Visual assessment of brain magnetic resonance imaging detects injury to cognitive regulatory sites in patients with heart failure

Heart failure causally affects the brain cortical structure: a Mendelian randomization study

Background

The effects of heart failure (HF) on cortical brain structure remain unclear. Therefore, the present study aimed to investigate the causal effects of heart failure on cortical structures in the brain using Mendelian randomization (MR) analysis.

Methods

We conducted a two-sample MR analysis utilizing genetically-predicted HF trait, left ventricular ejection fraction (LVEF), and N-terminal prohormone brain natriuretic peptide (NT-proBNP) levels to examine their effects on the cortical surface area (SA) and thickness (TH) across 34 cortical brain regions. Genome-wide association study summary data were extracted from studies by Rasooly (1,266,315 participants) for HF trait, Schmidt (36,548 participants) for LVEF, the SCALLOP consortium (21,758 participants) for NT-proBNP, and the ENIGMA Consortium (51,665 participants) for cortical SA and TH. A series of MR analyses were employed to exclude heterogeneity and pleiotropy, ensuring the stability of the results. Given the exploratory nature of the study, p-values between 1.22E-04 and 0.05 were considered suggestive of association, and p-values below 1.22E-04 were defined as statistically significant.

Results

In this study, we found no significant association between HF and cortical TH or SA (all p > 1.22E-04). We found that the HF trait and elevated NT-proBNP levels were not associated with cortical SA, but were suggested to decrease cortical TH in the pars orbitalis, lateral orbitofrontal cortex, temporal pole, lingual gyrus, precuneus, and supramarginal gyrus. Reduced LVEF was primarily suggested to decrease cortical SA in the isthmus cingulate gyrus, frontal pole, postcentral gyrus, cuneus, and rostral middle frontal gyrus, as well as TH in the postcentral gyrus. However, it was suggested to causally increase in the SA of the posterior cingulate gyrus and medial orbitofrontal cortex and the TH of the entorhinal cortex and superior temporal gyrus.

Conclusion

We found 15 brain regions potentially affected by HF, which may lead to impairments in cognition, emotion, perception, memory, language, sensory processing, vision, and executive control in HF patients.

Volumetric brain MRI signatures of heart failure with preserved ejection fraction in the setting of dementia

Heart failure with preserved ejection fraction (HFpEF) is an important, emerging risk factor for dementia, but it is not clear whether HFpEF contributes to a specific pattern of neuroanatomical changes in dementia. A major challenge to studying this is the relative paucity of datasets of patients with dementia, with/without HFpEF, and relevant neuroimaging. We sought to demonstrate the feasibility of using modern data mining tools to create and analyze clinical imaging datasets and identify the neuroanatomical signature of HFpEF-associated dementia. We leveraged the bioinformatics tools at Vanderbilt University Medical Center to identify patients with a diagnosis of dementia with and without comorbid HFpEF using the electronic health record. We identified high resolution, clinically-acquired neuroimaging data on 30 dementia patients with HFpEF (age 76.9 ± 8.12 years, 61% female) as well as 301 age- and sex-matched patients with dementia but without HFpEF to serve as comparators (age 76.2 ± 8.52 years, 60% female). We used automated image processing pipelines to parcellate the brain into 132 structures and quantify their volume. We found six regions with significant atrophy associated with HFpEF: accumbens area, amygdala, posterior insula, anterior orbital gyrus, angular gyrus, and cerebellar white matter. There were no regions with atrophy inversely associated with HFpEF. Patients with dementia and HFpEF have a distinct neuroimaging signature compared to patients with dementia only. Five of the six regions identified in are in the temporo-parietal region of the brain. Future studies should investigate mechanisms of injury associated with cerebrovascular disease leading to subsequent brain atrophy.

Impact and Implications of Neurocognitive Dysfunction in the Management of Ischemic Heart Failure

Neurocognitive dysfunction is common in heart failure (HF), with 30% to 80% of patients experiencing some degree of deficits in one or more cognitive domains, including memory, attention, learning ability, executive function, and psychomotor speed. Although the mechanism is not fully understood, reduced cardiac output, comorbidities, chronic cerebral hypoperfusion, and cardioembolic brain injury leading to cerebral hypoxia and brain damage seem to trigger the neurocognitive dysfunction in HF. Cognitive impairment is independently associated with worse outcomes including mortality, rehospitalization, and reduced quality of life. Patients with poorer cognitive function are at an increased risk of severe disease as they tend to have greater difficulty complying with treatment requirements. Coronary revascularization in patients with ischemic HF has the potential to improve cardiovascular outcomes but risks worsening neurocognitive dysfunction even further. Revascularization by coronary artery bypass grafting carries inherent risks for delirium, cognitive impairment, neurologic injury, and stroke, which are known to exacerbate the risk of neurocognitive dysfunction. Alternatively, percutaneous coronary intervention, as a less-invasive approach, has the potential to minimize the risk of cognitive impairment but has not yet been evaluated as an alternative to coronary artery bypass grafting in patients with ischemic HF. Therefore, it is paramount to raise awareness of the neurocognitive consequences in ischemic HF and devise strategies for recognition and prevention as an important target of patient management and personalized decision making that contributes to patient outcomes.

Abnormalities of hippocampus and frontal lobes in heart failure patients and animal models with cognitive impairment or depression: A systematic review

AIMS

This systematic review aimed to study the hippocampal and frontal changes of heart failure (HF) patients and HF animal models with cognitive impairment or depression.

METHODS

A systematic review of the literature was conducted independently by reviewers using PubMed, Web of Science, Embase, and the Cochrane Library databases.

RESULTS AND CONCLUSIONS

30 studies were included, involving 17 pieces of clinical research on HF patients and 13 studies of HF animal models. In HF patients, the hippocampal injuries were shown in the reduction of volume, CBF, glucose metabolism, and gray matter, which were mainly observed in the right hippocampus. The frontal damages were only in reduced gray matter and have no difference between the right and left sides. The included HF animal model studies were generalized and demonstrated the changes in inflammation and apoptosis, synaptic reduction, and neurotransmitter disorders in the hippocampus and frontal lobes. The results of HF animal model studies complemented the clinical observations by providing potential mechanistic explanations of the changes in the hippocampus and frontal lobes.

Is vitamin D supplementation of potential benefit for community-living people with Alzheimer's disease?

BACKGROUND

Vitamin D is associated not only with effects on calcium and bone metabolisms but also with many chronic diseases. Low vitamin D levels in patients with Alzheimer's disease have been widely reported in the literature.

AIM

The purpose of this study was to critically review the potential benefit of vitamin D supplementation in individuals with Alzheimer's disease living in the community.

METHODS

A systematic literature search was conducted in PubMed, CINAHL, EMBASE and the Cochrane Library for papers published 2011-2018.

RESULTS

Seven papers were selected, consisting of one clinical trial, five cohort studies and one systematic review. Studies showed an association only between vitamin D deficiency and lower attention in older people. None of the reviewed studies provided evidence of a positive impact of vitamin D supplementation on cognitive function in older people with Alzheimer's disease.

CONCLUSION

There was no evidence that vitamin D supplementation has a direct benefit for Alzheimer's disease. The review synthesised the existing body of knowledge and concluded that optimum levels of vitamin D (neither too low nor too high) do appear to have positive effects on patient outcomes and quality of life. It is still unclear why vitamin D intake is inadequate as people age. Further research is needed to clarify vitamin-D-related aspects of Alzheimer's disease.

The Emerging Role of Combined Brain/Heart Magnetic Resonance Imaging for the Evaluation of Brain/Heart Interaction in Heart Failure

Heart failure (HF) patients frequently develop brain deficits that lead to cognitive dysfunction (CD), which may ultimately also affect survival. There is an important interaction between brain and heart that becomes crucial for survival in patients with HF. Our aim was to review the brain/heart interactions in HF and discuss the emerging role of combined brain/heart magnetic resonance imaging (MRI) evaluation. A scoping review of published literature was conducted in the PubMed EMBASE (OVID), Web of Science, Scopus and PsycInfo databases. Keywords for searches included heart failure, brain lesion, brain, cognitive, cognitive dysfunction, magnetic resonance imaging cardiovascular magnetic resonance imaging electroencephalogram, positron emission tomography and echocardiography. CD testing, the most commonly used diagnostic approach, can identify neither subclinical cases nor the pathophysiologic background of CD. A combined brain/heart MRI has the capability of diagnosing brain/heart lesions at an early stage and potentially facilitates treatment. Additionally, valuable information about edema, fibrosis and cardiac remodeling, provided with the use of cardiovascular magnetic resonance, can improve HF risk stratification and treatment modification. However, availability, familiarity with this modality and cost should be taken under consideration before final conclusions can be drawn. Abnormal CD testing in HF patients is a strong motivating factor for applying a combined brain/heart MRI to identify early brain/heart lesions and modify risk stratification accordingly.

Aberrant static and dynamic functional network connectivity in heart failure with preserved ejection fraction

Aims

Heart failure may lead to brain functional alterations related to cognitive impairment. This study aimed to detect alterations of static functional network connectivity (FNC) and dynamic FNC in heart failure with preserved ejection fraction (HFpEF) and to estimate the association between the altered FNC and clinical features related to HFpEF.

Methods and results

The clinical and resting‐state functional magnetic resonance imaging (fMRI) data of HFpEF patients (n = 35) and healthy controls (HCs) (n = 35) were acquired at baseline. Resting‐state networks (RSNs) were established based on independent component analysis (ICA) and FNC analyses were performed. The associations between the FNC abnormalities and clinical features related to HFpEF were analysed. Compared with HCs, HFpEF patients showed decreased functional connectivity within the default mode network, left frontoparietal network, and right frontoparietal network and increased functional connectivity within the right frontoparietal network and visual network. Negative correlations were observed between decreased dynamic FNC and the left ventricular end‐diastolic diameter (LVDd) (r = −0.435, P = 0.015) as well as the left ventricular end‐systolic diameter (LVDs) (r = −0.443, P = 0.013).

Conclusions

The FNC disruption and altered temporal properties of functional dynamics in HFpEF patients may reflect the neural mechanisms of brain injury after HFpEF, which may deepen our understanding of the disease.

Dependence and reduced motor function in heart failure: future directions for well-being

While patients with heart failure experience a wide range of symptoms, evidence is mounting that patients with heart failure suffer from reduced functional independence. Given that the number of patients with heart failure is rising and considering the adverse outcomes of reduced functional independence, understanding the underlying mechanisms of reduced functionality in patients with heart failure is of increasing importance. Yet, little information exists on how heart failure negatively affects functional independence, including motor function. This article summarizes reports of reduced independence and highlights its significant adverse outcomes in the patients with heart failure. Finally, this article discusses potential causes of reduced independence based on existing reports of impaired central and peripheral nervous systems in the patients with heart failure. Overall, the article provides a solid foundation for future studies investigating motor impairments in patients with heart failure. Such studies may lead to advances in treatment and prevention of reduced independence associated with heart failure, which ultimately contribute to the well-being of patients with heart failure.

Quantitative magnetic resonance imaging assessment of brain injury after successful cardiopulmonary resuscitation in a rat model of asphyxia cardiac arrest

The aim of this study was to use dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted magnetic resonance imaging (DWI) to measure changes in blood-brain barrier (BBB) permeability and cerebral edema over time in a rat model of asphyxial cardiac arrest (ACA). ACA was established by endotracheal tube clamping. Male rats were randomized into a sham group (n = 5) and three ACA groups (n = 18). After return of spontaneous circulation (ROSC), the rats were randomized to perform DWI and DCE-MRI exam in the 6 h, 24 h and 72 h timepoint (ROSC + 6 h, ROSC + 24 h, and ROSC + 72 h). Results shows that fifteen of 18 animals achieved successful resuscitation in the ACA groups. The average apparent diffusion coefficient(ADC) value of the whole brain in ROSC + 6 h was markedly lower than those of the sham, ROSC + 24 h, and ROSC + 72 h. The aquaporin-4(AQP4) score in ROSC + 6 h was significantly higher than those in the other groups, which were negatively correlated with the ADC values. The ratio of whole brain to masseter muscle of volume transfer constant (rK^trans), tissue interstitium-to-plasma rate constant(rK_ep), and fractional extra-cellular space volume(rV_e) in ROSC + 6 h were all significantly higher than those in the sham, ROSC + 24 h, and ROSC + 72 h. The transforming growth factor β1(TGF-β1) and vascular endothelial growth factor A(VEGF-a) scores in ROSC + 6 h were significantly higher than those in the other groups, which were all positively correlated with rK^trans and rK_ep. In conclusions, brain injury is a frequent complication after CA and resuscitation. DWI and DCE-MRI can quantitatively evaluate brain injury in term of cerebral edema and BBB permeability after successful CPR.

Epigenetic gene expression links heart failure to memory impairment

In current clinical practice, care of diseased patients is often restricted to separated disciplines. However, such an organ-centered approach is not always suitable. For example, cognitive dysfunction is a severe burden in heart failure patients. Moreover, these patients have an increased risk for age-associated dementias. The underlying molecular mechanisms are presently unknown, and thus, corresponding therapeutic strategies to improve cognition in heart failure patients are missing. Using mice as model organisms, we show that heart failure leads to specific changes in hippocampal gene expression, a brain region intimately linked to cognition. These changes reflect increased cellular stress pathways which eventually lead to loss of neuronal euchromatin and reduced expression of a hippocampal gene cluster essential for cognition. Consequently, mice suffering from heart failure exhibit impaired memory function. These pathological changes are ameliorated via the administration of a drug that promotes neuronal euchromatin formation. Our study provides first insight to the molecular processes by which heart failure contributes to neuronal dysfunction and point to novel therapeutic avenues to treat cognitive defects in heart failure patients.

Brain Damage With Heart Failure: Cardiac Biomarker Alterations and Gray Matter Decline

Supplemental Digital Content is available in the text.

Rationale:

Heart failure (HF) following heart damage leads to a decreased blood flow due to a reduced pump efficiency of the heart muscle. A consequence can be insufficient oxygen supply to the organism including the brain. While HF clearly shows neurological symptoms, such as fatigue, nausea, and dizziness, the implications for brain structure are not well understood. Few studies show regional gray matter decrease related to HF; however, the underlying mechanisms leading to the observed brain changes remain unclear.

Objective:

To study the relationship between impaired heart function, hampered blood circulation, and structural brain change in a case-control study.

Methods and Results:

Within a group of 80 patients of the Leipzig Heart Center, we investigated a potential correlation between HF biomarkers and the brain’s gray matter density (GMD) obtained by magnetic resonance imaging. We observed a significant positive correlation between cardiac ejection fraction and GMD across the whole frontal and parietal medial cortex reflecting the consequence of HF onto the brain’s gray matter. Moreover, we also obtained a relationship between GMD and the NT-proBNP (N-terminal prohormone of brain natriuretic peptide)—a biomarker that is used for screening, diagnosis, and prognosis of HF. Here, we found a significant negative correlation between NT-proBNP and GMD in the medial and posterior cingulate cortex but also in precuneus and hippocampus, which are key regions implicated in structural brain changes in dementia.

Conclusions:

We obtained significant correlations between brain structure and markers of heart failure including ejection fraction and NT-proBNP. A diminished GMD was found with decreased ejection fraction and increased NT-proBNP in wide brain regions including the whole frontomedian cortex as well as hippocampus and precuneus. Our observations might reflect structural brain damage in areas that are related to cognition; however, whether these structural changes facilitate the development of cognitive alterations has to be proven by further longitudinal studies.

Can activity monitors predict outcomes in patients with heart failure? A systematic review

Actigraphy is increasingly incorporated into clinical practice to monitor intervention effectiveness and patient health in congestive heart failure (CHF). We explored the prognostic impact of actigraphy-quantified physical activity (AQPA) on CHF outcomes. PubMed and Medline databases were systematically searched for cross-sectional studies, cohort studies or randomised controlled trials from January 2007 to December 2017. We included studies that used validated actigraphs to predict outcomes in adult HF patients. Study selection and data extraction were performed by two independent reviewers. A total of 17 studies (15 cohort, 1 cross-sectional, 1 randomised controlled trial) were included, reporting on 2,759 CHF patients (22-89 years, 27.7% female). Overall, AQPA showed a strong inverse relationship with mortality and predictive utility when combined with established risk scores, and prognostic roles in morbidity, predicting cognitive function, New York Heart Association functional class and intercurrent events (e.g. hospitalisation), but weak relationships with health-related quality of life scores. Studies lacked consensus regarding device choice, time points and thresholds of PA measurement, which rendered quantitative comparisons between studies difficult. AQPA has a strong prognostic role in CHF. Multiple sampling time points would allow calculation of AQPA changes for incorporation into risk models. Consensus is needed regarding device choice and AQPA thresholds, while data management strategies are required to fully utilise generated data. Big data and machine learning strategies will potentially yield better predictive value of AQPA in CHF patients.

Cognitive impairment predicts mortality in outpatient veterans with heart failure

BACKGROUND

In our prior study of 250 outpatient veterans with heart failure (HF), 58% had unrecognized cognitive impairment (CI) which was linked to worsened medication adherence. Literature suggests HF patients with CI have poorer clinical outcomes including higher mortality.

OBJECTIVE

The study is to examine mortality rates in outpatients with HF and undiagnosed CI compared to their cognitively intact peers.

METHODS

This is a retrospective study for all-cause mortality.

RESULTS

During the 3-year follow up, 64/250 (25.6%) patients died: 20/106 (18.9%) with no CI, 29/104 (27.9%) with mild CI, and 15/40 (37.5%) with severe CI. Patients with CI were at increased risk for mortality (hazard ratio 1.82, p = 0.038). Those with severe CI had the worst outcome (hazard ratio 2.710, p = 0.011).

CONCLUSIONS

CI was an independent risk factor for mortality in patients with heart failure when controlling for age and markers of disease severity. Cognitive screening should be performed routinely to identify patients at greater risk for adverse outcomes.

Heart and brain interaction in patients with heart failure: overview and proposal for a taxonomy. A position paper from the Study Group on Heart and Brain Interaction of the Heart Failure Association

Heart failure (HF) is a complex clinical syndrome with multiple interactions between the failing myocardium and cerebral (dys-)functions. Bi-directional feedback interactions between the heart and the brain are inherent in the pathophysiology of HF: (i) the impaired cardiac function affects cerebral structure and functional capacity, and (ii) neuronal signals impact on the cardiovascular continuum. These interactions contribute to the symptomatic presentation of HF patients and affect many co-morbidities of HF. Moreover, neuro-cardiac feedback signals significantly promote aggravation and further progression of HF and are causal in the poor prognosis of HF. The diversity and complexity of heart and brain interactions make it difficult to develop a comprehensive overview. In this paper a systematic approach is proposed to develop a comprehensive atlas of related conditions, signals and disease mechanisms of the interactions between the heart and the brain in HF. The proposed taxonomy is based on pathophysiological principles. Impaired perfusion of the brain may represent one major category, with acute (cardio-embolic) or chronic (haemodynamic failure) low perfusion being sub-categories with mostly different consequences (i.e. ischaemic stroke or cognitive impairment, respectively). Further categories include impairment of higher cortical function (mood, cognition), of brain stem function (sympathetic over-activation, neuro-cardiac reflexes). Treatment-related interactions could be categorized as medical, interventional and device-related interactions. Also interactions due to specific diseases are categorized. A methodical approach to categorize the interdependency of heart and brain may help to integrate individual research areas into an overall picture.

Atrophy of the parahippocampal gyrus is prominent in heart failure patients without dementia

Aims

The exacerbation of heart failure (HF) induces brain damage and cognitive impairment (CI), which frequently attenuates the effects of treatment. However, it is not clear whether HF patients without clinical dementia demonstrate increased risk of CI. We examined whether local atrophy in the parahippocampal gyrus, a potential predictor of CI, is prominent in HF patients without clinical dementia.

Methods and results

Twenty stable HF patients with a history of admission due to decompensated HF or presentation of apparent pulmonary congestion following chest X‐ray and 17 controls were enrolled in this observational, analytical, cross‐sectional, case‐control study. Patients with dementia were excluded from this study based on the results of cognitive assessment. Three‐dimensional T1 weighted magnetic resonance image analysis was performed to evaluate the severity of local brain atrophy using software based on statistical parametric mapping. Z‐score values were calculated to evaluate the severity of atrophy in the total brain and parahippocampal gyrus. The severity of total brain atrophy was similar between HF patients (8.0 ± 2.9%) and controls (6.5 ± 3.1%). However, the Z‐score was significantly higher in the HF group (1.12 ± 0.49) in comparison with the control group (0.63 ± 0.36, P = 0.002). The Z‐score value did not correlate with age, ejection fraction, left atrial dimension, left ventricular dimensions, or brain natriuretic peptides in the HF group but did correlate with the Clinical Frailty Scale.

Conclusions

Local atrophy in the parahippocampal gyrus was prominent in HF patients without clinical dementia. This finding showed that HF patients without dementia feature a potential risk for developing CI.

Heart Failure-Induced Brain Injury

Heart failure (HF) is a systemic illness with grave implications for bodily functions. The brain, among other vital organs, often suffers insults as a result of HF, and both anatomic and functional brain abnormalities were found in the HF population. This injury was demonstrated across a wide range of clinical conditions and cardiac functions and was shown to affect patients' outcomes. Although reduced cardiac output and high burden of cardiovascular risk factors are the prevailing explanations for these findings, there are data showing the involvement of neurohormonal, nutritional, and inflammatory mechanisms in this complex process. Here, the authors review the suggested pathophysiology behind brain injury in HF, describe its effect on patients' outcomes, offer a diagnostic approach, and discuss possible therapeutic options.

Hippocampal and diencephalic pathology in developmental amnesia

Developmental amnesia (DA) is a selective episodic memory disorder associated with hypoxia-induced bilateral hippocampal atrophy of early onset. Despite the systemic impact of hypoxia-ischaemia, the resulting brain damage was previously reported to be largely limited to the hippocampus. However, the thalamus and the mammillary bodies are parts of the hippocampal-diencephalic network and are therefore also at risk of injury following hypoxic-ischaemic events. Here, we report a neuroimaging investigation of diencephalic damage in a group of 18 patients with DA (age range 11-35 years), and an equal number of controls. Importantly, we uncovered a marked degree of atrophy in the mammillary bodies in two thirds of our patients. In addition, as a group, patients had mildly reduced thalamic volumes. The size of the anterior-mid thalamic (AMT) segment was correlated with patients' visual memory performance. Thus, in addition to the hippocampus, the diencephalic structures also appear to play a role in the patients' memory deficit.

Left Ventricular Ejection Fraction Predicts Severity of Posttraumatic Stress Disorder in Patients With Implantable Cardioverter-Defibrillators

BACKGROUND

Implantable cardioverter-defibrillators (ICD) have provided effective therapy for fatal arrhythmia. However, ICD patients are known to develop psychological problems, such as posttraumatic stress disorder (PTSD), if they have experienced potentially fatal arrhythmia and ICD shocks. Little is known about the factors influencing PTSD in ICD patients.

HYPOTHESIS

Echocardiographic cardiac-function parameters might relate to psychological problems, especially PTSD, in ICD patients.

METHODS

A total of 128 outpatients with ICD implantation completed the Impact of Event Scale Revised (IES-R) questionnaire as a measurement of PTSD. Demographic and clinical characteristic data were collected from medical records.

RESULTS

The mean age of the ICD patients was 59 ± 16 years; 103 were male; and the mean left ventricular ejection fraction (LVEF) by echocardiography was 52.4% ± 18.3%. In the ICD patients, female sex and impaired LVEF were related to lower IES-R scores or led to PTSD (P = 0.01 and P = 0.03, respectively). Impaired LVEF also worsened 2 symptoms of PTSD, intrusion (P = 0.02) and hyperarousal (P = 0.03). In patients with LVEF <35%, there was a significant negative correlation between LVEF level and IES-R score (P = 0.045).

CONCLUSIONS

This study showed that LVEF was related to the severity of PTSD, especially in the ICD patients with LVEF of <35%. We should pay more attention to ICD patients with severely impaired left ventricular function to prevent psychological problems.

Daily Physical Activity Is Associated with Subcortical Brain Volume and Cognition in Heart Failure

Cognitive impairment in heart failure (HF) is believed to in part stem from structural brain alterations, including shrinkage of subcortical regions. Fortunately, neurocognitive dysfunction in HF can be mitigated by physical activity (PA), though mechanisms for this phenomenon are unclear. PA is protective against age-related cognitive decline that may involve improved structural integrity to brain regions sensitive to aging (e.g., subcortical structures). Yet, no study has examined the benefits of PA on the brain in HF and we sought to do so and clarify related cognitive implications. Fifty older adults with HF completed a neuropsychological battery and wore an accelerometer for 7 days. All participants underwent brain MRI. This study targeted subcortical brain volume given subcortical alterations are often observed in HF and the sensitivity of PA to subcortical structures in other patient populations. Participants averaged 4348.49 (SD=2092.08) steps per day and greater daily steps predicted better attention/executive function, episodic memory, and language abilities, p's<.05. Medical and demographically adjusted regression analyses revealed higher daily steps per day predicted greater subcortical volume, with specific effects for the thalamus and ventral diencephalon, p's<.05. Greater subcortical volume was associated with better attention/executive function, p<.05. Higher daily PA was associated with increased subcortical brain volume and better cognition in older adults with HF. Longitudinal work is needed to clarify whether daily PA can attenuate brain atrophy in HF to reduce accelerated cognitive decline in this population.

Structural brain alterations in heart failure: a review of the literature and implications for risk of Alzheimer's disease

Cardiovascular disease is a recognized contributor to the pathogenesis of Alzheimer's disease (AD). Heart failure (HF) is a cardiovascular subtype that can be used to model the contribution of cardiovascular disease to AD. Neuroimaging research indicates that HF patients exhibit a diverse range of structural brain alterations and epidemiological studies suggest HF may be an important risk factor for AD. The neural alterations observed in HF may overlap with those observed in AD and contribute to increased risk of AD in HF patients. To examine this possibility, we reviewed structural MRI studies in persons with HF. We examined subcortical brain regions affected in the early stages of AD (medial temporal lobes), as well as cortical alterations that typically occur in the later stages of AD. Our review indicates that patients with HF 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 AD patients, the mechanisms for structural brain changes in HF may stem from reductions in cerebral blood flow subsequent to cardiac deficiency. This review supports the hypothesis that HF may contribute to AD risk via widespread structural brain changes, including many of the same regions affected by AD. Case-controlled prospective neuroimaging studies with long-term follow-ups are needed to clarify the risk of AD in HF and elucidate the neural underpinnings of AD risk in HF.

Central nervous system circuits modified in heart failure: pathophysiology and therapeutic implications

The pathophysiology of heart failure (HF) is characterized by an abnormal activation of neurohumoral systems, including the sympathetic nervous and the renin-angiotensin-aldosterone systems, which have long-term deleterious effects on the disease progression. Perpetuation of this neurohumoral activation is partially dependent of central nervous system (CNS) pathways, mainly involving the paraventricular nucleus of the hypothalamus and some regions of the brainstem. Modifications in these integrative CNS circuits result in the attenuation of sympathoinhibitory and exacerbation of sympathoexcitatory pathways. In addition to the regulation of sympathetic outflow, these central pathways coordinate a complex network of agents with an established pathophysiological relevance in HF such as angiotensin, aldosterone, and proinflammatory cytokines. Central pathways could be potential targets in HF therapy since the current mainstay of HF pharmacotherapy aims primarily at antagonizing the peripheral mechanisms. Thus, in the present review, we describe the role of CNS pathways in HF pathophysiology and as potential novel therapeutic targets.

Preliminary observations on MRI correlates of driving independence and performance in persons with heart failure

PURPOSE/AIM

Heart failure patients often require assistance with activities of daily living, including driving. Recent work shows heart failure patients commit more errors on a simulated driving task relative to controls and cognitive dysfunction contributed to these errors. We sought to extend these findings by examining whether structural magnetic resonance imaging indices correlate with driving independence and performance in heart failure.

MATERIALS AND METHODS

Forty-nine heart failure patients underwent brain magnetic resonance imaging and performed a battery assessing attention/executive function and memory. A self-report instrument was used to assess independence in transportation. A subset of heart failure participants (N = 8) completed a validated driving simulator scenario.

RESULTS

Among the larger sample (N = 49), reduced gray matter correlated with greater dependence in transportation and worse attention/executive function; in turn, worse attention/executive function predicted greater assistance with transportation (p < 0.05). Among the subset that completed the driving simulator (N = 8), reduced gray matter correlated with more stop signs missed and increased white matter hyperintensities correlated with greater collisions, centerline crossings and time out of lane (p < 0.05). Poorer attention/executive function was also associated with more time over the speed limit on the driving simulation (p < 0.05). Follow-up analyses showed the above effects were largely independent of age.

CONCLUSIONS

Reduced structural brain integrity is associated with poorer reported and simulated driving in persons with heart failure. Larger prospective studies that employ on-road testing are needed to clarify brain changes and risk for unsafe driving in heart failure.

Reduced regional brain cortical thickness in patients with heart failure

AIMS

Autonomic, cognitive, and neuropsychologic deficits appear in heart failure (HF) subjects, and these compromised functions depend on cerebral cortex integrity in addition to that of subcortical and brainstem sites. Impaired autoregulation, low cardiac output, sleep-disordered-breathing, hypertension, and diabetic conditions in HF offer considerable potential to affect cortical areas by loss of neurons and glia, which would be expressed as reduced cortical thicknesses. However, except for gross descriptions of cortical volume loss/injury, regional cortical thickness integrity in HF is unknown. Our goal was to assess regional cortical thicknesses across the brain in HF, compared to control subjects.

METHODS AND RESULTS

We examined localized cortical thicknesses in 35 HF and 61 control subjects with high-resolution T1-weighted images (3.0-Tesla MRI) using FreeSurfer software, and assessed group differences with analysis-of-covariance (covariates; age, gender; p<0.05; FDR). Significantly-reduced cortical thicknesses appeared in HF over controls in multiple areas, including the frontal, parietal, temporal, and occipital lobes, more markedly on the left side, within areas that control autonomic, cognitive, affective, language, and visual functions.

CONCLUSION

Heart failure subjects show reduced regional cortical thicknesses in sites that control autonomic, cognitive, affective, language, and visual functions that are deficient in the condition. The findings suggest chronic tissue alterations, with regional changes reflecting loss of neurons and glia, and presumably are related to earlier-described axonal changes. The pathological mechanisms contributing to reduced cortical thicknesses likely include hypoxia/ischemia, accompanying impaired cerebral perfusion from reduced cardiac output and sleep-disordered-breathing and other comorbidities in HF.

Cerebral impairment in heart failure

Patients with heart failure (HF) exhibit a wide range of symptoms, including dyspnea, sleep-disordered breathing, autonomic abnormalities, cognitive dysfunction, and neuropsychological disturbances. These symptoms, which affect quality of life and morbidity and mortality in the condition, are largely related to structural and functional changes in the brain. There are increasing reports of brain abnormalities in HF, but often the linkages between brain injury and common HF clinical symptomatology are not clearly described. In this review, we will discuss the current evidence of brain injury and the associated clinical symptoms in HF, focusing on those brain regions that are commonly damaged in the condition. We will also provide a brief exploration of some potential mechanisms for brain injury in HF.

Is sleep quality related to cognition in individuals with heart failure?

OBJECTIVE

To examine how self-reported sleep quality and daytime symptoms are associated with selected domains of cognitive function among individuals with heart failure (HF).

BACKGROUND

HF patients suffer from poor sleep quality and cognitive decline. The relationship between sleep and cognition has not been well documented among individuals with HF.

METHODS

In this descriptive, cross-sectional study, 68 individuals with HF (male: 63%, mean age = 72 years, SD = 11) completed sleep questionnaires and a neuropsychological battery.

RESULTS

Participant had mean Pittsburgh Sleep Quality Index score of 5.04 (SD = 2.8). Regression analyses demonstrated neither sleep quality or excessive daytime sleepiness (EDS) were related to cognitive function, but daytime dysfunction was related to lower letter fluency and attention index.

CONCLUSION

Contrary to some earlier reports, subjective sleep and EDS in this group of individuals was not associated with cognitive decline.

Atrial fibrillation exacerbates cognitive dysfunction and cerebral perfusion in heart failure

BACKGROUND

Heart failure (HF) increases risk for cognitive impairment in part due to the negative effects of cardiac dysfunction on cerebral perfusion. Atrial fibrillation (AF), an independent risk factor for cognitive impairment, often accompanies HF and is associated with lower systemic perfusion. However, no study has examined the associations among AF, cognitive function, and cerebral perfusion in patients with HF.

METHODS

A total of 187 HF patients completed neuropsychological testing and underwent transcranial Doppler ultrasonography. Cerebral blood flow velocity of the middle cerebral artery (CBF-V) operationalized cerebral perfusion. A medical chart review ascertained AF.

RESULTS

History of AF was found in 32.1% of HF patients. HF patients with AF exhibited worse global cognition, memory, and CBF-V relative to patients without AF. These effects remained after HF severity and other demographic and medical factors were taken into account. Partial correlations controlling for possible confounds showed decreased CBF-V predicted worse cognition in multiple domains in the overall sample (r = 0.13 to 0.15, P < 0.05) and in the subgroup of HF patients with AF (r = 0.26 to r = 0.28, P < 0.05), but not among HF patients without AF.

CONCLUSIONS

AF exacerbates cognitive deficits in HF, possibly through its association with decreased cerebral perfusion. Longitudinal studies are needed to determine whether AF accelerates cognitive decline in HF and whether medical (e.g., ablation) and lifestyle interventions (e.g., exercise programs) that target cerebral perfusion improve cognitive outcomes in patients with HF and AF.

Experimental heart failure causes depression-like behavior together with differential regulation of inflammatory and structural genes in the brain

BACKGROUND

Depression and anxiety are common and independent outcome predictors in patients with chronic heart failure (CHF). However, it is unclear whether CHF causes depression. Thus, we investigated whether mice develop anxiety- and depression-like behavior after induction of ischemic CHF by myocardial infarction (MI).

METHODS AND RESULTS

In order to assess depression-like behavior, anhedonia was investigated by repeatedly testing sucrose preference for 8 weeks after coronary artery ligation or sham operation. Mice with large MI and increased left ventricular dimensions on echocardiography (termed CHF mice) showed reduced preference for sucrose, indicating depression-like behavior. 6 weeks after MI, mice were tested for exploratory activity, anxiety-like behavior and cognitive function using the elevated plus maze (EPM), light-dark box (LDB), open field (OF), and object recognition (OR) tests. In the EPM and OF, CHF mice exhibited diminished exploratory behavior and motivation despite similar movement capability. In the OR, CHF mice had reduced preference for novelty and impaired short-term memory. On histology, CHF mice had unaltered overall cerebral morphology. However, analysis of gene expression by RNA-sequencing in prefrontal cortical, hippocampal, and left ventricular tissue revealed changes in genes related to inflammation and cofactors of neuronal signal transduction in CHF mice, with Nr4a1 being dysregulated both in prefrontal cortex and myocardium after MI.

CONCLUSIONS

After induction of ischemic CHF, mice exhibited anhedonic behavior, decreased exploratory activity and interest in novelty, and cognitive impairment. Thus, ischemic CHF leads to distinct behavioral changes in mice analogous to symptoms observed in humans with CHF and comorbid depression.

The Effects of Aerobic Exercise on Cognitive and Neural Decline in Aging and Cardiovascular Disease

Aging is characterized by a decline in cognitive functions, particularly in the domains of executive function, processing speed and episodic memory. These age-related declines are exacerbated by cardiovascular disease (CVD) and cardiovascular risk factors (hypertension, diabetes, obesity, elevated total cholesterol). Structural and functional alterations in brain regions, including the fronto-parietal and medial temporal lobes, have been linked to age- and CVD-related cognitive decline. Multiple recent studies indicate that aerobic exercise programs may slow the progression of age-related neural changes and reduce the risk for mild cognitive impairment as well as dementia. We review age- and CVD-related decline in cognition and the underlying changes in brain morphology and function, and then clarify the impact of aerobic exercise on moderating these patterns.