SELECTION OF PATIENTS FOR RENAL-ARTERY REPAIR USING CAPTOPRIL TESTING

BACKGROUND: Prediction of improvement following surgical or radiologic intervention in patients thought to have renovascular hypertension (R VH) is often unreliable. Use of the angiotensin-converting enzyme inhi bitor captopril in conjunction with measurement of peripheral renin le vels or radioisotope renograms is thought to detect patients with func tionally significant renal artery stenosis, However, it is unclear whe ther these tests can identify patients whose hypertension will signifi cantly improve after renal artery repair. PATIENTS AND METHODS: The re cords of 52 consecutive hypertensive patients undergoing captopril stu dies followed by renal artery repair were reviewed, All patients had e ither renal artery stenosis >75% or venal artery occlusion, Preprocedu re evaluation included a captopril challenge test (measurement of peri pheral renin levels after captopril ingestion) (n = 12) or a captopril renogram (determination of renal blood flow and glomerular filtration rate before and after captopril administration) (n = 40), Either rena l artery bypass/nephrectomy (n = 41) or balloon angioplasty (n = 11) w as done in all patients (18 bilateral/34 unilateral). No periprocedura l deaths occurred. All surgically placed bypass grafts were shown to h e patent by contrast or carbon dioxide arteriography before hospital d ischarge. RESULTS: Preprocedure captopril tests were positive (suggest ive of RVH) in 39 patients (75%) and negative in 13 (25%). All patient s with positive captopril tests had improvement in their RVH after int ervention (17 cured, 22 improved) while 8 of 13 patients with negative captopril tests had no improvement in blood pressure control. Four of five false-negative tests were associated with a unilateral total ren al artery occlusion, making detection of a postcaptopril effect imposs ible. If these 4 patients are excluded from analysis, preprocedure cap topril testing was 98% accurate in predicting postprocedure outcome. C ONCLUSIONS: Preprocedure captopril testing permits extremely accurate selection of patients with renal artery stenosis who will benefit from venal artery repair.