Nitric oxide may contribute to nocturnal hemodynamic changes in cirrhotic patients

OBJECTIVE: Patients with liver cirrhosis have a nocturnal worsening of hemo dynamic parameters that has been associated with an increased risk of varic eal bleeding at nighttime. The aim of this study was to investigate whether nitric oxide and cytokines are implicated in these hemodynamic changes. METHODS: Ten cirrhotic patients and eight controls were studied. Mean blood pressure, heart rate, plasma norepinephrine, tumor necrosis factor alpha a nd interleukin-6 levels, and serum nitrite + nitrate levels were determined at 0800, 1600, and 2400 h. All determinations were performed in supine res t and at least 4 h after meals. In a second study, nitrite + nitrate levels were assessed in 10 cirrhotic patients before and after eating a standard meal. RESULTS: Mean arterial pressure levels that were always lower in the patien t group showed a nocturnal decrease in both groups of subjects. Heart rate values that were always higher in cirrhotic patients showed a nocturnal fal l in controls, whereas cirrhotics maintained elevated values at nighttime. Norepinephrine levels were higher in cirrhotics and maintained similar valu es during the study, whereas controls had a significant nocturnal decrease. Nitrite + nitrate levels that were higher in cirrhotic patients showed a s ignificant mean increase of 40% from morning (0800 h) to night (2400 h) in the patient group, whereas in controls no change was observed (p < 0.05). T umor necrosis factor alpha and interleukin-6 levels did not change either i n patients or controls during the entire period. Cirrhotic patients with or without ascites maintained a pattern of hemodynamic and biochemical change s similar to the pattern observed in the entire group of patients. Finally, no changes in serum nitrite + nitrate levels were observed in patients bef ore and after eating the standard meal. CONCLUSION: An increased nocturnal nitric oxide production might contribute to the hemodynamic changes observed in cirrhotic patients during nighttime . (Am J Gastroenterol 2000,95.1539-1544. (C) 2000 by Am. Cell. of Gastroent erology).