Influence of obstructive sleep apnea-hypopnea syndrome on blood pressure

Objective: To explore influence of obstructive sleep apnea-hypopnea syndrome(OSAHS) on blood pressure.Methods: A total of 112 patients underwent polysomnography monitoring.According to complicated with essential hypertension(EH) and OSAHS or not;and moderate-severe OSAHS was defined as apnea hypopnea index(AHI)20 times/min,all patients were randomly divided into four groups: normal blood pressure + mild OSAHS group(n=30),normal blood pressure + moderate-severe OSAHS group(n=25),EH + mild OSAHS group(n=22) and EH + moderate-severe OSAHS group(n=35).All indexes were analyzed and compared among all groups.Results:1.Among EH patients,compared with mild OSAHS group,there were significant increase in diastolic blood pressure when initial awakening [(93.45±12.24) mmHg vs.(100.31±9.97) mmHg]and significant decrease in pulse pressure(PP) before sleep and when initial awakening [before sleep:(58.41±15.52) mmHg vs.(47.71±11.46) mmHg,initial awakening:(55.77±17.42) mmHg vs.(41.51±11.86) mmHg,P0.01 all]in moderate-severe OSAHS group;among patients with normal blood pressure,there were no significant difference in above indexes between mild OSAHS group and moderate-severe OSAHS group;2.Compared with mild OSAHS group,there were significant increase in AHI,hypoxia index and saturation of arterial blood oxygen(SaO2) 90% time,and significant decrease in mean SaO2 and minimum SaO2 in moderate-severe OSAHS group(P0.01 all);3.Among EH patients,compared with mild OSAHS group,there were significant increase in ratio of non rapid-eye movement stage Ⅱ in total sleeping time(37.55% vs.47.13%,P0.01),and significant decrease in ratio of sober time after falling asleep in total sleeping time(22.83% vs.12.90%,P0.05)in moderate-severe OSAHS group.Conclusion: The OSAHS possesses significant influence on blood pressure in EH patients,it presented as diastolic blood pressure significantly increase when initial awakening,and PP significantly decrease before sleep and when initial awakening,and the more severe OSAHS is,the more severe these changes are;there is hypoxia in OSAHS patients at night,which may be an important mechanism of fluctuation of diastolic blood pressure in EH patients with OSAHS.