PARIS (FRONTLINE MEDICAL NEWS) – Transradial-access percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS) results in a significantly lower risk of acute kidney injury (AKI), compared with the transfemoral approach, according to a new analysis from the large randomized MATRIX trial.

The results of this prespecified secondary subgroup analysis of MATRIX suggest it’s time to update the classic “five golden rules” for reduction of contrast medium–induced AKI by adding a sixth. “Use a transradial approach,” Bernardo Cortese, MD , said at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.

“Even transient AKI is associated with an increase in adverse events and mortality,” noted Dr. Cortese, an interventional cardiologist and chief of clinical research at Fatebenefratelli Hospital in Milan.

He reported on 8,210 participants in the MATRIX trial (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) who were randomized to transradial- or transfemoral-access PCI for non–ST-elevation MI or ST-elevation MI.

The primary results of the 78-site, four-country European study, previously published, showed that transradial PCI reduced the composite risk of death, MI, stroke, or major bleeding by 17%, compared with transfemoral PCI, a benefit mainly driven by a marked reduction in clinically important bleeding ( Lancet. 2015 Jun 20;385[9986]:2465-76 ).

Left unanswered by the primary analysis was the question of whether transradial PCI in ACS patients also reduced AKI risk, as had previously been suggested by a meta-analysis of observational studies ( Int J Cardiol. 2015 Jan 20;179:309-11 ). In designing the MATRIX trial, Dr. Cortese and the other investigators decided to address that issue separately in a prespecified secondary analysis known as AKI-MATRIX. For this purpose, AKI was defined as either a post-PCI in-hospital increase in serum creatinine level of more than 25%, compared with the preangiography baseline, or an absolute increase in serum creatinine of greater than 0.5 mg/dL.

AKI occurred in 15.4% of ACS patients who underwent PCI with transradial access and 17.3% of those randomized to transfemoral access, for a significant 13% relative risk reduction. This was accomplished without any increase in the volume of contrast media required. The average was 200 mL in both study groups.

The reduction in AKI achieved with transradial-access PCI was seen in all patient subgroups, including those at increased AKI risk because of an estimated glomerular filtration rate below 60 mL/min, age 75 or older, Killup class III or IV, or a Mehran score greater than 10.

Dr. Cortese proposed several possible mechanisms for the observed reduction in AKI seen with transradial-access PCI. The major factor in his view is that the transradial approach entails less bleeding, as earlier demonstrated in the primary analysis – and bleeding has been associated with impaired renal perfusion in several prior studies. Also, it’s plausible that the passage of the catheter across the renal arteries during the transfemoral approach dislodges atherosclerotic debris, which then travels down the renal vessels.

The five golden rules for preventing contrast media–induced AKI, he noted, are

1. Discontinue nephrotoxic drugs before the procedure.

2. Identify high-risk patients.

3. Hydrate them.

4. Choose an ideal contrast medium.

5. Adapt the dose of contrast medium to the patient’s specific situation.

Discussant Jacek Legutko, MD, PhD , of Jagiellonian University in Krakow, Poland, said the primary results of the MATRIX trial published in 2015 have had a major impact on Polish interventional cardiology, where transradial PCI is now used in 80% of PCIs. The AKI study results will reinforce this trend, he added.

“You have shown something opposite to what we’ve thought in the past, that maybe, with a radial approach, we would use more contrast medium, which is a risk factor for AKI. In your study – at least in ACS with very experienced transradial operators – there was no increase in contrast volume, and the risk of AKI decreased,” Dr. Legutko said.

Asked about the possibility that transradial PCI might be associated with an increased risk of embolization to the brain, much as the transfemoral approach might cause embolization to the kidneys, Dr. Cortese said there was no significant difference between the two AKI-MATRIX study arms in rates of transient ischemic attack or stroke.

“I did my first transradial PCI in 2003, and I haven’t seen any increase in these events or later dementia,” he added.

The prespecified secondary analysis of the MATRIX trial was conducted without commercial support. The presenter reported serving as a consultant to Abbott, AstraZeneca, Daiichi Sankyo, Eli Lilly, and Stentys.

Simultaneous with his presentation in Paris, the AKI-MATRIX study was published online at


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