Imaging change cuts radiation exposure during TAVR procedures

Operators performing transcatheter aortic valve replacement (TAVR) procedures reduced radiation dose by 27 percent by modifying imaging settings. Using a lower setting didn’t affect screening time, procedure time, contrast use or procedural outcomes.

Divyesh Sharma, MRCP, of the Royal Victoria Hospital in Belfast, Northern Ireland, and colleagues reported these results in the June issue of Catheterization and Cardiovascular Interventions.

Use of TAVR as a treatment for inoperable and high-risk patients with severe aortic stenosis has increased in Europe and the U.S., with the possibility that this one day may become an option in even intermediate- and low-risk patients if it gains regulatory approvals. Imaging required during the procedure potentially exposes patients and heart teams to ionizing radiation, though.  

“This is important both for the safety of the interventional team and the patient in keeping with the [as low as reasonably achievable] principle,” they wrote. “Given that the [TAVR] has now become the established procedure and the case volume continues to rise rapidly, simple measures to reduce radiation dose have never been more pertinent.”

Their hospital performs between 70 and 90 TAVR procedures annually. For this study, they enrolled 72 patients over 11 months, with half undergoing TAVR using standard image acquisition settings and half with modified settings. The standard acquisitions included 15 pulse-progressive fluoroscopy and 15 frames per second, which changed to 3.75-7.5 pulse-progressive fluoroscopy and 3.75-7.5 frames per second for the modified setting.

Operators used the standard setting for the aortogram during valve implantation and during valve deployment.  

Both groups had 31 transfemoral and five subclavian procedures. The median cumulated dose area product with the standard setting was 102.4 Gy*cm2 vs. 74.6 Gy*cm2 with the lower setting. That finding was statistically significant. They reported no significant differences in screening time, procedure time, contrast volume or procedural outcomes.

For comparison, they also measured the dose area product for 40 PCIs performed in the same time period at the same laboratory. The dose area product was 74.6 Gy*cm2.

The lower setting is now their usual protocol, Sharma et al wrote, with a switch to the standard setting if necessary and when positioning and deploying the valve. They acknowledged the study relied on a small sample size at a single center, but the results show that a lower dose is achievable without compromising image quality or procedural outcomes.