Effect of L-arginine on endothelial dysfunction in patients with congenital mitral valve prolapse

АIM. To study the effect of L-arginine on endothelium-dependent vasodilatation in patients with congenital mitral valve prolapse and different degrees of regurgitation.Methods. The study included 86 patients [36 (41.9%) males and 50 (58.1%) females aged 15-25 (mean age 19.9±1.42) years] with signs of congenital mitral valve prolapse. The first group included 41 patients were L-arginine (Tivortin) as a prophylaxis medication. The second group included 45 patients who were not taking L-arginine. Subgroup A of each group included 20 and 22 patients with stage I of mitral regurgitation, accordingly; subgroup B of each group included 21 and 23 patients with stage II of mitral regurgitation, accordingly.Results. In patients of the first group with mitral valve prolapse and stages I and II of mitral regurgitation, distinct positive changes were observed after 6 months of treatment with L-arginine. Compared to baseline data, in patients of the first group with stage I of mitral regurgitation brachial artery diameter increased by 1,44 times (р 0.001), resistance index - by 1.5 times (р 0.001); in patients with stage II of mitral regurgitation the following parameters increased by 1.65 and 1.39 times (р 0.001 and р 0.01) accordingly. At the same time, parameters of NO-system also improved in patients of the first group with stages I and II of mitral regurgitation after 6 months of treatment: endothelial NO synthase activity increased by 1.18 and 1.29 times (р 0.05 and р 0.02) accordingly, NO level decreased by 1.17 and 1.18 times (р 0.05), inducible NO synthase activity - by 1.17 and 1.29 times (р 0.05 and р 0.02), and there was a reduction of peroxynitrite levels by 1.23 and 1.34 times (р 0.02 and р 0.01), endotheline-1 - by 1.07 and 1.26 times (р 0.05 and р 0.02), vascular endothelial growth factor - by 1.08 and 1.24 times (р 0.05 and р 0.01) accordingly.Conclusion. Recommended doses of L-arginine restores the stream-dependent vasodilation, activity of the NO-system and process of angiogenesis after 6 months of treatment.