NITRIC-OXIDE AND BLOOD-PRESSURE IN NORMOTENSIVE PATIENTS ON CHRONIC-HEMODIALYSIS

Blood pressure regulation during intermittent hemodialysis treatment i s only partially understood. The aim of this study was to investigate nitric oxide (NO) regulation and blood pressure (BP) in normotensive p atients on stable chronic hemodialysis (HD). Thirteen patients (mean a ge = 67 years) on thrice-weekly chronic HD were investigated. The mean Kt/V was 1.14. All patients were treated with erythropoietin. The mea n Hb level was 107 g/L, and the mean serum albumin level was 39.5 g/L. L-arginine, L-citrulline, asymmetric dimethlyarginine (ADMA), cyclic guanosine monophosphate (cGMP), and serum nitrate were measured 24 hou rs before, at the start, and at the end of HD. Ambulatory blood pressu re was measured for the 24 hours preceding the start of HD. All patien ts showed normal circadian rhythm. A significant decrease in systolic BP and ii? body weight during dialysis was seen. ADMA decreased 34%, c orrected for ultrafiltration, The L-arginine/L-citrulline ratio increa sed (p = 0.007) during dialysis, caused mainly by a significant decrea se to normal levels of L-citrulline. The ratio ADMA/L-arginine decreas ed significantly during dialysis. L-arginine decreased (p = 0.04) when values obtained 24 hours before dialysis and immediately predialysis were compared. No significant changes were found in L-citrulline value s. cGMP showed low mean levels and just an indication of change during dialysis (p = 0.059). Serum nitrate values were elevated at the start and end of dialysis but showed a significant decrease (p = 0.003) dur ing dialysis. This may indicate high NO production in normotensive pat ients on stable hemodialysis. In spite of a decrease of NO inhibitors, no episodes of hypotension were seen during the studied dialyses. Cha nges in the studied factors influenc-hypotension NO generation seem to be related mostly to the effects of the dialysis procedure.