Adrenal Vein Sampling

Patient Information

Video:

SIR Procedure Category

Venous Intervention – Medium Risk.

Indications

Biochemically proven Primary aldosteronism (Conn’s syndrome) patients pursuing surgical management to localize the source of aldosterone excess.

Contraindications

1. Patient prefers lifelong medical treatment.
2. Young patients (e.g. patient less than 40 years with recent-onset primary aldosteronism and clear-cut unilateral cortical adenoma on imaging)
3. Proven familial hyperaldosteronism type I or III.
4. Poor surgical candidate for adrenalectomy.
5. Adrenocortical Carcinoma.
6. Patient accepts a 20-50% chance of having the wrong adrenal removed.

Preprocedure Order Set

1. Anticoagulation and Antiplatelet Medications – Medium risk procedure order set. Link: http://radiologyreviewarticles.com/ir-2/anticoagulation-antiplatelet-medications-medium-risk-procedures/
2. If cosyntropin is not used, the procedure should be scheduled in the morning to avoid false-negative results attributable to diurnal fluctuation in the adrenocorticotropic hormone.
3. Outpatient procedure.
4. If possible, allow for the patient to be kept in the supine position for 1 hour before the procedure.
5. For hypertension control, peripheral α1-adrenergic receptor blockers (eg, doxazosin mesylate, prazosin hydrochloride, and terazosin hydrochloride) and the long-acting dihydropyridine or nondihydropyridine calcium-channel blockers (verapamil) are recommended because these agents negligibly affect renin secretion.
6. Correct hypokalemia.
7. Avoid Mineralocorticoid receptor antagonists (spironolactone, eplerenone) for at least 2 weeks if possible.
8. Avoid amiloride for at least 2 weeks if possible.
9. If amiloride or MR antagonist cannot be avoided, use plasma renin measurement. Direct renin 10. Cosyntropin (Cortrosyn) IV can be used – Controversial. Dose: Continuous cosyntropin infusion (50 µg/h started 30 minutes before sampling) or a bolus (250 µg) during the venous sampling.

Preprocedure Imaging

Contrast-enhanced CT can be helpful to identify the right adrenal vein anatomy.

Relevant Anatomy

Right Adrenal Vein – Normally there is a central vein that drains directly at the mid-posterior wall of the inferior vena cava. The central vein may be duplicated with some veins draining to the inferior phrenic or right renal vein. However, there is almost always a central vein entering the IVC. It is 1 -15 mm in length and averages 3.5 – 5 mm in diameter. These are some of the patterns helpful to recognize the right adrenal vein
1. Gland-like pattern with main central stem and numerous branches.
2. Delta pattern with a little filling of the internal structure.
3. Triangular pattern with blush-like appearance.
4. Central vein with thin stellate or spidery branches.
5. Presence of superficial or emissary veins from the adrenal capsule. It provides high confidence of confirmation. The emissary vein may communicate with the right renal vein, intercostal vein, phrenic vein, or IVC. The inferior emissary vein serves as a reliable landmark for the right adrenal vein

The veins should not communicate with the hepatic vein.

Sometimes, it may not have any of the above patterns. Cone beam CT can be helpful to confirm the location.

Left Adrenal Vein – It drains into the left renal vein and most of the time have a common trunk with the inferior phrenic vein. It is 1 – 4 cm in length and averages 4-5 mm in diameter. CT can be helpful to look for any variation of left renal vein-like retroaortic/circumaortic renal vein.

Sedation

Conscious sedation with Versed (Midazolam) and Fentanyl.

Procedure Steps

1. Universal protocol.
2. 6 French sheath in Right common femoral vein (right internal jugular access if pre-procedure CT favors IJV access)
3. Catheter choice: Cobra, Mikaelsson, SIM 1 based on comfort level or pre-procedure CT findings. Make a side hole as close to the tip of the catheter as possible. VAN catheter has additional perforation near the catheter tip and can be also be used.
4. Select the right adrenal vein. Confirm by gentle contrast injection. Use less than 3 ml. Don’t inject too hard. Avoid going too deeply in the adrenal vein – may lead to a false-negative result.
5. Cone-beam CT can be performed to confirm the location in difficult cases.
6. Obtain about 10 ml from the adrenal vein. Avoid forceful aspiration.
7. Obtain a sample from the peripheral vein. Some authors take the sample from the inferior vena cava or contralateral femoral vein.
8. If in doubt, send the sample to calculate the selective index (SI = Cortisol in adrenal vein/Cortisol in the peripheral vein). SI ≥2.0 under unstimulated conditions or ≥3.0 during cosyntropin stimulation is considered adequate. It takes 20 – 30 minutes to get the initial results.
9. If in doubt, increase the number of veins sampled and sample anything which looks like the adrenal vein. Label all the samples correctly to avoid confusion.
10. Select the left adrenal vein. It drains into the left renal vein. Simmons 2 or cobra catheter can be used. Obtain about 10 ml from the adrenal vein and 10 ml from the peripheral vein. Ideally, the left adrenal vein should be catheterized with 15 minutes of obtaining the right adrenal vein sample. Some authors favor two access and obtaining both adrenal vein samples simultaneously.
11. Remove the catheter and sheath. Apply manual pressure at the venotomy site till hemostasis is obtained.

Helpful tips

1. If the reverse catheter is selected, pull down from upper IVC to select accessory hepatic vein or adrenal vein if possible. If the vein is not selected, then repeat the step after turning the catheter about 30 degrees counter-clockwise to select the vein.
2. If the accessory hepatic vein is cannulated, rotate the catheter about 30 to 60 degree counter-clockwise and pull down gently. The right adrenal vein is generally within 5mm.
3. Gentle injection to avoid vein injury.
4. Look for slow flow and not a free flow of the sample.
5. If needed use 018 wire after placing a Tuohy-Borst on the back of the catheter.
6. Microcatheter to access the vein more peripherally can be used.
7. Hang the catheter hub over the side of the patient to as low as possible to improve aspiration.
8. If poor outflow, intermittent aspiration using a 10 mL syringe with some air can be helpful.

Interpretation of Results

Selectivity Index (SI): Ratio of the adrenal venous cortisol concentration to the peripheral cortisol concentration on each side. SI ≥2.0 under unstimulated conditions or ≥3.0 during cosyntropin stimulation confirms that the blood sample was obtained from the adrenal vein.

Lateralization index (LI): Aldosterone/Cortisol ratio on the dominant side divided by the Aldosterone/Cortisol ratio on the contralateral side. A LI greater than (or equal to) 4 indicates lateralization of aldosterone secretion.

If the right adrenal vein cannot be calculated, the Aldosterone/Cortisol ratio of the Left adrenal vein divided by the Aldosterone/Cortisol ratio of IVC can be used. Value >= 5.5 suggests that the left adrenal gland is the dominant side, and value =< 0.5 suggests the right adrenal gland is the dominant side (Reference: https://pubmed.ncbi.nlm.nih.gov/26435431/)

Contralateral Suppression Index: Adrenal venous Aldosterone/Cortisol ratio of the non-affected side divided by the peripheral venous Aldosterone/Cortisol ratio. Value < 1 on the side without any adrenal nodule indicates ipsilateral suppression and contralateral aldosterone overproduction. On the right side, the adrenal vein commonly shares egress in the IVC with accessory hepatic veins, which can generate artificial aldosterone suppression.

Calculated Right Adrenal Vein Aldosterone Levels Technique
Dilution Effect = Cortisol(Left adrenal vein) ÷ Cortisol(IVC)
Aldosterone(IVC) = 0.5 x (Aldosterone(Left Adrenal vein) + Aldosterone(Right Adrenal Vein)) ÷ Dilution Effect
Calculated Right Adrenal Vein Aldosterone Levels = [2 X Aldosterone(IVC) x (Cortisol(Left adrenal vein) ÷ Cortisol(IVC)] – Aldosterone(Left Adrenal vein)

Aldosterone(Left Adrenal Vein): Calculated Right Adrenal Vein Aldosterone
> 3: The Left Adrenal Gland is the dominant side
0.33 – 3: Bilateral disease
< 0.33: The right adrenal gland is the dominant side.
(Reference: https://pubmed.ncbi.nlm.nih.gov/39097226/)

Complications

1. Adrenal vein rupture and Hemorrhage. It usually resolves with conservative treatment and does not carry any sequelae. It can make subsequent adrenalectomy difficult due to adhesions.
2. Adrenal Vein Thrombosis and perforation.
3. Hypertensive crisis.
4. Adrenal insufficiency.

Post Procedure Patient Instructions

In order to perform a Venogram, the doctor has made a puncture in your skin. It is normal to have a little soreness or tenderness at the procedure site; this should gradually lessen each day.

1. ACTIVITY
• Rest and relax upon returning home.
• Do not take a shower for 24 hours.
• If you received sedation, do not drive or operate equipment for 24 hours.

2. RESTRICTIONS
• Resting for 72 hours will help prevent undue stress on the procedure site.
• Do not lift anything heavier than 10 pounds for 3 days.
• If you puncture site is in the groin, support you groin site with your hand when you
climb stairs or change positions.
• You may shower, but no tub baths for 5 days after the procedure.
• You may resume driving when your physician gives approval.

3. IF PROCEDURE SITE BLEEDS:
• You need to have someone stay with you for the first 24 hours because there is a small chance of bleeding.
• If bleeding occurs: apply pressure for 5 minutes with a clean towel and caregiver’s hand, uninterrupted.
• If bleeding does not stop: apply pressure again, call 911 and continue to hold pressure on site.
• If bleeding more than slow ooze, call 911 and continue to hold pressure on site.

4. MEDICATIONS
• Anticoagulants and Antiplatelet Medications – Restart based on this calculator Link:
• Discuss with your primary about restarting antihypertensives

Adrenal Vein Sampling