DETERMINATION OF URINARY N-ACETYL-BETA-GLUCOSAMINIDASE IN PATIENTS WITH HYPERTENSION AND RENAL-ARTERY STENOSIS

The purpose of the study was to measure the urinary excretion of N-ace tyl-beta-glucosaminidase (U-NAG) in patients suspected of having renov ascular hypertension and to compare the enzyme excretion before and af ter active intervention with operation or percutaneous transluminal re nal angioplasty (PTRA). Eighty-one patients with severe, therapy-resis tant hypertension were examined with regard to renal artery stenosis ( RAS). At least one significant renal artery stenosis was found in 61 p atients, whilst the remaining 20 patients were classified as having es sential hypertension. Enzyme levels were found to be significantly hig her in RAS patients as compared with patients with severe hypertension lacking significant renal artery stenosis, 0. 66 (0.41-0.9 1, median value, lst and 3rd quartiles) versus 0.35 (0.27-0.54), P < 0.01. Both groups of patients had significantly higher U-NAG values than a health y reference population (0.2, 0.13-0.27; P < 0.01). Forty of the RAS pa tients were randomized to surgery or PTRA and followed prospectively f or 2 years. After either renal vascular surgery or PTRA a significant rise in U-NAG excretion was observed 7-10 days after treatment. Urinar y NAG excretion remained elevated during long-term follow-up. It is su ggested that U-NAG should be determined in patients with therapy-resis tant hypertension with suspicion of renal artery stenosis.