The Value Of Integrated Backscatter On Detecting Left Atrial Thrombus By Transesophageal Echocardiography

Objective To explore the value of early detecting left atrial (LA) thrombus in atrial fibrillation underwent transesophageal echocardiography (TEE) with integrated backscatter. Methods 29 control group subjects and 71 patients with atrial fibrillation were enrolled to record the LA volume, LAA peak velocity and ejection fraction (EF) of LAA and left upper pulmonary venous flow (PVF) parameters; detect spontaneous echocardiographic contrast (SEC) and thrombus of LA and/or LAA; record the corrected IBS value of left ventricle, LA and left appendage (LAA) by TEE with integrated backscatter; compare the corrected IBS value of LA, LAA, difference of LAA-LA in different degree SEC, in different atrial fibrillation groups and control group; and a regression analysis on the relationship between corrected IBS value with appendage EF and peak velocity of LAA,LA volume were performed. Results (1) Patients with atrial fibrillation had a larger LA volume ( 111.86 ± 84.66cm3 vs 46.18 ±28.84cm3) , a lower LAA peak velocity (28.24±23.31cm/s vs 61.55±28.24cm/s), a lower appendage EF( 26.11 ±22.49% vs 72.83 ?29.48%), a reduced peak systolic/diastolic velocity and systolic/diastolic time integrated of PVF ( S/D:0.83 ?0.36 vs 1.50±0.61; SDT/DDT:0.87 ± 0.34 vs 1.4 ± 0.52 ) ; a higher IBS of LA and LAA(11.29±5.0dB vs 6.02?.29dB, 10.62 ± 7.0dB vs 4.65± 3.53dB) when compared with control group subjects. (2)There were significantly difference of SEC in different atrial fibrillation groups and healthy subjects; As the degree of SEC aggravate, the corrected IBS of LA and LAA were improved.(3) There were significantly different of corrected IBS value of LA, LAA and LAA-LA in different atrial fibrillation groups and healthy subjects, the corrected IBS value of LA, LAA and LAA-LA in thrombus groups was obviously high; Using the corrected IBS in LAA with 13dB as the cutoff value, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of diagnostic left thrombus in left artial was 80%, 95.6%, 87%, 92.9% and 80% respectively . Using the corrected IBS of the difference of LAA-LA with IdB or OdB as the cutoff value, there was also some value in detecting left atrial thrombus. (4)The correct IBS of LAA were significantly correlated with LA volume , the peak velocity of LAA and appendage EF (r=0.28 p<0.02; r=0.51 p<0.01;r=0.49 p<0.01); The correct IBS of LA were also significantly correlated with LA volume, the peak velocity of LAA and appendage EF (r=0.56 p<0.01 ; r=0.55 p<0.01; r=0.60 p<0.01).Conclusions (1)When compared with control group subjects, Patients of atrial fibrillation group: LA volume became amplify; the contract function index of LAA was descend; the parameter of PVF had changed; the correct IBS of LA and LAA enhanced. Meanwhile, the correct IBS of LA and LAA were significantly correlated with LA volume and the contract function index of LAA. (2)TEE with integrated backscatter can be used to quantify the stasis of flow, more objectively than grade of SEC. (3)The corrected IBS in LAA with 13dB as the cutoff value , was valuable for early predicting the left atrial thrombus in patients of left atrial fibrillation quantitatively and objectively, it can be used to guide anticoagulation and prognosis of atrial fibrillation clinically.