7132 Delayed Clinical Response To Unilateral Adrenalectomy In A Patient With Inconsistent Non-clearly Lateralized Primary Aldosteronism

Abstract Disclosure: S. Beland: None. M. St-Jean: None. Unilateral adrenalectomy (UA) is the preferred treatment for patients with lateralized primary aldosteronism (PA). While treatment with mineralocorticoid receptor antagonists is preferred for non-lateralized PA, evidence suggests that UA may be associated with clinical and biochemical responses in some patients. We present the case of a 53-year-old woman with resistant hypertension who was referred to our clinic in September 2022 for the management of PA. Her medical history included non-ischemic cardiomyopathy, dyslipidemia, and transient ischemic attack. At referral, antihypertensives included telmisartan, indapamide, and amlodipine. Her aldosterone renin ratio was 138 pmol*L/ng*L, and an oral salt loading suppression test showed a 24h urinary aldosterone of 32 pmol/day. An abdominal CT scan did not show any adrenal nodule. Adrenal vein sampling was conducted, and two different basal Lateralization Ratio (LR) were obtained despite similar cortisol levels. Basal LR at -5 min was 12 but dropped to 1.3 at 0 min. The LR following 250 mcg of IV cosyntropin was around 1. Contralateral suppression (Aopp/Ap) was 6.5. Due to the inconsistent basal LRs and the non-suppressed contralateral suppression, non-lateralized PA was considered, and spironolactone was prescribed. By August 2023, despite optimizing her medication consisting of 6 antihypertensive drugs and achieving plasma renin values of 54 ng/L, the patient’s blood pressures remained above 140/90 mmHg. Considering the patient’s resistant hypertension and known cardiomyopathy, we decided to proceed with UA, which was performed in October 2023. In the immediate post-op period, spironolactone dosage was decreased by 50%, and terazosin was discontinued. Surprisingly, plasma aldosterone on post-op day 1 was <70pmol/L. Nevertheless, two weeks following surgery, the patient’s blood pressure remained around 150/100 mmHg. Shortly after the two-week follow-up, the patient presented with new onset stuttering, paresthesia, and hypotension with systolic reaching 60 mmHg. Brain MRI and CT scans showed no evidence of stroke, suggesting that her symptoms could be attributed to cerebral hypoperfusion secondary to changes in blood pressure. Her antihypertensive regimen was reviewed accordingly, and close clinical follow-ups were conducted. As of November 2023, the patient’s blood pressure has remained under 120/80, and all antihypertensive medications, except bisoprolol, were discontinued. Notably, one-month post-UA, plasma aldosterone and renin levels were 160 and 185 pmol/L, respectively. This case thus supports the potential benefit of UA in some patients with non-clearly lateralized PA, especially those resistant to treatment, and emphasizes the need to conduct close post-op monitoring. Finally, this case also highlights the need to obtain both basal and post-ACTH values during AVS. Presentation: 6/1/2024