Relationship between left atrial appendage morphology and stroke in patients with atrial fibrillation.

BACKGROUND

Atrial fibrillation (AF) is an important cause of stroke. Given the morbidity and mortality associated with stroke, the risk stratification of patients based on left atrial appendage (LAA) characteristics is of great interest.

OBJECTIVE

To explore the association between LAA morphology and LAA characteristics including the extent of trabeculations, orifice diameter, and length with prevalent stroke in a large cohort of patients with drug refractory AF who underwent AF ablation to develop mechanistic insight regarding the risk of stroke.

METHODS

An institutional cohort of 1063 patients referred for AF ablation from 2003 to 2012 was reviewed to identify patients that underwent preprocedural cardiac computed tomography (CT). LAA morphology was characterized as chicken wing, cactus, windsock, or cauliflower by using previously reported methodology. Left atrial size and LAA trabeculations, morphology, orifice diameter, and length were compared between patients with prevalent stroke and patients without prevalent stroke.

RESULTS

Of 678 patients with CT images, 65 (10%) had prior stroke or transient ischemic attack. In univariate analyses, prevalent heart failure (7.7% in cases vs 2.8% in controls; P = .033), smaller LAA orifice (2.26 ± 0.52 cm vs 2.78 ± 0.71 cm ; P < .001), shorter LAA length (5.06 ± 1.17 cm vs 5.61 ± 1.17 cm; P < .001), and extensive LAA trabeculations (27.7% vs 14.4%; P = .019) were associated with stroke. LAA morphologies were unassociated with stroke risk. In multivariable analysis, smaller LAA orifice diameter and extensive LAA trabeculations remained independently associated with thromboembolic events.

CONCLUSIONS

The extent of LAA trabeculations and smaller LAA orifice diameter are associated with prevalent stroke and may mediate the previously described association of cauliflower LAA morphology with stroke.