Correlation Between Nocturnal Heart Rate And White Matter Hyperintensity Volume In Patients With Cerebral Small Vessel Disease

BackgroundWhite matter hyperintensity(WMH)is one of the main imaging markers of cerebral small vessel disease,and it is the imaging manifestation of white matter demyelination,which can be caused by a variety of etiologies.Currently,the generally accepted WMH pathogeneses mainly include hypoxia-ischemia,endothelial dysfunction,blood-brain barrier disruption,and infiltration of inflammatory mediators or cytokines.White matter hyperintensity(WMH)can be seen in the deep and periventricular white matter and detected on a fluid-attenuated inversion recovery MRI sequence.Both neurons and glial cells are components of the central nervous system,in which,oligodendrocytes form the myeline sheath to surround and protect axons.Anatomically,the myelinated axons and glial cells are morphological and functional coupled,constituting jointly as the cerebral white matter(WM)and holding accountable for the normal appearance of WM.Any kind of damage in WM composition,for example,myelin pallor,demyelination,axonal loss,gliosis,oligodendrocyte apoptosis and edema,may change the normal structures of WM and result in WM hyperintensities on magnetic resonance scans.In the human body,the Circadian rhythms of heart rate(HR)and blood pressure(BP)play an important part in the maintenance of homeostasis.The normal circadian pattern of blood pressure and heart rate is characterized by a decrease during sleep.However,in some people,HR and BP often do not drop at night during sleep,and may even rise paradoxically.Studies have found that these abnormal HR patterns are linked to an increased risk for cardiovascular events and target organ damage in both normotensive and hypertensive individuals.Moreover,better control of sleep BP has been shown to exert greater protection against stroke and cardiovascular events in many studies.Age and hypertension are widely considered to be the main risk factors for white matter hyperintensity(WMH),but they do not account for all the pathophysiological mechanisms of WMH.Therefore,exploring the correlation between WMHV and other vascular factors and identifying relevant factors that may contribute to the progression of WMH are important for improving our understanding of the etiology and progression of WMH,and may have implications for clinical treatment.ObjectiveThis study aimed to examine the association of heart rate(HR),heart rate variability,and common vascular risk factors with WMH burden in patients with cerebral small vessel disease(CSVD),and to identify associated factors that may contribute to the progression of WMH.MethodsThis study consecutively enrolled 778 patients who were diagnosed with CSVD in the First Affiliated Hospital of Zhengzhou University between January 2017 and May 2021.All of them underwent 24-hour ambulatory blood pressure electrocardiogram,detection of relevant blood parameters,and brain magnetic resonance imaging(MRI).Univariate and multivariate logistic analyses were performed in spss 26.0 to explore the relationship between heart rate measurements,vascular risk factors,blood indices and log WMHV4.ResultsMultivariate logistic analysis showed that nocturnal HR(OR(95%CI):1.053(1.007,1.102),P=0.025),homocysteine(OR(95%CI):1.016(1.001,1.032),P=0.041)and cerebral infarction(OR(95%CI):2.023(1.338,3.06),P=0.001)were independently associated with WMHV.Similar associations were not observed for daytime HR,HR variability,other vascular risk factors and WMHV.nighttime HR、Hcy and cerebral infarction were independently associated with WMHV.With the increase of nighttime HR and Hcy,WMHV also increased accordingly;the level of WMHV in patients with cerebral infarction was higher.Conclusion1.The nocturnal heart rate and homocysteine level of patients with severe WME were higher than those of patients with mild WMH.2.The proportion of patients with previous cerebral infarction in the severe WMH group was higher than that in the mild WMH group.3.Nighttime heart rate、homocysteine level and previous cerebral infarction were independently associated with WMHV,suggesting independent roles of them in white matter hyperintensity.