Value of left atrial appendage measurement parameters based on coronary CT angiography in predicting cardiogenic stroke in patients with nonvalvular atrial fibrillation / 中华放射学杂志

ABSTRACT

Objective:To investigate the predictive value of measurement parameters of left atrial appendage by coronary CTA (CCTA) for the risk of cardiogenic stroke (CS) in patients with nonvalvular atrial fibrillation (NVAF).Methods:The clinical and examination data of 179 patients with NVAF who underwent CCTA examination were retrospectively analyzed. The selected patients were grouped according to the outbreak of acute ischemic stroke and TIA within 2 years after CCTA examination. Patients who met the criteria for CS were selected as cases (87 patients), and those with neither stroke nor TIA as controls (92 patients). The diameter and area of left atrial appendage (LAA) orifice, the LAA depth, and the LAA volume were measured by using dedicated software. The parameter was corrected using the body surface area (BSA) to obtain the correction index of corresponding parameter. The independent samples t test, Mann-Whitney U test, and Chi-square test were used to compare the differences in various indicators between the two groups. Binary logistic regression was used to analyze the impacts of body mass index (BMI), hyperlipidemia, the duration years of atrial fibrillation, left atrial appendage area index (LAAOA Index), and the left atrial appendage emptying fraction (LAAEF) on the risk of CS. The ROC curve was used to evaluate the predictive value of LAAOA Index and LAAEF for the onset of CS. Results:The correction index of the left atrial appendage orifice maximum and minimum diameter, the left atrial appendage orifice area, and the maximum & minimum left atrial appendage volume and the LAAEF in the case group were (1.80±0.21) cm/m 2, (1.19±0.17) cm/m 2, (3.20±0.71) cm 2/m 2, (7.91±1.92) ml/m 2, (5.03±1.40) ml/m 2, (36.20±10.54)%, and those value in the control group were (1.64±0.24) cm/m 2, (1.06±0.19) cm/m 2, (2.65±0.64) cm 2/m 2, (6.61±1.68) ml/m 2, (3.67±1.28) ml/m 2, (45.25±10.07)%, the differences were statistically significant ( t= 4.783, 4.647, 5.481, 4.826, 6.823, and -5.875, all P<0.001). Binary logistic regression analysis showed that the increase in LAAOA Index ( P= 0.005) and the decrease in LAAEF ( P<0.001) were independent risk factors for CS in NVAF patients. The area under the ROC curve (AUC) of LAAOA Index was 0.712 (95%CI 0.639-0.777), and the best diagnostic cut-off was 3.16 cm 2/m 2; the AUC of LAAEF was 0.734 (95%CI 0.663-0.797), the cut-off was 38.71%; the AUC of LAAOA Index-LAAEF was 0.786 (95%CI 0.718-0.843). The difference of AUC value between LAAOA Index and LAAEF was not statistically significant ( Z= 0.448, P= 0.654). The difference of AUC between the LAAOA Index-LAAEF and LAAOA Index ( Z=2.667, P=0.008) and between the LAAOA Index-LAAEF and LAAEF ( Z=2.061, P=0.039) were statistically significant. Conclusions:CCTA can provide a one-stop and relatively accurate evaluation of the size and function of the left atrial appendage by post-processing the coronary vascular scan data. Left atrial appendage measurement parameters from CCTA can be used as a supplement to the CHA2DS2-VASc score, and provide quantitative indicators for the risk assessment of CS in patients with NVAF.