Decreased LA Appendage Peak Velocity May Be a Risk Factor for SCI.
There may be a link between decreased peak velocity in the left atrial appendage (LAA) and silent cerebral infarcts (SCI), according to research presented on Tuesday.
"Volumetric and functional changes of the left atrium have been linked to stroke in the past, especially in patients with atrial fibrillation," said presenter Maurice Pradella, MD, a cardiovascular radiologist with a special interest in the left atrium, has been a research fellow in the Department of Radiology at Northwestern University Feinberg School of Medicine in Chicago and is currently deputy section head of cardiothoracic radiology in the Department of Radiology at University Hospital Basel in Switzerland.
"The underlying principle of these observations is hypothesized to be related to changes in atrial flow hemodynamics, which lead to thrombus formation," he continued. "The American Heart Association supported us at Northwestern to study left atrial hemodynamics using 4D-flow MRI and their associations with silent brain infarction in a cohort of Multi-Ethnic Study of Atherosclerosis (MESA) participants."
The goal of the study was to identify left atrial (LA) and LAA flow parameters linked to SCI. A total of 125 patients (age: 72.7±7.4 years, 54% women) underwent both brain and cardiac MRI including 4D-flow in 2018-2020. Board-certified neuroradiologists read brain MRIs for SCI. LA and LAA were segmented on phase-contrast magnetic resonance angiography that was derived from 4D-flow. The researchers calculated blood stasis and peak velocity as parameters for hemodynamics assessment.
In addition, the researchers analyzed LA function on a stack of short-axis CINE series to measure LA volumes and LA emptying fractions. They also identified cardiovascular risk factors and patient demographics linked to SCI.
Recognizing SCI Risk May Improve Patient Care
Of the 125 study participants, 26 (21%) had a minimum of one SCI on brain MRI.
"We found that besides older age, a decrease in peak velocity in the left atrial appendage was associated with silent brain infarction in our cohort," Dr. Pradella said, noting that demographics (other than age), other CV risk factors, and volumetric-based LA parameters were not associated with SCI in the multivariable regression model.
"We did a comprehensive analysis of the left atrium and investigated volumes, functional parameters and multiple flow parameters," Dr. Pradella noted, adding that he found it interesting that LAA peak velocity was the only statistically important factor.
Identifying reduced LAA peak velocity as a potential new risk factor for SCI could have important implications for patient care, he said.
"If our findings are confirmed in larger samples—and, especially, in a multi-center setting—we might be able to identify patients at-risk for silent brain infarction who could benefit from treatments such as anticoagulation therapy to prevent stroke," he said.
Access the presentation, "Altered Left Atrial 3D Blood Flow Dynamics Are Associated with Silent Cerebral Infarction: The Multi-Ethnic Study of Arteriosclerosis," (T3-SSCA05-3) on demand at Meeting.RSNA.org Dr. Pradella earned an RSNA Trainee Research Prize for his paper.