Diagnostic uses of angiotensin-converting enzyme inhibitors in renovascular hypertension.

The response to angiotensin-converting enzyme inhibitors (ACEIs) can be of considerable help in the diagnosis of human renovascular hypertension (RVH) in three settings. First, a particularly dramatic antihypertensive response or a decline in glomerular filtration rate (GFR), as indexed by a rise in serum creatinine or blood urea nitrogen concentrations, are useful clues to the presence of renovascular hypertension. Second, an exaggerated rise in plasma renin activity (PRA) after short-term captopril administration is a very promising screening test for this condition. Third, ACEI-induced changes in single-kidney hemodynamics (assessed by renography) may be helpful in confirming the diagnosis and offers the prospect of localizing the ischemic kidney.