Nowadays,with the improvement of people's living standards and the acceleration of the aging process of population,cerebral small vessel disease has seriously endangered the life health and quality of life of the elderly.Hypertension has been paid more and more attention as an important risk factor of cerebral small vessel disease.However,in the management of hypertension,people generally concentrate on the influence of mean arterial pressure,ignoring the role of variability and circadian rhythm of blood pressure nowadays.By expounding the pathogenesis of cerebral small vessel disease and the recent studies on blood pressure variability and circadian rhythm of blood pressure,this review discusses a series of scientific problems such as the effects of blood pressure variability and circadian rhythm of blood pressure on the occurrence and development of cerebral small vessel disease.

Objective To explore the relationship between blood pressure variability(BPV),white matter lesions(WMLs),regional cerebral blood flow(rCBF)and cognitive function.Methods The degree of WMLs was assessed by Fazekas scale.rCBF was detected by brain perfusion imaging.Twenty-four hour ambulatory blood pressure monitoring was used to calculate the blood pressure coefficient of variation(CV)to measure BPV.Cognitive function was assessed by Montreal cognitive assessment(MoCA).Results Multivariate Logistic regression analysis showed that compared with those in 24 h systolic blood pressure CV Q1 group,mean white matter blood flow(MWCBF)in Q3 group and Q4 group were significantly decreased(OR=5.63,95%CI:1.31-24.14,OR=9.70,95%CI:2.23-42.17),the risk of moderate to severe cognitive impairment was significantly increased(OR=5.37,95%CI:1.24-23.21;OR=10.44,95%CI:2.39-45.65);the risk of severe WMLs in the Q4 group was significantly increased(OR=9.61,95%CI:2.00-46.26).Person correlation analysis showed that mean diurnal systolic blood pressure(MDSBP),mean nocturnal systolic blood pressure(MNSBP),mean diurnal diastolic blood pressure(MDDBP)and mean nocturnal diastolic blood pressure(MNDBP)were negatively correlated MWCBF(all P<0.01).MoCA score was positively correlated with MWCBF(P<0.01),and negatively correlated with daytime systolic blood pressure coefficient of variation(dSBPCV),nighttime systolic blood pressure coefficient of variation(nSBPCV),daytime diastolic blood pressure coefficient of variation(dDBPCV),nighttime diastolic blood pressure coefficient of variation(nDBPCV)and Fazekas score(all P<0.01).Fazekas score was positively correlated with dSBPCV,nSBPCV,dDBPCV and nDBPCV(all P<0.01),and negatively correlated with MWCBF(P<0.01).Conclusions High BPV is an independent risk factor for cognitive impairment in WMLs patients.Lower MWCBF is associated with lower MoCA score and higher BPV.

Biological clock proteins are involved in the regulation of many important physiological processes, including blood pressure. The deletion or mutation of core circadian clock genes may cause elevated blood pressure levels and disrupted blood pressure rhythms, exacerbating vascular function damage, and ultimately leading to the occurrence, development and poor outcome of ischemic stroke. This article reviews the molecular mechanism of biological clock rhythm, the relationship between biological clock gene and blood pressure regulation mechanism, the mechanism of circadian rhythm disorder in the occurrence and development of hypertension, and the relationship between blood pressure rhythm disorder and stroke.