Serum nitrate concentrations in patients with peripheral arterial occlusive disease

Nitric oxide (NO), an endogenous product of L-arginine oxidation, seems to account for the vasodilatatory effect of the endothelium-derived relaxing factor. It was the aim of the present study to measure serum nitrate concentrations, the degradation product of nitric oxide in patients with peripheral arterial occlusive disease (PAOD). 20 patients with PAOD in Fontaine stage IIb, 10 patients in stage III and IV respectively were included in the study. Serum samples for determination of nitrate were taken at admission after fasting overnight. Nitrate concentrations were determined using a recently developed high performance liquid chromatography which allows direct measurement of nitrate. The control group comprised 14 age and risk factor matched volunteers. We found significantly increased nitrate concentrations in patients with PAOD compared to the control group [stage IIb: 6.65 +/- 1.58 mumol/l; stage III: 6.94 +/- 1.85 mumol/l, stage IV: 7.05 +/- 1.16 mumol/l; control: 4.41 +/- 1.24 mumol/l], however no significance was calculated within the different PAOD groups. There was no association of either diabetes mellitus, hypertension and smoking behaviour with increased nitrate levels. These data might indicate that NO might be involved in adaptive vasodilatation already in the early phase of the disease. The source of nitrate in PAOD patients, however, remains unclear.