The comparison of plasma levels of Endothelial Nitric Oxide Synthetase between the patients with coronary slow flow and healthy population before and after effort.

Objective: Endothelial dysfunction caused by diffuse atherosclerosis plays a key role inthe etiopathogenesis of slow coronary flow (SCF) even if there is not any obstructiveepicardial lesion. Endothelial nitric oxide synthase (eNOS) is an enzyme involved in thesynthesis of nitric oxide in the course of the oxidation of L-arginine to L-siturillin.Reduced plasma levels of eNOS is an important indicator of endothelial dysfunction. Inthis study, it was aimed to determine plasma levels of eNOS and to investigate itsrelationship with effort in SCF patients.Method: 22 patients have SCF in at least one coronary artery (19 men and 3 women;mean age 48.5 ± 10.9) and 17 healthy individuals (12 males, 5 females; mean age 48.7 ±9.6) were included in this study. TIMI frame count method was used in determiningSCF. Plasma levels of eNOS before and after effort and mean platelet volume (MPV)were measured in patients and control group.Results: Basal plasma levels of eNOS was lower in the patient group than in the controlgroup (32.58 ± 21.36, 48,16 ± 24.35, p=0.040). Plasma eNOS levels were decreasedsignificantly more in patient group when compared to the control group after exertion(25.02 ± 17.69, 44.13 ± 17.39, p=0.002). When basal plasma levels of eNOS comparedto plasma eNOS levels after exercise in patients; while the plasma eNOS levels afterexercise was observed to be decreased significantly in patients (32.57 ± 21.36, 25.02 ±17.69, p<0.0001), the basal plasma levels of eNOS and post-exercise plasma eNOSlevels in control group tends to decrease however it was not statistically significant(48,16 ± 24.35, 44.13 ± 17.39, p=0.35). MPV levels were significantly higher in SCFpatients when compared with control group (9.21 ± 2.5, 7.77 ± 0.90, p=0.027). In SCFpatients with at there was a significant correlation between both baseline and postexerciseplasma levels of eNOS and TIMI frame counts (r=0.51, p=0.015, r=0.58,p=0.005, respectively). Also a significant correlation observed between MPV and TIMIframe counts in patients with SCF (r = 0.44, p=0.04). In addition, there was a negativecorrelation between both plasma levels of eNOS basal and after exercise and levels ofMPV in patients with SCF (r=-0.48, p=0.025, r=-0.44, p=0.041, respectively).Conclusion: Decreased plasma levels of eNOS both at rest and after exercise and anincreased level of MPV may play a role in the etiopathogenesis of myocardial ischemiain SCF patients in whom endothelial dysfunction caused by diffuse atherosclerosis atmicrovascular level.