Author + information
- Received August 26, 2013
- Revision received January 9, 2014
- Accepted January 10, 2014
- Published online May 1, 2014.
- Maria Carmo P. Nunes, MD, PhD∗,†,
- Mark D. Handschumacher, BS†,
- Robert A. Levine, MD†,
- Marcia M. Barbosa, MD, PhD∗,
- Vinicius T. Carvalho, MD∗,
- William A. Esteves, MD∗,
- Xin Zeng, MD, PhD†,
- J. Luis Guerrero, BS‡,
- Hui Zheng, PhD§,
- Timothy C. Tan, MD, PhD† and
- Judy Hung, MD†∗ ()
- ∗School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
- †Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
- ‡Cardiovascular Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
- §Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
- ↵∗Reprint requests and correspondence:
Dr. Judy Hung, Blake 256, Cardiac Ultrasound Laboratory, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114.
Objectives 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).
Background 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.
Methods 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 r3] where r was obtained from 3D cross-sectional area). The lower the LA shape index, the more spherical the shape.
Results 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.
Conclusions 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.
This study was partly supported by grants from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brasília, Brazil) and by the National Institutes of Health/National Heart, Lung, and Blood Institute grant no. R01 HL092101 (Dr. Hung). All authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received August 26, 2013.
- Revision received January 9, 2014.
- Accepted January 10, 2014.
- American College of Cardiology Foundation