The Endothelial Nitric Oxide Synthase (NOS3-786T>C) Genetic Polymorphism in Chronic Heart Failure: Effects of Mutant -786C allele on Long-term Mortality.

BACKGROUND

Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte function. We investigated the NOS3-786T>C polymorphism in chronic heart failure (CHF) and its effects on long-term mortality.

METHODS

Ninety-one patients with CHF who were referred to the Department of Cardiology of Siyami Ersek Cardiovascular and Thoracic Surgery Center for cardiopulmonary exercise testing between April 2001 and January 2004 and 30 controls were enrolled in this study. Patient were followed prospectively for a period of 1 to 12 years.

RESULTS

Patients and controls were divided into three groups: TT, TC and CC, according to their NOS3-786T>C polymorphism. We noted that there was no significant difference in the genotype distribution between patients and controls. There was also no significant difference in endothelial nitric oxide synthase (eNOS) gene polymorphism between ischemic HF and nonischemic HF. During the follow-up period, 61 (67%) deaths occurred. The nonsurvivor group had lower left ventricular ejection fraction (LVEF) (p = 0.01), reduced peak oxygen consumption (p = 0.04) and were of older age (p = 0.001). Age, LVEF, peak oxygen consumption and genotype were found to be predictors of mortality (p < 0.05). Additionally, mortality was significantly increased in -786CC genotype patients compared to TT genotype patients (hazard ratio = 2.2; p = 0.03). By multivariate analysis, age and eNOS genotype were determined to be significant independent predictors of death. Additionally, Kaplan-Meier analysis confirmed that homozygote -786C genotype was associated with an increased risk of death (χ2 = 4.6, p = 0.03).

CONCLUSIONS

Our findings showed that the NOS3-786T>C polymorphism was associated with an increased risk of mortality in patients with CHF.