E2501. Vessel Navigation Improves Cannulation Success Rates in Adrenal Vein Sampling
  1. Iris Lee; Monash Health Imaging
  2. Kenneth Lau; Monash Health Imaging
Adrenal vein sampling (AVS) is considered the gold standard for subtyping and lateralisation of the cause of Primary Hyperaldosteronism, the most common curable cause of secondary hypertension. Difficulty in cannulation of the right adrenal vein (RAV) is usually the limiting factor in AVS. Vessel navigation (VN) allows the fusion of computed tomography adrenal images with live fluoroscopic images which may limit the areas of search. The aim of this retrospective study was to assess whether VN increases the efficacy in AVS.

Materials and Methods:
All consecutive adult patients referred for AVS from July 2016 to September 2018 were included in the non-VN group, and after the implementation of VN in October 2019, consecutive referrals from November 2019 to February 2020 were included in the VN group. Ring markers placed at the ostia of adrenal veins on previous adrenal CT were fused with angiographic images. AVS was performed pre- and post-synthetic ACTH stimulation. The technical success of adrenal vein cannulation was defined by a selectivity index (a ratio of adrenal vein cortisol and peripheral vein cortisol levels) of >= 2 pre-ACTH stimulation, and >= 5 post-ACTH stimulation. The cannulation success rates of the RAV and left adrenal vein (LAV), screening time and radiation dose were compared between the two groups using Fisher exact test with p < 0.05 being considered significant.

18 non-VN patients (66% male, mean age 53) and 23 VN patients (52% male, mean age 52) were included. The LAV cannulation success rate increased from 88.9% to 100% between non-VN and VN groups pre-ACTH, and from 83.3% to 100% post-ACTH. There was a statistically significant improvement of RAV cannulation success rate of 55.6% to 87% (p = 0.036) between non-VN and VN groups pre-ACTH, and from 66.7% to 91.3% post- ACTH. The average fluoroscopy time (23 minutes non-VN vs 16 minutes VN) , total dose area product (DAP) (532195 mGycm2 non-VN vs 81933 mGycm2 VN) and Air Kerma (1209 mGy non-VN vs 678 mGy VN) were all significantly lower in the VN group than the non-VN group.

Vessel Navigation, an image fusion technology, can improve the success rate of AVS, especially for novice and inexperienced proceduralists and at low-volume institutions where AVS procedures are not frequently performed. VN increases the ease of finding the adrenal veins, particularly the RAV, with better localisation of adrenal venous ostia and navigation through venous anatomical variations. Implementation of VN significantly reduces procedure time and radiation exposure to both patients and operators. Given that CT of the adrenal glands is performed as part of the evaluation of PA, implementation of VN would be practical at many centres and at no substantial cost.