Older patients with severe heart failure have impaired verbal memory
MedWire News: Older patients with severe heart failure are more likely to have an impaired verbal memory than younger ones, say researchers.
Cognitive impairment in older patients with heart failure has been studied previously, with inconsistent results, write Joanne Festa (Columbia University Medical Center, New York, USA) and co-authors in the Archives of Neurology.
To investigate further, the team studied the effects of left ventricular ejection fraction (LVEF) on memory in 207 patients (74% men, 60.4% White, 24.6% African-American) with heart failure.
Between September 2006 and September 2008, all patients underwent neurocognitive assessment for verbal memory, using the Hopkins Verbal Learning Test total immediate recall and recognition recall subscales, and visual memory using the Brief Visuospatial Memory Test-Revised total immediate recall and delayed recall subscales.
Memory function was measured using the memory composite score (MCS), defined as the mean of the summed visual and verbal memory z-scores, where a negative score indicates worse performance.
The researchers used echocardiography to measure LVEF (classified as less than 30%, or 30% or greater) and stratified patients into quartiles according to their age in years: 45 or under, 46-55, 56-62, and 63 or over.
Multivariate analysis adjusting for gender, race, and statin therapy revealed that there was a significant interaction between age and LVEF for memory function (p=0.008).
Patients aged 63 years or younger maintained stable memory function irrespective of LVEF, report the authors. By contrast, patients aged 63 years or older showed a significant average decline of 0.95% in MCS when LVEF decreased below 30% (p<0.02).
Verbal delayed recall (Hopkins Verbal Learning Test delayed recall, p=0.02) and verbal recognition recall (Hopkins Verbal Learning Test recognition recall, p=0.05) were the components of memory most affected by low LVEF in patients older than 62 years.
"An interaction exists between age and LVEF such that older patients with low LVEF had significantly reduced memory, particularly verbal delayed recall and recognition," report Festa and team.
They hypothesize that the effects of low LVEF on memory dysfunction could be mediated by hypoxia-sensitive structures in the brain that are affected by low-flow states, such as the hippocampus.
"However, the effect of low LVEF on memory in patients [with HF] is not entirely explained by LVEF," they add.
Further research is needed to elucidate additional mechanisms underlying cognitive dysfunction in patients with HF such as neurodegeneration, inflammation, and white matter disease burden, the team concludes.
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By Piriya Mahendra