Bedside MATRIX score to predict crossover from transradial to femoral approach before PCI: Eurointervention study

A simple to use eight item checklist based bedside MATRIX score has been recently devised and validated to predict which acute coronary syndrome (ACS) patients will require crossover from the radial to femoral artery during per cutaneous coronary intervention (PCI). This risk prediction tool was derived and externally validated in a study,  now published in Eurointervention Journal, by Gragnano et al.

The radial artery is recommended by international guidelines as the default vascular access in patients with ACS managed invasively. However, crossover from radial to femoral access is required in 4-10% of cases and has been associated with worse outcomes. No standardised algorithm exists to predict the risk of radial crossover.

To fill this lacunae Gragnano et al, turned to the MATRIX trial, a randomized study of 8,104 patients undergoing either radial or femoral access for PCI of ACS. Of those assigned to transradial PCI, 183 (4.4%) crossed over to femoral access because the operator either had issues with the puncture or sheath insertion or was unable to complete angiography or PCI (mostly because of vessel tortuosity of vasospasm).

From the derivation cohort of 4,197 patients randomized to radial access, they identified eight independent predictors of crossover and these were used to develop the MATRIX score. Scores, ranging from 0 to 100, are calculated using a nomogram. In the study, 1,279 patients had a MATRIX score ≥ 41 and these patients had a more than threefold higher risk of radial crossover compared with those with a lower score (OR 3.67; 95% CI 2.71-4.97). The results were similar when the right or left radial artery was used for access.

The MATRIX score (age, height, smoking, renal failure, prior coronary artery bypass grafting, ST-segment elevation myocardial infarction, Killip class, radial expertise) showed a c-index for radial crossover of 0.71 (95% CI: 0.67-0.75) in the derivation cohort.

External validation was accomplished among 3,451 and 491 ACS patients managed invasively and randomised to radial access from the RIVAL and RIFLE-STEACS trials, respectively.

Discrimination ability was modest in the RIVAL (c-index: 0.64; 95% CI: 0.59-0.67) and RIFLE-STEACS (c-index: 0.66; 95% CI: 0.57-0.75) cohorts. Thus, a cut-off of ≥41 points was selected to identify patients at high risk of radial crossover.

Prior to the publication of the MATRIX score, it was believed that women might be at higher risk for crossover, said Gragnano, but female sex was not a significant predictor of radial failure in MATRIX and didn't factor into the risk score.

"We know patients often ask to proceed with the radial artery because they know, often through the media, that it's better and more comfortable," he said. "In cases of NSTEMI, where you're not really rushing and have 12 hours to proceed with PCI, then you can discuss more clearly with the patient the risks of performing PCI with the radial artery. In some cases, you might also consider the use of femoral artery if the risk of crossover is very high."

Patients at high predicted risk of radial failure may be considered for more extensive use of ultrasound-guided radial artery cannulation to prevent issues in arterial puncture or sheath insertion (accounting for 20% of radial crossover cases in our cohorts). Also, before attempting radial access, a careful examination of the femoral arteries appears desirable if a high risk of crossover exists in order to plan safe alternative vascular access.

The novel score may assist operators in anticipating and potentially better addressing issues with radial access in clinical practice and provides a new opportunity to investigate the risks and benefits of radial access versus direct femoral access in this high-risk patient subset.

Source: Eurointervention: DOI: 10.4244/EIJ-D-21-00441