US Registry Data Support Wider Adoption of Transradial PCI in STEMI Patients

The use of transradial percutaneous coronary intervention (PCI) in patients with ST-segment myocardial infarction (STEMI) is on the rise in the United States, according to a large registry study published online December 19, 2012, ahead of print in the Journal of the American College of Cardiology. Compared with the femoral approach, radial access is associated with reduced bleeding and in-hospital mortality, suggesting that wider adoption of the approach may improve outcomes.

Researchers led by Sunil V. Rao, MD, of the Duke Clinical Research Institute (Durham, NC), began by analyzing data on 294,769 patients from the National Cardiovascular Data Registry CathPCI Registry who underwent PCI for STEMI at 1,204 hospitals between 2007 and 2011. Among STEMI patients receiving PCI, the prevalence of transradial access rose from 0.9% in the first quarter of 2007 to 6.4% in the third quarter of 2011 (P < 0.0001).

To better compare patient and hospital characteristics and outcomes by access site, the researchers then focused on a population of 90,819 STEMI patients treated at 541 centers performing both radial and femoral PCI. A total of 6,159 patients (6.8%) within this cohort were treated via transradial access, with the proportion varying from 0.2% to 76.6% (median 2.7%) among participating hospitals.

Lower Mortality, Bleeding Risks

Median door-to-balloon times (78 vs. 74 minutes) and fluoroscopy times (12.80 vs. 10.40 minutes) were higher with radial vs. femoral access; contrast volume, however, was lower with radial (180 vs. 185 mL; P < 0.0001 for all comparisons), as were vascular complications requiring treatment (0.13% vs. 0.49%; P < 0.001).

Unadjusted rates of in-hospital mortality (primary endpoint) and bleeding within 72 hours were lower with radial access, while procedural success rates were similar for both techniques. These patterns remained after adjustment that involved inverse probability weighting and propensity-score matching (table 1).

Table 1. Association Between Access Route and Outcome: Radial vs. Femoral


Adjusted RR

95% CI

Procedural Success



In-Hospital Mortality



Bleeding ≤ 72 Hrs



The number-needed-to-treat to prevent 1 bleeding event with transradial access was 25 and to prevent 1 death was 207.

Capturing the US Experience

In an email communication with TCTMD, Dr. Rao said that, first and foremost, “We have to remember that this is an observational study so we cannot infer causality. . . . There are randomized trials (conducted outside the United States) showing that transradial primary PCI reduces mortality compared with transfemoral PCI.” But only a US-based randomized trial would allow a full understanding of the tradeoff between the longer door-to-balloon time and improved outcomes documented by the current registry, he said.

In addition to the recently presented STEMI-RADIAL study, Dr. Rao highlighted 3 ongoing trials from outside the United States—EASY-B2B, SAFARI-STEMI, and MATRIX—looking at the interaction between access route and pharmacology in the STEMI population. “Also, we hope to be able to launch a US-based radial vs. femoral trial in the near future,” he added.

In a telephone interview with TCTMD, James Tift Mann III, MD, of Wake Heart and Vascular Associates (Raleigh, NC), added that the need for such a trial stems from the fact that radial access is far less common in the United States than elsewhere. As such, operators have lower case volume with the technique, he added.

Volume is so low, in fact, that conducting a clinical trial on this topic in the United States is not worth the effort, asserted Philippe Généreux, MD, of Columbia University Medical Center (New York, NY).

“Right now if you did a trial strictly in the United States with low volume operators in radial, of course you’re going to see less benefit with radial,” he told TCTMD in an interview, adding that this might change over the course of enrollment and randomization as experience grows.

A better question to ask is why the United States is so slow to adopt the technique, said Dr. Généreux. “I’m very concerned that, despite all the studies published between 2007 and 2011, we only improved by 5%,” he said. “High-volume [PCI] centers are still not adopting radial.”

‘Never Be Dogmatic’

Currently, Dr. Rao said, “lower-risk patients tend to have radial access for PCI, but since higher-risk patients are not only high risk for mortality but for bleeding, one could imagine that using radial access in such cases would only augment the mortality reduction,” though the theory has not been tested.

“There [also] are clearly some centers and operators that have a ‘radial first’ approach to their patients, and this is expanding over time,” he reported. So long as patients are not in cardiogenic shock, Dr. Rao said, centers experienced in radial access tend to use it.

“As training opportunities expand, newly graduating fellows get into their practice, and the overall rate of radial increases, my guess is that transradial primary PCI will become more common,” Dr. Rao noted, adding, “My hope is that we don't forsake one for the other—all interventional cardiologists should know how to obtain radial access quickly and safely, as well as how to obtain femoral access quickly and safely.”

Similarly, Dr. Généreux advised, “We should never be dogmatic. This is not radial for all. We need to customize choice of access. . . . Very experienced operators know how to do both radial and femoral and how to select the appropriate antithrombotic regimen, which should be bivalirudin as the default in such patients.”

The Demands of STEMI

Dr. Rao emphasized that “operators should not do transradial primary PCI until they and their staff are experienced with elective transradial PCI. The time pressures are unique to the STEMI setting and radial approach for these sick patients should only be used by experienced operators and centers.”

Dr. Mann added, “I don’t think it’s harder. It’s just that there’s pressure to get it done quickly. The clinical setting is much more stressful [than in an elective case]. Patients come in. Everybody’s rushing. Patients have chest pain and potential for complications. . . . That does translate to the physician, who recognizes that and has to focus more intently on [getting access].”

However, “I think it’s important to emphasize that there is no group of patients in which transradial is more efficacious than patients with acute coronary syndromes, particularly patients with acute MI,” Dr. Mann stressed, citing higher risk of access-site bleeding and the variety of anticoagulants used in that population.

Study Details

There were numerous baseline differences between the femoral and radial groups. For example, patients receiving transradial vs. transfemoral PCI were more likely to be younger, male, heavier, and have peripheral vascular disease and less likely to have a history of MI or to have undergone prior PCI or CABG.


Baklanov DV, Kaltenbach LA, Marso SP, et al. The prevalence and outcomes of transradial percutaneous coronary intervention for ST-segment elevation myocardial infarction: Analysis from the NCDR (2007 to 2011). J Am Coll Cardiol. 2012;Epub ahead of print.



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Caitlin E. Cox is News Editor of TCTMD and Associate Director, Editorial Content at the Cardiovascular Research Foundation. She produces the…

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  • Drs. Rao, Généreux, and Mann report no relevant conflicts of interest.