Renal Artery Aneurysm Due to Fenestration of a Branch of the Renal Artery: A Case Study.

Artery fenestration is a congenital vascular malformation, often of the intracranial arteries, that causes an aneurysm. However, there have been no reports of artery fenestration causing renal aneurysm. We present the case of a 58-year-old man who developed renin-dependent hypertension. He was aware of heaviness of the head, and his blood pressure was 196/134 mm Hg on 5 mg of amlodipine. Laboratory tests showed hypokalemia, hyperreninemia, and hyperaldosteronemia. An enhanced 3-dimensional computed tomography scan showed a 19-mm renal aneurysm in a branch of the left renal artery, and renal arteriography showed a fenestration in the aneurysm-forming branch. Coil embolization was performed on the central side of the artery forming the aneurysm and fenestration, after which blood pressure, serum potassium, and plasma renin levels improved. The patient in the present case had renin-dependent hypertension as a result of decreased renal blood flow caused by the renal aneurysm and fenestration, which is considered an extremely rare etiology of hypertension.