Captopril renal scintigraphy: a new standard for predicting outcome after renal revascularization

Captopril renal scintigraphy (CRS) is a nuclear medicine technique for evaluating each kidney independently for changes in glomerular filtration rate and perfusion induced by captopril-associated alterations in vascular tone. This study was undertaken to determine the role of CRS in predicting the response to renal revascularization.

The study group consisted of all patients who underwent preintervention CRS and arteriography, followed by renal revascularization performed between December 1987 and February 1992. After cessation of administration of angiotensin-converting enzyme inhibitors for 48 hours, a standard renogram was obtained, a 50 mg dose of captopril was given, and a second renogram was obtained. A captopril-induced change in the renogram was present when a normal pre-captopril renogram became abnormal after captopril administration. An abnormal baseline scan by definition cannot have a captopril-induced change. Blood pressure before revascularization was compared with blood pressure at 3 to 6 months after the procedure according to American Heart Association criteria for hypertension response.

Fifty patients received renal revascularization by operation (28 patients) or balloon angioplasty (22 patients). Preoperative captopril-induced changes were present in 29 of the 50 patients. Among the 29 patients with captopril-induced changes, hypertension was cured or improved in 26. When captopril-induced changes were not present, only one of 21 patients improved (p < 0.00001).

On the basis of these data, CRS appears to reliably predict hypertension response to revascularization in patients with renovascular disease.