A Clinical Study On Risk Factors Of Cerebral Microbleeds In Ischemic Stroke Patients With Non-valvular Atrial Fibrillation

Objective: Cerebral microbleeds(CMBs)is one of the common small cerebral vascular diseases,which is associated with ischemic and hemorrhagic strokes.Non-valvular atrial fibrillation(NVAF)is an important risk factor of stroke,especially cardiogenic stroke.NVAF patients usually need long-term oral anticoagulant treatment to prevent embolization,and such treatment increases the incidence of intracranial hemorrhage(ICH).CMBs are the precursor of ICH,and many studies have confirmed the correlation between NVAF and CMBs.The detection rate of CMBs is higher in patients with NVAF,so it is necessary to find the risk factors related to the occurrence of CMBs in patients with NVAF.In this study,the clinical data includig previous history,cerebrovascular risk factors,and laboratory examinations of the enrolled ischemic stroke(IS)patients with NVAF was collected retrospectively.The susceptibility weighted imaging(SWI)was used to diagnose CMBs.We explored the risk factors of CMBs in IS patients with NVAF.Methods: We collected clinical data of IS patients with NVAF who were admitted to the neurology department of People’s Hospital of Liaoning Province from April 2016 to September 2019,which completed routine brain magnetic resonance sequence and SWI tests.Patients with non-cardiogenic stroke,other serious diseases or factors that affect the outcome were excluded.The enrolled patients were divided into CMBs(+)group and CMBs(-)group based on SWI results,and the clinical data collected mainly including gender and age.Vascular risk factors and previous history of drugs;anticoagulation score(CHA2DS2-VASc)and bleeding risk score(HAS-BLEDS);NIHSS of acute IS patients and MRS of previous IS patients;related blood test indexes,such as blood routine test,coagulation function,brain natriuretic peptide(BNP)etc;cardiac ultrasound,etc.CMBs was diagnosed as lesions on the SWI sequence with a diameter of no more than 10 mm,generally round,well-bounded,homogeneous andlow-signal region of 2-5mm,with lesions surrounding the brain parenchyma,except for SWI low-signal caused by other reasons.CMBs were devided into different groups according to the location and numbers in SWI imagings.SPSS21.0 software was used for statistical analysis.Analyse the independent risk factors of CMBs in IS patients with NVAF by using multivariate Logistic regression analysis.Results: In this study,117 NVAF patients were enrolled.The average age of the patients was 76.22±8.12 years old,with 67 males(57.3%)and 69 patients(59.0%)in the CMB(+)group.According to the location of CMBs,21 cases(17.9%)were in cerebral lobe,18 cases(15.4%)in deep or subtensive zone,and 30 cases(25.6%)in mixed locations.According to the severity(numbers of CMBs),the CMBs(+)group are subdivided into 25 cases(21.4%)of mild group(1-2 CMBs),28 cases(23.9%)of moderate group(3-10 CMBs)and 16 cases(13.7%)of severegroup(>10 CMBs).Variables with statistical significance in univariate analysis(P< 0.05)were used as independent variables,and CMBs,CMBs distribution location and severity were used as dependent variables in multivariate logistic regression analysis.The result shows that hypertension and BNP were independently correlated with CMBs in NVAF IS patients(P=0.007,P=0.047).The history of hypertension,stroke and statins were independently correlated with the location of CMBs in IS patients with NVAF: hypertension was independently correlated with the occurrence of deep or subtentorial CMBs in IS patients with NVAF(P=0.049);the history of hemorrhagic stroke was not only independently correlated with the occurrence of cerebral lobe CMBs in IS patients with NVAF(P<0.05),but also independently correlated with the occurrence of deep or subtentorial CMBs(P<0.05);the statin use history was independently associated with the occurrence of mixed location CMBs in IS patients with NVAF(P=0.036).In different severity CMBs groups of IS patientswith NVAF,the difference of the proportion of hypertension,hemorrhagic stroke history and BNP level was statistically significant(P<0.05).The presence of these factors alone would increase the load of CMBs.Conclusions: Hypertension are related to the occurrence of CMBs in IS patientswith NVAF,it mainly affects the deep CMBs or subtentorial CMBs,and increases the load of CMBs.Statin use history was independently related to the occurrence of CMBs in the mixed site of NVAF patients.BNP was correlated with the occurrence of CMBs in patients with NVAF,and was positively correlated with CMBs severity,but there was no significant difference in CMBs at different location.