Correlation between plasma total nitric oxide levels and cerebral vasospasm and clinical outcome in patients with aneurysmal subarachnoid hemorrhage in Indian population

CONTEXT: Cerebral vasospasm remains a major cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). Reduced bioavailability of nitric oxide has been associated with the development of cerebral vasospasm after aSAH. Such data is not available in Indian population. AIMS: The objective of the study was to measure the plasma total nitric oxide (nitrite and nitrate-NO(x)) level in aSAH patients and healthy controls treated at a tertiary hospital in India and to investigate a possible association between plasma total nitric oxide level and cerebral vasospasm and clinical outcome following treatment in patients with aSAH. SETTINGS AND DESIGN: A case-control study of aSAH patients was conducted. Plasma total NO(x) levels were estimated in aSAH patients with and without vasospasm and compared the results with NO(x) levels in healthy individuals. MATERIALS AND METHODS: aSAH in patients was diagnosed on the basis of clinical and neuro-imaging findings. Plasma total NO(x) levels in different subject groups were determined by Griess assay. RESULTS: Plasma total NO(x) level was found to be significantly decreased in patients with aSAH when compared to controls. Plasma total NO(x) level in the poor-grade SAH group was lower than that in the good-grade SAH group. Plasma total NO(x) level further reduced in patients with angiographic (P < 0.05) and clinical vasospasm. CONCLUSIONS: Reduced plasma NO(x) level is seen in aSAH patients as compared to normal individuals. In aSAH patients reduced levels are associated with increased incidence of cerebral vasospasm and poor outcome. Plasma total NO(x) level could be used as a candidate biomarker for predicting vasospasm and outcome for this pathology.