• Users Online: 708
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 4  |  Issue : 2  |  Page : 102-106

Adrenal vein sampling: Radiation dose reduction on new angiography platform


1 Department of Imaging, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, England
2 Department of Endocrinology, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, England
3 Department of Endocrine and Thyroid Surgery, Imperial College London, Hammersmith Hospital, London, England

Date of Submission06-Jan-2020
Date of Decision06-Dec-2020
Date of Acceptance06-Dec-2020
Date of Web Publication21-Jul-2020

Correspondence Address:
Dr. Ali Alsafi
Department of Imaging, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London
England
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/AJIR.AJIR_24_20

Rights and Permissions
  Abstract 

Objectives: Primary aldosteronism is one of the most common causes of secondary hypertension. Distinguishing unilateral from bilateral disease is essential as those with unilateral adrenal disease will benefit from adrenalectomy. This is best achieved by adrenal vein sampling (AVS) which may be a difficult procedure with significant radiation to both patient and operator. This study aims to measure the radiation dose during AVS before and after the installation of a new angiography platform. Materials and Methods: The dose area product (DAP), air kerma, and fluoroscopy time were collected retrospectively together with demographic data for the first ten patients who underwent AVS between April and September 2018 following the installation of the Philips Azurion 7 M20 interventional platform. These results were compared with those from ten patients who underwent AVS before the installation of the new machine using the Philips Allura Xper FD20 platform. Mann–Whitney test was used to compare DAP, air kerma, and fluoroscopy time. P < 0.05 was considered statistically significant. Results: Successful bilateral adrenal vein catheterization was achieved in all cases in both groups. There was no significant difference in fluoroscopy time: 5.5 (3.3–10.8) min (new) versus 5.3 (4.5–8.4) min (old) (P = 0.9502). The DAP and air kerma were both significantly lower on the new machine: 11.3 (5.2–26.7) Gy.cm2 versus 45.5 (17.2–56.5) Gy.cm2 (P = 0.0089) and 201.5 (88.1–464.0) mGy versus 682.5 (300.5–998.5) mGy (P = 0.0115), respectively. Conclusion: The installation of the Philips Azurion 7 M20 interventional platform has allowed a significant reduction in radiation dose during AVS.

Keywords: Adrenal glands, dosimetry, hyperaldosteronism, interventional, radiation dosage, radiology, vascular surgical procedures


How to cite this article:
Alsafi A, Wernig F, Todd J, Tan T, Palazzo F F, Meeran K, Jackson JE. Adrenal vein sampling: Radiation dose reduction on new angiography platform. Arab J Intervent Radiol 2020;4:102-6

How to cite this URL:
Alsafi A, Wernig F, Todd J, Tan T, Palazzo F F, Meeran K, Jackson JE. Adrenal vein sampling: Radiation dose reduction on new angiography platform. Arab J Intervent Radiol [serial online] 2020 [cited 2020 Sep 27];4:102-6. Available from: http://www.arabjir.com/text.asp?2020/4/2/102/290306


  Introduction Top


Primary aldosteronism is now recognized as being a common cause of hypertension and is associated with a higher risk of serious cardiovascular complications than in those patients with blood pressure-matched essential disease.[1],[2],[3] Once autonomous secretion of aldosterone independent of regulators[4],[5] has been confirmed biochemically, adrenal venous sampling (AVS) is the gold standard modality used to differentiate those individuals with unilateral secretion due to an adrenal adenoma (Conn's syndrome) from those with bilateral adrenal hyperplasia, as the former is likely to benefit considerably from unilateral adrenalectomy.[6]

AVS is a technically challenging procedure with a significant learning curve and may result in significant radiation exposure to both patient and operator.[7] The published median dose area product (DAP) for AVS ranges between 32.5 Gy.cm2 and 72.2 Gy.cm2,[8],[9],[10],[11] although doses as low as 15.7 Gy.cm2 have been reported using the intraprocedural measurement of cortisol.[11]

New dose constraints

The Ionising Radiation (Medical Exposure) Regulations 2017 (IR (ME) R17) came into force on 6 February 2018 in the United Kingdom, replacing and revoking IR (ME) R2000. One of the changes in these new regulations is a reduction in the maximum yearly radiation dose to the lens of the eye of the operator from 150 mSv to 20 mSv. This has resulted in an even greater awareness of radiation exposure resulting in a nationwide move to upgrade interventional radiology rooms with machines that reduce radiation exposure to both operator and patient while maintaining image quality. In line with this policy, we have replaced an Allura Xper FD20 (Philips Healthcare, Best, The Netherlands) with a Philips Azurion 7 M20 (Philips Healthcare, Best, The Netherlands). The Azurion 7 M20 incorporates the ClarityIQ system by Philips with real-time image processing for noise reduction, edge enhancement, and motion correction with additional filtering and optimized protocols lowering radiation dose while maintaining a diagnostic image quality. The larger screen also allows for improved visualization at lower radiation doses.[12],[13]

The aim of this article is to assess and compare radiation dose (DAP, air kerma, and fluoroscopy time) during adrenal venous sampling at a tertiary referral center before and after the installation of a new angiography machine.


  Materials and Methods Top


The first ten patients to undergo adrenal venous sampling between April and September 2018 following the installation of the Philips Azurion angiography machine were identified from the picture archiving and communication system. Demographic data and procedural details, including the success of adrenal vein catheterization, fluoroscopy time, DAP, and air kerma were collected retrospectively. These results were compared with those of the last ten patients to undergo AVS on the Philips Allura machine. To exclude variations in patient size as being the cause of differences in radiation dose between the two groups, measurements of abdominal circumference and anteroposterior (AP) abdominal diameter were made at the level of the adrenal glands on the most recent computed tomography (CT) or magnetic resonance imaging performed before AVS.

Adrenal vein sampling technique

As the technique of adrenal vein sampling (AVS) varies somewhat between centers,[14],[15] we will briefly describe our own protocol. All procedures are performed as day cases. Sampling is performed through a right femoral venous puncture with a 4Fr Glidecath® hydrophilic coated Cobra catheter (Terumo, Tokyo, Japan) within which we punch two holes 2 mm from its tip in the sagittal plane of the lumen as originally described by Doppman and Gill.[15] A fluoroscopy rate of 15 frames/s is used, and digital subtraction angiography images are acquired at 2 frames/s.

The right adrenal vein is always catheterized first, and venography is performed to confirm normal adrenal vein opacification. If appropriately positioned, a 5–10 ml sample of blood is obtained by slow aspiration after discarding the first 2–3 ml of catheter dead space. If there is any concern that the catheter tip was not ideal during aspiration, then an additional sample is obtained after again confirming an appropriate catheter position. Each sample bottle is numbered in turn, and these numbers are transcribed onto a diagram of normal venous anatomy [Figure 1] used by our department for all venous sampling procedures to document the vessel from which the sample has been aspirated. The common trunk of the left adrenal and inferior phrenic veins is then catheterized. In approximately 90% of cases, this can be achieved with the same catheter. In the remainder, a 5 French Sidewinder II catheter (Cardinal Health, Santa Clara, CA, USA) is used. Venography is performed to confirm a satisfactory catheter position, and a venous sampling is obtained in the same way as previously described. We neither use cone-beam CT (CBCT) nor image fusion to aid cannulation. A single sample is then obtained from the low inferior vena cava (IVC). All sampling is done without Synacthen stimulation. All samples are taken to the endocrine laboratory by the operator immediately after the procedure with a copy of the venous map.
Figure 1: Venous sampling map used by the authors for all venous sampling procedures on which sampled vessels are indicated in the order they are obtained with a legend indicating the vessels sampled on the right-hand side

Click here to view


Successful catheterization

Serum cortisol and aldosterone concentrations are measured in all samples. Successful adrenal vein catheterization is considered to have been achieved when the adrenal vein cortisol concentration is at least twice that of the low IVC.[5]

Statistical analysis

GraphPad Prism 6.0 for Mac OS (GraphPad Software Inc., San Diego, CA, USA) was used for statistical analysis. The Mann–Whitney test was used to compare DAP, air kerma, and fluoroscopy time. Unpaired student t-test was used to compare the abdominal circumference and AP diameters. All results are expressed as mean or median and interquartile range. P < 0.05 were considered statistically significant.


  Results Top


The Philips Allura (M: F = 5:5) and Philips Azurion groups (M: F = 3:7) had a median age of 49.8 years (29.7–63.0) and 47.3 (26.0–66.2), respectively. All patients were referred with a confirmed diagnosis of primary aldosteronism, one of whom had recurrence 10 years following previous left adrenalectomy at another center without prior venous sampling. AVS was performed to confirm the absence of residual functioning adrenal tissue on that side.

The median DAP on the Azurion of 11.3 (5.2–26.7) Gy.cm2 was significantly lower than the 45.5 (17.2–56.5) Gy.cm2 on the Philips Allura. (P = 0.0089, Mann–Whitn1 [Figure 2]. The median air kerma on the Azurion was 201.5 (88.1–464.0) mGy, which was significantly lower than that on the Philips Allura, 682.5 (300.5–998.5) mGy (P = 0.0115, Mann–Whitney test) [Figure 3].
Figure 2: Dose area product in Gy.cm2 during adrenal vein sampling before and after installation of the Philips Azurion angiography machine. **P < 0.01, Mann–Whitney test. Line = median, box = interquartile range, whiskers = 95% confidence interval

Click here to view
Figure 3: Air kerma (mGy) during adrenal vein sampling before and after installation of the Philips Azurion angiography machine. *P < 0.05, Mann–Whitney test. Line = median, box = interquartile range, whiskers = 95% confidence interval

Click here to view


There was no significant difference in fluoroscopy time between the Allura and Azurion groups with median fluoroscopy times of 5.5 (3.3–10.8) min and 5.3 (4.5–8.4) min, respectively. (P = 0.9502, Mann–Whitney test) [Figure 4]. There was no significant difference between the two patient groups in the mean abdominal circumference or abdominal AP diameter, excluding patient size variation as a potential confounder [Table 1].
Figure 4: Fluoroscopy time (min) before and after installation of the Philips Azurion angiography machine. Line = median, box = interquartile range, whiskers = 95% confidence interval

Click here to view
Table 1: Abdominal circumference and anteroposterior diameter on cross.sectional imaging for the Allura and Azurion groups

Click here to view


Successful bilateral adrenal venous catheterization confirmed by an appropriate elevation of cortisol concentration with respect to the IVC was achieved in all but one patient. This “failed” left adrenal venous catheterization occurred in the individual referred with recurrent hyperaldosteronism 10 years following previous left adrenalectomy performed at another center. AVS was performed to exclude functioning adrenal tissue on the left side, and this was confirmed by the baseline cortisol and aldosterone concentrations in the left adrenal vein sample.


  Discussion Top


Primary aldosteronism is a much more common cause of hypertension than previously recognized, and this has resulted in a significant increase in the number of patients referred for adrenal venous sampling.[3] Bilateral adrenal vein catheterization may be difficult, although success rates are high in tertiary referral centers when the procedures are performed by single operators.[7],[16] This is true of our own institution, where a single operator has achieved a 97% successful bilateral sampling rate over the past 8 years using the technique described in this article.

Less-experienced operators, however, may fail to catheterize the right adrenal vein in up to 50% of cases, and several techniques have been tried in an attempt to improve these results including intraprocedural CBCT, which has reported successful catheterization rates of 89–95%[16],[17],[18],[19] and intraprocedural cortisol assays with reported success rates of 81%–93%.[20],[21] The first of these is associated with an increased radiation dose, and both are costlier than the conventional catheterization technique described here. The median DAP during AVS in the study was 11.3 Gy.cm2, which is lower than previously published reports ranging between 32.5 Gy.cm2 and 72.2 Gy.cm2[8-11] including on some new generation angiography machines. Some of the differences may be, as some groups use CBCT to improve the success rate at the expense of an increased dose. Differences in operator experience are also likely to significantly affect radiation exposure during AVS.

Intraprocedural image fusion of prior CT data with live fluoroscopic images has been shown to aid right adrenal vein catheterization and to reduce both fluoroscopy time and radiation exposure.[10] The authors of this article have shown a relative reduction in their radiation use, but the technique is still associated with a significant radiation dose and a prolonged procedure time. It may be a useful technique to help inexperienced operators improve right adrenal vein catheterization during initial procedures. Regardless of the technique that is used, it is important that every effort is made to reduce radiation dose to both patient and operator during adrenal vein sampling, and our results demonstrate that a significant reduction has been achieved in our own practice since the installation of the Philips Azurion 7 M20 angiography platform while maintaining a 100% adrenal vein catheterization rate.

We chose AVS in order to compare radiation dose before and after installation of the new machine as the procedure has a well-defined endpoint with an objective measure of success, therefore reducing subjective confounders. Most other interventional radiology procedures have many other variables making a fair comparison of the two angiography platforms difficult. It is likely, however, that this radiation dose reduction translates to other X-ray-guided interventions. The Azurion 7 M20 includes hardware and software upgrades which allow real-time pixel shifting to correct for motion, as well as noise reduction by temporal and spacial pixel averaging.[12],[13] These changes, together with optimized protocols and a larger viewing screen, counterbalance the reduction in radiation dose and allow for maintained diagnostic image quality.[12],[22]

Some of the limitations of this article include the small sample size, but this is mitigated by controlling for confounders including gender and weight as well as all procedures being performed by a single operator. No real-time dosimetry measurements were taken, instead, the DAP and air kerma were obtained from the Allura and Azurion's internal dose reporting systems. As the measurement methods are similar, however, this allowed for a fair comparison. The retrospective nature of this study makes it difficult to account for all confounders; however, the study reflects clinical practice.

The installation of the Philips Azurion 7 M20 angiography machine has resulted in a fourfold reduction in DAP and a threefold reduction in air kerma during adrenal venous sampling. This reduction in radiation dose had no effect on the success rate of AVS and no effect on fluoroscopy time. This reduction in radiation dose to the patient will also significantly reduce radiation dose to the operator, which is particularly important in view of the recently introduced IRR17 radiation protection rules.

Financial support and sponsorship

Nil.

Conflicts of interest

The authors have no conflict of interest.

 
  References Top

1.
Savard S, Amar L, Plouin PF, Steichen O. Cardiovascular complications associated with primary aldosteronism: a controlled cross-sectional study. Hypertension 2013;62:331-6.  Back to cited text no. 1
    
2.
Catena C, Colussi G, Nadalini E, Chiuch A, Baroselli S, Lapenna R, et al. Cardiovascular outcomes in patients with primary aldosteronism after treatment. Arch Intern Med 2008;168:80-5.  Back to cited text no. 2
    
3.
Hannemann A, Wallaschofski H. Prevalence of primary aldosteronism in patient's cohorts and in population-based studies-a review of the current literature. Horm Metab Res 2012;44:157-62.  Back to cited text no. 3
    
4.
Conn JW, Cohen EL, Rovner DR, Nesbit RM. Normokalemic primary aldosteronism. A detectable cause of curable “essential” hypertension. JAMA 1965;193:200-6.  Back to cited text no. 4
    
5.
Funder JW, Carey RM, Mantero F, Murad MH, Reincke M, Shibata H, et al. The management of primary aldosteronism: Case detection, diagnosis, and treatment: An endocrine society clinical practice guideline. J Clin Endocrinol Metab 2016;101:1889-916.  Back to cited text no. 5
    
6.
Christakis I, Livesey JA, Sadler GP, Mihai R. Laparoscopic adrenalectomy for conn's syndrome is beneficial to patients and is cost effective in England. J Invest Surg 2018;31:300-6.  Back to cited text no. 6
    
7.
Jakobsson H, Farmaki K, Sakinis A, Ehn O, Johannsson G and Ragnarsson O, et al. Adrenal venous sampling: The learning curve of a single interventionalist with 282 consecutive procedures. Diagnostic Intervent Radiol (Ankara, Turkey) 2018;24:89-93.  Back to cited text no. 7
    
8.
Bundy JJ, Chick JF, Hage AN, Gemmete JJ, Srinivasa RN, Johnson EJ, et al. Contemporary interventional radiology dosimetry: Analysis of 4,784 discrete procedures at a single institution. J Am Coll Radiol 2018;15:1214-21.  Back to cited text no. 8
    
9.
Fuss CT, Treitl M, Rayes N, Podrabsky P, Fenske WK, Heinrich DA, et al. Radiation exposure of adrenal vein sampling: A German multicenter study. Eur J Endocrinol 2018;179:261-7.  Back to cited text no. 9
    
10.
Morita S, Yamazaki H, Endo K, Suzaki S, Mitsuhashi A, Shiohara T, et al. Image fusion guidance with pre-procedural CT with real-time fluoroscopy for adrenal venous sampling. Cardiovasc Intervent Radiol 2018;41:1214-22.  Back to cited text no. 10
    
11.
Page MM, Taranto M, Ramsay D, van Schie G, Glendenning P, Gillett MJ, et al. Improved technical success and radiation safety of adrenal vein sampling using rapid, semi-quantitative point-of-care cortisol measurement. Ann Clin Biochem 2018;55:588-92.  Back to cited text no. 11
    
12.
Studzińska E, Staniszewska MA. Impact of allura clarity technology on radiation dose exposure during left atrial appendage closure. Pol J Radiol 2017;82:598-602.  Back to cited text no. 12
    
13.
14.
Daunt N. Adrenal vein sampling: How to make it quick, easy, and successful. Radiographics 2005;25 Suppl 1:S143-58.  Back to cited text no. 14
    
15.
Doppman JL, Gill JR. Hyperaldosteronism: Sampling the adrenal veins. Radiology 1996;198:309-12.  Back to cited text no. 15
    
16.
Harvey A, Kline G, Pasieka JL. Adrenal venous sampling in primary hyperaldosteronism: Comparison of radiographic with biochemical success and the clinical decision-making with “less than ideal” testing. Surgery 2006;140:847-53.  Back to cited text no. 16
    
17.
Vonend O, Ockenfels N, Gao X, Allolio B, Lang K, Mai K, et al. Adrenal venous sampling: evaluation of the German Conn's registry. Hypertension 2011;57:990-5.  Back to cited text no. 17
    
18.
Chang CC, Lee BC, Liu KL, Chang YC, Wu VC, Huang KH. Non-stimulated adrenal venous sampling using Dyna computed tomography in patients with primary aldosteronism. Sci Rep 2016;6:37143.  Back to cited text no. 18
    
19.
Onozawa S, Murata S, Tajima H, Yamaguchi H, Mine T, Ishizaki A, et al. Evaluation of right adrenal vein cannulation by computed tomography angiography in 140 consecutive patients undergoing adrenal venous sampling. Eur J Endocrinol 2014;170:601-8.  Back to cited text no. 19
    
20.
Viste K, Grytaas MA, Jørstad MD, Jøssang DE, Høyden EN, Fotland SS, et al. Efficacy of adrenal venous sampling is increased by point of care cortisol analysis. Endocr Connect 2013;2:236-42.  Back to cited text no. 20
    
21.
Reardon MA, Angle JF, Abi-Jaoudeh N, Bruns DE, Haverstick DM, Matsumoto AH, et al. Intraprocedural cortisol levels in the evaluation of proper catheter placement in adrenal venous sampling. J Vasc Interv Radiol 2011;22:1575-80.  Back to cited text no. 21
    
22.
Schmidt M, Tesche C, Hapfelmeier A, Finsterer S, Valassis G, Ebersberger U, et al. Significant radiation dose reduction using a novel angiography platform in patients undergoing cryoballoon pulmonary vein isolation. J Thorac Imaging 2020;35:167-72.  Back to cited text no. 22
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed247    
    Printed19    
    Emailed0    
    PDF Downloaded30    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]