Reduced Left Atrial Appendage Flow Is Associated With Future Atrial Fibrillation After Cryptogenic Stroke

Elsevier

Available online 15 May 2023

Journal of the American Society of EchocardiographyAuthor links open overlay panel, , , , , , , , , Background

Hemostasis within the left atrial appendage (LAA) is a common cause of stroke, especially in patients with atrial fibrillation (AF). Although LAA flow provides insights into LAA function, its potential for predicting AF has yet to be established. The aim of this study was to explore whether LAA peak flow velocities early after cryptogenic stroke are associated with future AF on prolonged rhythm monitoring.

Methods

A total of 110 patients with cryptogenic stroke were consecutively enrolled and underwent LAA pulsed-wave Doppler flow assessment using transesophageal echocardiography within the early poststroke period. Velocity measurements were analyzed offline by an investigator blinded to the results. Prolonged rhythm monitoring was conducted on all participants via 7-day Holter and implantable cardiac monitoring devices, with follow-up conducted over a period of 1.5 years to determine the incidence of AF. The end point of AF was defined as irregular supraventricular rhythm with variable RR interval and no detectable P waves lasting ≥30 sec during rhythm monitoring.

Results

During a median follow-up period of 539 days (interquartile range, 169-857 days), 42 patients (38%) developed AF, with a median time to AF diagnosis of 94 days (interquartile range, 51-487 days). Both LAA filling velocity and LAA emptying velocity (LAAev) were lower in patients with AF (44.3 ± 14.2 and 50.7 ± 13.3 cm/s, respectively) compared with patients without AF (59.8 ± 14.0 and 76.8 ± 17.3 cm/sec, respectively; P < .001 for both). LAAev was most strongly associated with future AF, with an area under the receiver operating characteristic curve of 0.88 and an optimal cutoff value of 55 cm/sec. Age and mitral regurgitation were independent determinants of reduced LAAev.

Conclusions

Impaired LAA peak flow velocities (LAAev < 55 cm/sec) in patients with cryptogenic stroke are associated with future AF. This may facilitate the selection of appropriate candidates for prolonged rhythm monitoring to improve its diagnostic accuracy and implementation.

Section snippetsStudy Population

Our study cohort included consecutive patients with cryptogenic stroke at Ziekenhuis Oost-Limburg in Belgium between 2017 and 2022. The diagnosis of stroke was based on clinical examination by the attending neurologist and findings on computed tomography or brain magnetic resonance imaging. Patients with transient ischemic attacks were enrolled only if symptoms at presentation were aphasia, limb weakness, or hemianopsia. All patients were admitted to the stroke unit and underwent ≥24 hours of

Patient Characteristics

Among 141 patients with cryptogenic stroke, 31 (22%) were excluded. TEE was unachievable in two patients (1%), and in 29 patients (21%), pulsed-wave Doppler flow LAA interrogation by TEE was lacking. The baseline characteristics of the study population (n = 110) are summarized in Table 1. The mean age was 67 ± 12 years, and the majority were men (52%). The median CHA2DS2-VASc score was 3 (IQR, 2-4), implying a theoretical AF-related stroke risk of >5.9% per year (without anticoagulation).21

Discussion

To the best of our knowledge, this is the first study evaluating LAA peak flow velocity measurements in patients with acute cryptogenic stroke who underwent long-term continuous cardiac rhythm monitoring to detect subclinical AF (Central Illustration). The main findings of this study are as follows: (1) reduced LAAev is strongly and independently associated with future AF occurrence after stroke, and (2) a cutoff value of 55 cm/sec yields sensitivity of 90% and specificity of 76% to unmask

Conclusion

LAA peak flow velocities measured early after cryptogenic stroke can identify patients at high risk for underlying AF, in whom prolonged rhythm monitoring using implantable cardiac monitoring should be considered. This finding may improve the diagnostic accuracy and cost-effectiveness of implantable cardiac monitoring in daily clinical practice.

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2023 by the American Society of Echocardiography.

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