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Left atrial thrombus predicts transient ischemic attack in patients with atrial fibrillation
Marcus F Stoddard1, Pradeep Singh, Buddhadeb Dawn
1Department of Medicine, Division of Cardiology, University of Louisville, Louisville, Ky 40292, USA. mfstod01@louisville.edu
Insights
Left atrial thrombus is a significant predictor of transient ischemic attack (TIA) in patients with atrial fibrillation (AF). This study found LA thrombus strongly associated with TIA risk, supporting a thromboembolic mechanism.
Area of Science:
- Cardiology
- Neurology
- Medical Imaging
Background:
- Atrial fibrillation (AF) is a known cause of cardioembolic stroke due to left atrial (LA) thrombus.
- The link between LA thrombus and transient ischemic attack (TIA) in AF patients requires further elucidation.
Purpose of the Study:
- To investigate the association between LA thrombus and TIA in patients with AF.
- To identify predictors of TIA in this patient population.
Main Methods:
- Prospective follow-up of 261 adult AF patients undergoing transesophageal echocardiography (TEE).
- Patients were monitored for TIA over a mean duration of 30.3 months.
- Multivariate logistic regression and Kaplan-Meier survival analysis were employed.
Main Results:
- LA thrombus was identified in 18% of patients.
- LA thrombus emerged as the sole independent predictor of TIA (OR 7.7, P =.0001) when TEE variables were included.
- Patients with LA thrombus had a significantly lower TIA-free survival rate and a higher annual TIA event rate (9.2% vs. 1.9%).
Conclusions:
- This is the first prospective study to demonstrate a significant association between LA thrombus and TIA in AF patients.
- LA thrombus is a strong predictor of TIA, supporting a thromboembolic etiology.
- Clinical parameters and other TEE findings were not independently predictive of TIA.
Background:
Atrial fibrillation (AF) is widely accepted as a direct cause of cardioembolic stroke from left atrial (LA) thrombus formation. However, the relationship between LA thrombus and transient ischemic attack (TIA) in patients with AF is less well established.
Methods:
Two hundred sixty-one adult patients (mean age 66 +/- 11 years, 220 men and 41 women) with AF undergoing transesophageal echocardiography (TEE) were prospectively followed up for TIA (mean duration 30.3 +/- 20.6 months).
Results:
LA thrombus was present in 18% (n = 46) and LA spontaneous echocardiographic contrast in 50% (n = 131) of the group. Nineteen of 261 patients had TIA during follow-up. Multivariate logistic regression showed congestive heart failure (CHF) as the only predictor of TIA when a model of clinical variables was constructed (odds ratio [OR] 2.7, P =.04). Age, sex, hypertension, and use of warfarin or aspirin were not predictors. When TEE variables were added to the model, LA thrombus became the only predictor of TIA (OR 7.7, P =.0001). Survival free of TIA (Kaplan-Meier) was significantly less (P =.0001) in patients with LA thrombus compared with those without, and the annual TIA event rate was 9.2% per year versus 1.9% per year (P <.0001), respectively.
Conclusions:
To our knowledge, this is the first prospective study documenting an association between LA thrombus and TIA in patients with AF. Other TEE variables, including aortic atheromata, and clinical parameters were not independently predictive. These data support a likely thromboembolic mechanism for TIA from LA thrombus in patients with AF.