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

【背景】在脑卒中监护病房，心源性脑栓塞有时因左心耳血栓飞溅消失而难以诊断。【假设】超声造影时LAA强度变化水平降低可能是心栓子性脑卒中发生的直接证据。【方法】连续113例脑梗死患者发病后7 d内经食管超声心动图参数及止血指标测定。采用多普勒组织显像法测定了左心室a孔静脉滴注Levovist^<TM> (1500 mg)时的心内强度变化，以及左心室a的峰值空血流速度和侧壁速度。所有病例均采用乳胶聚集法测定血清纤维蛋白单体（FM）水平，作为体内高凝状态和血栓形成的敏感诊断指标。随访时间为354±111天（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） LAA强度变化明显小于阴性组（7.5±2.4 vs. 13.6±4.2 dB， P< 0.001）。在LAA血栓阴性组，FM水平与LAA强度变化（R=- 0.641， P= 0.021）、排空血流峰值速度（R=- 0.281， P= 0.031）、侧壁流速（R=- 0.353， P= 0.0152）显著相关，但与左房尺寸和LAA面积无关。Cox比例风险多因素分析显示，LAA强度变化是LAA血栓形成的独立预测因子（风险比为5.321 / +1SD； 95%置信区间为1.484 ~ 11.010，P= 0.003）。强度变化<10 dB的32例脑血管事件发生率明显高于强度变化【大于或等于】10 dB的81例（37.5% vs. 8.6%， P< 0.001）。【结论】Levovist^<TM>输注过程中LAA强度变化可作为诊断LAA功能障碍和预测血栓飞溅后心源性卒中复发的替代指标。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