Radial-Access Associated with One-Third Less Bleeding in Rescue PCI After Fibrinolysis

In patients undergoing rescue PCI following fibrinolytic therapy, access via the radial artery occurs in less than 15% of all cases, according to an analysis of a large “real-world” registry.

For patients who undergo transradial PCI, the risks of bleeding are significantly lower compared with those who undergo conventional transfemoral PCI, although radial-access rescue PCI was not associated with a reduction in all-cause mortality unlike other STEMI trials. 

“We were a bit surprised to see that only 15% of all the patients undergoing rescue PCI nationally in the study period were treated with transradial access,” said senior investigator Jay Giri, MD, University of Pennsylvania Perelman School of Medicine (Philadelphia). “You’d have thought it might have been the access site of choice for anybody that’s comfortable using it. However, it doesn’t look like that’s the case. It’s a very underutilized bleeding-avoidance strategy in a group of STEMI patients exposed to a lot of agents that can cause bleeding.” 

In the US, rescue PCI is performed in the minority of cases, mainly because there has been substantial effort to build up systems of care for early interventional therapy. But as Giri told TCTMD, approximately 7% to 10% of STEMI patients in the US are still treated with fibrinolytic therapy. “Given that there are between 300,000 to 500,000 STEMIs per year, it’s not a trivial number of patients,” he said.

Published December 21, 2015 in the Journal of the American College of Cardiology: Cardiovascular Interventions, the analysis included 9,494 patients undergoing rescue PCI following fibrinolytic therapy in the National Cardiovascular Data Registry (NCDR) CathPCI Registry.

Despite the potential for bleeding, 85.8% of patients included in the analysis were treated via the femoral artery and 14.2% underwent transradial PCI. Interestingly, patients treated with transradial access had a lower preprocedure predicted bleeding risk score than those treated with the conventional femoral approach, a finding highlighting the “risk-treatment paradox.”

In an editorial, Ehtisham Mahmud, MD, and Mitul Patel, MD, both from the University of California, San Diego, are blunt in their assessment of the findings: “This study is another example of the failure to adequately utilize radial access as a bleeding avoidance strategy in the highest-risk patients.”

They point out that radial-access PCI remains “scarcely utilized in STEMI patients.” As for the reasons why radial-access is underused for rescue PCI patients—a group at the highest risk for bleeding—the editorialists say inadequate training, especially in low-volume centers with low-volume operators, might be one reason. Other reasons include a “perceived ease of femoral access” in sicker patients or an underappreciation of bleeding as an independent predictor of adverse outcomes.

To TCTMD, Giri said the reasons behind the decision to intervene via the femoral artery rather than the radial artery is not addressed in this study, but he suspects there remains some discomfort with radial access in certain patients. While every operator “hates bleeding,” some “might also be a little bit concerned with the idea that these are patients who have been through a lot already,” said Giri. “They’ve had a STEMI, thrombolytics, now they’re on the table, so they decide to ‘play it safe’. It goes back to doing what’s comfortable, to doing what they’ve done over the course of a career.”

Risk-treatment paradox

In the NCDR analysis, treatment with transradial PCI in the rescue setting was associated with a significant 33% reduction in bleeding compared with femoral-access PCI. The unadjusted bleeding rate was 6.9% among patients treated via the radial artery and 12.0% for those undergoing transfemoral PCI. Overall, there were fewer blood transfusions, vascular complications, access-site bleeding events and hematomas, and less retroperitoneal bleeds with radial PCI.

Overall, there was no difference in mortality among patients treated with either access site (odds ratio 0.81; 95% CI 0.53-1.25).

Previous studies, including the RIVAL study, have shown a reduction in mortality among STEMI patients treated with radial-access PCI, a benefit likely derived from the reduction in bleeding. Those trials included primary-PCI patients whereas the NCDR analysis of rescue PCI included patients who were “partially treated” with fibrinolytics, said Giri. In addition, higher-risk patients requiring femoral-artery access for hemodynamic support were excluded from the analysis.

To TCTMD, Giri noted the mortality rate observed in the analysis—1.7% in the radial arm vs 2.6% in the femoral group—is lower than would be expected in the rescue PCI setting. He attributes this to the exclusion of the critically ill patients requiring hemodynamic support. Mahmud and Patel, the editorialists, agree with the reasoning, adding “this could also have contributed to the inability to demonstrate a mortality difference with the radial-access approach.”

Falsification endpoint

Of note, there was a significant reduction in gastrointestinal (GI) bleeding, which served as “falsification endpoint,” with radial-access PCI. A reduction in GI bleeds with radial-access PCI would not be expected in this setting. The falsification endpoint was introduced as a methodological safeguard to eliminate potential confounding. Despite adjusting for multiple variables in the propensity-matched analysis, it is difficult, even in a detailed study with ample clinical data on patient and procedural characteristics, to adjust away the propensity for bleeding, according to investigators.

“It again wraps back to the risk-treatment paradox,” said Giri. “The patients who are being treated with femoral access are sicker. They are more likely to bleed up front, whether it’s from the access site or elsewhere.”

The GI bleeding reduction might have the effect of undercutting the primary message, “which is the adjusted outcome, but on the other hand it’s the most rigorous way of performing the analysis and presenting data without bias to the reader,” he added.

Sources: 
1. Kadakia MB, Rao SV, McCoy L, et al. Transradial versus transfemoral access in patients undergoing rescue percutaneous coronary intervention after fibrinolytic therapy. J Am Coll Cardiol: Cardiovasc Interv 2015; epub before print.
2. Mahmud E, Patel M. Radial access for rescue percutaneous coronary intervention. J Am Coll Cardiol: Cardiovasc Interv 2015; epub before print.

Disclosures:

• Dr. Giri reports no conflicts of interest.
• Dr. Mahmud has served on the advisory board of The Medicines Company, Medtronic, and Corindus; has served on the Speakers Bureau for Medtronic; has participated in educational programs with Abbott Vascular; has received clinical trial support from Corindus; and has served on the clinical events committee for St. Jude Medical.
• Dr. Patel has served on the Speakers Bureau for AstraZeneca.

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