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In patients with ST-segment elevation myocardial infarction (STEMI), use of radial access for primary percutaneous coronary intervention (PCI) reduces major bleeding and adverse events compared with femoral access, according to a subanalysis of the HORIZONS-AMI trial published in the December 2011 issue of EuroIntervention.

In the multicenter HORIZONS-AMI (Harmonizing Outcomes with RevascularIZatiON and Stents in Acute Myocardial Infarction) trial, 3,602 STEMI patients undergoing primary PCI were first randomized to anticoagulation with unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor (GPI) or bivalirudin monotherapy. After angiography, 3,006 patients with lesions eligible for stenting were randomized 3:1 to a PES (Taxus Express2) or a BMS (Express2; both Boston Scientific, Natick, MA).

In a post-hoc analysis, researchers led by Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), compared clinical outcomes of the 3,344 primary PCI patients (including both PES and BMS) who were treated via either radial (n = 200) or femoral access (n = 3,134).

Outcomes Improve with Radial

After PCI, TIMI-3 flow was achieved in a higher proportion of the radial group than the femoral group (96.8% vs. 91.1%; P = 0.004).

At both 30 days and 1 year, the radial group showed an advantage over the femoral group for the coprimary endpoints of non-CABG-related major bleeding and net adverse cardiac events (NACE; major non-CABG bleeding or MACE) as well as in MACE (death, reinfarction, TVR, or stroke) and death or reinfarction (table 1).

Table 1. One-Year Outcomes by Access Site

 
By multivariable analysis, radial access was an independent predictor of freedom from NACE (OR 0.44; 95% CI 0.26-0.75; P = 0.002), MACE (OR 0.44; 95% CI 0.22-0.84; P = 0.01), and major bleeding (OR 0.40; 95% CI 0.18-0.90; P = 0.02) at 1 year in the radial group, with a trend for reduced death or reinfarction (OR 0.50; 95% CI 0.22-1.12; P = 0.09).

Total procedural time (from first to last angiogram), fluoroscopy time, and amount of contrast used did not differ between the 2 approaches, while door-to-balloon and total ischemic times  were longer in the radial group (table 2).

Table 2. Time Intervals by Access Site

Bivalirudin + Radial the Best Combo

The lowest rates of non-CABG major bleeding and NACE were seen in patients who received bivalirudin and radial PCI, whereas the highest rates occurred in those who received heparin plus a GPI and femoral access (P for trend < 0.0001 and 0.0003, respectively).

Recently, the randomized RIFLE STEACS (Radial versus Femoral Randomized Investigation in ST Elevation Acute Coronary Syndrome) trial, presented at the annual Transcatheter Cardiovascular Therapeutics symposium in San Francisco, CA, in November 2011, showed a clear benefit for radial access, including cardiac mortality, but only a small proportion of patients received bivalirudin. The current study is the first to report results for the “era of contemporary antithrombotic regimens (including bivalirudin),” Dr. Stone and colleagues write.

Consistent with previous findings, the current study suggests that radial access can prevent up to half of postprocedural bleeding complications, mainly due to a reduction of access-site-related large hematomas (> 5 cm). This “would be expected to result in fewer transfusions, less complications from hemodynamic compromise, and a reduced need to discontinue life-saving medications, such as aspirin and thienopyridines,” the authors say. Together these advantages are likely to lead to improved survival.

Most Data Pointing in the Same Direction

In an interview with TCTMD, coauthor Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), said it is reassuring that data from the current study, the STEMI subanalysis from RIVAL, and the randomized RIFLE trial all point toward a clinical benefit with radial access.

Sunil V. Rao, MD, of Duke University Medical Center (Durham, NC), agreed, noting that the magnitude of the bleeding reduction in RIFLE was similar to that seen here, and tracked with a mortality benefit. However, he pointed out in a telephone interview with TCTMD, the HORIZONS-AMI data are underpowered to show a mortality difference.

What sets the current study apart is the role of bivalirudin, Dr. Rao commented. “We don’t yet know what the interaction is between antithrombotic choice and vascular access site choice,” he said. “By and large, if you look at observational data, radial operators tend to stick with heparin, while femoral operators tend to like bivalirudin. But there are theoretical reasons why combining them would be attractive—radial to reduce vascular access type bleeding and bivalirudin for all bleeding. This is something we need to explore more.”

Since bivalirudin is the strongest predictor of remaining free of bleeding, to tease out the contribution of radial access, Dr. Généreux called for a head-to-head trial of radial vs. femoral access in which all patients receive bivalirudin and the femoral arm also employs a closure device.

Who Is Ready for Radial?

At this point, dedicated radialists consider radial the default approach for STEMI patients, Dr. Rao said. But Dr. Généreux cautioned that it is important not to be dogmatic. With the clock ticking on viable myocardium, both experts advocated a cut-off for attempting radial access—perhaps 5 minutes—after which operators should switch to femoral. Prepping both wrist and groin is important, they added, not only in case of radial bailout but to accommodate the possible need for an intraortic balloon or pacemaker. In addition, it is crucial that the cath lab staff be educated to set up cases quickly, Dr. Rao said.

As for when an operator is ready for radial primary PCI, Dr. Rao said the answer depends on both the number of procedures under his belt and his femoral crossover rate. In general, operators should feel comfortable with the approach, and begin with relatively stable patients, Dr. Généreux advised. In addition, some types of patients are less than ideal candidates. For example, Dr. Généreux noted that he tends to steer clear of patients with prior CABG and recommends that in high-risk Killip class IV patients radial access be used only by very experienced radial operators.

Note: Drs. Stone, Généreux and several other coauthors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.

Related Stories:

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• Transradial Approach Safe, Effective in STEMI
• RIFLE STEACS: Radial Approach Safer Than Femoral in STEMI