A 5-F introducer sheath was inserted into the radial artery, and a guide wire and a 5-F Simon II catheter were introduced into the ascending aorta. Image source: Korean J Radiol 2006;7(1):7–13.

Radial access for PCI in patients with acute coronary syndromes (ACS) does not reduce death, heart attack, stroke or major bleeding compared with femoral access, according to the late-breaking RIVAL trial presented April 4 at the American College of Cardiology (ACC) scientific sessions. However, the significantly lower rate of complications at the access site and improved patient comfort might be a reason to use the radial approach.

Previous small trials have been unable to establish a clinical advantage between coronary angiography via the femoral artery in the groin or the radial artery in the wrist, and there remains considerable disagreement amongst cardiologists about the best approach, the authors wrote in the Lancet, where the study was simultaneously published. The radial procedure rate in the U.S. is 4.2 percent, according to the ACC NCDR data from the third quarter of 2010.

Therefore Sanjit Jolly, MD, of McMaster University's Population Health Research Institute in Hamilton, Ontario, and colleagues sought to determine if radial vs. femoral access for PCI can reduce the composite of death, MI, stroke or non-CABG major bleeding in patients with acute coronary syndrome.

Between June 2006 and November 2010, they enrolled 7,021 patients from 158 hospitals in 32 countries and randomly assigned them to radial (3,507 patients) or femoral access (3,514).

The primary outcome was death, MI, stroke or non-CABG-related major bleeding at 30 days. The primary outcome occurred in 3.7 percent of 3,507 patients in the radial access group compared with 4 percent of 3,514 in the femoral access group.

“Both approach showed similar, very high PCI success rates, about which was uncertain prior to this trial,” Jolly said.

High-volume centers performed better with the transradial approach. “We know that the more you do, the better you get, particularly with the radial approach,” Jolly said. Of the six pre-specified subgroups, there was a significant interaction for the primary outcome with benefit for radial access in highest tertile volume radial centers and in patients with STEMI. However, during the press conference, Jolly acknowledged that there is not a single, distinguishable number of procedures that makes an operator proficient.

The rate of death, MI or stroke at 30 days was 3.2 percent of 3,507 patients in the radial group compared with 3.2 percent of 3,514 in the femoral group—which is not statistically significant.

The rate of non-CABG-related major bleeding at 30 days was 0.7 percent of 3,507 patients in the radial group compared with 0.9 percent of 3,514 patients in the femoral group. “While there was a positive trend toward less bleeding in the radial group, it was not statistically significant,” Jolly said.

“Our results did show a more than 60 percent reduction in major vascular complication rates,” Jolly said. At 30 days, 42 of 3,507 patients in the radial group had large hematomas compared with 106 of 3,514 in the femoral group. Pseudoaneurysm needing closure occurred in seven of 3,507 patients in the radial group compared with 23 of 3,514 in the femoral group.

Also, the patients preferred the radial approach for subsequent procedures.

While there was not a cost-effectiveness analysis in this study, the researchers are following up with one, which will look at the costs to the hospital setting. However, Jolly told Cardiovascular Business News that they did examine length of hospitalization. “Our prior meta-analysis showed that the reduction in the hospital length of stay was actually half a day. While we did not detect a difference in hospital length of stay in RIVAL, one of the caveats is that we could not measure differences smaller than a whole day based on our case reports—we had hours instead of days,” he said.

Martin B. Leon, MD, director of the Center for Interventional Vascular Therapy at New York Presbyterian Hospital/Columbia Medical Center in New York City, noted to Cardiovascular Business News that “length of stay will become more of an issue in the U.S. because there is more of a trend toward performing more outpatient angioplasty in low-risk, stable patients. Therefore, the radial approach could become a more attractive option for those patients.”

Based on their findings, the researchers concluded that the “radial and femoral approaches are both safe and effective for PCI. However, the lower rate of local vascular complications may be a reason to use the radial approach.”

In the accompanying Lancet commentary, Carlo di Mario, MD, and Nicola Viceconte, MD, from the Royal Brompton Hospital in London, wrote: "After this study, there is little justification to ignore one of the main developments in interventional cardiology and stubbornly refuse to embrace a technique likely to reduce minor adverse events (but in patients with STEMI, possibly also major adverse events and mortality) and improve patient comfort."

“Operators with a high workload of acute procedures should seriously consider re-training in radial angioplasty, and all new trainees should be taught and become proficient with this approach,” they added. “Conversely, it is important not to demonize the femoral approach, which is more suitable when large guiding catheters are required and prolonged procedural time is expected for complex lesions."

The study is funded by Sanofi-Aventis and Bristol-Myers Squibb (through CURRENT), Population Health Research Institute and Canadian Network and Centre for Trials Internationally (CANNeCTIN, an initiative of Canadian Institutes of Health Research).