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Left atrial size and the risk of ischemic stroke in an ethnically mixed population
M R Di Tullio1, R L Sacco, R R Sciacca
1Department of Medicine, Columbia-Presbyterian Medical Center, New York, NY, USA. md42@columbia.edu
Insights
Left atrial enlargement increases ischemic stroke risk, particularly in men and younger adults. This association is influenced by factors like left ventricular hypertrophy in women, with potential racial disparities needing further study.
Area of Science:
- Cardiology
- Neurology
- Epidemiology
Background:
- The link between left atrial size and ischemic stroke is debated, with prior research suggesting it may be sex-specific and influenced by left ventricular mass.
- Existing data on this association predominantly comes from white populations, limiting generalizability.
Purpose of the Study:
- To investigate the association between left atrial size and ischemic stroke risk within a multiethnic cohort.
- To determine if this association differs across age, gender, and race-ethnicity strata.
Main Methods:
- A population-based case-control study involving patients with first ischemic stroke and matched community controls.
- Left atrial diameter, indexed by body surface area, was measured using 2D transthoracic echocardiography.
- Conditional logistic regression was employed to assess stroke risk associated with left atrial index, adjusting for confounding factors.
Main Results:
- Left atrial index was significantly associated with an increased risk of ischemic stroke in the overall population.
- The association was prominent in men and individuals younger than 60 years, but not significant in women or older adults.
- Left ventricular hypertrophy notably attenuated the association in women. Trends suggested varying risk across racial/ethnic groups.
Conclusions:
- Left atrial enlargement is an independent risk factor for ischemic stroke, even after accounting for left ventricular hypertrophy.
- The association is robust in men across all ages, while in women, it is less pronounced and influenced by factors like left ventricular hypertrophy.
- Further research is warranted to explore potential interracial differences in the relationship between left atrial size and stroke risk.
Background And Purpose:
The association between left atrial size and ischemic stroke is controversial and has been suggested to exist only in men and to be mediated by left ventricular mass. Data are available almost exclusively for white patients. The purpose of this study was to evaluate the association between left atrial size and ischemic stroke in a multiethnic population.
Methods:
A population-based case-control study was conducted in 352 patients aged >39 years with first ischemic stroke and in 369 age-, gender-, and race-ethnicity-matched community controls. Left atrial diameter was measured by 2-dimensional transthoracic echocardiography and indexed by body surface area. Conditional logistic regression analysis was performed to assess the risk of stroke associated with left atrial index in the overall group and in the age, gender, and race-ethnic strata after adjustment for the presence of other stroke risk factors.
Results:
Left atrial index was associated with ischemic stroke in the overall group (adjusted OR 1.47 per 10 mm/1.7 m(2) of body surface area; 95% CI 1.03 to 2.11). The association was present in men (adjusted OR 2.81, 95% CI 1.42 to 5.57) but not in women (adjusted OR 1.08, 95% CI 0.70 to 1.66), and in patients aged <60 years (adjusted OR 3.78, 95% CI 1.36 to 10.54) but not >60 years (adjusted OR 1.23, 95% CI 0.84 to 1.81). Subgroup analyses showed the risk to be present in men across all age subgroups. In women, the lack of association between left atrial index and stroke was most strongly influenced by left ventricular hypertrophy. A trend toward an association between left atrial index and stroke was observed in whites (adjusted OR 1.81, 95% CI 0.81 to 4.09) and Hispanics (adjusted OR 1.61, 95% CI 0.98 to 2.65) but was less evident in blacks (adjusted OR 1.25, 95% CI 0.74 to 2.14).
Conclusions:
Left atrial enlargement is associated with an increased risk of ischemic stroke after adjustment for other stroke risk factors, including left ventricular hypertrophy. The association is observed in men of all ages, whereas in women it is attenuated by other factors, especially left ventricular hypertrophy. Interracial differences in the stroke risk may exist that need further investigation.