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Stroke prevention in AF is guided by clinical factors with inadequate predictive power. Most thrombi observed in AF are observed in the left atrial appendage (LAA). This study was designed to 1) determine the LAA volume among patients with AF and a history of stroke compared to AF patients without a history of stroke, 2) identify a LAA volume threshold that significantly increases the risk of stroke in AF patients, and 3) determine the relative predictive value of LAA size compared with the CHADS and CHADS-VASC models when applied to patients without a history of prior stroke.
Patients (N=48) with a history of atrial fibrillation and stroke were compared with controls (N=48) with a history of atrial fibrillation but no history of stroke. MRA images from case and control populations were segmented to determine LAA volume.
Patients with a history of stroke had larger LAA mean volumes than controls (28.8 ± 13.5 cm3 vs. 21.7 ± 8.27 cm3, P = 0.002). LAA volume > 34 cm3 was identified as a threshold that conveys a significantly increased risk of stroke (Multivariable OR 7.11, P = 0.003). LAA volume increases of 10 cm3 conveys a greater risk of stroke (Multivariable OR 1.88 per +10 cm3, p=0.007) than a 1 point increase in the CHADS2 score (Multivariable OR 1.52 per +1 point, p=0.06) when applied to a primary prevention population.
Larger LAA volume is associated with stroke in the setting of atrial fibrillation. LAA volume analysis by MRA can potentially improve risk stratification for stroke in AF patients.
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.-10:45 a.m.
Session Title: Arrhythmias: AF/SVT II
Abstract Category: 4. Arrhythmias: AF/SVT
Presentation Number: 1107-55
- 2013 American College of Cardiology Foundation