Safety Similar With Radial vs Ulnar Approach in Cardiac Cath

Patrice Wendling

February 16, 2018

A new meta-analysis supports using the ulnar artery as an alternative to the radial artery during coronary catheterization but also highlights the steep learning curve associated with this approach.

There was no significant difference in the risk for major adverse cardiovascular events — a composite of MI, stroke, urgent target-vessel revascularization, and mortality — among patients treated with a transulnar or transradial approach during PCI or diagnostic procedures (odds ratio [OR], 0.90; 95% CI, 0.66–1.23).

Arterial access time, fluoroscopy time, and contrast load were also similar between groups.

Access-site failure, however, was more than twice as likely with the transulnar approach (OR, 2.63; 95% CI, 2.07–3.34), according to the meta-analysis of six trials, published online February 1 in Catheter and Cardiovascular Interventions.

The finding is not surprising at all, senior author, Astin Lee, MD, from Wollongong Hospital, Australia, told | Medscape Cardiology.

"Even when personally in my hands, the access-site failure is about twice as high as the radial artery cannulation," he said. "I suspect it is the deeper location of the artery, it is more difficult to palpate, and also the fact that the nerve lies next to the artery [means] you have to be cautious entering the nerve."

For these reasons, as well as randomized data showing a higher risk for hematoma formation with transulnar access, "It's not a very common approach to use a priori," commented Sunil Rao, MD, a radial-access proponent at Duke University Medical Center in Durham, North Carolina, who was not involved in the study.

"I think many of us are using it if the radial artery is not palpable," he said. "It's an issue really of which artery is dominant. In many patients who have a diminutive radial artery, the ulnar artery is dominant, it's very large, and it's easier just to access that artery. But it's usually in those particular situations or if radial access has failed then either we go to the other side, the contralateral radial, or we use the ipsilateral ulnar approach."

Rao said he uses an arm approach in about 96% of cases and less than 10% of those are transulnar.

There's no way to know how often it's used nationally, however, because transulnar access is not captured in registries, he noted. The National Cardiovascular Data Registry/CathPCI Registry includes the radial, brachial, and femoral access sites, but it captures the most successful access site, so it's not known about laterality or crossovers in the current data sets.

In the meta-analysis, there was a nonsignificant trend toward increased crossover to another access route with the transulnar approach (OR, 2.14; 95% CI, 0.89–5.15).

The finding did not change in a sensitivity analysis that removed one study, in which the interventionalists' experience with transulnar access was limited at just 20 to 50 coronary procedures per year. That trial, AURA of ARTEMIS, was stopped early because of the inferiority of the transulnar approach.

"The learning curve is significant. However, in the hands of experienced radial operators, presumably someone who does more than 150 radial artery cannulations a year, it is not that great a learning curve to go to the ulnar artery," said Lee.

He suggests the ulnar artery is an attractive option in cases where operators want to preserve the radial artery for bypass grafting or as arteriovenous fistulae for hemodialysis. Alternatively, it should be considered in patients in whom the radial artery is no longer accessible because of occlusion or severe spasm or in whom known loops and bifurcations may make radial artery cannulation challenging.

Among the 5276 patients in the analysis, the investigators found no significant difference between the transulnar or transradial approach in the risk for bleeding or hematoma formation (OR, 1.18; 95% CI, 0.60–2.34), arterial occlusion (OR, 1.06; 95% CI, 0.60–1.87), or vasospasm (OR, 0.85; 95% CI, 0.51–1.43).

Five trials reported no pseudo-aneurysms, and one trial reported a single episode of arteriovenous fistulae formation in the transulnar group.

Lee noted that some operators are also concerned about the potential for hand ischemia with transulnar access given that the ulnar artery supplies the bulk of the palmar arch; however, that has not been borne out in any studies.

"As far as the complications go, I think it's a little bit less of an effect of volume because the complications are primarily related to the hemostasis process and the fact the ulnar artery is just deeper," Rao said. "It's more of an anatomical issue than I think it is a proficiency issue."

One thing that could increase success rates and lower the risk for ulnar nerve damage is the use of ultrasound, Rao suggested. Trainees who grew up using ultrasound are already very comfortable using ultrasound-guided access, while his generation is gradually getting on board.

"Because the ulnar artery is deeper, I would almost say that it's essential now if you want to get ulnar access to use ultrasound guidance," Rao added.

Lee said he does not use ultrasound in his practice but can see the utility of ultrasound assessment of both the radial and ulnar arteries before any cannulation. He also recommends that operators gain proficiency in cannulating the ulnar artery in case the need arises.

"In an emergency situation or in a patient with shock or with high risk of bleeding, if you aren't able to access the radial artery in most cases you may be forced to use the femoral artery with higher risks of bleeding et cetera. But if you are capable of accessing the ulnar artery, it is a safe and viable alternative," Lee said.

Lee and Rao report having no conflicts of interest.

Catheter Cardiovasc Interv. Published online February 1, 2018. Abstract

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