RIVAL

In Review

Jolly, S.S. et al. "Radial versus femoral access for coronary angiography and intervention in patients with acute coronary syndromes". The Lancet. 2011. 377(9775):1409-1420.
PubMed • Full text • PDF

Clinical Question

Among patients with acute coronary syndromes (ACS) undergoing coronary angiography, is radial access superior to femoral access?

Bottom Line

Among patients with ACS undergoing coronary angiography radial access is non-inferior to femoral access with respect to death, MI, stroke and non-CABG-related bleeding, however, radial access is associated with significantly lower vascular complications.

Major Points

Patients presenting with acute ACS are often emergently taken to the catheterization lab as part of an early invasive treatment strategy. Administration of anticoagulation/anti-platelet agents are the standard of care and carry with them the risk of bleeding. Major bleeding is a common non-cardiac complication of PCI and at 30 days, approximately 5% of patients with ACS experience major bleeding events . Up to 80% of all major bleeding events associated with PCI may be access-site related and correlated with this, is a step-wise increase in 30-day mortality as the severity of bleeding increases from mild to moderate to severe .

Initial catheters used in the 1970s were large in diameter and required femoral artery canalization for adequate access. The femoral artery is a large, high pressure vessel and achieving hemostasis post-procedure can be challenging and is associated with major bleeding events and other vascular complications like hematoma and pseudoaneyrusm formation. Radial access is now technologically feasible albeit more technically challenging. The radial artery is a superficial and readily compressible artery and a transradial approach theoretically mitigates many of the bleeding risks that a transfemoral approach presents while improving patient comfort and potentially improving mortality. Despite this, the transfemoral approach remains the most common access site for PCI .

Published in 2011, the RadIal Vs femorAL access for coronary intervention (RIVAL) trial randomized 7,021 patients with ACS where an invasive approach was planned to receive either radial or femoral access for PCI. At 30 days, there was no statistical difference in the primary outcome of a composite of death, MI, stroke or non-CABG-related major bleeding between the two arms of the trial (3.7% vs. 4.0%, p=0.50, [CI 0.72-1.17]). There were significantly fewer vascular complications in the radial access group with respect to hematomas (1.2% vs 3.0%, p<0.0001, [CI 0.28-0.57]) and pseudoaneurysms needing closure (0.2% vs. 0.65%, p=0.006, [CI 0.13-0.71]. There was a significant interaction between the primary outcome and centers having the highest volume of radial PCIs (HR 0.49, p=0.015, [CI 0.28-0.87]), suggesting that in high volume centers radial access may be superior to femoral access. Interestingly, in patients with STEMI there was a significant benefit in the primary outcome when using the radial approach (HR 0.60, p=0.026, [CI 0.38-0.94]). The RIVAL trial was the first large trial comparing radial versus femoral access in PCI and while there was no difference in the primary outcome between the two arms, this trial established the non-inferiority of PCI via radial artery in ACS in general while showing superiority in STEMI patients. Subsequent trials including the RIFLE-STEACS trial (n=1,001 patients) and MATRIX trial (n=8,404) have similarly showed a trend towards decreased adverse clinical events with a radial approach. The RIFLE-STEACS trial showed a mortality benefit in STEMI patients undergoing PCI radially and the MATRIX trial showed a mortality benefit (secondary outcome) in all ACS patients undergoing PCI radially.

Guidelines

As of July 2016, no U.S. guidelines have been published that reflect the results of this trial. However, the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) have updated guidelines to reflect results from this trial:

• For patients with STEMI undergoing primary PCI:
  • Radial access should be preferred over femoral access if performed by an experienced radial operator (Class IIa, level A)

Design

• Multinational, multicenter, randomized controlled trial
• N = 7,021 patients with ACS undergoing PCI
• Setting: 158 centers in 32 countries
• Enrollment: June 2006 - Nov 2010
• Follow-up: 30-days
• Analysis: Intention to treat
• Primary outcomes: Composite of death, MI, stroke, or non-CABG-related major bleeding at 30 days

Population

Inclusion Criteria

• ACS with or without ST segment elevation
• An invasive approach was planned
• Interventional cardiologist was willing to proceed with either radial or femoral access (had expertise for both with at least 50 radial procedures within previous year)
• Positive Allen’s test

Exclusion Criteria

• Cardiogenic shock
• Severe peripheral vascular disease precluding a femoral approach
• Previous CABG with use of more than one internal mammary artery

Baseline Characteristics

From the Radial group’’

• Demographics: Age 62 years, male 74.1%
• Diagnosis at admission: UA 44.3%, NSTEMI 28.5%, STEMI 27.2%
• Ethnicity: European 72.9%, Black 0.5%, South Asian 13.8%, East Asian 4.2%, Other 8.5%
• PMH: Diabetes 22.3%, HTN 60.4%, Current smoker 30.9%, MI 18.8%, PCI 12.3%, CABG 2.3%, PVD 2.6%

Interventions

• Randomization to either radial access or femoral access for PCI
  • All patients otherwise received standard medical therapy

Outcomes

‘’Comparisons are radial vs. femoral’’

Primary Outcomes

Death, MI, stroke, or non-CABG related bleeding at 30 days

3.7% vs. 4.0% (HR 0.92, 95% CI 0.72-1.17 P=0.50)

Secondary Outcomes

Major vascular complications

1.4% vs. 3.7% (HR 0.37, 95% CI 0.27-0.52 P=<0.0001)

Death, MI, stroke at 30 days

3.2% vs. 3.2% (HR 0.98, 95% CI 0.76-1.28 P=0.90)

Non-CABG major bleeding at 30 days

0.7% vs. 0.9% (HR 0.73, 95% CI 0.43-1.23 P=0.23)

Death at 30 days

1.3% vs. 1.5% (HR 0.86, 95% CI 0.58-1.29 P=0.47)

MI at 30 days

1.7% vs. 1.9% (HR 0.92, 95% CI 0.65-1.31 P=0.65)

Stroke at 30 days

0.6% vs. 0.4% (HR 1.43, 95% CI 0.72-2.83 P=0.30)

Adverse Events

• Major adverse CV events in radial group: Non-CABG major bleeding 0.7%, Death 1.3%, MI 1.7%, Stroke 0.6%

Criticisms

• Low overall rate of bleeding compare to other trials (trial interventionalists were likely more experienced than in real world setting)

Funding

• Sanofi-Aventis, Population Health Research Institute, and Canadian Network for Trials Internationally (CANNeCTIN), an initiative of the Canadian Institutes of Health Research.