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JACC Cardiovasc Imaging. 2014 May;7(5):453-61. doi: 10.1016/j.jcmg.2014.01.013.

Role of LA shape in predicting embolic cerebrovascular events in mitral stenosis: mechanistic insights from 3D echocardiography.

Author information

1
School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil; Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
2
Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
3
School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil.
4
Cardiovascular Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
5
Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
6
Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: jhung@partners.org.

Abstract

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 r(3)] 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.

KEYWORDS:

3D echocardiography; embolic events; left atrial function; left atrial shape; mitral stenosis

PMID:
24831206
PMCID:
PMC4373610
DOI:
10.1016/j.jcmg.2014.01.013
[Indexed for MEDLINE]
Free PMC Article
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