Captopril-stimulated renal vein renin measurements in the diagnosis of atherosclerotic renovascular hypertension.

The diagnostic utility of post-captopril renal vein renin (RVR) measurements was quantitated in 43 patients (mean age 62, range 41 to 77 years) undergoing aortography to rule out renovascular hypertension (RVHT), and then compared with that of pre-captopril RVR measurements. Four patterns of post-captopril RVR secretion were defined: 1) unilateral hypersecretion (stenotic/peripheral [S/P] > 2.0) and contralateral suppression (C/P) (< 1.25) (n = 12); 2) bilateral hypersecretion (S/P > 2.0, C/P > 1.25) (n = 14); 3) bilateral suppression (peripheral plasma renin activity [PRA] < 1.0 ng/mL/h) (n = 12); and 4) "normal" (RVR/PRA < 2.0 bilaterally) (n = 5). Using the radiologic findings as the definitive test, the sensitivity and specificity of post-captopril RVR measurements in detecting unilateral or bilateral renal artery stenoses (85% or greater of lumen) was 61 and 96%, and 92 and 90%, respectively, a significant improvement compared with those of pre-captopril RVR measurements (44 and 62%, and 17 and 93%, respectively). Post-captopril RVR measurements facilitated the diagnosis of both hypersecretion and, when present, contralateral suppression of renin, and therefore, are useful in the diagnosis of atherosclerotic RVHT, and in planning its treatment. However, confirmation by more extensive prospective studies, including treatment outcome, is needed.