EUROMAX substudy suggests transradial approach does not improve clinical outcomes


Martial Hamon (Department of Clinical Research, University of Caen, Caen, France) and others report in Circulation: Cardiovascular Interventions, according to the results of a prespecified analysis of the EUROMAX  (European ambulance acute coronary syndrome) trial, that the transradial approach for coronary interventions is not associated with significantly better 30-day clinical outcomes compared with the transfemoral approach—this goes against the findings of previous studies.

Hamon et al report both EUROMAX and HORIZON-AMI (Harmonizing outcomes with revascularization and stents in acute myocardial infarction) found that bivalirudin reduced the risk of bleeding compared with heparin, but add that HEAT-PPCI (How effective are antithrombotic therapies in primary percutaneous coronary intervention) did not find the drug to reduce bleeding. They explain that the lack of bleeding benefit with bivalirudin in HEAT-PPCI was attributed to the use of the transradial approach and “the lower dose of heparin without systematic use of glycoprotein IIn/IIIa inhibitors [GPI]”. Noting that a separate prespecified analysis of EUROMAX has already shown that bivalirudin reduces the risk of bleeding “even in the setting of low-dose heparin without GPI”, the aim of this analysis was to determine whether the selection of the transradial approach affected 30-day outcomes and/or mitigated the bleeding reduction benefit of bivalirudin.

In the EUROMAX study, patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) were randomised to receive bivalirudin or heparin. However, choice of access site—transradial or transfemoral—was at the discretion of the operator. Of the 2,152 patients for whom access-site data were available, 47% underwent the transradial approach. Hamon et al note that the transradial patients tender to have a lower risk of complications than the transfemoral patients—for example, they were younger, more likely to be male, and less likely to have a history of coronary artery bypass grafting (CABG).

The 30-date rates of the EUROMAX composite primary endpoint—death and non-CABG protocol major bleeding—and the key secondary endpoints (such as major adverse cardiac events) were significantly lower in the transradial group. However in a multivariate analysis, the adjusted odds ratio for all outcomes were similar for transradial and transfemoral groups except for stroke, which was lower with the transradial approach. Additionally, there were no differences in the rates of major or minor bleeding between groups. The authors comment: “Bivalirudin was an independent predictor of reduced risk of bleeding whereas access site was not.”

Hamon et al state there are several “plausible explanations” for why they, unlike the authors of previous studies, did not find the transradial approach to improve clinical outcomes, including that PCI practice has evolved from the PCI techniques used in the studies that did show the transradial approach to improve outcomes, that trials in which patients were randomised to the transradial or transfemoral approach may have “inadvertently” excluded patients with a higher risk for radial access failure (eg. females) and “thereby possibly magnifying the beneficial impact of radial access”, and that the use of vascular closure devices in some of the earlier studies comparing the transradial approach with the transradial approach was low (vascular closure devices are known to reduce bleeding).

However, the authors comment: “Regardless of the debate for the presence or magnitude of the clinical benefits associated with the radial approach, there are unquestionable benefits in patient comfort and important economic implications associated with immediate ambulation and early hospital discharge.”