Structural brain alterations in heart failure: implications for risk of Alzheimer's disease
Cardiovascular disease is a recognized contributor to the pathogenesis of Alzheimer's disease. Heart failure is a cardiovascular subtype that can be used to model the contribution of cardiovascular disease to Alzheimer's disease.
Neuroimaging research indicates that patients with heart failure exhibit a diverse range of structural brain alterations and epidemiological studies suggest heart failure may be an important risk factor for Alzheimer's disease.
The neural alterations observed in heart failure may overlap with those observed in Alzheimer's disease and contribute to increased risk of Alzheimer's disease in patients with heart failure.
To examine this possibility, researchers reviewed structural MRI studies in persons with heart failure. Subcortical brain regions affected in the early stages of Alzheimer's disease ( medial temporal lobes ) were examined, as well as cortical alterations that typically occur in the later stages of Alzheimer's disease.
The review has indicated that patients with heart failure exhibit greater neural atrophy and white matter microstructural alterations of nearly every region of the Papez circuit ( e.g., hippocampus, cingulate gyrus, thalamus, mammillary bodies, and fornix ), as well-significant alterations in cortical and cerebellar regions.
Based on animal research and past work in patients with Alzheimer's disease, the mechanisms for structural brain changes in heart failure may stem from reductions in cerebral blood flow subsequent to cardiac deficiency.
This review supports the hypothesis that heart failure may contribute to Alzheimer's disease risk via widespread structural brain changes, including many of the same regions affected by Alzheimer's disease.
Case-controlled prospective neuroimaging studies with long-term follow-ups are needed to clarify the risk of Alzheimer's disease in heart failure and elucidate the neural underpinnings of Alzheimer's disease risk in heart failure. ( Xagena )
Alosco ML, Hayes SM, Heart Fail Rev 2015; Epub ahead of print