The transradial approach reduces the risk of kidney injury in acute patients

It remains unclear whether transradial access, compared with transfemoral access, presents a different risk of post-procedural kidney injury for patients admitted with acute coronary syndrome. Historically, it has been considered (without any evidence) that, given the higher difficulty associated with transradial access, it would require longer fluoroscopy time and higher contrast volume, which would eventually be associated with a higher risk of peri-procedural kidney injury. This study aims to challenge the historical association between transradial access and a higher incidence of acute kidney injury.

This work, based on the MATRIX-Access (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial, assessed the incidence of acute kidney injury in patients with acute coronary syndrome.

Among 8404 patients, 194 (2.3%) were excluded due to missing creatinine values or for being on dialysis.

The primary AKI-MATRIX endpoint was acute kidney injury (AKI), defined as an absolute (>0.5 mg/dL) or a relative (>25%) increase in baseline creatinine values.

AKI occurred in 634 patients (15.4%) with transradial access and 712 patients (17.4%) with transfemoral access (odds ratio [OR]: 0.87; 95% confidence interval [CI]: 0.77 to 0.98; p = 0.0181).

The relative increase criterion (>25%) was noted in 633 patients (15.4%) with transradial access versus 710 patients (17.3%) with transfemoral access (p = 0.0195). The absolute criterion (>0.5 mg/dL increase in basal creatinine) occurred in 175 patients (4.3%) with transradial access versus 223 patients (5.4%) with transfemoral access, a significant difference in favor of transradial access (p = 0.0131).

By implementing the Kidney Disease Improving Global Outcomes criteria, acute kidney injury was 3-fold less frequent with transradial access than with transfemoral access.

Dialysis was needed in 6 patients (0.15%) in the transradial access group and 14 patients (0.34%) in the transfemoral access group (p = 0.081).

The stratified analysis suggested greater benefit with transradial access in patients who presented greater baseline risk for AKI.

Conclusion

In patients with acute coronary syndrome (with and without ST-segment elevation) who underwent invasive management, transradial access was associated with a reduced risk of acute kidney injury compared with transfemoral access.

Editorial

The AKI-MATRIX trial is the first among large-scale randomized studies with a pre-especified prospective analysis of the prevalence of kidney injury in relation to transradial access, used in procedures.

Upon analysis of the degree of kidney injury, stages 1 and 2 were similar for both approaches, but the incidence of stage 3 injury was reduced in 40% with transradial access.

The prevalence of kidney injury has varied greatly from one study to the other, basically due to differences in definition and studied populations.

In any case, it seems to be clear that even a small increase in baseline creatinine level is associated with both short-term and long-term morbidity and mortality.

Previous hydration with saline is the only class I measure for patients with moderate to high risk of kidney injury requiring catheterization. The problem is that this is not an option for patients with an ongoing infarction, which means that minimizing contrast volume is of the utmost importance.

Some drugs, such as statins, might reduce the risk of injury while others, such as inhibitors of the renin-angiotensin axis and diuretic, may increase it.

Finally, we are yet to find an explanation why transradial access lowers the risk of kidney injury, since contrast volume was identical for both approaches. A possibility is that the passage of guidewires and catheters through the abdominal aorta might cause microembolisms in the renal arteries, which could be prevented by using the transradial access.

Original title: Acute Kidney Injury After Radial or Femoral Access for Invasive Acute Coronary Syndrome Management. AKI-MATRIX.

Reference: Giuseppe Andò et al. J Am Coll Cardiol. 2017 May 11. Epub ahead of print.

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