Nitric oxide: link between endothelial dysfunction and inflammation in patients with peripheral arterial disease of the lower limbs.

OBJECTIVES

To analyse the role of nitric oxide (NO) in peripheral arterial disease (PAD) and its association with inflammation and brachial artery flow-mediated dilation (BAFMD) as an estimation of endothelial dysfunction.

MATERIAL AND METHODS

Cross-sectional study of 82 patients with ischaemia (50 with Fontaine stage II and 32 with Fontaine stage III-IV) in whom BAFMD, hsCRP and nitrite levels in plasma were determined by colorimetric assay using the Griess reaction. They were compared with a control group of healthy subjects (n=41) with ABI >0.9, under 30 years of age.

RESULTS

No significant differences were found between the different stages of ischaemia in relation to risk factors or concomitant treatments. The patients with PAD had significantly higher NO levels in plasma than the control group (23.92+/-23.27 microM vs. 12.77+/-11.12 microM, P=0.001). However, no statistically significant differences were observed in the NO levels between the two groups of patients with PAD (25.24+/-24.47 microM vs. 21.86+/-19.86 microM, P=0.38). Neither were differences found between the two in BAFMD (4.7+/-4.2 vs. 4.3+/-2.8, P=0.1). The hsCRP values were statistically higher in PAD stage III-IV (8.2+/-13.5 vs. 29.2+/-33.2, P=0.0001).

CONCLUSIONS

The presence of elevated NO values in PAD, in conjunction with elevated CRP levels, reinforces the theory that atherosclerosis has an inflammatory nature. Its lack of correlation with the clinical severity, also occurring in BAFMD, lends weight to the hypothesis that endothelial dysfunction is an event which takes place in the first stages of the disease.