Intensity variation in the left atrial appendage during contrast echocardiography is a novel predictor for the occurrence of cardioembolic stroke

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【Background】 It is sometimes difficult to make a diagnosis of cardiogenic brain embolism in stroke care unit due to the splashing and vanishing of the thrombus from left atrial appendage (LAA). 【Hypothesis】 Decreased levels of the intensity variation in the LAA during contrast echocardiography may be a direct evidence for the cardioembolic stroke occurrence. 【Methods】 Trans-esophageal echocardiographic parameters and hemostatic markers were examined in 113 consecutive patients with cerebral infarction within 7 days after the onset. We measured intra-cardiac intensity variation during intravenous bolus infusion of Levovist^<TM> (1,500 mg) at the orifice of the LAA, as well as the LAA peak emptying flow velocity and lateral wall velocity by the Doppler tissue imaging. Serum levels of fibrin-monomer (FM) were measured by latex aggregation method in all cases as a sensitive marker for sure diagnoses of hypercoagulable state and thrombus formation in vivo. The patients were followed for a m … More ean of 354±111 (ranges 36-585) days. The primary end-points were ischemic stroke recurrence and/or death. 【Results】 LAA intensity variation was significantly smaller in LAA thrombus positive group (n=20) than in negative group (7.5 ± 2.4 vs. 13.6 ± 4.2 dB, P<.001). In LAA thrombus negative group, FM levels were significantly correlated with LAA intensity variation (R=-.641, P=.021), peak emptying flow velocity (R=-.281, P=.031), and lateral wall velocity (R=-.353, P=.0152), but not with left atrial dimension or LAA area. The Cox proportional hazards multivariate analysis showed that the LAA intensity variation was an independent predictor of LAA thrombus formation (hazard ratio, 5.321 per +1SD decrease ; 95% confidence interval 1.484-11.010, P=.003). The cerebrovascular event rates were markedly higher in the 32 cases with intensity variation <10 dB than in the 81 cases with intensity variation 【greater than or equal】 10 dB (37.5% vs. 8.6%, P<.001). 【Conclusion】 LAA intensity variation during Levovist^<TM> infusion could used as a surrogate marker to diagnose LAA dysfunction and to predict the recurrence of cardioembolic stroke after the splashing of the thrombus. Less