Effectiveness of low rate fluoroscopy at reducing operator and patient radiation dose during transradial coronary angiography and interventions.

Objectives: This study sought to determine the efficacy of low rate fluoroscopy at 7.5 frames/s (FPS) versus conventional 15 FPS for reduction of operator and patient radiation dose during diagnostic coronary angiography (DCA) and percutaneous coronary intervention (PCI) via the transradial approach (TRA).

Background: TRA for cardiac catheterization is potentially associated with increased radiation exposure. Low rate fluoroscopy has the potential to reduce radiation exposure.

Methods: Patients undergoing TRA diagnostic angiography ± ad-hoc PCI were randomized to fluoroscopy at 7.5 FPS versus 15 FPS prior to the procedure. Both 7.5 and 15 FPS fluoroscopy protocols were configured with a fixed dose per pulse of 40 nGy. Primary endpoints were operator radiation dose (measured with dosimeter attached to the left side of the thyroid shield in μSievert [μSv]), patient radiation dose (expressed as dose-area product in Gy·cm(2)), and fluoroscopy time.

Results: From October 1, 2012 to August 30, 2013, from a total of 363 patients, 184 underwent DCA and 179 underwent PCI. Overall, fluoroscopy at 7.5 FPS compared with 15 FPS was associated with a significant reduction in operator dose (30% relative reduction [RR], p < 0.0001); and in patient's dose-area product (19% RR; p = 0.022). When stratified by procedure type, 7.5 FPS compared with 15 FPS was associated with significant reduction in operator dose during both DCA (40% RR; p < 0.0001) and PCI (28% RR; p = 0.0011). Fluoroscopy at 7.5 FPS, compared with 15 FPS, was also associated with substantial reduction in patients' dose-area product during DCA (26% RR; p = 0.0018) and during PCI (19% RR; p = 0.13). Fluoroscopy time was similar in 7.5 FPS and 15 FPS groups for DCA (3.4 ± 2.0 min vs. 4.0 ± 4.7 min; p = 0.42) and PCI (11.9 ± 8.4 min vs. 13.3 ± 9.7 min; p = 0.57), respectively.

Conclusions: Fluoroscopy at 7.5 FPS, compared with 15 FPS, is a simple and effective method in reducing operator and patient radiation dose during TRA DCA and PCI.