Transradial PCI Finally Normalized in the U.S., Though Holdouts Remain

LONG BEACH, Calif. -- Radial artery access has become the dominant approach for percutaneous coronary intervention (PCI), with real-world practice supporting the safety benefits of this strategy, according to registry data from the last decade.

Adoption of transradial PCI rose from approximately 20% of cases in 2013 to nearly 60% in 2022, based on 6.7 million cases from the CathPCI registry analyzed by Reza Fazel, MD, of Beth Israel Deaconess Medical Center in Boston, and colleagues.

The greatest adoption of radial access was observed in cases of ST-segment elevation myocardial infarction (STEMI), "which is encouraging and remarkable," Fazel said during a press conference here at the annual meeting of the Society for Cardiovascular Angiography & Interventions (SCAI).

Session panelist Ian Gilchrist, MD, of Penn State Health Milton S. Hershey Medical Center in Hershey, Pennsylvania, nevertheless said it was "disappointing" that the U.S. still lags behind the rest of the world regarding transradial adoption, citing 90%+ penetrance in the U.K. "There [are] operators that just won't convert," he commented.

J. Dawn Abbott, MD, of Rhode Island Hospital in Providence, agreed and cited prior research showing that the biggest predictor of whether someone gets transradial PCI is what hospital they show up to. "Now we can look at the barriers [to radial access] and try to get a little more consistency in care," she suggested as a fellow panel participant.

Confirming results from randomized trials, Fazel reported that radial access was associated with mostly superior outcomes compared with femoral access in real-world practice, as supported by an instrument variable analysis restricted to the 2.2 million most recent PCIs in the CathPCI registry:

• Death: 1.16% vs 1.31% (P<0.001)
• Major access site bleeding: 0.34% vs 0.98% (P<0.001)
• Other vascular complication: 0.12% vs 0.32% (P<0.001)

Fazel reported that there was, however, a "small but significant" increase in the risk of ischemic stroke when comparing radial versus femoral access (0.32% vs 0.27%, P<0.001). This was not wholly unexpected, given the clinical plausibility and signals of this increased stroke risk that fell short of significance in the trials, he said.

To provide conclusive evidence, a randomized trial would need 300,000 patients for 80% power to detect this small excess stroke risk, he said, suggesting the unlikelihood of such an effort. For comparison, even the largest trial to date on radial versus femoral access, MATRIX, had 8,404 people randomized, he noted.

Gilchrist suggested the stroke risk can be improved if operators change how and where they drive the wire during PCI.

Guidelines already favor a radial-first strategy for PCI, as randomized trials have consistently linked radial access to benefits such as reduced bleeding, infection, and readmissions after PCI. Additionally, a survival advantage emerged in 2022 when the trials were pooled together.

"Honestly I don't think we need another study to show these benefits," Abbott said.

Notably, one known downside of transradial PCI is the potential for radial artery occlusion. This is a complication that may restrict future percutaneous operations and use of the artery as a conduit for coronary artery bypass grafting surgery.

SCAI session discussant Margaret McEntegart, MD, of NewYork-Presbyterian/Columbia University Irving Medical Center in New York City, cautioned operators not to be "zealots" about going radial. She urged that they maintain their femoral skills for patients with vessel size issues or other reasons necessitating more support.

Indeed, Fazel said that for the present report, patients with cardiogenic shock and those who had PCI with mechanical circulatory support -- complex groups believed by many to fare better with a femoral approach -- were excluded in order to maintain equipoise for the outcomes analysis.

Differences in the reported clinical outcomes were greatest in the higher-risk STEMI and non-ST-elevation acute coronary syndrome (ACS) groups. For the non-ACS group, the mortality benefit and the increased stroke risk did not reach statistical significance.

Transradial and transfemoral PCI resulted in the same 0.31% rate of gastrointestinal or genitourinary bleeding in the registry.

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