SAN DIEGO (FRONTLINE MEDICAL NEWS)The unshakable grip that transfemoral access has held on coronary artery catheterization for the U.S. practice of interventional cardiology may finally loosen with results from an 8,000-patient, multinational controlled trial.

MATRIX showed that transradial access for coronary catheterization of patients with acute coronary syndrome (ACS) produced significantly fewer access-site bleeding events and significantly improved patient survival, compared with transfemoral access.

“Our results, in conjunction with the updated meta-analysis, suggest that the radial approach should become the default access for patients with acute coronary syndrome undergoing invasive management,” Dr. Marco Valgimigli said at the annual meeting of the American College of Cardiology. “Access site does matter, and a reduction in access-site bleeding complications seems to translate into a mortality benefit,” said Dr. Valgimigli, an interventional cardiologist at Erasmus University Medical Center in Rotterdam, the Netherlands.

The MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial enrolled 8,404 ACS patients at 78 sites in four European countries: Italy, Spain, Sweden, and the Netherlands. The study randomized patients undergoing percutaneous coronary intervention (PCI) to catheterization via either the patient’s radial or femoral artery. After 30 days, the combined rate of death, myocardial infarction, stroke, and major bleeding was reduced by an absolute rate of 1.9% among the patients treated with transradial access, a 17% relative risk reduction that was statistically significant for one of the study’s two primary endpoints.

This outcome difference seemed driven primarily by significant reductions in major bleeds and specifically major access-site bleeds, and this led to a statistically significant reduction in all-cause death by 0.6%, a 28% relative risk reduction in 30-day mortality tied to transradial access, Dr. Valgimigli said.

“I think this will be the study that helps change guidelines, to make radial artery access the default approach,” commented Dr. Sanjit S. Jolly , an interventional cardiologist at McMaster University in Hamilton, Ont.

“The United States is very behind in the use of transradial access; it’s used in about 20% of coronary PCIs,” noted Dr. Cindy L. Grines , an interventional cardiologist at the Detroit Medical Center. “We need to make a concerted effort in the United States to retrain practitioners to do transradial procedures. This approach is initially more time consuming, involves more radiation exposure, and can be frustrating, so we probably need to incentivize physicians by increasing their reimbursement for transradial PCIs and by making it part of quality assurance programs. Unless we do something like that, transradial use may not change,” Dr. Grines said in an interview.

The significant superiority of transradial over transfemoral access for both patient survival and for one of the study’s primary endpoints contrasted with the neutral result seen in an earlier major study that compared the two access approaches, RIVAL (Radial Versus Femoral Access for Coronary Angiography and Intervention in Patients With Acute Coronary Syndromes; Lancet 2011;377:1409-20 ).

Dr. Valgimigli also reported results from a meta-analysis that combined the MATRIX and RIVAL results as well as data from a few additional much smaller trials. This combined analysis, which involved a total of more than 19,000 ACS patients randomized to PCI via one of the two access sites, further confirmed that transradial catheterization linked with statistically significant reductions in death, in major bleeds not associated with coronary artery surgery, and in the combined endpoint of death, myocardial infarction, and stroke, he said. Concurrent with his report at the meeting, the MATRIX results as well as the updated meta-analysis results, appeared in an article published online ( Lancet 2015 [doi:10.1016/S0140-6736(15)60292-6] ).

The MATRIX study used only highly experienced interventionalists who had extensive familiarity with performing PCI using both types of access. They successfully used transradial access in 94% of patients randomized to that approach, but in the other 6% technical difficulties resulted in a crossover to the transfemoral route. Among patients randomized to transfemoral access, 2% required crossover to a transradial procedure.

MATRIX was an investigator-initiated study that received grant support from Terumo and the Medicines Co. Dr. Valgimigli had no relevant financial disclosures. Dr. Jolly has been a consultant to AstraZeneca, has been a speaker on behalf of St. Jude, and has received research grants from Medtronic. Dr. Grines has been a consultant to and received honoraria from Abbott Vascular, the Medicines Co., Merck, and the Volcano Group. On Twitter @mitchelzoler


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