| Part 1Prevalence and determinants of asymptomatic intracranial arterial stenosis assessed by transcranial DopplerObjectives: To investigate the prevalence and determinants of asymptomatic intracranial arterial stenosis which included 24-h blood pressure and blood pressure variability in an untreated population from hypertension outpatient clinic.Methods: Outpatients who were not on antihypertensive medication from the Clinic for Ambulatory Blood Pressure Monitoring,Department of Hypertension,Ruijin Hospital were recruited from the year of 2009 to 2013.Transcranial Doppler was used to assess the stenosis at the bilateral anterior,middle and posterior cerebral arteries and vertebral arteries.T test and Chisquare test were used to compare the difference between patients with stenosis and those without.Multiple logistic regression was used to analyze the determinants of intracranial arterial stenosis.Results: The 1130 participants whose age averaged 51 years included 49%males,63% hypertensives and 5.3% diabetic patients.The prevalence of intracranial arterial stenosis was 7.4%(84 cases).The stenosis located mainly at anterior(45 cases)or middle(44 cases)cerebral arteries,less frequently at posterior(16 cases)or vertebral(7 cases)arteries.No difference in clinic characteristics was found between patients with and without stenosis,except that the 24 h systolic blood pressure(132 vs 126 mm Hg,P<0.001)and average real variability of 24 h systolic blood pressure(9.9 vs 9.4 mm Hg,P=0.01)were significantly higher in patients with intracranial arterial stenosis.Multivariate logistic regression analysis showed that women had more risk of intracranial arterial stenosis than men by 72%(95% CI,6%-179%,P=0.026),and for each 10 mm Hg higher 24-h systolic blood pressure,the risk increased by 56%(29%-88%;P<0.001).Systolic blood pressure elevation for each 10 mm Hg,irrespective of the time interval(daytime,nighttime,morning),was associated with increased risk of intracranial arterial stenosis by 34-47%(P all <0.001).But the association between 24 h average real variability and asymptomatic intracranial arterial stenosis became insignificant after adjustment for 24 h systolic blood pressure level and other conventional risk factors.Conclusions: Asymptomatic intracranial arterial stenosis was moderately prevalent in Chinese patients at hypertension clinic,for which systolic blood pressure was an important determinant.Part 2Association of home blood pressure and variability with asymptomatic intracranial arterial stenosisObjectives: The investigation of the first part showed that asymptomatic intracranial arterial stenosis was associated with the 24-h ambulatory blood pressure.However,it is unclear if intracranial arterial stenosis was associated with home blood pressure and variability.The current study therefore aimed to analyze this association.Methods: Data of the outpatients who were not on antihypertensive medication and have performed 7-day home blood pressure monitoring in the Department of Hypertension,Ruijin Hospital from the year of 2009 to 2013 was investigated in the present study.Average level of the 7-day total,morning and evening home blood pressure,and blood pressure variability indices,including standard deviation(SD),coefficient variation(CV),variability independent of mean(VIM),average real variability(ARV),maximum-minimum difference(MMD)were calculated.Transcranial Doppler was used to assess the stenosis at the bilateral anterior,middle and posterior cerebral arteries and vertebral arteries.T test,analysis of variance and covariance were used to compare the home blood pressure(morning and evening blood pressure)and variability between patients with stenosis and those without.Multiple logistic regression was used to analyze the association of home blood pressure and variability with intracranial arterial stenosis.Results: 1)The 704 participants whose age averaged 49.6 years included53.8% males and 5.7% diabetic patients.The average office and home blood pressure were 130/81 mm Hg and 129/82 mm Hg,respectively.2)The prevalence of hypertension at home,in the morning and in the evening were43.5%,45.9% and 41.9%,respectively.3)The 7-day total blood pressure variability were higher than the day-to-day blood pressure variability.The systolic/diastolic SD,CV,VIM,ARV,and MMD were respectively 8.2/5.3mm Hg vs.5.0/3.3 mm Hg,6.3/6.5% vs.3.9/4.1%,8.2/5.3 vs.5.0/3.3mm Hg,6.3/3.6 vs.5.1/3.4 mm Hg,and 34/22 vs.14/9.3 mm Hg.4)Sixty-one patients(8.7%)had intracranial arterial stenosis.Compared to patients without intracranial stenosis,patients with stenosis were more likely female(61% vs.45%,P=0.02),had higher systolic blood pressure of home(134.5 vs.128.6mm Hg),morning(133.6 vs.128.5 mm Hg),and evening(135.4 vs.128.6mm Hg,P?0.002),and larger 7-day total home systolic blood pressure variability(SD,9.1 vs.8.1 mm Hg;CV,6.8 vs.6.3%;VIM,8.8 vs.8.2;ARV,7.0 vs.6.2 mm Hg;MMD,37.8 vs.34.0 mm Hg;P?0.05),while there was no difference in home diastolic blood pressure,7-day total and day-to-day diastolic blood pressure variability(P?0.07).5)Multivariate logistic regression analysis showed that asymptomatic intracranial arterial stenosis were independently associated with office,home,home morning and evening systolic blood pressure,and the 7-day morning systolic blood pressure variability indices including SD,CV,VIM,ARV,and MMD(P?0.03),but not with the 7-day diastolic variability and day-to-day home blood pressure variability(P?0.08).Conclusions: Asymptomatic intracranial arterial stenosis was significantly associated with home systolic blood pressure and moring blood pressure variability.Home blood pressure as a widely used out-of-office measurement was an important determinant of intracranial arterial stenosis.Part 3Association between hypertensive subtypes and asymptomatic intracranial arterial stenosisObjectives: To investigate the association of hypertensive subtypes such as white-coat hypertension,masked hypertension,sustained hypertension with asymptomatic intracranial arterial stenosis.Methods: Data of the outpatients who were not on antihypertensive medication and have performed 7-day home blood pressure monitoring(Omron 7051)in the Department of Hypertension,Ruijin Hospital from the year of 2009 to 2013 was investigated in the present study.White-coat hypertension,masked hypertension,and sustained hypertension were classified according to the thresholds of an office blood pressure of 140/90 mm Hg and a home blood pressure of 135/85 mm Hg.Transcranial Doppler was used to assess the stenosis at the bilateral anterior,middle and posterior cerebral arteries and vertebral arteries.Chi square test was used to compare the prevalence of intracranial arterial stenosis among the three subtypes of hypertension.Multiple logistic regression was used to analyze the associations of intracranial arterial stenosis with the hypertension subtypes.Results: Among the 704 patients,340(48.3%)were normotensives,155(22.0%)had masked hypertension,58(8.2%)white-coat hypertension and151(21.5%)sustained hypertension.The prevalence of intracranial arterial stenosis was highest in patients with sustained hypertension(10.6%),moderately higher in patients with masked hypertension(9.7%)and in normotensives(8.2%),and lowest in patients with white-coat hypertension(3.5%).However,the difference among the four groups was statistical insignificant(P=0.39).Multivariate logistic regression analysis showed no significant association between asymptomatic intracranial arterial stenosis and the three hypertensive subtypes(P=0.22).Results were similar when the analyses were based on ambulatory blood pressure.Conclusions: Masked hypertension and white-coat hypertension can be diagnosed by the out-of-office blood pressure monitoring.However,due to the small sample size of the present study,no association was observed between the three subtypes of hypertension and asymptomatic intracranial arterial stenosis. |
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