Transradial vascular access is often preferred over the transfemoral route in percutaneous coronary intervention (PCI) for its lower associated risks of bleeding and vascular complications. But transfemoral access is overall better at accommodating the larger catheters and sheaths frequently needed for PCI of complex lesions.

Now, a randomized trial adds to observational evidence that transradial complex PCI can be safely performed using thin-walled introducer sheaths that preserve the large-bore internal diameters of introducers used for femoral access but are slim enough for the radial artery.

Use of such a thin-walled 7F introducer sheath allowed complex-lesion procedures to reap the benefits of radial access without safety issues or sacrificing procedural success, the researchers report. The risk of clinically important bleeding or vascular complications needing intervention, the primary endpoint, in radial procedures was less than one-fifth of transfemoral-access procedures using standard 7F introducers.

Radial-access procedures in the 388-patient trial, called COLOR (Complex Large-Bore Radial PCI), exclusively used the Glidesheath Slender (Terumo) 7F thin-walled radial introducer sheath. Femoral procedures used standard 7F sheaths designed for femoral access.

“In the majority of complex PCI, we tend to use the 7F Glidesheath. It gives us the ability to use regular guiding catheters but is virtually one size [1F] smaller in outer diameter, so it will cause less radial-artery occlusion,” principal investigator Maarten A.H. van Leeuwen, MD, PhD, Isala Heart Center, Zwolle, the Netherlands, told theheart.org | Medscape Cardiology.

With that device, he said, “performing a complex PCI through the radial artery is similar to and as easy as in the femoral artery. I was convinced about that, but now also our study shows that it will lead to a similar procedural success rate as the in femoral artery.”

Other companies market such thin-walled introducers for radial access, including the RAIN Sheath (Cordis) and the Prelude IDeal (Merit Medical). The COLOR results may apply as well to them, “but that would require confirmation in studies because they are not completely similar,” said van Leeuven.

He is senior author on the trial’s publication May 18 in JACC: Cardiovascular Interventions. The results were also presented the same day by lead author Thomas A. Meijers, MD, Isala Heart Center, during the virtual Congress of European Association of Percutaneous Cardiovascular Interventions (EuroPCR 2021).

The multicenter randomized trial “confirms that radial access is safe even in complex PCI requiring large-bore guiding catheters, with fewer bleeding events and vascular complications compared with femoral access,” agrees an accompanying editorial. The reduced bleeding risk with radial access was driven by bleeding that met Bleeding Academic Research Consortium (BARC) 2 criteria, the editorialists observe.

Moreover, “procedural success and clinical outcomes are comparable between the two access sites in complex coronary lesions,” and the 3.6% rate of crossover from radial to femoral access was low, write Marco Valgimigli, MD, PhD, and Antonio Landi, MD, both from Cardiocentro Ticino Institute, Ente Ospedaliero Cantonale, Lugano, Switzerland.

The trial randomly assigned patients undergoing planned PCI for complex lesions — of which more than half were chronic total occlusions (CTO); the others included heavily calcified, left-main, and complex bifurcation coronary lesions — to the transradial or transfemoral procedures, 194 in each group. They received similar periprocedural medications and their activated clotting time levels were comparable, the group reports.

The procedural success rate was 89.2% for transfemoral and 86.0% for transradial cases (P = .29). The groups did not differ significantly in procedure duration, volume of contrast agent used, or radiation dose.

Rates of the primary endpoint reflecting bleeding and vascular complications at discharge were 19.1% for transfemoral and 3.6% for transradial procedures (P < .001).

The discharge rate of major adverse cardiac events (MACE), which included death, myocardial infarction (MI), or repeat target-vessel revascularization, was not significantly different, at 2.6% and 3.1% for transfemoral and transradial cases, respectively.

Discharge MACE events in COLOR consisted entirely of periprocedural MI. Of note, the Ultimaster Tansei (Terumo) sirolimus-eluting stent had been “highly recommended” for all procedures but, ultimately, hardware choices, with the exception of the Glidesheath introducer, were left to operator discretion.

MACE rates at 30 days were 2.6% in the transfemoral-access group and more than twice as high, 6.7%, in the transradial-access group (P = .06).

“Importantly, one would expect that the mitigation of bleeding and vascular complications with radial access would favorably (or at least neutrally) affect the 30-day MACE rate,” the editorialists write.

But given that the numerically higher rate with transradial access was of “borderline statistical significance,” they continue, “in this regard, as properly acknowledged by the investigators, the trial is inconclusive, given the small sample size and the low number of events. Therefore, this finding should not be overemphasized.”

van Leeuwen agreed that the trial was grossly underpowered for MACE and, besides, there seemed to be no biologically plausible explanation for a higher MACE rate with transradial access. “So, it can only be hypothesis-generating.”

COLOR was supported by Terumo EMEA. van Leeuwen is a consultant for Terumo. Meijers reports no relevant relationships. Disclosures for the other authors are in the report. Valgimigli discloses receiving grants from Abbott, Terumo, Medicure, and AstraZeneca; and personal fees from Abbott, Chiesi, Bayer, Daiichi Sankyo, Amgen, Terumo, Alvimedica, AstraZeneca, Biosensors, and Idorsia. Landi reports no relevant relationships.

JACC Cardiovasc Interv. Presented May 18, 2021. Abstract, Editorial

Congress of the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) 2021. Presented May 18, 2021.

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