OBJECTIVETo investigate the change of circadian blood pressure variability (BPV) and plasma neopterin before and after surgery (uvulopalatopharyngoplasty) for patients with obstructive sleep apnea syndrome (OSAS).

METHODSA total of 382 OSAS patients underwent uvulopalatopharyngoplasty were divided into three groups based on polysomnography (PSG) results: mild OSAS (n = 206), moderate OSAS (n = 108) and severe OSAS (n = 68). Plasma neopterin, 24-hour ambulatory blood pressure monitoring (ABPM), PSG were measured before and 3 months after surgery.

RESULTSPlasma neopterin increased in proportion to severity of OSAS before surgery (15.08 nmol/L, 27.68 nmol/L and 37.32 nmol/L in patients with mild to severe OSAS) which were significantly reduced post surgery (9.92 ng/ml, 15.07 ng/ml and 18.54 ng/ml, all P < 0.05 vs. pre-surgery). The incidence of non-dipper curve in three OSAS groups were 50.2%, 72.7% and 86.5%, respectively before surgery and the values decreased to 34.8%, 48.2% and 49.2% after surgery (all P < 0.05 vs. pre-surgery). Relevance analysis indicates that D-value of nocturnal and diurnal blood pressure was negatively correlated with plasma neopterin.

CONCLUSIONOur findings indicated that plasma neopterin and the incidence of non-dipper could reliably reflect OSAS severity and could thus be used to evaluate the surgery efficacy. Plasma neopterin might be an important player in the pathophysiology of OSAS via modulating blood pressure variability.