RENAL-ARTERY STENOSIS TOWARDS THE YEAR-2000

Functional diagnostic tests for selecting patients for renal arteriogr aphy The functional diagnostic tests now available to select patients for renal arteriography, such as captopril-renal scintigraphy and the captopril-peripheral vein renin test, have a high degree of diagnostic accuracy, 70% sensitivity at 90% specificity, but they are still not good enough to assess the large population of hypertensives for renal artery stenosis. The use of the angiotensin converting enzyme (ACE) in hibitor challenge and the introduction of a new pharmacon, technetium- labelled mercapto-triglycine, have not sufficiently increased the valu e of scintigraphy and further improvement in the near future seems unl ikely. The use of clinical criteria to identify high-risk patients A m ore realistic approach to the diagnosis of renal artery stenosis is to seek simple and sensible clinical criteria to identify high-risk pati ents. The blood pressure response to 2 months of treatment with a stan dardized two-drug regimen is a suitable criterion. Interim analysis of an ongoing prospective multicentre study in the Netherlands indicates that the prevalence of renal artery stenosis is as high as 25% in pat ients who are resistant to the combination of 10 mg amlodipine + 50 mg atenolol, compared with 15% in patients resistant to the combination of 20 mg enalapril + 25 mg hydrochlorothiazide. When drug resistance i s used as the selection criterion for arteriography, the total number of cases detected with intra-arterial digital subtraction angiography does not seem to differ according to which of these drug regimens is u sed. Future possibilities The current enthusiasm for percutaneous tran sluminal renal angioplasty (PTRA) and stenting may be premature. With further improvement of non-invasive techniques to visualize the renal arteries, such as colour Doppler ultrasound with microparticle contras t enhancement or magnetic resonance angiography, it should become more attractive to follow patients with renal artery stenosis while they a re being treated with drugs rather than automatically resorting to PTR A.