| Part one Study of factors associated with left atrial appendage filling defects on early-phase cardiac computed tomography angiography in patients with nonvalvular atrial fibrillationObjective:The significance of left atrial appendage(LAA)filling defects on early-phase cardiac computed tomography angiography(CTA)remains uncertain.This study retrospectively investigated predictive factors of LAA filling defects on early-phase cardiac CTA and analyzed its clinical significance.Methods:A total of 68 patients with nonvalvular atrial fibrillation(AF)and early filling defect on cardiac CTA who underwent transthoracic echocardiography(TTE)and transesophageal echocardiography(TEE)were enrolled(48 males,20 females;mean±standard deviation age 62.72±8.13years).Additionally,68 sex and age-matched patients with normal LAA filling were included as the control group.Cardiac CTA,ultrasound,clinical and laboratory data were analyzed.All patients enrolled in the study(n=136)were divided into 3 groups(no,mild to moderate and severe filling defect)according to the visual severity of the early filling defect.The ratio of LAA Hounsfield units(HU)to that of ascending aorta(AA)on cardiac CTA early phase(LAA/AA)and the difference(in HU)between early and delayed phase of the LAA(LAAe-LAAd)were measured.The correlation of these parameters with left atrial appendage flow velocity(LAAFV)were analyzed and the differences in LAAFV between the three groups were compared.Baseline data between groups were analyzed using t-,Mann Whitney,and chi-squared tests.Multivariable logistic regression analysis was used to adjust for confounders.Spearman correlation analysis was used to confirm correlations between variables.Results:1.Early LAA filling defects occurred significantly(P<0.05)more frequently in patients with persistent AF during imaging,congestive heart failure,a history of brain infarction,and accelerated heart rate.There was no significant(P>0.05)difference in age,gender,BMI,time since AF diagnosis,hypertension,diabetes mellitus,coronary heart disease,hyperlipidemia,smoking,anticoagulation or antiplatelet medication between the two groups.2.Among the CTA parameters,LAVI,LAAVI,LAA orifice area,LAA long and short diameters,and LAA depth were significantly(P<0.001)increased in the filling defect compared with the control group.There was no significant(P>0.05)difference between the two groups in LAA shape,LSPV orifice area,left upper and lower pulmonary vein cotrunk,LAA orifice position,or LAA ridge width.3.With regard to TEE and TTE parameters,LAAFV and LVEF decreased significantly(P<0.001),whereas the LAA SEC ratio increased significantly(P<0.001)in the filling defect compared with control group.There was no significant(P>0.05)difference in e’between the two groups.4.The erythrocyte count,hemoglobin,aspartate aminotransferase,and serum uric acid were significantly higher in the early filling defect than in the control group(P<0.05).There was no significant(P>0.05)difference in red cell distribution width,platelet distribution width,white blood cell count,platelet count,alanine aminotransferase,creatinine,total cholesterol,triglycerides,high-density lipoprotein,low-density lipoprotein,and fibrinogen between the two groups.5.Decreased LAA flow velocity(LAAFV;odds ratio(OR)=0.918;95%confidence interval(CI):0.883–0.954;P<0.001)and increased left atrial volume index(LAVI;OR=1.055;95%CI:1.012–1.099;P=0.011)were significantly associated with early-phase cardiac CTA LAA filling defects.The LAAFV threshold for predicting early LAA filling defects was 40.5 cm/s,with an area under the receiver operating characteristic(ROC)curve(AUC)of 0.905(sensitivity82.4%,specificity 91.2%);the LAVI predictive threshold was 58.77 m L/m~2(AUC=0.840,sensitivity 85.3%,specificity 72.1%).6.A significant positive correlation was detected between LAAFV and the LAA/AA(r=0.688;P<0.001),as well as the LAAe-LAAd(r=0.641;P<0.001).There were significant(P<0.05)differences in LAAFV between different filling defects.Conclusions:Decreased LAAFV and increased LAVI are independent factors associated with LAA filling defects only on early-phase cardiac CTA.Early-phase cardiac CTA LAA filling defect is associated with LAA emptying dysfunction.These findings contribute to thrombosis risk stratification in patients with AF.Part two Study of the correlation between left atrial appendage filling defect restricted to the early phase of cardiac computed tomography angiography in patients with nonvalvular atrial fibrillation and ischemic strokePurpose: LAA is the major source of thrombus in AF patients.To investigate the relationship between LAA filling defects restricted to the early phase of cardiac computed tomography angiography(CTA)in patients with non-valvular AF and ischemic stroke.Materials and Methods: A total of 152 patients with non-valvular AF were retrospectively enrolled and divided into two groups according to the stroke history,as confirmed by brain computed tomography(CT)or magnetic resonance imaging(MRI),as the non-stroke group(n=89,51 males,38 females,mean age 61.64±11.19 years)and stroke group(n=63,35 males,54 females,mean age 67.25±8.12 years),respectively.The numbers of patients with filling defects in the early phase of cardiac CTA images without thrombi were recorded.Morphological parameters of the LAA were measured for all participants.All patients with early-phase filling defects(n=44)were assigned to two groups according to ischemic stroke history: the filling defects with stroke group(n=28,15 males,13 females,mean age 66.7±8.5 years)and the filling defects without stroke group(n=16,9 males,7 females,mean age 61.0 ±10.3 years).The clinical characteristics and LAA morphological parameters were compared.Results: 1.Compared with the non-stroke group,patients in the previous stroke group were older,had a lower LVEF,and had a lower BMI(P=0.001,<0.001,and =0.036,respectively).The previous stroke group had a higher proportion of hypertension and diabetes mellitus than the non-stroke group(P=0.01,=0.017,respectively).There were no significant differences between the two groups in terms of sex,type of AF,time since AF diagnosis,the prevalence of congestive heart failure,dyslipidemia,and coronary artery disease(P>0.05).2.The previous stroke group had a higher proportion of early LAA filling defects and a higher LAA volume index than the non-stroke group(P<0.001,and P=0.046,respectively).There were no significant differences between the two groups in the LAA orifice area,LAA orifice long diameter,LAA orifice short diameter,LAA morphology,distance from the LAA ostium to the first LAA bend,angle of the first LAA bend,LAA depth,or LAA volume.3.After adjusting for other risk factors by the multivariate logistic regression analysis,early LAA filling defect(OR,4.339;95% CI:1.951-9.653;P=0.000),age(OR,1.067;95% CI:1.024-1.111;P=0.002),and diabetes(OR= 2.850;95% CI:1.251-6.494;P=0.013)were independent risk factors for ischemic stroke.4.The clinical characteristics and LAA morphological parameters were not significantly different between the filling defects with stroke group and the group without stroke(P>0.05).Conclusion: AF patients with LAA transient filling defects in the early-phase of cardiac CTA had an increased risk of ischemic stroke compared to those without filling defects.This finding may help to optimize stroke risk stratification in patients with AF and provide the decision basis for adopting the best stroke prevention plan in clinical practice. |
