Cognitive function may deteriorate faster after MI, angina

Incident coronary heart disease (CHD) might be an early indicator of accelerated cognitive decline, according to work published ahead of print in the Journal of the American College of Cardiology.

CHD—one of the leading causes of mortality worldwide—predisposes patients to cerebrovascular damage, Wuxiang Xie, PhD, the study’s lead author and a research fellow at the Imperial College School of Public Health in London, and co-authors wrote in the journal. It’s been linked to cerebral ischemic lesions that in turn result in cognitive impairment, and in many cases CHD been implicated in the pathological “cascade” of vascular dementia and Alzheimer’s disease.

“The atherosclerotic process and related hypoperfusion have been proposed to underlie vascular-related cognitive impairment, and these occur during a period prior to the CHD event,” Xie and colleagues said. “Thus, it is reasonable to assume that patients with CHD have faster rates of cognitive decline before the event.

“No studies have measured both the short-term cognitive decline after incident CHD and the cognitive changes occurring in the years before and after CHD; thus, the pattern of cognitive trajectory remains largely unknown.”

Xie et al. examined cognitive function in 7,888 stroke-free participants from the English Longitudinal Study of Aging, a community-based cohort study of adults aged 50 and up. Patients with a history of stroke, heart attack, angina or a confirmed diagnosis of dementia or Alzheimer’s were excluded from the study, as were those who experienced stroke during follow-up.

The researchers assessed participants’ cognitive function in eight waves over a period of 12 years, using three rudimentary tests to gauge each person’s cognitive state over time. Verbal memory was assessed with immediate and delayed recall of a set of 10 unrelated words; semantic fluency was tested by asking patients to name as many animals as they could in 1 minute; and temporal orientation was assessed through four questions regarding the current date.

During the dozen years of follow-up, 5.6% of patients experienced a heart attack or angina, and those with CHD showed faster rates of cognitive decline in all three tests. Patients who had difficulty with temporal orientation were more likely to be diagnosed with angina, while heart attack patients had worse overall cognitive decline and were more likely to present with deficiencies in verbal memory or semantic fluency.

Xie’s team failed to find a link between cognitive decline and pre-CHD diagnosis and didn’t identify any short-term cognitive decline after CHD events occurred.

“This finding is interesting given that previous research has often supported the hypothesis that the link between cardiovascular health and cognitive function is via cerebrovascular-related structural brain damage, which manifests as acute cognitive impairment and/or accelerated short-term cognitive decline,” Suvi P. Rovio, PhD, and colleagues wrote in a related JACC editorial. “The finding from the present study provides evidence that the CHD event as such does not necessarily cause acute structural alterations in the brain, but that the incident coronary heart disease might act more via longer-term alterations affecting the cerebral vascular function.”

Rovio et al. said the exact mechanisms behind Xie and colleagues’ research need further looking into, but for now the study highlights the influential role of CV risk factors and CV health as determinants of cognitive health down the line.

“Coronary heart disease might be a critical factor for the slope of the cognitive trajectory to meet the cut-off level for clinical cognitive impairment prematurely and to simultaneously reduce the amount of cognitively vital years,” they wrote.