as RIFLE-STEACS and MATRIX. “The mechanism of the mortality benefit remains somewhat elusive,” he said in email. “It’s probably not all bleeding reduction, although reducing bleeding is a good thing.” He noted that an analysis from the MATRIX trial suggested that the mortality reduction might be the result of less acute kidney injury with radial access.

I think what we’re seeing here are the kinds of positive things we’ve known to be associated with radial access. Roxana Mehran

Amer Ardati, MD (University of Illinois at Chicago), who also wasn’t involved in the study, pointed to a 2018 update from the American Heart Association on best practices for transradial access in ACS, one that included a review of the available evidence showing a roughly 30% reduction in all-cause mortality at 30 days with the radial approach. In this higher-risk population, said Ardati, there are a number of studies now pointing to a reduction of all-cause mortality, “which is the whole point of ACS intervention,” he said. “The onus is on the community to say ‘why not’ transradial as the default option in ACS patients.”

Even if the mechanism behind the reduction in mortality is not fully known, Nadia Sutton, MD (University of Michigan, Ann Arbor), believes the decreased bleeding risk is enough of a reason to prefer radial access for PCI. 

“Other benefits of radial access are reduced time to ambulation, less overall discomfort and back pain, improved patient satisfaction with their procedure, and cost savings related to lower bleeding complication rates and reduced length of stay,” she said in an email. “If there is also a mortality benefit compared with current safe femoral practices, then that is the most compelling reason to prefer radial access.” 

More Than 30,000 Patients

The new meta-analysis, which was published January 28, 2021, in Catheterization and Cardiovascular Interventions, included 31 trials and 30,096 patients, of whom 21,225 underwent PCI. Six studies enrolled only patients with chronic coronary syndrome and 18 included only patients with ACS. Among the latter studies, 12 included only patients with STEMI, such as STEMI-RADIAL and SAFARI-STEMI. 

Overall, radial access was associated with a statistically significant 47% lower risk of major bleeding and a 68% lower risk of vascular complications. There was no difference in the risk of MI or stroke among those treated with the two approaches. Past studies of radial access for coronary angiography and PCI have shown it is associated with higher risk of subclinical cerebral embolism on ultrasound or magnetic resonance imaging, the researchers point out in their paper.

The onus is on the community to say ‘why not’ transradial as the default option in ACS patients. Amer Ardati

“The whole notion of more strokes with radial-access, I’m glad to see that’s gone away,” said Mehran. “With a larger number of patients and with increasing operator experience, you’re going to see less complications associated with radial access. I think what we’re seeing here are the kinds of positive things we’ve known to be associated with radial access. It’s another a bleeding avoidance strategy that turns out to enhance mortality.”

Compared with transfemoral access, the radial approach was associated with a 26% lower risk of all-cause mortality overall, although the reduction was only statistically significant in patients presenting with ACS. In a meta-regression analysis, there was no correlation between major bleeding and mortality, a finding that sows doubt as to whether reducing bleeding is the main cause for the survival benefit.

Mehran noted that the present study can’t identify the reasons for the lower risk of death, but she suspects that when operators avoid bleeding they focus more on achieving the best cardiovascular outcomes possible. In ACS, for example, avoiding bleeding allows physicians to prescribe potent antithrombotic agents without having to worry about access-site issues. While this hypothesis explaining the reduction in bleeding can’t be proven, “I think it makes clinical sense,” said Mehran. 

Still, Ardati thinks the reduction in bleeding is likely the biggest driver of the mortality benefit. “We know that major and minor bleeding is associated with adverse events in acute coronary syndrome,” he said. “The major bleeding events that are associated with the access site can be catastrophic, and I think that’s probably the highest-yield bucket of where we’re seeing the advantages of radial.”   

Learning Curves

Mehran said that at their large, academic medical center, operators went the radial route in fewer than 10% of cases 5 years ago, but today roughly 35% to 40% of coronary interventions are transradial. The hospital is aiming to get that number up even higher, although there will be limits as to how high it can go. “Mount Sinai is a tertiary referral center, and most patients who are refused for CABG or PCI are sent to us,” she said. “These are really difficult patients. We’re always looking to do radial, but in the most complex patients, where you need a support device, we will use the femoral approach.”

The learning curve for radial access is fairly modest, Ardati said, with data suggesting it takes 30 to 50 cases before operators are equally proficient with transradial and transfemoral interventions. At his center, more than 95% of coronary interventions go the radial route, he added. Rao said contemporary US data on the adoption of transradial coronary interventions are lacking, but he ballparks it around 50%. “The reason I say that is that the rate of radial access adoption in the VA system nationally is north of 65% now and the private sector has tended to lag behind a bit,” he said.

Sutton said training programs should ensure fellows have sufficient exposure to performing PCI via both femoral and radial access. 

“Versatility as an interventional cardiologist is very important,” she said. “Standard and large- bore femoral access management is still a critical part of training as it is needed for mechanical circulatory support and structural procedures. Fellows need sufficient exposure and volume during training to be able to obtain and manage femoral access and bleeding complications when they occur.”

She also noted that with fluoroscopic and ultrasound guidance, as well as the routine use of closure devices when the patient’s anatomy is favorable, femoral access safety has likely improved over time.