“Relieving the Pressure” With Unilateral Adrenalectomy in a Case of Chronic Resistant Hypertension From Primary Aldosteronism

Abstract

Introduction: Primary aldosteronism is an under-recognized cause of resistant hypertension that is associated with an increased risk of cardiovascular disease and mortality. While surgical intervention may not lead to complete resolution of hypertension, partial success (defined by reduction in blood pressure and/or medications) can be achieved and future cardiovascular risks can be minimized. We present a case of a patient with primary aldosteronism whose chronic resistant hypertension improved significantly after unilateral adrenalectomy. Clinical Case: A 54-year-old female with resistant hypertension for 17 years and hypokalemia was diagnosed with primary aldosteronism. The patient had uncontrolled hypertension despite atenolol 50 mg, nifedipine XL 60 mg, triamterene-hydrochlorothiazide 37.5-25 mg, lisinopril 40 mg daily.Laboratory evaluation was significant for plasma aldosterone concentration (PAC) 26.8 ng/dL (reference: 0.0–30.0 ng/dL), plasma renin activity (PRA) 0.168 ng/mL/hr (reference: 0.167–5.380 ng/mL/hr), PAC/PRA ratio 159.5, and potassium of 3.2 mmol/L (reference: 3.5–4.5mmol/L). Other workup showed plasma normetanephrines 128 pg/mL (reference: 0–145 pg/mL), metanephrines 25 pg/mL (reference: 0–62 pg/mL), and two normal midnight salivary cortisol tests. Saline infusion testing confirmed primary aldosteronism with a non-suppressed aldosterone level of 15.6 ng/dL (normal <5 ng/dL). Abdominal imaging revealed two low-density right adrenal nodules consistent with adenomas and thickening of the left adrenal gland. The patient underwent adrenal vein sampling (AVS) with cosyntropin stimulation, which showed lateralization to the right adrenal. Despite adding clonidine 0.1 mg three times daily, hydralazine 25 mg three times daily and spironolactone 100 mg daily (which substituted triamterene-hydrochlorothiazide) after AVS, her blood pressure remained uncontrolled with blood pressure ranging from 150–180/90–110 mmHg. A laparoscopic right adrenalectomy was performed. Pathology revealed two adrenal cortical adenomas. At the one-month post-operative visit, her potassium was normal, PAC was 4.3 ng/dL, and blood pressure improved on a reduced regimen of atenolol, lisinopril, and nifedipine. Conclusion: In patients with chronic uncontrolled hypertension due to primary aldosteronism, surgical intervention may not lead to complete resolution of hypertension but may lead to partial clinical success. Residual hypertension may be due to underlying vascular changes associated with long-term exposure to elevated aldosterone. The post-operative PAC in our case was less than 5 ng/dL suggesting biochemical cure and potentially reduced cardiovascular risk. This case emphasizes that adrenalectomy should be considered in resistant hypertension, even if complete clinical cure may not be attainable to reduce future cardiovascular events.