a new study suggests. “We found people with worsening diastolic dysfunction have more white matter hyperintensities on brain imaging and greater difficulty with executive functioning, suggesting that diastolic dysfunction is a common modifiable risk factor for cognitive impairment,” said lead author Alicia S. Parker, MD. Dr. Parker is assistant professor of cognitive and behavioral neurology at the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health, San Antonio.
“This is an entirely new finding. While there have been some small studies suggesting a link between diastolic dysfunction and a reduction in working memory, this is by far the largest dataset on this topic and the first study that has included brain imaging and neuropsychological measures,” she said.
“Diastolic dysfunction is very common in the older population, and we need to do more to find it and treat it to help prevent or reduce cognitive decline,” Dr. Parker added.
This research is being presented online as part of the 2020 American Academy of Neurology Science Highlights.
Dr. Parker explained that systolic dysfunction is known to have a major effect on cardiovascular outcomes and has been found to be associated with cognitive decline. Proposed mechanisms for cognitive decline in patients with systolic dysfunction include low cardiac output, embolic infarctions, and hypoxic changes, among others.
“There is increasing interest in analyzing the influence of diastolic dysfunction on cardiovascular outcomes, and the effects of diastolic dysfunction on cognition are not currently well delineated, which this study seeks to address,” she added.
“While these results are new, they are not surprising. In general, we are finding more and more that heart health is connected to brain health,” she commented.
Dr. Parker and her colleagues started the current research after noticing in clinic that among patients with significant diastolic dysfunction, there were often changes on brain MRI imaging, and the patients often had trouble with executive function. “The effect of diastolic dysfunction on cognition has not been well characterized, so we wanted to look at this,” she said.
The investigators analyzed data from the Framingham Heart Study Offspring Cohort at examination 8, collected between 2005 and 2008. The study sample included 1,438 individuals older than 55 years who had undergone neuropsychological assessment and echocardiographic diastolic measurement. Systolic measurements were normal for the participants, and they did not currently have dementia, stroke, or other neurologic illness.
Results showed that increasing E/E’ ratio (the ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity) indicated increasing diastolic dysfunction and was associated with an increase in the incidence of mild cognitive impairment (hazard ratio, 1.29; 95% confidence interval, 1.01-1.66; P < .043).
An increased E/E’ ratio was associated with increased executive function impairment in the “similarities” (beta, –0.29; P < .002) and “phonemic fluency” (–1.28; P < .001) tasks.
Participants with moderate to severe diastolic dysfunction were more impaired with respect to both similarities (–0.62; P < .046) and phonemic fluency (–2.60; P < .023).
Data from 1,217 participants showed that among those with mild diastolic dysfunction, there was a trend toward an increase in white matter hyperintensities (0.11; P < .105). For participants with moderate to severe diastolic dysfunction, white matter hyperintensities were increased (0.30; P < 0.001).
The results were unchanged after the researchers adjusted for many other predictors of cognitive decline affecting diastolic function.
The researchers conclude: “As cerebral small vessel disease clinically presents with executive dysfunction, these results align well.” They add that replication in additional cohorts and analyses of cognition in treatment trials of diastolic dysfunction are warranted.