P1849Predictors of high radiation exposure in patients undergoing contemporary transfemoral transcatheter aortic valve implantation (TF-TAVI)
Authors: Vendrik J , Vlastra W , Koch K T , Vis M M , Wykryzkowska J J , De Winter R J , Henriques J P S , Piek J J , Baan J , Delewi R 
Published: October 2019

Abstract

Background
Transfemoral transcatheter aortic valve implantation (TF-TAVI) is a minimally invasive and life-saving treatment option in patients with severe aortic valve stenosis. The number of TAVI procedures has rapidly expanded over the past decade and will continue to expand, as will the total occupational radiation exposure for the interventional cardiologist. Therefore, interventional cardiologist are at increasing risk for developing radiation induced diseases like cataract, premature vascular aging and left-sided brain tumors.

Objectives
In the current study we determined pre-procedural characteristics associated with high radiation exposure during transfemoral TAVI to raise awareness and increase the use of adequate radiation protection.

Methods
Radiation exposure (patient exposure in DAP in mGy·cm2) was collected during (TF)-TAVI procedures (July 2014- August 2018). Univariate and multiple regression analyses were performed to identify pre-procedural factors associated with high radiation exposure.

Results
A total of 654 TF-TAVI procedures were included. Patients had a median STS-score of 4% and 47% was male. The median radiation exposure was 38,016 mGy·cm2 (24,451–55,747) and the median fluoroscopy time was 16 minutes (IQR: 11–19). During the four year study period, the mean radiation exposure per TAVI procedure decreased with 30%, while the total fluoroscopy time declined with 28%.
The majority of the population underwent the TAVI procedure under local anesthesia (99%) and were implanted with the Edwards SAPIEN 3 valve (92%). Balloon predilatation was used during 88% and balloon post-dilatation was performed in only 5% of the procedures.
Patient characteristics associated with high radiation exposure included BMI >25 (OR: 6.0, 95% CI: 3.9–9.4, p<0.001), male gender (OR: 2.8, 95% CI: 1.8–4.4, p<0.001), a large pre-procedural CT-measured valve area (>450 mm2) (OR: 1.8, 95% CI: 1.1–2.8, p=0.01), presence of a pacemaker or ICD (OR: 2.0, 95% CI: 1.0–3.9, p=0.04) and a history of atrial fibrillation (OR: 1.5, 95% CI: 1.0–2.3, p=0.04). Moreover, the performance of predilatation (OR: 2.7, 95% CI: 1.5–4.8, p=0.001) and valve-in-valve procedures (OR: 3.3, 95% CI: 1.1–10.2, p=0.04) was associated to high radiation exposure.
Predictors of radiation exposure

Conclusions
The performance of transfemoral TAVI in patients with a large stature (male, BMI >25, valve area >450 mm2), in certain groups of fragile patients (presence of pacemaker or ICD, atrial fibrillation), and performing relatively complex procedures (predilatation and valve-in-valve) was associated with high radiation exposure. These patient characteristics and procedural strategies are known before the patient enters the catheterization laboratory. Hence, in the current era of a rapidly expanding number of TAVI procedures, operators should minimize their own health risk in these high-radiation-exposure-risk TAVI procedures.

Acknowledgement/Funding
None