P1360Association between left atrial appendage dysfunction and thromboembolic risk in nonvalvular atrial fibrillation. (18th June 2020) - Mao, Y
Abstract : Abstract: Background/Introduction: Atrial fibrillation (AF) is associated with higher risk for thromboembolism, and the discriminative ability of the widely used CHA2DS2-VASc scores for risk stratification is modest. Although the presence of thrombus in the LAA is the most powerful predictors for thromboembolic risk, they are often absent in patients with AF and prior stroke. AF may be related to myocardial fibrosis, and even though left atrial fibrosis is associated with mechanical dispersion, this phenomenon is not well studied in LAA. We hypothesized that detection of LAA dysfunction and mechanical dispersion using strain echocardiography is useful in the identification of cardiac thromboembolism. Purpose: The aim of this study was to determine the association of LAA mechanics assessed using strain analysis with previous thromboembolic events in patients with nonvalvular AF and to assess the potential incremental significance of LAA mechanical dispersion over the traditional risk stratification scheme. Methods: A group of 116 patients with AF referred for TEE was prospectively analyzed. LAA strain and mechanical dispersion in parallel with other conventional TEE parameters were analyzed in terms of their association with previous embolic stroke and peripheral embolization. Results: Patients with embolic events had a higher mean CHA2DS2-VASc score, higher incidence of LAA dense SEC or thrombi, and other clinical data were comparable. Patients with embolic events had greater impairment in the LA standard parameters, and lower global and regional LAA longitudinal strain than those of the controls. LAA MD was significantly higher in patients with embolization than in those without it (18.91 ± 7.19 %vs 13.8 ± 5.54%; P < .001). In ROC analysis, cut-off values for LAA MD, LAEF, LAA GLS for the presence of dense SEC/ thrombus were >20.21 % (p = 0.0076), ≤31.11 % (p = 0.017), and ≤ 7.31 % (p = 0.014), respectively. LAA MD, LAEF, LAA thrombus and CHA2DS2-VASc scores were independently associated with the presence of thromboembolism in multivariate analyses, and LAA MD had additional significance over the CHA2DS2-VASc score. Conclusion: LAA MD, LAA thrombi and LAEF had statistically significant meaning for the presence of prior embolism that was independent of the standard planimetric and volumetric measurements. What's more, LAA MD had an incremental value over CHA2DS2-VASc score in risk stratification and warrants testing in a larger study.