Evaluation of Serum Nitric Oxide in Essential Hypertension and Its Correlation With Severity of Disease

ABSTRACT Objective: Hypertension is the most common cardiovascular disease and one of the most important public health concerns all over the world. Primary or essential hypertension is the major form of arterial hypertension without any definitive cause. It results from increase vascular tone and resistance which may be confined to the lower level of endothelial derived relaxing factor such as nitric oxide (NO). Hence, the objective of this study is to find out whether any correlation exists between the concentrations of serum NO (nitrite) and essential hypertensive patients categorized according to the Joint National Committee 7 classification. Methods: We selected age- and sex-matched 24 healthy individuals as controls and 35 essential hypertensive patients as cases. Out of 35 cases, 24 were included in stage 1 and 11 in stage 2 of essential hypertension. We estimated serum NO levels in study groups basing on the principle of Griess reaction. Results: We observed reduction in mean serum NO level in cases which was statistically highly significant as compared to controls (8.14±0.33 vs. 13.53±0.38 µmol/L, p<0.001) and also in stage 2 patients when compared with stage 1 patients (5.97±0.31 vs. 9.15±0.28 µmol/L, p<0.001). In hypertensive patients, serum NO showed a highly significant inverse correlation to both systolic (r=−0.89, p<0.001) as well as diastolic (r=−0.64, p<0.001) blood pressure. Conclusion: Thus, we can conclude that lower level of serum NO can be an important causative factor in the progress of essential hypertension. Keywords: Essential hypertension, Endothelial-derived relaxing factor, Nitric oxide, Joint National Committee 7.