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

[背景]在卒中监护病房中，由于左心耳(LAA)血栓的飞溅和消失，有时很难做出心源性脑栓塞的诊断。[假设]声学造影过程中左心耳强度变化水平的降低可能是心栓性卒中发生的直接证据。[方法]对113例脑梗塞患者发病后7d内经食道超声心动图参数和止血标志物进行检测。我们测量了在左心耳口静脉注射Levovist(1,500 mg)时心脏内强度的变化，以及多普勒组织成像测量左心耳最大排空血流速度和侧壁血流速度。用胶乳聚集法测定血清纤维蛋白单体(Fm)水平，作为明确诊断体内高凝状态和血栓形成的敏感指标。对这些患者进行了m-…追踪。平均为354±111(范围36-585)天。主要终点为缺血性卒中、复发和/或死亡。[结果]LAA血栓阳性组(n=20)的LAA强度变化值明显小于LAA血栓阴性组(7.5±2.4比13.6±4.2分贝，P<0.01)。在血栓阴性组，FM水平与左房强度变异(R=-.641，P=.021)、峰值排空速度(R=-.281，P=.031)、侧壁速度(R=-.353，P=.0152)显著相关，而与左房内径和左房面积无关。COX比例风险多因素分析显示，左心耳强度变异是左心耳血栓形成的独立预测因子(危险比，每+1SD下降5.321；95%可信区间1.484-11.010，P=0.003)。脑血管事件发生率在信号变异<10分贝的32例明显高于信号变异大于或等于10分贝的81例(37.5%vs.8.6%，P&t；.001)。[结论]静脉滴注Levovist时LAA强度变化可作为诊断LAA功能障碍和预测血栓溅出后心栓性卒中复发的替代指标。较少

【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