Nunes Maria Carmo P, Handschumacher Mark D, Levine Robert A, Barbosa Marcia M, Carvalho Vinicius T, Esteves William A, Zeng Xin, Guerrero J Luis, Zheng Hui, Tan Timothy C, Hung Judy
School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil; Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
JACC Cardiovasc Imaging. 2014 May;7(5):453-61. doi: 10.1016/j.jcmg.2014.01.013.
This study was designed to assess the role of left atrial (LA) shape in predicting embolic cerebrovascular events (ECE) in patients with mitral stenosis (MS).
Patients with rheumatic MS are at increased risk for ECE. LA remodeling in response to MS involves not only chamber dilation but also changes in the shape. We hypothesized that a more spherical LA shape may be associated with increased embolic events due to predisposition to thrombus formation or to atrial arrhythmias compared with an elliptical-shaped LA of comparable volume.
A total of 212 patients with MS and 20 control subjects were enrolled. LA volume, LA emptying fraction, and cross-sectional area were measured by 3-dimensional (3D) transthoracic echocardiography. LA shape was expressed as the ratio of measured LA end-systolic volume to hypothetical sphere volume ([4/3π r(3)] where r was obtained from 3D cross-sectional area). The lower the LA shape index, the more spherical the shape.
A total of 41 patients presented with ECE at the time of enrollment or during follow-up. On multivariate analysis, LA 3D emptying fraction (adjusted odds ratio [OR]: 0.96; 95% confidence interval [CI]: 0.92 to 0.99; p = 0.028) and LA shape index (OR: 0.73; 95% CI: 0.61 to 0.87; p < 0.001) emerged as important factors associated with ECE, after adjustment for age and anticoagulation therapy. In patients in sinus rhythm, LA shape index remained associated with ECE (OR: 0.79; 95% CI: 0.67 to 0.94; p = 0.007), independent of age and LA function. An in vitro phantom atrial model demonstrated more stagnant flow profiles in spherical compared with ellipsoidal chamber.
In rheumatic MS patients, differential LA remodeling affects ECE risk. A more spherical LA shape was independently associated with an increased risk for ECE, adding incremental value in predicting events beyond that provided by age and LA function.
本研究旨在评估左心房（LA）形态在预测二尖瓣狭窄（MS）患者发生栓塞性脑血管事件（ECE）中的作用。
风湿性MS患者发生ECE的风险增加。MS引起的LA重塑不仅涉及心房扩张，还包括形态改变。我们假设，与具有相同容积的椭圆形LA相比，更接近球形的LA形态可能因易于形成血栓或发生房性心律失常而与栓塞事件增加有关。
共纳入212例MS患者和20例对照者。采用三维（3D）经胸超声心动图测量LA容积、LA排空分数和横截面积。LA形态用测量的LA收缩末期容积与假设球体容积（[4/3πr(3)]，其中r由3D横截面积得出）的比值表示。LA形态指数越低，形态越接近球形。
共有41例患者在入组时或随访期间发生ECE。多因素分析显示，在调整年龄和抗凝治疗后，LA的3D排空分数（校正比值比[OR]：0.96；95%置信区间[CI]：0.92至0.99；p = 0.028）和LA形态指数（OR：0.73；95%CI：0.61至0.87；p < 0.001）是与ECE相关的重要因素。在窦性心律患者中，LA形态指数仍与ECE相关（OR：0.79；95%CI：0.67至0.94；p = 0.007），独立于年龄和LA功能。体外模拟心房模型显示，与椭圆形心房相比，球形心房内的血流更易出现停滞。
在风湿性MS患者中，不同的LA重塑影响ECE风险。更接近球形的LA形态与ECE风险增加独立相关，在预测事件方面除了年龄和LA功能外还增加了额外价值。
