JACC: Pelvic lead shielding reduces operator rad dose
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Helmut W. Lange, MD, of Kardiologisch-Angiologische Praxis Herzzentrum Bremen, and Heiner von Boetticher, PhD, of the Institute for Radiology and Academy for Radiation Protection, both in Bremen, Germany, noted that procedures using radial access have been shown to have some benefits compared with the femoral approach, including lower vascular complication and less patient discomfort. But interventional cardiologists who use the radial method face higher operator radiation exposure, which may pose an impediment to uptake of the transradial approach.
“The closer position of the operator relative to the x-ray tube is inherent to the radial procedure,” they wrote. “We have previously reported that the operator dose was doubled for diagnostic procedures and 50 percent higher for interventions” (Catheter Cardiovasc Interv 2006;67:12-16).
Pelvic lead shielding, when used in femoral access cardiac catheterization, had been shown to reduce operator radiation exposure, they wrote, but it had not been studied in the context of radial access procedures. To evaluate the efficacy of pelvic lead shielding, they designed a randomized study that allowed them to compare operator radiation dose using the radial approach and the femoral approach.
Patients enrolled in the study were scheduled for elective, outpatient coronary angiography and were randomly allocated to a femoral or radial approach with or without the pelvic lead shielding. The study cohort included only cases where the procedure was uncomplicated, and the right radial or right femoral artery was accessed without difficulties; aortic valve stenosis or bypass grafts were not present; and aortography was not performed. They identified 210 patients who met those criteria, with 107 in the radial access group (51 without and 56 with pelvic lead shielding) and 103 in the femoral access group (50 without and 53 with pelvic lead shielding).
For the pelvic lead shielding, they used a custom-made lead blanket that extended from the patient's diaphragm to the knees. An electronic radiation dosimeter was attached to the operator’s breast pocket on the outside of the lead apron and used to measure operator radiation exposure.
Operator radiation dose with radial access decreased from 20.9 uSv with no pelvic lead shielding to 9 uSv with pelvic lead shielding. With femoral access, the operator radiation dose decreased from 15.3 uSv to 2.9 uSv. The absolute reduction in dose-area product (DAP)-normalized operator dose was similar for both radial and femoral access.
“Our study proves that the pelvic lead shield is a highly effective protection device reducing radiation dose from 20.9 to 9 uSv for radial coronary angiography,” they wrote. They added that pelvic lead shielding was effective for the femoral approach, too, but noted that an operator performing a radial procedure still received a higher DAP-normalized dose than did an operator performing a femoral procedure.
“Although pelvic lead shielding is highly effective in reducing radiation, it cannot close the ‘radiation gap’ for the operator between radial and femoral access,” they concluded. “We believe that further reductions in radiation exposure for radial operators are possible and should be aimed for, such as a combination of the pelvic lead shield and the protection board.”
They cautioned that the study population involved uncomplicated cases that were performed by Lange to avoid having to adjust for operator experience and procedural factors. The efficacy of pelvic lead shielding might differ with a different patient population or operators, they wrote.