Predictors of patient radiation exposure during transcatheter aortic valve replacement

Background: Transcatheter aortic valve replacement (TAVR) exposes patients to radiation. Objectives: We sought to identify factors associated with higher radiation exposure and to quantify their relative influence, which may inform reduction of this hazard. Methods: All TAVR procedures at Rhode Island Hospital between March 20, 2012 and February 12, 2017 were included. Procedures were performed by two co-primary operators using a Siemens Artis Zeego system. Radiation metrics were generated by the imaging system. The primary metric was dose-area product (DAP, Gy*cm²), and secondary metrics were reference point air kerma (mGy) and fluoroscopy time (minutes). Data collected for the STS/ACC TVT Registry were utilized to develop a multivariable linear regression model predicting DAP. Results: In 294 TAVRs, median DAP was 169 Gy*cm² [interquartile range (IQR) 106–238]. The r² values for the full 27-variable DAP model and reduced eight-variable model were 0.457 and 0.420, respectively. Valve area, aortic insufficiency, and procedure year (suggesting absence of a learning curve) were non-significant predictors in the full model, while increasing weight, cutdown transfemoral access, higher pre-procedure creatinine and hemoglobin, and vascular complications predicted higher DAP in both models. Results were unchanged when DAP was log-transformed. Secondary models for air kerma and fluoroscopy time revealed similar predictors. Conclusion: Factors associated with increased procedural complexity and duration as well as radiation attenuation and scatter predict increased patient radiation exposure during TAVR. Modification of procedural technique, especially using percutaneous femoral vascular access, may facilitate reduction in exposure.