NEW ORLEANS – With broader use of radial-artery access for percutaneous coronary interventions already gaining momentum in the United States, results from the largest study by far to compare radial- and femoral-artery approaches may give an extra boost to the radial camp.
While results from the Radial vs Femoral Access for Coronary Intervention (RIVAL) trial showed primary end point equivalence for the two arterial access strategies in a 7,000-patient randomized trial, radial access may have won by not losing.
Dr. Sanjit S. Jolly
"The similar efficacy helps the radial approach, because there was a persistent uncertainty whether it really was as good as femoral, Dr. Sanjit S. Jolly, lead investigator of the trial, said at the annual meeting of the American College of Cardiology.
In addition, the study’s findings "in high-volume centers and in patients with ST elevation myocardial infarctions will produce more momentum for a shift," he predicted.
Interventional cardiologists in some countries have embraced radial-artery access for placing catheters aimed at the coronaries into patients. Dr. Jolly, a cardiologist at McMaster University in Hamilton, Canada, cited a greater than 90% rate among French interventionalists and a greater than 95% rate in Canada. But as recently as last summer, U.S. cardiologists used radial access for a mere 4% of their coronary catheterizations, based on data collected by the National Cardiovascular Data Registry, said Dr. Edward J. McNulty, an interventional cardiologist at Kaiser Permanente San Francisco.
The U.S. numbers clearly have a long way to go before they start to resemble what is now routine in many other places, but some clues at the meeting suggest they began trending up even before Dr. Jolly delivered the RIVAL results. For example, in a separate talk earlier in the meeting, Detroit interventionalist Dr. Akshay Khandelwal recounted his personal experience introducing radial access into his practice starting about 18 months ago. His cases gradually shifted, and by March roughly 75% of his coronary procedures used radial access. Following his lead, his colleagues at Henry Ford Hospital, Detroit, began to become radialists, too, and as of March 2011 a quarter of his cath lab’s coronary work occurred via the patient’s wrist, said Dr. Khandelwal, director of outpatient cardiovascular services at Henry Ford.
"At Columbia [University’s Center for Interventional Vascular Therapy] the frequency of radial access has increased," agreed Dr. Martin B. Leon, who directs the center in New York. "It was in single digits in 2010, but now, for the first time, it’s more than 20%. It’s climbing quickly. Many operators are becoming more interested in gaining expertise, particularly younger operators," he said.
Part of this shift is driven by physicians who believe they might achieve better results, with less bleeding and access site complications, and part comes from patient demand because most patients find the radial approach more comfortable. "Patients like it, and I think that will drive the option," Dr. McNulty said. Another important factor is cost.
"There is a recent trend in the U.S. to do more outpatient angioplasty in low-risk and stable patients," Dr. Leon said, and radial access makes same-day discharge feasible much more often than does femoral access. "If that trend continues, and the predictions are it will, you can imagine that the radial approach will be attractive."
Until RIVAL, prior comparisons of radial and femoral entry had been too small for a definitive comparison. Dr. Jolly and his associates designed their study to test their hunch that radial entry might actually produce better outcomes. (Dr. Jolly admitted that in his own interventional practice he performs about 80% of his cases by radial entry.) "Our hypothesis was a paradigm shift" that radial would result in a significantly reduced rate of a primary outcome of death, myocardial infarction, stroke, and bleeding not related to coronary bypass during the 30 days following percutaneous coronary intervention in patients with acute coronary syndrome.
The ambitious study enrolled 7,021 patients at 158 sites in 32 countries, piggybacked onto an acute coronary syndrome trial that tested clopidogrel and aspirin treatment (CURRENT–OASIS 7). The patient’s average age was 62 years, nearly three-quarters were men, and 45% had unstable angina, with the remaining patients split evenly between ST elevation myocardial infarction (MI) and non–ST-elevation MI.
The combined end point occurred in roughly 4% of patients in both groups. The rate of major bleeds not associated with coronary artery bypass surgery also occurred at roughly similar rates, just under 1%, in both the radial and femoral groups, an unexpected failure for the radial approach. "We expected to see a large decrease in major bleeds" in the radial access patients, Dr. Jolly said. "A take-home message is that in acute coronary syndrome both access site and non–access site bleeds are important." Concurrently with Dr. Jolly’s report, an article with the results was published online in The Lancet (Lancet 2011 April 4 [doi:10.1016/S0140-6736(11)60404-2]).