Higher Bleeding Risks, Radial Advantages Confirmed in Women With ACS Undergoing PCI: MATRIX Subanalysis

omen with acute coronary syndromes undergoing coronary angiography and, if indicated, PCI are more likely than men to experience severe bleeding and access-site complications, and radial access is effective at reducing these events, a new subanalysis of the MATRIX trial confirms.

Partly due to underdiagnosis , and partly to underuse of preventative medications , women typically present to the cath lab with more advanced coronary artery disease and experience more complications, including more severe bleeding, during their procedures. Proponents of radial-artery PCI have long argued that radial access may help close the gender gap, and a number of smaller studies have supported this contention.

MATRIX is the largest randomized trial of radial versus femoral access in ACS that includes sufficient numbers of women to allow for sex-based comparisons, according to Sunil Rao, MD (Duke Clinical Research Institute, Durham, NC), who commented on this substudy for TCTMD . “This study is largely confirmatory, [but] it has a tremendous amount of statistical power to look at what they wanted to look at,” he said. “Women continue to be underserved in terms of best practices to reduce risk, and that includes radial approach. So as we start accumulating evidence in this particular area, I hope that we can start to reverse some of that risk/treatment paradox.”

For this subanalysis, published in the January 8, 2018, issue of JACC: Cardiovascular Interventions, researchers led by Giuseppe Gargiulo, MD (Bern University Hospital, Switzerland), looked at the 8,404 European patients (26.6% women) who had ACS with or without ST-segment elevation and were randomized in the MATRIX trial to undergo treatment with an invasive approach using either radial or femoral access. Women presented with a higher burden of disease than men and were less likely to have received aspirin and P2Y12 inhibitors prior to arrival in the cath lab.

After adjustment for baseline characteristics, there were no differences in MACCE (death, MI, or stroke) and net adverse clinical events (NACE; defined as MACCE or major bleeding) between men and women, but men were at lower risk for access-site bleeding (adjusted RR 0.64; 95% CI 0.49-0.85), severe bleeding (adjusted RR 0.17; 95% CI 0.06-0.50), and transfusion (adjusted RR 0.56; 95% CI 0.37-0.87) compared with women.

Comparing radial and femoral, there was no significant interaction for either MACCE or NACE with regard to sex (P for interaction = 0.15 and 0.18, respectively). Both MACCE and NACE were significantly reduced with radial versus femoral access in women, while these reductions only trended favorably for radial in men.

Outcomes With Regard to Access and Sex

Radial access was consistently associated with lower all-cause mortality in both women and men, and there was no signal for interaction between access site and sex for stroke, MI, cardiovascular mortality, stent thrombosis, TVR, or the composite of access-site surgery or blood transfusion. BARC type 3 or 5 bleeding was similarly reduced by radial access in both sexes (P for interaction = 0.45), though this only reached statistical significance in women (RR 0.58; 95% CI 0.34-0.98).

“Our current findings are in agreement with those of previous observational studies, and those reported in the RIVAL (Radial Vs femorAL access for coronary intervention) trial,” the authors write. “Against the widespread belief that radial access and use of bivalirudin represent competing treatment strategies to minimize bleeding risks, our findings support their complementary role to mitigate both access-site and non-access-site bleeding risks, both in male and female patients.”

Gargiulo and colleagues also mention the SAFE-PCI for Women study, led by Rao, which was stopped early but did show advantages with radial access in women with regard to bleeding and vascular complications in a secondary analysis. “Hence, the apparent lack of benefit of radial over femoral access in this study likely reflects limited study power more than lack of treatment effect in women,” they say.

The authors also note a higher crossover rate from radial to femoral access in women compared with men (7.6% vs 5.2%) in their analysis, writing that this likely “reflects greater challenges in women to obtain vascular access when attempting [transradial], likely because of smaller and more prone to spasm radial arteries.” However, compared with those receiving transfemoral access, overall procedure duration was shorter for women and no additional fluoroscopy was needed either, they say. “This observation suggests that female patients who are intervened upon via the radial access do not pose specific further technical challenges once vascular access has been established,” Gargiulo and colleagues add.

Ultimately, these findings “contribute to support the concept that radial access should be preferred over the femoral access, adding to the current knowledge firm evidence that this approach is applicable to both male and female patients, and that probably it is even more beneficial in women who are characterized by increased risk of bleeding and access-site-related complications,” the authors conclude.

An Appeal for Radial

In an editorial accompanying the study, Guilliame Plourde, MD, PhD, and Olivier Bertrand, MD, PhD (Quebec Heart and Lung Institute, Canada), write that “considering the large benefits for women using radial-artery access, every effort should now be made to reduce the risk of spasm and increase the likelihood of a ‘clean’ radial access, for example by using ultrasound guidance or smaller sheaths and catheter sizes” of 4 to 5 Fr.

It is now “clear” that radial access benefits women who undergo diagnostic angiography or PCI for an ACS, they say, and “these benefits are consistent with bleeding and vascular complications reduction observed in mixed-sex populations.” Additional efforts need to be made to “complete coronary procedures initiated via the radial artery in women,” Plourde and Bertrand conclude, and “operators should now offer radial access to all, especially to women, who might benefit most from it!”

At this point, Rao said, three obstacles remain in the way of further widespread adoption of transradial access: a dearth of research, opportunities for operator training, and lack of institutional support to start programs. “The evidence gap is clearly being addressed,” he observed. “We do need more opportunities for training programs, particularly for people who are out in practice. . . . And then we have to figure out a way to support not just the physicians or the operators but also their nursing staff [and] the administration, to help them understand that this is not a big investment in terms of equipment and really underscore what the value equation for adopting radial is.”

In the last 10 years, the proportion of transradial procedures has increased 40-fold according to National Cardiovascular Data Registry numbers, Rao said. “That's pretty good. It's not where we want it, but it's pretty good.”

Photo Credit: Sunil Rao