Reduced Left Atrial Rotational Flow Is Independently Associated With Embolic Brain Infarcts

Elsevier

Available online 17 May 2023

JACC: Cardiovascular ImagingAuthor links open overlay panel, , , , , , , , , , , , AbstractBackground

Up to 25% of embolic strokes occur in individuals without atrial fibrillation (AF) or other identifiable mechanisms.

Objectives

To assess whether left atrial (LA) blood flow characteristics are associated with embolic brain infarcts, independently of AF.

Methods

The authors recruited 134 patients: 44 with a history of ischemic stroke and 90 with no history of stroke but CHA2DS2VASc (congestive heart failure, hypertension, age ≥75 [doubled], diabetes, stroke [doubled], vascular disease, age 65 to 74, and sex category [female]) score ≥1. Cardiac magnetic resonance (CMR) evaluated cardiac function and LA 4-dimensional flow parameters, including velocity and vorticity (a measure of rotational flow), and brain magnetic resonance imaging (MRI) was performed to detect large noncortical or cortical infarcts (LNCCIs) (likely embolic), or nonembolic lacunar infarcts.

Results

Patients (41% female; age 70 ± 9 years) had moderate stroke risk (median CHA2DS2VASc = 3, Q1-Q3, 2-4). Sixty-eight (51%) had diagnosed AF, of whom 58 (43%) were in AF during CMR. Thirty-nine (29%) had ≥1 LNCCI, 20 (15%) had ≥1 lacunar infarct without LNCCI, and 75 (56%) had no infarct. Lower LA vorticity was significantly associated with prevalent LNCCIs after adjustment for AF during CMR, history of AF, CHA2DS2VASc score, LA emptying fraction, LA indexed maximum volume, left ventricular ejection fraction, and indexed left ventricular mass (odds ratio [OR]: 2.06 [95% CI: 1.08-3.92 per SD]; P = 0.027). By contrast, LA flow peak velocity was not significantly associated with LNCCIs (P = 0.21). No LA parameter was associated with lacunar infarcts (all P > 0.05).

Conclusions

Reduced LA flow vorticity is significantly and independently associated with embolic brain infarcts. Imaging LA flow characteristics may aid identification of individuals who would benefit from anticoagulation for embolic stroke prevention, regardless of heart rhythm.

Key Words

embolic brain infarct

left atrial myopathy

rotational flow

vorticity

Abbreviations and Acronyms4D-flow

4-dimensional flow

CMR

cardiac magnetic resonance

DWI

axial diffusion-weighted imaging

FLAIR

fluid-attenuated inversion recovery

LNCCI

large noncortical or cortical infarct

MRI

magnetic resonance imaging

SNCI

smaller noncortical lesion

© 2023 Published by Elsevier on behalf of the American College of Cardiology Foundation.

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