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ACC: MATRIX Scores for Transradial

— But Angiomax again comes up short against unfractioned heparin.

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SAN DIEGO -- It's been hard to make a case against radial access for percutaneous coronary interventions, and as evidence continues to accumulate, radial may soon be every center's preferred method.

So said , director of the structural heart disease program at Henry Ford Hospital in Detroit, in response to findings from the MATRIX study, which compared transradial with transfemoral approaches in 8,404 patients undergoing stenting for treatment of acute coronary syndrome.

The study found that patients were less likely to have major adverse cardiovascular events at 30 days if they underwent PCI using transradial approach versus transfemoral, although the difference was not statistically significant. But there was a significant difference in major bleeding events and in mortality.

The results of the trial were reported at the American College of Cardiology meeting here and simultaneously published online by

Patients in the radial access arm (n=4,197) had fewer major adverse cardiovascular events -- 369 or 8.8% -- than did the 4,207 patients assigned to transfemoral access, among whom 429 or 10.3% experienced a major cardiovascular event or Bleeding Academic Research Consortium (BARC) major bleeding event. But that difference failed to meet the prespecified two-sided α of 0.025 for superiority.

The rate of major bleeding was 1.6% in the transradial arm versus 2.3% in the transfemoral group (relative risk 0.67, 95% CI 0.49-0.92, P=0.013) and all-cause mortality was 1.6% versus 2.2% (RR 0.72, 95% CI 0.53-0.99, P=0.045) favoring transradial.

, of Erasmus Medical College in Rotterdam, The Netherlands, who reported the findings, noted that success with transradial was directly related to a center's experience with the approach so that centers with the most experience -- at least 75 transradial procedures per year -- had the best outcomes.

O'Neill agreed that experience drives excellence in transradial and he noted that the U.S. had been a slow adapter of transradial technology, but that is changing rapidly. He said that about 50% of procedures at his hospital are now done transradially.

That pattern mirrors what has been happening nationally. In 2011 only about 5% of PCI was done transradially, but by 2013 more than a third of PCIs in the U.S. used the transradial approach.

In addition to the comparison between radial and femoral approaches, the MATRIX investigators also compared the use of bivalirudin (Angiomax) with unfractionated heparin in patients from the MATRIX cohort, and Valgimigli reported the results from that comparison in a separate late-breaking clinical trials presentation.

In the catheterization lab, 3,610 patients were randomized to bivalirudin and 3,603 to unfractionated heparin with planned or bailout glycoprotein IIb/IIIa inhibitors.

The combined primary endpoint of death, MI, or stroke occurred in 10.3% of the bivalirudin patients versus 10.9% of the heparin patients. When major bleeding was factored into that combined endpoint, the rate was 11.2% versus 12.4% bivalirudin versus heparin. In neither case was the difference statistically significant.

When individual endpoints were assessed there were fewer all-cause deaths in the bivalirudin arm, 1.7% versus 2.3% (P=0.042) and less bleeding with bivalirudin -- 1.4% versus 2.5% -- which was significant at P=0.001.

But the other components of the endpoint were virtually the same with the exception of stent thrombosis, which was higher with bivalirudin -- 1.0% versus 0.6%, a difference that reached (barely) statistical significance at P=0.048.

The findings from MATRIX echo HEAT-PCI in which bivalirudin also came up short in a comparison with heparin.

Disclosures

The MATRIX trial was sponsored by The Medicines Company and Terumo.

Valgimigli disclosed financial relationships with Abbott Vascular, AstraZeneca Pharmaceuticals LP, Correvio International; Medtronic, and The Medicines Company.

O'Neill had no relevant financial disclosures.

Primary Source

American College of Cardiology

Valgimigli M, et al "Minimizing adverse haemorrhagic events by transradial access site and systemic implementation of AngioX: bivalirudin vs. heparin | clinical trial - MATRIX: bivalirudin vs. heparin" ACC 2015.

Secondary Source

The Lancet

Valgimigli M, et al "Radial versus femoral access in patients with acute coronary syndromes undergoing invasive management: a randomised multicentre trial" The Lancet 2015; DOI: 10.1016/S0140-6736(15)60292-6.

Additional Source

American College of Cardiology

Valgimigli M, et al "Minimizing adverse haemorrhagic events by transradial access site and systemic implementation of AngioX: Radial vs. femoral | clinical trial - MATRIX: radial vs. femoral" ACC 2015.