Studies Explore How, When Radial PCI Benefits ACS/STEMI Patients

Percutaneous coronary intervention (PCI) via radial access safely reduces vascular complications compared with femoral access in patients with acute coronary syndromes including ST-segment elevation myocardial infarction (STEMI), but the benefit is seen mainly when procedures are performed by experienced radial operators at high-volume centers. The findings were published online November 20, 2013, ahead of print in the Journal of the American College of Cardiology.

In the STEMI-RADIAL study, Ivo Bernat, MD, PhD, of University Hospital and Faculty of Medicine Pilsen (Pilsen, Czech Republic), and colleagues randomized 707 STEMI patients referred to 4 high-volume radial centers (>80% cases/year) within 12 hours of symptom onset to primary PCI via radial (n = 348) or femoral (n = 359) access.

Baseline features of the 2 groups were similar, except for a higher incidence of hypertension in the radial group. There were no differences in total ischemic time, door-to-balloon time, or total procedural and fluoroscopy times. Overall, radial patients required less contrast (170 ± 71 mL vs. 182 ± 60 mL; P = 0.01).

Radial PCI Safer

At 30 days, rates of major bleeding and vascular complications (the primary endpoint) as well as NACE (death, MI, stroke, and major bleeding/vascular complications) were lower in the radial group than the femoral group. However, no differences were seen in MACE (death, MI, stroke) or mortality. Among vascular complications, only the incidence of hematoma larger than 15 cm was reduced by radial access; rates of GI bleeding, transfusion, or vascular access site complications were similar between the groups (table 1).

Table 1. Clinical Outcomes at 30 Days by Access Site



(n = 348)

(n = 359)

P Value

Major Bleeding/
Vascular Complications




Hematoma > 15 cm
















In addition, the intensive care unit stay was shorter in the radial group compared with the femoral group (2.5 ± 1.7 days vs. 3.0 ± 2.9 days; P = 0.0038).

The Effect of Procedure Volume

In the second study, Sanjit S. Jolly, MD, MSc, of Hamilton General Hospital (Hamilton, Canada), and colleagues looked at more than 7,000 ACS patients in the RIVAL trial who were randomized to catheterization via radial or femoral access. At 30 days there was no difference between the groups in the composite primary outcome of death, MI, stroke or non-CABG-related major bleeding (P = 0.50), although radial access reduced major vascular complications by 63%.

The time from randomization to completion of PCI was similar between the radial and femoral groups in high-volume radial centers (>75% of procedures performed radially; 55 min vs. 51 min; P = 0.78), although radial access took longer in intermediate-volume (40% radial) and low-volume (20% radial) centers (P < 0.001 for both).

For the primary outcome and MACE, a benefit for radial over femoral PCI was evident in high-volume radial centers but not in intermediate- or low-volume centers (P for interaction = 0.0.021 and 0.013, respectively). Radial access reduced major vascular complications regardless of center volume, although the advantage was greatest in the highest-volume hospitals (P for interaction = 0.019). On the other hand, rates of study-defined non-CABG major bleeding were similar between radial and femoral patients at all volume levels, though an advantage for radial was seen for ACUITY-defined major bleeding at all radial volumes (table 2). 

Table 2. Outcomes for Radial vs. Femoral by Radial PCI Center Volume





P Value

Primary Outcome
High Volume
Intermediate Volume
Low Volume




High Volume
Intermediate Volume
Low Volume




Non-CABG Major Bleeding
High Volume
Intermediate Volume
Low Volume







Major Vascular Complications
High Volume
Intermediate Volume
Low Volume






 < 0.001

There were no differences between radial and femoral PCI for the primary outcome or non-CABG major bleeding regardless of radial operator volume. However, major vascular complications were reduced by radial access for all tertiles of operator volume, although the most-experienced operators had the best results (P for interaction = 0.009).

The benefit of radial access persisted even after adjustment for the higher proportion of STEMI patients undergoing PCI at high-volume radial centers (HR 0.50; 95% CI 0.28-0.88).

In multivariable analysis, increasing PCI center volume (per 50 PCIs for median operator at the center) and operator volume were independently associated with improved rates of the primary outcome (adjusted HR 0.92; 95% CI 0.88-0.96). Similarly, among radial patients, radial center volume (adjusted HR 0.88; 95% CI 0.80-0.97) and operator volume (HR 0.90; 95% CI 0.83-0.98) were also independently associated with lower rates of the primary outcome, while the same did not hold true for femoral patients with regard to femoral PCI center or operator volume.

Ready for a Paradigm Shift

In an accompanying editorial, Robert J. Applegate, MD, of Wake Forest School of Medicine (Winston-Salem, NC), said the existing data suggest that radial procedures are at least equivalent to femoral with regard to mortality and may in fact reduce the outcome.

He notes that lingering concerns about radial primary PCI--eg, that it takes longer, may jeopardize door-to-balloon time goals, is associated with higher radiation exposure, and limits interventional options in complex cases--are mitigated when the procedure is performed by experienced operators at high-volume centers.

Given the reassuring findings of the current studies, it is time for a paradigm shift to a preferred radial approach for primary PCI, Dr. Applegate concludes.

Changing the Mindset

In a telephone interview with TCTMD, Ian C. Gilchrist, MD, of Hershey Medical Center (Hershey, PA), said multiple studies have now shown that radial primary PCI reduces bleeding and vascular complications, and signals of a mortality benefit keep cropping up. But whether or not the latter is ultimately confirmed in larger trials is less important to converting US operators to radial primary PCI than developing “the mindset that this is an evolutionary step forward” in interventional technique, he asserted.

Dr. Gilchrist noted that in both the RIVAL and the SAFE-PCI randomized studies, femoral complication rates were much lower than expected, undermining the argument that a radial advantage may be due to worse femoral technique at radial centers, he said, adding that radial operators in the trials were very experienced in both approaches.

As for the level of radial proficiency needed to undertake primary PCI, Dr. Gilchrist said that a specific number of procedures is less important than the operators’ honest assessment of whether they are comfortable with the technique and knows when to switch to femoral access if necessary. He also stressed that a knowledgeable and committed hospital team is key to achieving good radial STEMI outcomes.

Dr. Gilchrist noted that radial primary PCI may hold an advantage even for STEMI patients who require assist devices that the small wrist arteries will not accommodate since a femoral artery can be accessed by another operator without interrupting the revascularization procedure. 




1. Jolly SS, Cairns J, Yusuf S, et al. Procedural volume and outcomes with radial or femoral access for coronary angiography and intervention. J Am Coll Cardiol. 2013;Epub ahead of print.

2. Bernat I, Horak D, Stasek J, et al. ST elevation myocardial infarction treated by radial or femoral approach in a multicenter randomized clinical trial: The STEMI-RADIAL trial. J Am Coll Cardiol. 2013;Epub ahead of print.

3. Applegate RJ. Radial access for primary PCI for STEMI: Time for a paradigm shift? J Am Coll Cardiol. 2013;Epub ahead of print.


  • Drs. Bernat and Applegate report no relevant conflicts of interest.
  • Dr. Jolly reports receiving institutional research grants from Bristol-Myers Squibb, Medtronic, and Sanofi-Aventis and consulting fees from AstraZeneca, Eli Lilly, and Sanofi-Aventis.
  • Dr. Gilchrist reports serving as a consultant for Abbott Vascular and The Medicines Company.