Endocrine Abstracts

A 65-year-old Afro-Caribbean gentleman, with a >10-year history of hypertension, frequently recorded blood pressures of >160/80 mmHg. His serum electrolytes showed Na⁺ 145 mmol/l and K⁺ 3.2 mmol/l. MRI demonstrated 13 mm left medial-limb adrenal adenoma. His hypertension was uncontrolled on treatment with amlodipine 10 mg OD, spironolactone 50 mg OD, losartan100 mg OD and doxazosin 16 mg OD. Although his quality of life was reduced, and he disliked the polypharmacy, he did not wish to undergo invasive investigations and surgery to pursue potential cure. The diagnosis of primary aldosteronism (PA) was confirmed off interfering medicines: aldosterone 661 pmol/l, renin activity <3.3 pmol/l per min, ARR >200 (PA likely if >60). ¹¹C-metomidate PET CT scan demonstrated a 15 mm left adrenal nodule with high uptake; SUV time of flight (TOF) 30.4, SUVmax ratio, left to right, 1.92 (normal <1.25). He was enrolled into FABULAS (Feasibility study of endoscopic radiofrequency ABlation, with ULtrasound guidance, as a non-surgical, adrenal sparing treatment for aldosterone-producing adenomas), a prospective safety and efficacy evaluation of 30 patients with unilateral left-sided aldosterone-producing adenomas (APA). Under ultrasound guidance, a Starmed catheter was passed, through a 19-guage needle in the stomach wall, into the APA. During the procedure, undertaken under GA, blood pressure was monitored and biochemical assessments of adrenomedullary activation were made. There were no adverse events. 48 h after ablation, a study-protocol CT scan demonstrated regional fat stranding, consistent with intervention, and no evidence of complications. At six-months post-ablation the patient felt well and reported significant improvement in his quality of life. His blood pressure (average of 12 home readings over 3 days) had decreased, from 161/81 mmHg to 123/79 mmHg, off all antihypertensive medications. He was cured biochemically: Na⁺ 140 mmol/l, K⁺ 4.7 mmol/l, aldosterone 209 pmol/l, renin activity 13.3 pmmol/l per min, ARR 17.2. Repeat ¹¹C-metomidate PET CT scan demonstrated minimal left adrenal nodule uptake; SUV TOF 4.6, SUVmax ratio, left to right, 1.04 (normal <1.25). This patient case illustrates how minimally invasive ablation of a left adrenal APA, delivered by an ultrasound-guided endoscopic route, can achieve biochemical and clinical cure in a patient unwilling to have adrenalectomy. Fewer than 1% of patients with PA are currently diagnosed and, of those proceeding to adrenalectomy, fewer than 50% are completely cured of hypertension. As the frequency of PA diagnosis increases, ablation has the potential to increase capacity for intervention, by minimising morbidity and time off work.