Study On The Risk Prediction Model Of Left Atrial Appendage Thrombosis In Patients With Nonvalvular Atrial Fibrillation

BackgroundAtrial fibrillation（AF）related ischemic stroke has brought heavy medical burden to patients and families due to its high death and disability rate,which has attracted extensive clinical attention and attention.Cardiogenic thrombosis is the main cause of increased risk of stroke and embolism,and is also the basis of clinical anticoagulant therapy.In NVAF patients,more than 90%of thrombus originated from the left atrial appendage.The prevention and treatment of stroke and embolism is in the first place in the comprehensive management of AF.CHA2DS2-VASc score is recommended to evaluate stroke risk and guide anticoagulation in patients with NVAF due to its simplicity and practical application.However,CHA2DS2-VASc score is based on the risk factors of stroke events in patients with NVAF in a cohort study,and is not a direct assessment of the risk of left atrial appendage thrombosis.Clinically,some NVAF patients with low-risk CHA2DS2-VASc score also developed left atrial appendage thrombosis（LAAT）.In patients with cardiogenic thrombosis or spontaneous imaging,the annual incidence of embolic events has been demonstrated to be 13.8%,although the anticoagulant threshold of CHA2DS2-VASc score is not reached and anticoagulant therapy should be given.However,the current clinical judgment of left atrial appendage thrombosis often relies on esophageal ultrasound,cardiac CT,nuclear magnetic imaging means,which have not been carried out in many primary hospitals.Therefore,in order to identify left atrial appendage thrombosis in early stage and initiate anticoagulation therapy in time,this study intends to screen out the predictors of left appendage thrombosis in NVAF patients through multi-factor analysis based on easily available clinical indicators.The left atrial appendage thrombosis risk prediction model and scoring system were established to evaluate the risk of thrombosis in patients with NVAF.ObjectiveTo investigate the risk factors of left appendage thrombosis in patients with NVAF,establish a risk prediction model and scoring system for left atrial appendage thrombosis in patients with NVAF,identify patients at high risk of left atrial appendage thrombosis,and guide the development of individualized anticoagulation strategies.MethodsUsing a retrospective case-control study design,data of 436 patients with NVAF who were hospitalized in the Department of Cardiology,the First Affiliated Hospital of Kunming Medical University from January 2020 to September 2022 were collected,and they were divided into the thrombus group（111 cases）and non-thrombus group（325 cases）according to TEE examination results.Clinical data of patients in the two groups were collected and recorded through the inpatient medical record system,including demographic information,vital signs on admission,co-existing diseases,drug use,laboratory test indicators,TTE,TEE,ECG and other data.Baseline data were compared between the two groups,and the risk factors that may be related to the formation of left atrial appendage thrombosis were screened out by single Logistic analysis.In the single factor analysis,the index with P<0.05 was used as the potential predictor.After multicollinearity was excluded,continuous variables were converted into categorical variables and included in the multivariate analysis.In multivariate analysis,binary Logistic stepwise regression was used to establish the risk prediction model of left atrial appendage thrombosis in NVAF patients,and the degree of differentiation and calibration of the model were evaluated.According to the regression coefficientβvalue of the model,each risk factor was assigned a score,and finally the model was transformed into a risk scoring system.The score of each study object was calculated,and risk stratification was performed according to the score situation and the proportion of patients with left atrial appendage thrombosis corresponding to different scores.The prediction performance of this score and CHA2DS2-VASc score for left atrial appendage thrombosis risk in NVAF patients was compared.Results1、Multivariate analysis showed that persistent atrial fibrillation（OR=3.392,95%CI 1.975-5.824）,LVEF<50%（OR=2.993,95%CI 1.084-8.264）,RBC≥4.8×10¹²/L（OR=1.925,95%CI 1.143-3.242）,FIB≥4g/L（OR=3.026,95%CI 1.324-6.920）,age≥67 years（OR=2.095,95%CI 1.246-3.524）,mitral regurgitation（OR=2.330,95%CI 1.244-4.361）,LAD≥39mm（OR=2.153,95%CI 1.222-3.793）,ventricular septal thickness≥12mm（OR=1.922,95%CI 1.151-3.209）were independent risk factors for left atrial appendage thrombosis（P<0.05）.2、The NVAF risk prediction model of left atrial appendage based on the above indexes can be expressed as:Logit（P）=-3.752+1.221×persistent AF+1.096×LVEF+0.655×RBC+1.107×FIB+0.740×age+0.846×mitral regurgitant flow+0.767×LAD+0.653×ventricular septal thickness.HL test of model P=0.669（>0.05）,R²=0.332,ROC curve analysis for predicting the probability of thrombus of left atrial ear suggested:AUC=0.815,95%CI 0.769-0.860,the calibration degree and prediction ability of the model were good.When the cut-off value for predicting the probability of left atrial appendage thrombosis was 23.46%,the sensitivity was 81.1%,and the specificity was 70.2%.3、The Perfamli score is established by each variable in the model and named after the first letter:The total score ranged from 0 to 11 points,including persistent AF（2 points）,EF<50%（2 points）,RBC≥4.8×10¹²/L（1 point）,FIB≥4g/L（2 points）,age≥67 years old（1 point）,mitral regurgitation（1 point）,LAD≥39mm（1 point）,and ventricular septal thickness≥12mm（1 point）.The LAAT diagnostic threshold was 4 points when the Yoden index was at its maximum.<4 was classified as low-risk group and≥4 was classified as high-risk group.The sensitivity and specificity of LAAT diagnosis were 85.6%and 68%.4、ROC curve analysis showed that all diagnostic indexes of Perfamli score were better than CHA2DS2-VASc score:AUC（0.831 vs 0.626）,sensitivity（85.6%vs79.3%）,specificity（68%vs 36.61%）,missed diagnosis rate（14.4%vs 20.7%）,misdiagnosis rate（32%vs 63.38%）,all P<0.05.ConclusionsThe results were as follows:persistent AF（P）,LVEF<50%（E）,RBC≥4.8×10¹²/L（R）,FIB≥4g/L（F）,age≥67 years（A）,mitral regurgitation（M）,LAD≥39mm（L）and ventricular septal thickness≥12mm（I）established Perfamli scores can be used to assess the risk of left atrial appendage thrombi in patients with NVAF and provide reference for the formulation of individualized anticoagulation strategies.