More Than an Accessory: Renal Artery Stenosis in a Second Renal Artery Driving Uncontrolled Hypertension

Introduction: Renovascular hypertension may result from renal artery stenosis (RAS), because significant compromise in renal blood flow results in excessive renin release and drives renin-angiotensin system (RAAS) activation from the affected kidney. This may not be expected from a stenosed accessory artery, which would supply only a limited portion of the kidney. However, an uncommon anatomic variant with two ipsilateral renal arteries originating from the aorta does exist. We hereby present a case of uncontrolled renovascular hypertension emanating from RAS of one of two such renal arteries, initially confused for an accessory artery. Case Description: A 51 year-old male presented to nephrology clinic with recently uncontrolled hypertension. Previously controlled on lisinopril and hydrochlorothiazide, blood pressure was now uncontrolled on five blood pressure agents of different classes. Secondary workup was pursued showing a direct renin concentration of 1,704 pg/mL (plasma renin activity of 324 ng/mL/h). A renal Doppler study described an “accessory” renal artery having 60-99% stenosis whereas the “main” left and right renal arteries showed 0-59% stenosis. Given renin elevation and worsening hypertension, a contrast enhanced CT scan was done showing two left renal arteries of similar caliber originating from the aorta with one having severe proximal stenosis. Angioplasty with stenting was done following which serial renal Dopplers confirmed resolution of stenosis up to two years later. On the most recent follow up, his blood pressure remained controlled on lisinopril-HCTZ 20-12.5mg daily alone. Discussion: This case describes an unusual scenario where one of two ipsilateral renal arteries of similar size had severe stenosis, leading to renovascular hypertension. The initial Doppler study might have been misleading pointing to a potentially insignificant, albeit stenotic, accessory renal artery. The severely high renin activity levels was the main clue that prompted further evaluation of this ultrasound finding ultimately leading to stenting which proved impactful on his hypertension management. In investigating renovascular hypertension, one should utilize renin levels and consider unusual anatomy when a stenosed accessory renal artery is described.