Can adrenal venous sampling be done for bilateral (B/L) adrenal masses in a patient with elevated cortisol levels and possible adrenal Cushing's syndrome?

Adrenal Venous Sampling for Bilateral Adrenal Masses in Cushing's Syndrome

Yes, adrenal venous sampling (AVS) is indicated and valuable for patients with bilateral adrenal masses and elevated cortisol levels suggesting adrenal Cushing's syndrome, as it can distinguish unilateral from bilateral cortisol production and guide appropriate surgical management. 1, 2

Rationale for AVS in Adrenal Cushing's with Bilateral Masses

AVS serves a critical role in these patients for several reasons:

• Distinguishes unilateral from bilateral cortisol production: When imaging shows bilateral adrenal masses, AVS can determine if cortisol excess is coming predominantly from one side or both sides 3
• Guides surgical approach: Helps determine whether unilateral or bilateral adrenalectomy is appropriate 4
• Prevents unnecessary bilateral adrenalectomy: May allow for unilateral adrenalectomy in select cases, avoiding lifelong steroid dependence 5

AVS Protocol for Cortisol Evaluation

The procedure for AVS in suspected adrenal Cushing's typically includes:

• Dexamethasone suppression: Performed during AVS to suppress any residual ACTH influence 5
• Sampling locations: Blood samples collected from both adrenal veins and a peripheral vein 6
• Measurements: Cortisol and epinephrine levels are measured (epinephrine confirms successful catheterization) 5
• Interpretation metrics:
  • Adrenal vein to peripheral vein cortisol ratio >6.5 suggests a cortisol-secreting adenoma 5
  • Cortisol lateralization ratio (dominant side/non-dominant side) >2.3 indicates unilateral disease with high specificity 6

Clinical Decision Making Based on AVS Results

Unilateral Dominant Cortisol Production

• AVS finding: Cortisol lateralization ratio >2.3 6
• Management: Unilateral adrenalectomy of the dominant side 3
• Expected outcome: Resolution of hypercortisolism with preservation of some adrenal function 3

Bilateral Cortisol Production

• AVS finding: Cortisol lateralization ratio <1.1 with elevated bilateral adrenal vein to peripheral vein cortisol ratios 6
• Management options:
  • Bilateral adrenalectomy (complete or subtotal) 5
  • Medical management with steroidogenesis inhibitors in poor surgical candidates 2

Important Considerations

• Surgical expertise: AVS is technically challenging and should be performed at centers with experience 1
• Post-surgical monitoring: Patients who undergo unilateral adrenalectomy require monitoring for adrenal insufficiency and potential recurrence 3
• Pathology correlation: Most bilateral cases represent ACTH-independent macronodular adrenal hyperplasia 7

Potential Pitfalls

• Technical failure: Successful bilateral adrenal vein catheterization can be challenging; epinephrine gradients confirm proper catheter placement 5
• Interpretation challenges: Overlap in cortisol values between unilateral and bilateral disease can occur 6
• Surgical decisions: Despite AVS results, adrenal mass size (>4 cm) may influence surgical decisions due to malignancy concerns 7

AVS has been shown to contribute to appropriate treatment decisions in patients with ACTH-independent hypercortisolism and bilateral adrenal lesions, potentially avoiding inappropriate bilateral adrenalectomy or chronic medical therapy with steroidogenesis inhibitors 3.