Radial vs Femoral Access in STEMI
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD
Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco
Source: Romagnoli E, et al. Radial versus femoral randomized investigation in ST-segment elevation acute coronary syndrome. The RIFLE-STEACS (Radial Versus Femoral Randomized Investigation in ST-Elevation Acute Coronary Syndrome) study. J Am Coll Cardiol 2012; Jul 27. [Epub ahead of print.]
Primary percutaneous coronary intervention (PCI) saves lives in patients suffering from ST-elevation myocardial infarction (STEMI). However, these patients are at high-risk for bleeding complications due to the invasive nature of the procedure in combination with the use of antithrombins and antiplatelet agents. Radial artery access is associated with lower bleeding rates compared to femoral artery access for PCI. However, adoption of radial access has been slow in the United States, with a small minority of cases performed via this route. The recent RIVAL trial showed that radial access results in lower vascular access complications and bleeding rates than femoral access in patients with acute coronary syndromes. Subgroup analysis suggested that there was a mortality benefit in the group of patients presenting with STEMI. In this study, Romagnoli and colleagues perform a multicenter, randomized study comparing radial vs femoral access as the initial strategy in patients presenting with STEMI.
Over a period of 2 and a half years, 1001 patients with STEMI undergoing primary PCI were randomized to radial (n = 500) or femoral (n = 501) access. The study was performed in four high-volume centers and all operators performed at least 150 PCIs per year, with at least 50% performed via the radial artery. Exclusion criteria included contraindication to either radial or femoral access, stroke within the preceding 4 weeks, anticoagulant therapy with a presumed international normalized ratio > 2, or other severe bleeding diathesis. Importantly, cardiogenic shock and/or hemodynamic instability were not exclusion criteria. The primary endpoint of the study was the 30-day incidence of net adverse clinical events (NACE), defined as the composite of cardiac death, myocardial infarction (MI), stroke, target lesion revascularization, and non-coronary artery bypass graft (CABG)-related major bleeding. Secondary endpoints were 30-day individual components of NACE and length of stay.
Procedural anticoagulation was achieved with unfractionated heparin and the choice of additional antithrombotic agents (e.g., glycoprotein IIb/IIIa inhibitors or bivalirudin). Unless clinically indicated for another reason, all anticoagulants were discontinued at the end of the procedure, whereas glycoprotein IIb/IIIa inhibitor boluses were followed by a ≥ 12-hour infusion. All patients were pretreated with aspirin plus a loading dose of clopidogrel (300 to 600 mg) and were discharged on dual antiplatelet therapy for 12 months. More than 75% of all STEMIs presenting to the participating centers during the enrollment period were enrolled in the study, around 10% were in Killip class III/IV, and 8% required intra-aortic balloon counterpulsation during the procedure.
The baseline characteristics were similar between groups. There was no difference in symptom-to-balloon or door-to-balloon times between groups. The primary endpoint of 30-day NACE was lower in the radial arm compared with the femoral arm (13.6% vs 21.0%; P = 0.003). Analysis of individual NACE components showed fewer cardiac deaths in the radial group compared with the femoral group (5.2% vs 9.2%; P = 0.020), but similar rates of MI (1.2% vs 1.4%; P = 1.000), target lesion revascularization (1.2% vs 1.8%; P = 0.604), and stroke (0.8% vs 0.6%; P = 0.725). Bleeding was less frequent in the radial group (7.8% vs 12.2%; P = 0.026), mainly due to a 60% decrease in access site-related bleeding (2.6% vs 6.8%; P = 0.002). Indeed, non-access site-related bleeding (53% of total bleeding events) was similar (5.2% vs 5.4%; P = 1.0). Hospital stay was shorter in the radial group than in the femoral group (5 [range, 4 to 7] days vs 6 [range, 5 to 8] days, P = 0.008).
Multivariate analysis confirmed the radial approach as an independent negative predictor of 30-day NACE (hazard ratio [HR] 0.7; P = 0.028). The overall rate of access site crossover was 9.6% (n = 47) in the radial arm and 2.8% (n = 14) in the femoral arm. Cardiogenic shock at presentation (HR 3.4; P = 0.01), unknown peripheral vascular disease (HR 2.6; P = 0.02), and previous thrombolytic administration (HR 2.2; P = 0.041) were the main determinants of vascular access crossover.
The authors conclude that radial access in patients with STEMI is associated with lower morbidity and cardiac mortality. Thus, it should become the recommended approach in these patients, provided adequate operator and center expertise is present.
Commentary
In clinical trials involving PCI, bleeding is universally associated with worse long-term outcomes, not just in-hospital outcomes, often including higher mortality rates. The precise mechanism of this remains obscure. The converse is also true — bleeding avoidance strategies are usually associated with improved outcomes, and the choice of radial over femoral access is just that, a bleeding avoidance strategy. This approach has been shown to result in fewer access site complications and lower bleeding rates in prior clinical trials. The current study takes the highest risk PCI population — those with STEMI — and demonstrates that radial access is associated with lower bleeding rates and lower cardiac mortality.
This is a large study performed in four high-volume centers, and the clinical trial design was robust. These factors strengthen the conclusions drawn from the paper. There are some important limitations to the manuscript. We are never told what methods of closure were used for the femoral arteries, and this may have an impact on bleeding. In addition, there was a low rate of bivalirudin use (~ 8%). This may have contributed to the high rate of bleeding in the femoral arm.
There appeared to be equipoise between radial and femoral access in patients presenting with ACS in the RIVAL trial, yet there is a mortality benefit with radial access for patients with STEMI in this trial. This raises a conundrum: Should operators use radial access in the STEMI patients, the sickest patients in whom they are rushing to reach door-to-balloon times? Should they continue to use femoral access in other cases? The answer is not immediately clear. This study was performed by high-volume, experienced radial operators and the results may not be applicable to occasional radial operators. Less experienced operators may take longer to perform the PCI radially and this may offset the clinical benefit of reduced bleeding. In the era of widespread closure devices and more specific antithrombins, such as bivalirudin, is radial access still superior? This is not known. However, radial access is associated with lower costs and increased patient satisfaction. There may also be a clinical benefit to using radial access as the preferred strategy in STEMI.
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