Radial-Access Rare in STEMI Post-Lytic 'Rescue' PCI: NCDR

Pam Harrison

December 22, 2015

PHILADELPHIA, PA — Less than 15% of rescue PCIs in acute ST-elevation MI (STEMI), necessitated by failed fibrinolytic therapy, were performed via the transradial approach in a large, real-world registry[1], even though the risk of bleeding is reduced with transradial compared with femoral access.

"Transradial rates are still surprisingly low for a population that you would expect to be at high risk for bleeding," Dr Jay Giri (Perelman School of Medicine at the University of Pennsylvania, Philadelphia) told heartwire from Medscape in written correspondence.

"My opinion is that the broad spectrum of interventional cardiologists studied did not feel comfortable enough with the approach to employ it in what they probably viewed as a complex clinical situation, which rescue PCI inherently is," he added.

"Efforts by leaders in radial artery catheterization worldwide—including some of my coauthors—to train operators in the technique remain incredibly important."

The study is published in the December 21, 2015 issue of JACC: Cardiovascular Interventions.

The study population was derived from the National Cardiovascular Data Registry (NCDR) CathPCI Registry. Patients presenting with a STEMI who were initially treated with fibrinolytic therapy and who subsequently underwent rescue PCI via either a transfemoral or a transradial approach were included in the analysis.

Rescue PCI was defined as PCI for STEMI after failure of full-dose fibrinolytic therapy. Among 9494 patients in the registry who underwent rescue PCI, 14.2% had radial-access while 85.8% had femoral-access PCI.

"Unadjusted analysis demonstrated a significantly lower incidence of the primary bleeding end point in the radial-access group compared with the femoral-access group," lead author Dr Mitul Kadakia (Perelman School of Medicine) and colleagues write.

Bleeding End Points (Unadjusted Analysis)

Even Transradial approach (%) Transfemoral approach (%) P
Primary bleeding end point 6.9 12.0 <0.0001
Blood transfusions 1.1 2.8 0.0003
Vascular complications 0 0.4 0.02
Access-site bleeding events 0.2 1.1 0.001
Access-site hematomas 0.22 1.0 0.004
Retroperitoneal bleeding events 0% 0.4% 0.02

There was also a borderline mortality benefit in favor of the radial-access group at 1.7% compared with 2.6% for the femoral-access group (P=0.05).

Inverse probability of treatment weighting (IPTW) analysis showed that radial access reduced the risk of bleeding by 33% compared with femoral access, at an odds ratio (OR) of 0.67 (P=0.003).

On the other hand, in-hospital mortality rates were not significantly different between the two approaches, as Kadakia points out.

The falsification end point of gastrointestinal bleeding demonstrated that there was also 77% less gastrointestinal bleeding in the radial group compared with the femoral group, again after IPTW adjustment, at an OR of 0.23 (P=0.05). As Giri explained, the group wanted to answer the question as to whether transradial access independently decreased bleeding events compared with transfemoral access.

"One can only truly assess this question accurately if the studied patients in the two groups are equal in all other ways," Giri said. "And we attempted to create this equality through propensity matching."

Gastrointestinal bleeding was selected as a falsification end point, as rates should not have been affected by the access site used, he added.

As results indicated, gastrointestinal bleeding in fact was higher in the femoral arm.

"This implies that despite propensity matching, the femoral patients were inherently more likely to bleed than the radial patients, [although] we cannot say for sure how much of the bleeding benefit in the radial group was due to the radial access and how much was due to the fact that patients [in the radial group] were inherently less likely to bleed," Giri said. "But both play a role in the differences seen."

Risk-Treatment Paradox

Investigators also observed a "risk-treatment paradox," where transradial access was less likely to be used in patients who had a significantly lower risk of bleeding as predicted by bleeding risk scores.

"We were surprised to see how few of these rescue-PCI cases were approached with transradial access, given the increase in bleeding one might expect when performing a procedure on a patient who recently received thrombolytic therapy," Giri said in a statement.

"Even more interesting was the finding that among the group studied, patients at the highest risk for bleeding—those who would benefit from transradial access—were least likely to received that procedure."

"This counterintuitive finding is a demonstration of the 'risk-treatment paradox,' showing that doctors in these cases made treatment decisions based on what they are most comfortable with rather than what is best for the patient."

Negative Effects of Bleeding

In an accompanying editorial[2], Drs Ehtisham Mahmud and Mitual Patel (University of California, San Diego, La Jolla) point out that the negative long-term adverse effects of bleeding after PCI are well recognized and given this, it is "remarkable" that the use of radial access for rescue PCI is under 15% in contemporary interventional practice in the US.

Furthermore, they add, the radial-access approach is widely underutilized in STEMI patients overall.

Despite the amount of attention the topic has been given over the past decade, "in 80% of the hospitals in the United States, radial access is still used in <10% of PCI procedures," Mahmud and Patel observe.

They speculate that concern about meeting door-to-balloon time goals and a possible delay in reperfusion as a result of operator inexperience with radial PCI might be one explanation for its limited use in the US.

However, use of the transradial approach in the US is increasing. As previously reported by heartwire , the proportion of radial PCI procedures increased from 1.2% in 2007 to 16.1% in 2013, with radial PCI accounting for 6.3% of all procedures in the CathPCI Registry during this 5-year period.

Giri and Kadakia had no relevant financial relationships. Disclosures for the coauthors are listed in the article. Mahmud has served on the advisory board of the Medicines Company, Medtronic, and Corindus; has served on the speaker's 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. Patel has served on the speaker's bureau for AstraZeneca.

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