ENHANCEMENT OF NITRIC-OXIDE PRODUCTION AFTER ARTERIAL RECONSTRUCTION IN PATIENTS WITH ARTERIOSCLEROSIS OBLITERANS

Purpose: Nitric oxide (NO) not only relaxes vascular smooth muscles, b ut it also reduces platelet adhesion and is itself a potent antiaggreg atory substance. Experimental studies have shown that the release of N O is modulated by the blood flow. However, little clinical information is available about the effects of hemodynamic changes after arterial reconstruction on NO production. We therefore examined whether the pla sma levels of nitrite (NO2-) and nitrate (NO3-) ions increased after a rterial reconstruction in patients with arteriosclerosis obliterans (A SO). Methods: Blood samples were obtained from the femoral artery in s even patients who underwent arterial reconstruction and seven healthy individuals (control). NO2- and NO3- levels were measured using high-p erformance liquid chromatography before the operation and 1 hour and 1 4 days after the operation. In addition, the mean femoral artery blood flow and ankle-brachial pressure index (ABI) were also measured using a duplex and Doppler velocimeter both before and after the operations . Results: In the control subjects, the mean plasma NO2-, NO3-, and NO x (NO2- plus NO3-) levels in the femoral artery were 0.37 +/- 0.15 mu mol/L, 45.6 +/- 10.8 mu mol/L, and 46.0 +/- 10.9 mu mol/L, respectivel y. Before the operation in the patients with ASO, the mean plasma NO3- (23.8 +/- 2.2 mu mol/L) and NOx levels (24.0 +/- 2.3 mu mol/L) were s ignificantly lower than those in the control subjects, whereas the pla sma NO2- levels (0.27 +/- 0.04 mu mol/L) were comparable between the t wo groups. At 14 days after operation, the mean plasma NO3- and NOx le vels in the femoral artery were significantly increased to 42.8 +/- 5. 6 mu mol/L and 43.4 +/- 5.6 mu mol/L compared with those before the op eration, whereas the mean plasma NO2- levels (0.50 +/- 0.05 mu mol/L) changed significantly. The mean ABI and the mean how rate before the o peration were 0.32 +/- 0.07 and 344 +/- 145 ml/min, respectively. Both the ABI and the mean flow rate significantly increased to 1.04 +/- 0. 06 and 627 +/- 141 ml/min after the operation. Conclusions: In patient s who have ASO, the mean plasma level of NO is significantly lower tha n that of healthy individuals. In patients with ASO, the mean blood fl ow increased significantly after arterial reconstruction. This hemodyn amic improvement may thus enhance NO production and may also help to m aintain the patency of the bypass graft or native artery.