Case Author(s): Thomas H. Vreeland, M.D., Tom R. Miller, M.D., Ph.D., Jerold W. Wallis, M.D., Henry D. Royal, M.D. , 7/21/94 . Rating: #D2, #Q5

Diagnosis: Renal Artery Stenosis

Brief history:

This is a 60 year-old man with hypertension undergoing evaluation for renal artery stenosis.

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Full history/Diagnosis is available below

Diagnosis: Renal Artery Stenosis

Full history:

This is a 60 year-old physician otherwise in good health who experienced sudden onset of hypertension.

Findings:

For the first study the patient was given 2.5 mg enalapril intravenously over a five minute period followed by administration of Tc-99m MAG3. There is marked asymmetry in function, with normal uptake and excretion by the right kidney (on the viewer's right), but significant retention of radiopharmaceutical by the left kidney with little or no excretion. Based on initial uptake of tracer, relative split function was equal, with 49% on the right and 51% on the left. The second study, performed without administration of enalapril, shows dramatically improved left renal function. Uptake and excretion are only minimally delayed on the left.

Discussion:

Renal scintigraphy with angiotensin converting enzyme inhibitors is a sensitive and specific way to screen patients with suspected renovascular hypertension. Either the rapid-onset intravenous ACE inhibitor enalapril, or the slower-acting oral captopril agent may be used. Enalapril is probably preferable because of its faster and more reproducible effect. If the initial study performed with the ACE inhibitor is normal, some practicioners will not do the baseline study. If the initial study is abnormal, as in the present case, it is essential that the baseline examination be performed to evaluate the possibility of unilateral, non-renovascular renal disease.

Followup:

After the renal scinitgraphy an arteriogram was performed showing a high-grade left renal artery lesion just distal to the ostium with only minimal disease on the right. The left renal artery lesion was treated by balloon angioplasty with only a minimal residual stenosis. The blood pressure promptly returned to a level close to normal.

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Major teaching point(s):

Renal scintigraphy with angiotensin converting enzyme inhibitors is an accurate non-invasive way to screen patients for renovascualr hypertension.

ACR Codes and Keywords:

References and General Discussion of Renal Scintigraphy (Anatomic field:Genitourinary System, Category:Organ specific)

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Case number: rs001

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