Available online 17 May 2023
Author links open overlay panel, , , , , , , , , , , , AbstractBackgroundUp to 25% of embolic strokes occur in individuals without atrial fibrillation (AF) or other identifiable mechanisms.
ObjectivesTo assess whether left atrial (LA) blood flow characteristics are associated with embolic brain infarcts, independently of AF.
MethodsThe 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.
ResultsPatients (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).
ConclusionsReduced 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 Wordsembolic brain infarct
left atrial myopathy
rotational flow
vorticity
Abbreviations and Acronyms4D-flow4-dimensional flow
CMRcardiac magnetic resonance
DWIaxial diffusion-weighted imaging
FLAIRfluid-attenuated inversion recovery
LNCCIlarge noncortical or cortical infarct
MRImagnetic resonance imaging
SNCIsmaller noncortical lesion
© 2023 Published by Elsevier on behalf of the American College of Cardiology Foundation.
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