Higher Radiation Dose in Patients and Operators with Radial Approach (RAD-MATRIX Dosimeter)

Both physicians and patients are exposed to higher radiation doses during radial access PCI compared to femoral, according to this large contemporary study on high volume PCI operators of ACS patients.

Even though the difference in radiation exposure was relatively small for patients (approximately 10% higher for radial PCI) this translated into double the exposure to operators’ thorax.

For every 100 femoral procedures, operators receive doses equivalent to 6 chest x-rays, while for every 100 radial procedures, doses equal 11.5 x-rays.

The RAD-MATRIX was a substudy of the MATRIX trial, which randomized over 8,400 ACS patients with or without STEMI to radial or femoral PCI between October 2011 and November 2014. The substudy focused on 18 operators who collectively performed 777 of those procedures (398 radial).

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Operators wore dedicated dosimeters on their left wrist, at mid-chest outside the protective lead apron, and at head level, to measure eye exposure. Additionally, all operators used standard protection, which included a screen fixed to the PCI table to protect their lower body and a mobile screen suspended from the roof to protect their upper body.

Chest, head and wrist doses were similar when comparing left and right radial access sites.

According to the study, the incremental operator effective dose for a single radial vs. femoral procedure is about 1.1 μSv. Extrapolated over 300 procedures, this corresponds to additional 330 μSv, or the equivalent of 17 additional chest X-rays.

The RAD-MATRIX outcomes contradict a recent meta-analyzis that suggests radiation exposure decreases over time, as operators’ experience increases.

The difference observed in this study was seen in highly experienced radial access operators, which is why we would expect even more significant differences in less experienced operators.

The difference in bleeding and vascular complications justifies, without question, the slightly higher patient exposure. As regards physicians, we should continue to use the radial approach as often, but with caution, taking all the necessary protection measures available.

Original Title: Radiation exposure and vascular access in acute coronary syndromes: The RADMatrix Trial. J Am Coll Cardiol. 2017; Epub ahead of print.

Presenter: Alessandro Sciahbasi.

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