New tools in diagnosing renal artery stenosis

Abstract

and furosemide in various combinations. The patient was referred for surgical treatment. However, before the surgery could be performed, the patient had an episode of fever and right lumbar pain associated with a rise in the serum creatinine to 160 to 190 mmol/L (1.8 to 2.2 mg/dL). Renography demonstrated a decrease in function of the right kidney. A second renal angiogram showed an occlusion of the right renal artery (not amenable to percutaneous transluminal angioplasty) and an unchanged stenosis on the left (Fig. 1B). Plasma renin activity was 25.4 ng/h/mL in the right renal vein, 5.9 ng/h/mL in the left vein, and 5.2 ng/hr/mL in the vena cava. His blood pressure was reduced to 160/85–100 mm Hg by treatment with metoprolol, pinacidil, furosemide, and spironolactone. In addition, the patient received acetylsalicylic acid, 150 mg daily. Nephrectomy of the right kidney was performed, and a saphenous vein bypass graft was constructed CASE PRESENTATION between the aorta and the left renal artery distal to the stenosis. A 58-year-old man had a routine health examination at his Postoperatively, his blood pressure was 130–150/90–95 mm Hg general practitioner’s office. The blood pressure was 220/150 without antihypertensive therapy; the serum creatinine fell to mm Hg. His blood pressure had been normal at a similar 110 to 120 mmol/L (|1.3 mg/dL). examination three years previously. Fifteen months later, the patient’s diastolic blood pressure The patient was referred to hospital. Evaluation revealed: rose to a level of 120 to 130 mm Hg despite resumption of grade-3 hypertensive changes in the retina; a cardiothoracic antihypertensive treatment. Abdominal angiography showed ratio of 18/36 on chest x-ray; left-ventricular hypertrophy on occlusion of the saphenous vein bypass graft and progression the electrocardiogram; slight dilation and hypertrophy of the of the stenosis of the left renal artery (Fig. 1C). Surgery was left ventricle on echocardiography; serum creatinine, 100 to attempted to construct a spleno-renal anastomosis, but the 130 mmol/L (1.1 to 1.5 mg/dL); serum potassium, 2.7 mmol/L; blood flow in the anastomosis intraoperatively was low due to urine protein excretion of 1.0 to 1.5 g/L; and normal microscopy atherosclerosis of the splenic artery. Therefore, reconstruction of the urine. Renography showed that the right kidney’s funcof the left renal artery was done using synthetic materials. tion was 25% of the total renal function, both with and without Postoperatively, his blood pressure was 135/90 mm Hg, serum furosemide and without antihypertensive therapy. Renal vein creatinine was 120 to 130 mmol/L (|1.4 mg/dL), and treatment catheterization was performed for determination of renin conconsisted of metoprolol, bendroflumethiazide, and acetylsalicentration; plasma renin concentration was 260 mIU/L in the cylic acid. right renal vein, 62 mIU/L in the left renal vein, and 96 mIU/L Two years later, the patient’s course was complicated by a in the arterial plasma. Conventional renal angiography showed cerebrovascular insult, with aphasia and hemiparesis on the atherosclerosis of the aorta, bilateral renal artery stenosis, and right side due to an infarction in the left cerebral hemisphere. a small right kidney. On the left side, the stenosis was 7 mm Rehabilitation was partly successful, but some neurologic defilong; it started 7 mm after the ostium, and the diameter of the cits remained. He regained his ability to walk but required a arterial lumen was reduced to 4 mm. On the right side, a very cane. He also recovered the power of speech with very little severe stenosis was demonstrated at the ostium (Fig. 1A). dysarthria. Blood pressure was difficult to control despite treatment On follow-up five years later, a 24-hour blood pressure meawith a calcium channel blocker, a b-adrenoreceptor blocker, an surement was performed. The average 24-hour level was 130/88 a-adrenoreceptor blocker, alphamethyldopa, spironolactone, mm Hg, the daytime level was 135/91 mm Hg, and the nighttime level was 120/78 mm Hg. The antihypertensive therapy consisted of a calcium channel blocker and a thiazide. The Nephrology Forum is funded in part by grants from Amgen, Incorporated; AstraZeneca LP; Merck & Co., Incorporated; Dialysis Clinic, Incorporated; and R & D Laboratories. DISCUSSION