Objectives Impaired left atrium (LA) and left atrial appendage (LAA) hemodynamics are risk factors (RF) for atrial thrombus formation and stroke. They can be assessed in vivo using 4D-flow-MRI; however, most studies involve clinical patient samples. We aimed to investigate demographic and cardiovascular (CV)-RF associations with LA and LAA hemodynamics in an observational study sample. Material and methods Participants from the multi-ethnic study of atherosclerosis from our institution were approached to undergo cardiac MRI, including 4D-flow-MRI. LA and LAA volume, blood stasis (%voxel with velocity < 0.1 m/s), and peak velocity (PV, top 5% of voxels) were calculated. CV-RF (demographics, history of atrial fibrillation (AF), body mass index (BMI), etc.) were available through study records and investigated in multivariable linear regression models. Results One hundred fifty-eight participants were included (age: 72.8 ± 7.3 years, 53% female). Higher age and AF were associated with lower PVLA (βage: −0.16, p < 0.01; βAF: −2.81, p < 0.05) and higher LA stasis (βage: 0.64, p < 0.001; βAF: 5.60, p < 0.05). On the other hand, diabetes and left ventricular ejection fraction were associated with higher PVLA (βdiabetes: 3.29, p < 0.01; βLVEF: 0.11, p < 0.05), and diabetes was also associated with lower LA stasis (β: −6.12, p < 0.05). PVLAA was lower in Black participants (β: −2.64, p < 0.01) and AF (β: −4.33, p < 0.001). LAA stasis was lower in males (β: −5.36, p < 0.01), white participants (β: −3.69, p < 0.05), diabetes (β: −4.54, p < 0.01) and higher BMI (β: −0.42, p < 0.05) while higher LA volume (β: 0.12, p < 0.01) was associated with higher LAA stasis. Conclusion We identified RF associated with impaired LA and LAA hemodynamics in an observational study cohort. Key Points <Emphasis Type="BoldItalic">Question</Emphasis> Are there associations of demographic and CV factors with impaired atrial hemodynamics from 4D-flow cardiac MRI? <Emphasis Type="BoldItalic">Findings</Emphasis> 4D-flow MRI identified, amongst others, higher age, race, history of AF, and BMI in a sub-cohort of the Multi-Ethnic Study of Atherosclerosis. <Emphasis Type="BoldItalic">Clinical relevance</Emphasis> Understanding risk factor associations with atrial hemodynamics could aid in identifying subclinical atrial thrombus formation risks, potentially allowing for earlier preventive strategies against diseases such as stroke in diverse populations. Graphical Abstract

Demographic and cardiovascular risk factors associated with blood flow characteristics of the left atrium and left atrial appendage

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2025年10月30日

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Maurice Pradella,
Justin J. Baraboo,
Stanley H. Chu,
Anthony Maroun,
Julia M. Hwang,
Mitchell A. Collins,
Amanda L. DiCarlo,
Elizabeth K. Weiss,
Lihui Zhao,
Rod Passman,
Susan R. Heckbert,
Philip Greenland,
Michael Markl

摘要

Objectives

Impaired left atrium (LA) and left atrial appendage (LAA) hemodynamics are risk factors (RF) for atrial thrombus formation and stroke. They can be assessed in vivo using 4D-flow-MRI; however, most studies involve clinical patient samples. We aimed to investigate demographic and cardiovascular (CV)-RF associations with LA and LAA hemodynamics in an observational study sample.

Material and methods

Participants from the multi-ethnic study of atherosclerosis from our institution were approached to undergo cardiac MRI, including 4D-flow-MRI. LA and LAA volume, blood stasis (%voxel with velocity < 0.1 m/s), and peak velocity (PV, top 5% of voxels) were calculated. CV-RF (demographics, history of atrial fibrillation (AF), body mass index (BMI), etc.) were available through study records and investigated in multivariable linear regression models.

Results

One hundred fifty-eight participants were included (age: 72.8 ± 7.3 years, 53% female). Higher age and AF were associated with lower PV_LA (β_age: −0.16, p < 0.01; β_AF: −2.81, p < 0.05) and higher LA stasis (β_age: 0.64, p < 0.001; β_AF: 5.60, p < 0.05). On the other hand, diabetes and left ventricular ejection fraction were associated with higher PV_LA (β_diabetes: 3.29, p < 0.01; β_LVEF: 0.11, p < 0.05), and diabetes was also associated with lower LA stasis (β: −6.12, p < 0.05). PV_LAA was lower in Black participants (β: −2.64, p < 0.01) and AF (β: −4.33, p < 0.001). LAA stasis was lower in males (β: −5.36, p < 0.01), white participants (β: −3.69, p < 0.05), diabetes (β: −4.54, p < 0.01) and higher BMI (β: −0.42, p < 0.05) while higher LA volume (β: 0.12, p < 0.01) was associated with higher LAA stasis.

Conclusion

We identified RF associated with impaired LA and LAA hemodynamics in an observational study cohort.

Key Points

Question Are there associations of demographic and CV factors with impaired atrial hemodynamics from 4D-flow cardiac MRI?

Findings 4D-flow MRI identified, amongst others, higher age, race, history of AF, and BMI in a sub-cohort of the Multi-Ethnic Study of Atherosclerosis.

Clinical relevance Understanding risk factor associations with atrial hemodynamics could aid in identifying subclinical atrial thrombus formation risks, potentially allowing for earlier preventive strategies against diseases such as stroke in diverse populations.

Graphical Abstract