Analysis Of Risk Factors Of Ischemic Stroke In Chinese Patients With Nonvalvular Atrial Fibrillation

BackgroundAtrial fibrillation（AF）is the most common persistent arrhythmia in clinical practice,Its incidence is generally increasing globally,and it has become an important public health problem that endangers human health.Research evidence shows that AF is one of the main risk factor for ischemic stroke（IS）,which increases the risk of stroke by about 5 times and has a high rate of death and disability.Therefore,early identification of high-risk groups and effective anticoagulation prevention are essential.At this stage,the CHA₂DS₂-VAS_C score based on clinical risk factors is widely recommended,but it’s effectiveness in guiding clinical anticoagulation prevention is controversial,the ability of this scoring system to predict atrial fibrillation stroke needs to be further improved.In recent years,studies have found that in addition to clinical risk factors,the structure and function of the left atrium and a variety of biomarkers are closely related to the risk of stroke.Studies have shown that serum uric acid（SUA）and hematocrit（Hct）levels are related to the incidence of stroke in the general population.Therefore,it is necessary to comprehensively evaluate the risk factors of stroke with atrial fibrillation,optimize the existing risk scoring system,and improve the value of guiding anticoagulation to prevent stroke,so as to reduce the burden of AF-related stroke.Objectives1.To explore the relationship between serum uric acid and hematocrit levels and ischemic stroke in patients with nonvalvular atrial fibrillation（NVAF）,and whether the combination of CHA2DS2-VASC score and multiple risk factors can improve its diagnostic value.2.Through follow-up of patients after atrial fibrillation radiofrequency surgery,determine the predictive factors of atrial fibrillation recurrence and stroke.Subjects and Methods（1）Subjects:This study collected 1068 patients with atrial fibrillation who were planned to undergo cardiac radiofrequency ablation at Huazhong Fuwai Hospital from January 2018 to June 2019.All patients underwent left atrial CTA examination before surgery.Exclusion criteria:1.Patients with valvular atrial fibrillation;2.Familial hypercholesterolemia;3.Structural heart disease;4.Patients with tumor and blood system diseases.Finally,845 patients were enrolled,491 cases undergoing cardiac radiofrequency ablation after excluding surgical contraindications.（2）Methods:By consulting the hospitalized medical records,collecting clinical data of all patients,including demographic data,past medical history,laboratory test indicators,Transthoracic color Doppler ultrasound and left atrial CTA results,CHA2DS2-VASc score was performed on all patients.Based on the patient’s stroke/transient ischemic attack（TIA）history and the results of Computed Tomography（CT）or Magnetic Resonance Imaging（MRI）examinations to determine whether the patient has acute ischemia stroke,they are divided into stroke group and non-stroke group;And follow up the surgical patients by telephone or outpatient data,record postoperative atrial fibrillation recurrence and stroke events,and the time of the eventData AnalysisSPSS and Med Calc software were used for statistical analysis.Measurement data were expressed as mean±standard deviation or median（P25,P75）,and two independent sample t-tests or non-parametric tests were used for comparison between groups.The enumeration data is expressed by the number of cases and the percentage（%）,and the comparison between groups is performed by the chi-square test.Logistic stepwise regression analysis was used to explore the independent risk factors of ischemic stroke in NVAF patients.Draw receiver operating characteristic（ROC）curves of different detection methods,and calculate the area under the curve.The difference of the area under the different ROC curve is tested by De Long.COX stepwise regression analysis was used on the follow-up data to determine the predictors of the outcome event.All tests used two-tailed test,P<0.05 indicates that the difference is statistically significant.Results1.Analysis of stroke related factors of atrial fibrillation（1）In the end,845 patients were enrolled,including 171 in the stroke group and674 in the non-stroke group.The SUA（375.0±72.6umol/L）of the stroke group was higher than that of the non-stroke group（293.2±70.2umol/L）,and the Hct level（39.6±5.1%）was significantly lower than that of the non-stroke group（42.0±4.7%）,the difference was statistically significant Academic significance（P<0.001）.（2）Logistic stepwise regression analysis,after correcting for confounding factors,high SUA（OR=1.025,95%CI:1.017-1.032,P<0.001）and low Hct（OR=3.327,95%CI:1.476-7.500,P=0.004）are Independent risk factors for IS in NVAF patients（3）According to ROC curve,the best cut-off point for SUA level is 321.5umol/L,CHA2DS2-VASC score≥2 combined with SUA≥321.5umol/L and low Hct level（male:≤42%,female:≤37%）predict NVAF patients IS risk,the area under the ROC curve is 0.847（95%CI,0.814-0.880）.Compared with the CHA2DS2-VASC score≥2（0.697,95%CI:0.657-0.738）alone,the area under the curve increases by0.150,and the Z statistic is 10.589,the diagnostic value is significantly improved（P<0.0001）.2.Analysis of follow-up results of patients undergoing radiofrequency ablation for atrial fibrillation（1）Among the enrolled 845 patients,491 surgical patients were followed up:46patients（9.4%）with ischemic stroke,and the follow-up time was 25.1±5.6 months;116 patients（23.6%）with recurrence of atrial fibrillation,The follow-up time was23.1±8.4 months;51 cases（10.4%）were lost to follow-up,and 5 cases（1.0%）died from all causes.（2）Multivariate COX regression analysis showed that SUA≥321.5umol/L and low Hct were not associated with the risk of atrial fibrillation recurrence and stroke after surgical treatment,while persistent AF was the recurrence of atrial fibrillation after radiofrequency ablation（HR=2.056,95%CI:1.029-4.109,P=0.041）and stroke（HR=2.452,95%CI:1.217-4.939）,P=0.012),the LAA shape is chicken wing type（HR=0.271,95%CI:0.108-0.678,P=0.005）is an independent protective factor for stroke.Conclusion1.For patients with serum uric acid≥321.5umol/L and low hematocrit（male:≤42%,female:≤37%）,we should pay close attention to their stroke risk.2.For surgical treatment of NVAF patients,persistent AF patients have a high postoperative atrial fibrillation recurrence rate and ischemic brain The risk of stroke is high,and patients with chicken-wing LAA have a lower risk of ischemic stroke after surgery.