Low cardiac index is associated with incident dementia and Alzheimer disease: the Framingham Heart Study

Long-Term High-Fat Diet Impairs AQP4-Mediated Glymphatic Clearance of Amyloid Beta

As a risk factor for Alzheimer's disease (AD), studies have demonstrated that long-term high-fat diet (HFD) could accelerate the deposition of amyloid beta (Aβ) in the brain. The glymphatic system plays a critical role in Aβ clearance from the brain. However, studies investigating the effects of long-term HFD on glymphatic function have reported paradoxical outcomes, and whether glymphatic dysfunction is involved in the disturbance of Aβ clearance in long-term HFD-fed mice has not been determined. In the present study, we injected fluorescently labeled Aβ into the hippocampus and found that Aβ clearance was decreased in HFD-fed mice. We found that long-term HFD-fed mice had decreased glymphatic function by injecting fluorescent tracers into the cisterna magna and corpus striatum. In long-term HFD-fed mice, aquaporin-4 (AQP4) polarization in the cortex was disrupted, and glymphatic clearance activity was positively correlated with the AQP4 polarization index. In HFD-fed mice, the disturbance of Aβ clearance from the hippocampus was exacerbated by TGN-020, a specific inhibitor of AQP4, whereas TGN-073, an enhancer of AQP4, ameliorated it. These findings suggest that long-term HFD disrupts Aβ clearance by inhibiting AQP4-mediated glymphatic function. The underlying mechanism may involve the disruption of AQP4 polarization.

Increased risk of dementia differs across cardiovascular diseases and types of dementia - Data from a nationwide study

AIMS

Dementia is a major health problem. Cardiovascular diseases (CVD) and risk factors are associated with incident dementia. However, whether there is an association among CVD, Alzheimer's disease (AD) and vascular dementia (VD) at the population level remains unclear.

METHODS

We analysed the association between CVD (heart failure [HF], atrial fibrillation [AF], myocardial infarction [MI], peripheral arterial disease, stroke and transient ischemic attack) and the incidence of dementia using nationwide FinnGen data of 218,192 individuals. The last follow-up information on dementia was available from October 2021.

RESULTS

The age at the end of the follow-up was 61.7 ± 17.1 years, and 53% were women. Overall, we observed 9701 (4.4%) dementia, 6323 (2.9%) AD and 1918 (0.7%) VD cases. Individuals with CVD had a higher risk of developing dementia than unexposed individuals. In the multivariable-adjusted Cox models, stroke was most strongly associated with dementia (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.6-1.8). CVD was more strongly associated with VD than with AD. Individuals with HF and MI had an increased risk of AD (HF: HR 1.11, 95% CI 1.04-1.19; MI: HR 1.10, 95% CI 1.02-1.18). AF was associated with VD (HR 1.58, 95% CI 1.42-1.77), but not with AD (HR 1.03, 95% CI 0.97-1.09). Clinical characteristics, such as diabetes, smoking and alcohol abuse, were associated with both types of dementia.

CONCLUSION

All major CVDs were associated with an increased risk of developing dementia, particularly VD. Therefore, CVD onset should prompt an assessment of cognitive decline and possible preventive measures.

Cerebral hypometabolism mediates the effect of stroke volume on cognitive impairment in heart failure patients

AIMS

The present study aimed to phenotype the cerebral structural and glucose metabolic alterations in patients with heart failure (HF) using simultaneous positron emission tomography (PET)/magnetic resonance (MR) and to investigate their relationship to cardiac biomarkers and cognitive performance.

METHODS AND RESULTS

Forty-two HF patients caused by ischaemic heart disease (mean age 67.2 ± 10.4, 32 males) and 32 age- and sex-matched healthy volunteers (mean age 61.3 ± 4.8, 18 males) were included in this study. Participants underwent simultaneous cerebral fluorine-18 (18 F) fluorodeoxyglucose PET/MR followed by cardiac MR scan, and neuropsychological scores were obtained to assess cognitive performance. The grey matter volume (GMV) and standardized uptake value ratio (SUVR) were calculated to examine cerebral structural and metabolic alterations. Cardiac biomarkers included cardiac MR parameters and cardiac serum laboratory tests. Mediation analysis was performed to explore the associations among cerebral alterations, cardiac biomarkers, and cognitive performance. HF patients demonstrated notable cognitive impairment compared with normal controls (P < 0.001). Furthermore, HF patients exhibited regional brain hypometabolism in the bilateral calcarine cortex, caudate nucleus, thalamus, hippocampus, precuneus, posterior cingulate cortex, lingual and olfactory cortex, and GMV reduction in bilateral thalamus and hippocampus (cluster level at P < 0.05, Gaussian random field correction). The SUVR of the hypometabolic brain regions was correlated with the Montreal Cognitive Assessment (MoCA) scores (r = 0.55, P = 0.038) and cardiac stroke volume (r = 0.49, P = 0.002). Cerebral hypometabolism played a key role in the relationship between the decreased stroke volume and MoCA scores, with a mediation effect of 33.2%.

CONCLUSIONS

HF patients suffered cerebral metabolic and structural alterations in regions associated with cognition. The observed correlation between cardiac stroke volume and cognitive impairment underscored the potential influence of cerebral hypometabolism, suggesting that cerebral hypometabolism due to chronic systemic hypoperfusion may significantly contribute to cognitive impairment in HF patients.

Resting heart rate causally affects the brain cortical structure: Mendelian randomization study

Resting heart rate (RHR) has been linked to impaired cortical structure in observational studies. However, the extent to which this association is potentially causal has not been determined. Using genetic data, this study aimed to reveal the causal effect of RHR on brain cortical structure. A Two-Sample Mendelian randomization (MR) analysis was conducted. Sensitivity analyses, weighted median, MR Pleiotropy residual sum and outlier, and MR-Egger regression were conducted to evaluate heterogeneity and pleiotropy. A causal relationship between RHR and cortical structures was identified by MR analysis. On the global scale, elevated RHR was found to decrease global surface area (SA; P < 0.0125). On a regional scale, the elevated RHR significantly decreased the SA of pars triangularis without global weighted (P = 1.58 × 10-4) and the thickness (TH) of the paracentral with global weighted (P = 3.56 × 10-5), whereas it increased the TH of banks of the superior temporal sulcus in the presence of global weighted (P = 1.04 × 10-4). MR study provided evidence that RHR might be causally linked to brain cortical structure, which offers a different way to understand the heart-brain axis theory.

Association between Coronary Heart Disease, Heart Failure, and Risk of Alzheimer's Disease: A Systematic Review and Meta-Analysis

Background

Cardiovascular diseases such as coronary heart disease (CHD), heart failure (HF), and stroke have been linked to the development of Alzheimer's disease (AD). However, previous studies have reported inconsistent results. The study aimed to investigate the association between CHD, HF, and the risk of AD using a meta-analysis.

Methods

STATA 12.0 software is used to compute odds ratios (ORs)/relative risks (RRs) and 95% confidence intervals (CIs) for the association between CHD, HF, and the risk of AD.

Results

A total of 12 studies (including N = 36,913 individuals with AD and N = 1,701,718 participants) investigated the association between CHD and the risk of AD. Meta-analysis indicated that CHD was associated with an increased risk of AD with a random effects model (OR/RR: 1.22, 95% CI: 1.00-1.48, I2 = 97.2%, P < 0.001). Additionally, seven studies (including N = 5,119 individuals with AD and N = 1,231,399 participants) investigated the association between myocardial infarction (MI) and the risk of AD. Our meta-analysis demonstrated no significant association between MI and the risk of AD with a fixed effects model (RR: 1.09, 95% CI: 0.91-1.30, I2 = 42.8%, P = 0.105). Finally, six studies (including N = 83,065 individuals with AD and N = 2,414,963 participants) examined the association between HF and the risk of AD. Our meta-analysis revealed that HF was associated with an increased risk of AD using a random effects model (RR: 1.53, 95% CI: 1.05-2.24, I2 = 96.8%, P < 0.001).

Conclusion

In conclusion, our meta-analysis suggests that CHD and HF are associated with an increased risk of developing AD. Nonetheless, more large-scale prospective studies are necessary to further investigate the associations between CHD, HF, and the risk of AD.

A Correlative Relationship Between Heart Failure and Cognitive Impairment: A Narrative Review

Heart failure (HF) is a chronic condition affecting millions of people worldwide. While the cardinal manifestations of HF are related to the cardiovascular system, it has become progressively evident that mild cognitive impairment (MCI) is also a significant complication of the disease. In fact, a significant number of patients with HF may experience MCI, which can manifest as deficits in attention, memory, executive function, and processing speed. The mechanisms responsible for cognitive dysfunction in HF are intricate and multifactorial. Possible factors contributing to this condition include decreased cerebral blood flow, thrombogenicity associated with HF, systemic inflammatory conditions, and proteotoxicity. MCI in HF has significant clinical implications, as it is linked to poorer quality of life, increased morbidity and mortality, and higher healthcare costs. Additionally, MCI can disrupt self-care behaviors, adherence to medication, and decision-making abilities, all of which are crucial for effectively managing HF. However, there is currently no gold standard diagnostic tool and follow-up strategy for MCI in HF patients. There is limited knowledge on the prevention and treatment of MCI. In conclusion, MCI is a common and clinically important complication of HF. Considering the substantial influence of MCI on patient outcomes, it is imperative for healthcare providers to be cognizant of this issue and integrate cognitive screening and management strategies into the care of HF patients.

Age at Onset of Heart Failure and Subsequent Risk of Dementia: A Longitudinal Cohort Study

BACKGROUND

The average age at onset of heart failure (HF) shows a progressive decrease in recent years; however, the association between age at onset of HF and risk of subsequent dementia remains undetermined.

OBJECTIVES

The study sought to examine whether younger onset age of HF is associated with a higher risk of incident dementia.

METHODS

Individual-level data from the UK Biobank cohort study were analyzed in the present study. Cox regression models and the propensity score matching method were used to analyze the associations of HF and its onset age with subsequent all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD).

RESULTS

Compared with 442,791 participants without HF, those with HF had a higher risk of all-cause dementia (HR: 1.14). Among 14,413 participants with HF, multivariable-adjusted HRs for all-cause dementia, AD, and VD were 1.18, 1.64, and 1.27, respectively, per 10-year decrease in age at HF onset. The propensity score matching analyses found that the strength of association between HF and all-cause dementia increased with decreasing onset age of HF (≥75 years, HR: 1.05; 65-74 years, HR: 1.10; <65 years, HR: 1.67) after multivariable adjustment. Similarly, participants with onset age of HF <65 years had the greatest HRs for incident AD and VD, compared with their matched control subjects.

CONCLUSIONS

Younger age at HF onset was associated with increased risk of dementia. Individuals with an onset age of HF before 65 years of age may represent a particularly vulnerable population for dementia irrespective of subtypes and need careful monitoring and timely intervention to attenuate subsequent risk of incident dementia.

Role of fruit and vegetables in sustaining healthy cognitive function: evidence and issues

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCT), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCT indicate benefits to differing aspects of cognition following citrus and berry fruits, cocoa and peanuts, but the data are limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCT are limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data and lack of consideration of individual differences, which may explain the weaker findings from RCT. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.

Genetic Evidence for Causal Association Between Atrial Fibrillation and Dementia: A Mendelian Randomization Study

Background The knowledge gap regarding whether the correlation between atrial fibrillation (AF) and dementia in observational studies is causation or driven by other shared risk factors remains substantially unfilled. Methods and Results We performed a comprehensive 2-sample Mendelian randomization study to evaluate the causal effect of AF on overall dementia and its subtypes, including vascular dementia, Alzheimer dementia, Lewy body dementia, and frontotemporal dementia. The primary results in inverse variance-weighted analyses were further validated by various Mendelian randomization sensitivity analyses. Additionally, we conducted multivariable Mendelian randomization to examine 10 candidate mediators of the causal association of AF and dementia. Genetic predisposition to AF was modestly associated with an increased risk of overall dementia (odds ratio, 1.140 [95% CI, 1.023-1.271]; P=0.018) and strongly associated with vascular dementia (odds ratio, 1.350 [95% CI, 1.076-1.695]; P=0.010). Genetically predicted AF indicated neutral effects on Alzheimer dementia, Lewy body dementia, and frontotemporal dementia. In multivariable Mendelian randomization analysis, the total effect of AF on overall dementia was remarkably attenuated by adjusting for genetic effect for ischemic stroke (odds ratio, 1.068 [95% CI, 0.953-1.197]; P=0.259) and low cardiac output (odds ratio, 1.046 [95% CI, 0.926-1.181]; P=0.475), indicating that the causal association of genetically predicted AF with dementia was potentially mediated by ischemic stroke and low cardiac output. The causal effect of genetically predicted AF on dementia was independent of cerebral small-vessel disease and brain volume phenotypes. Conclusions Our findings provided novel evidence supporting the causal effect of genetically predicted AF on dementia mediated by ischemic stroke and low cardiac output. Future clinical trials are warranted to evaluate the potential role of appropriate AF management in dementia prevention.

A comparison of the effects of NOAC and VKA therapy on the incidence of dementia in patients with atrial fibrillation: A systematic review and meta-analysis

Atrial fibrillation (AF) patients are more susceptible to dementia, but the results about the effect of oral anticoagulants (OACs) on the risk of dementia are not consistent. We hypothesize that OAC is associated with a reduced risk of dementia with AF and that nonvitamin K antagonist oral anticoagulants (NOAC) are superior to vitamin K antagonists (VKA). Four databases were systematically searched until July 1, 2022. Two reviewers independently selected literature, evaluated quality, and extracted data. Data were examined using pooled hazard ratios (HRs) and 95% confidence intervals (CIs). Fourteen research studies involving 910 patients were enrolled. The findings indicated that OACs were associated with a decreased risk of dementia (pooled HR: 0.68, 95% CI: 0.55-0.82, I2  = 87.7%), and NOACs had a stronger effect than VKAs (pooled HR: 0.87, 95% CI: 0.79-0.95, I2  = 72%), especially in participants with a CHA2DS2VASc score ≥ 2 (pooled HR: 0.85, 95% CI: 0.72-0.99). Subgroup analysis demonstrated no statistical significance among patients aged <65 years old (pooled HR: 0.83, 95% CI: 0.64-1.07), patients in "based on treatment" studies (pooled HR: 0.89, 95% CI: 0.75-1.06), or people with no stroke background (pooled HR: 0.90, 95% CI: 0.71-1.15). This analysis revealed that OACs were related to the reduction of dementia incidence in AF individuals, and NOACs were better than VKAs, remarkably in people with a CHA2DS2VASc score ≥ 2. The results should be confirmed by further prospective studies, particularly in patients in "based on treatment" studies aged <65 years old with a CHA2DS2VASc score < 2 or without a stroke background.

Sacubitril/Valsartan and Cognitive Outcomes in Heart Failure With Reduced Ejection Fraction

Background

Recent trial data refute concerns about neurocognitive off-target effects of neprilysin inhibition with sacubitril and suggest benefit in patients with heart failure and ejection fraction >40%. We hypothesized that sacubitril/valsartan is associated with improved cognitive outcomes in patients with heart failure and reduced ejection fraction (HFrEF).

Objectives

The purpose of this study was to compare 3-year cognitive outcomes in patients with HFrEF who receive sacubitril/valsartan vs angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs).

Methods

Retrospective cohort study of: 1) 11,313 adults with HFrEF (International Classification of Diseases-10th Revision-Clinical Modification [ICD-10-CM] codes: I50.2 or I50.4) started on sacubitril/valsartan between 1/1/2015 and 12/31/2019; and 2) 11,313 propensity matched patients receiving ACEI/ARB during that time. Data were obtained from the TriNetX Research Network, encompassing 41 health care organizations in the United States. Primary endpoint was the composite of cognitive decline (ICD-10-CM: R41.8), dementia (ICD-10-CM: F01-F03), and Alzheimer's disease (ICD-10-CM: G30).

Results

At 3 years, 858 patients on sacubitril/valsartan met the primary endpoint vs 1,209 on ACEI/ARB (3-year incidence: 10.7% vs 15.0%; HR: 0.69; 95% CI: 0.63-0.75; P < 0.001), with consistently lower rates of cognitive decline (9.5% vs 13.3%; HR: 0.69; 95% CI: 0.63-0.76; P < 0.001), dementia (3.4% vs 5.0%; HR: 0.65; 95% CI: 0.57-0.77; P < 0.001), and Alzheimer's disease (0.6% vs 1.3%; HR: 0.48; 95% CI: 0.35-0.66; P < 0.001) in the sacubitril/valsartan cohort. Results were consistent in matched sex and race subgroups. Three-year mortality was 22.0% on sacubitril/valsartan vs 24.6% on ACEI/ARB (HR: 0.89; 95% CI: 0.84-0.94; P < 0.001).

Conclusions

Sacubitril/valsartan was associated with lower 3-year rates of neurocognitive disorders when compared to ACEI/ARBs in patients with HFrEF.

Association between cardiopulmonary function, health-related quality of life and cognitive impairment among the older nursing home residents in Shanghai, China

BACKGROUND

This study aimed to examine the association between cardiopulmonary function, health-related quality of life (HRQOL) and cognitive function among nursing home residents aged 80 years and over.

METHODS

A nursing home-based, cross-sectional study was implemented among 677 aged over 80 years in Shanghai, China. A total of 197 participants underwent effective cardiopulmonary function examinations. Mini-Mental Status Examination (MMSE) and Short Form-36 scales (SF-36) were used to assess cognitive function and HRQOL, respectively.

RESULTS

Decline in left ventricular ejection fractions (LVEF) [adjusted odds ratio (AOR), 1.98; 95% confidential interval (CI), 1.03-3.81)] and vital capacity (VC) (AOR, 2.08; 95%CI, 1.07-4.04) was associated with cognitive impairment. After adjusting confounding factors, relationships between cognitive function and physical functioning (PF) (AOR, 0.98; 95%CI, 0.97-0.99) still existed.

CONCLUSIONS

Healthcare professionals should pay more attention to cardiopulmonary health and HRQOL in the nursing home residents. Actions of public health strategies focus on the improvement of cardiopulmonary function, and PF among older nursing home residents with cognitive impairment is required.

Clonal hematopoiesis with DNMT3A mutation is associated with lower white matter hyperintensity volume

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) increases the risk of cerebrovascular events, while its association with cerebral white matter hyperintensity (WMH) is undemonstrated. We evaluated the effect of CHIP and its major driving mutations on cerebral WMH severity.

METHODS

From an institutional cohort of a routine health check-up program with a DNA repository database, subjects who were ≥50 years of age, with one or more cardiovascular risk factors but no central nervous system disorder, and performed brain MRI were included. Along with the presence of CHIP and its major driving mutations, clinical and laboratory data were obtained. WMH volume was measured in total, periventricular, and subcortical regions.

RESULTS

Among the total 964 subjects, 160 subjects were classified as CHIP positive group. CHIP was most frequently associated with DNMT3A mutation (48.8%), followed by TET2 (11.9%) and ASXL1 (8.1%) mutations. Linear regression analysis adjusting for age, sex, and conventional cerebrovascular risk factors suggested that CHIP with DNMT3A mutation was associated with the lower log-transformed total WMH volume, unlike other CHIP mutations. When classified according to variant allele fraction (VAF) value of DNMT3A mutation, higher VAF classes were associated with the lower log-transformed total WMH and the lower log-transformed periventricular WMH volume, but not with the log-transformed subcortical WMH volumes.

CONCLUSIONS

Clonal hematopoiesis with DNMT3A mutation is quantitatively associated with a lower volume of cerebral WMH, especially in the periventricular region. CHIP with DNMT3A mutation might have a protective role in the endothelial pathomechanism of WMH.

Septal E/e' Ratio Is Associated With Cerebral White Matter Hyperintensity Progression in Young-Old Hypertensive Patients

Background: The incidence of hypertension increases with age, as does that of brain abnormalities associated with cerebral pathologic and functional degeneration. Little is known about the relationship between hypertension-related cardiac changes and cerebral pathologic degeneration. We examined the relationship between left ventricular (LV) diastolic dysfunction and cerebral white matter hyperintensity (WMH) progression in young-old hypertensive patients. Methods and Results: This single-center prospective longitudinal observational study included 156 individuals aged 65-75 years with well-controlled hypertension, normal LV contraction, and no history of symptomatic heart failure. WMH was quantified on brain magnetic resonance imaging (MRI). The primary outcome was the rate of WMH volume progression between the baseline and follow-up MRI (∆WMH). Participants were classified into tertiles on the basis of ∆WMH (small, medium, and large ∆WMH). The mean (±SD) age at recruitment was 69.6±2.8 years, and the mean follow-up period was 4.6 years. The ratio of early diastolic mitral inflow velocity to early diastolic septal mitral annulus velocity (septal E/e') was significantly higher in the large ∆WMH group than in the small and medium ∆WMH groups. On multiple regression analysis, septal E/e' was significantly positively associated with square-root-transformed ∆WMH (β=0.457, P<0.001). Conclusions: Septal E/e' was significantly positively associated with the rate of progression of WMH volume, suggesting that LV diastolic dysfunction is associated with the progression of abnormal brain aging.

White matter injury, cholesterol dysmetabolism, and APP/Abeta dysmetabolism interact to produce Alzheimer's disease (AD) neuropathology: A hypothesis and review

We postulate that myelin injury contributes to cholesterol release from myelin and cholesterol dysmetabolism which contributes to Abeta dysmetabolism, and combined with genetic and AD risk factors, leads to increased Abeta and amyloid plaques. Increased Abeta damages myelin to form a vicious injury cycle. Thus, white matter injury, cholesterol dysmetabolism and Abeta dysmetabolism interact to produce or worsen AD neuropathology. The amyloid cascade is the leading hypothesis for the cause of Alzheimer's disease (AD). The failure of clinical trials based on this hypothesis has raised other possibilities. Even with a possible new success (Lecanemab), it is not clear whether this is a cause or a result of the disease. With the discovery in 1993 that the apolipoprotein E type 4 allele (APOE4) was the major risk factor for sporadic, late-onset AD (LOAD), there has been increasing interest in cholesterol in AD since APOE is a major cholesterol transporter. Recent studies show that cholesterol metabolism is intricately involved with Abeta (Aβ)/amyloid transport and metabolism, with cholesterol down-regulating the Aβ LRP1 transporter and upregulating the Aβ RAGE receptor, both of which would increase brain Aβ. Moreover, manipulating cholesterol transport and metabolism in rodent AD models can ameliorate pathology and cognitive deficits, or worsen them depending upon the manipulation. Though white matter (WM) injury has been noted in AD brain since Alzheimer's initial observations, recent studies have shown abnormal white matter in every AD brain. Moreover, there is age-related WM injury in normal individuals that occurs earlier and is worse with the APOE4 genotype. Moreover, WM injury precedes formation of plaques and tangles in human Familial Alzheimer's disease (FAD) and precedes plaque formation in rodent AD models. Restoring WM in rodent AD models improves cognition without affecting AD pathology. Thus, we postulate that the amyloid cascade, cholesterol dysmetabolism and white matter injury interact to produce and/or worsen AD pathology. We further postulate that the primary initiating event could be related to any of the three, with age a major factor for WM injury, diet and APOE4 and other genes a factor for cholesterol dysmetabolism, and FAD and other genes for Abeta dysmetabolism.

Mechanisms and Clinical Manifestations of Cognitive Decline in Atrial Fibrillation Patients: Potential Implications for Preventing Dementia

Atrial fibrillation (AF) patients face an approximate 1.5-fold increased risk of cognitive decline compared with the general population. Among poststroke AF patients, the risk of cognitive decline is even higher with an estimated threefold increase. This article provides a narrative review on the current evidence and highlights gaps in knowledge and areas for future research. Although earlier studies hypothesized that the association between AF and cognitive decline is mainly a consequence of previous ischemic strokes, more recent evidence also suggests such an association in AF patients without a history of clinical stroke. Because AF and cognitive decline mainly occur among elderly individuals, it is not surprising that both entities share multiple risk factors. In addition to clinically overt ischemic strokes, silent brain infarcts and other brain injury are likely mechanisms for the increased risk of cognitive decline among AF patients. Oral anticoagulation for stroke prevention in AF patients with additional stroke risk factors is one of the only proven therapies to prevent brain injury. Whether a broader use of oral anticoagulation, or more intense anticoagulation in some patients are beneficial in this context needs to be addressed in future studies. Although direct studies are lacking, it is reasonable to recommend optimal treatment of comorbidities and risk factors for the prevention of cognitive decline and dementia.

The neuroprotective effects of oxygen therapy in Alzheimer’s disease: a narrative review

Alzheimer’s disease (AD) is a degenerative neurological disease that primarily affects the elderly. Drug therapy is the main strategy for AD treatment, but current treatments suffer from poor efficacy and a number of side effects. Non-drug therapy is attracting more attention and may be a better strategy for treatment of AD. Hypoxia is one of the important factors that contribute to the pathogenesis of AD. Multiple cellular processes synergistically promote hypoxia, including aging, hypertension, diabetes, hypoxia/obstructive sleep apnea, obesity, and traumatic brain injury. Increasing evidence has shown that hypoxia may affect multiple pathological aspects of AD, such as amyloid-beta metabolism, tau phosphorylation, autophagy, neuroinflammation, oxidative stress, endoplasmic reticulum stress, and mitochondrial and synaptic dysfunction. Treatments targeting hypoxia may delay or mitigate the progression of AD. Numerous studies have shown that oxygen therapy could improve the risk factors and clinical symptoms of AD. Increasing evidence also suggests that oxygen therapy may improve many pathological aspects of AD including amyloid-beta metabolism, tau phosphorylation, neuroinflammation, neuronal apoptosis, oxidative stress, neurotrophic factors, mitochondrial function, cerebral blood volume, and protein synthesis. In this review, we summarized the effects of oxygen therapy on AD pathogenesis and the mechanisms underlying these alterations. We expect that this review can benefit future clinical applications and therapy strategies on oxygen therapy for AD.

[Dihydroquercetin as a systemic neuroprotector for the prevention and treatment of β-amyloid-associated brain diseases]

Dihydroquercetin (DHQ) is a plant-derived polyphenol belonging to the group of flavonoids. In models associated with abnormal accumulation of β-amyloid in the brain (Alzheimer's disease and cerebral amyloid angiopathy), DHQ demonstrates the ability to disaggregate toxic forms of β-amyloid and prevent their formation. It is believed that this phenomenon underlies the protective effect of DHQ on brain neurons. However, pharmacokinetic data doubt the central mechanism of action of DHQ because this compound does not penetrate well into the brain. A hypothesis is put forward about the systemic nature of the neuroprotective action of DHQ, since this compound has multiple biological activities at the level of the whole organism. To characterize DHQ (and similar compounds), it is proposed to introduce the term «systemic neuroprotector».

Cognitive function in late-stage HFpEF patients with tricuspid regurgitation undergoing transcatheter tricuspid valve intervention

OBJECTIVES

This study evaluates the impact of transcatheter tricuspid valve interventions (TTVI) on cognitive function (CF), quality of life (QOL), and exercise capacity in late-stage heart failure with preserved ejection fraction (HFpEF) and relevant tricuspid regurgitation (TR).

BACKGROUND

Reduced cardiac output (CO) critically affects CF. Severe TR aggravates CO reduction in HFpEF, while TTVI has been demonstrated to re-establish CO to a significant extent. The effect of TTVI on CF of HFpEF patients has so far not been investigated.

METHODS

Assessment of CF was performed using the standardized Montreal Cognitive Assessment test in 34 symptomatic HFpEF patients with at least severe TR before and 3 months after TTVI alongside echocardiographic examinations and assessment of exercise capacity and QOL.

RESULTS

Median age of the patients was 81.0 [78.8; 83.0] years and 50.0% were female. CF was impaired in 67.6% of the patients. TR ≤ moderate was achieved in 94.1% of the cases. Overall CF improved significantly (from 20.6 ± 3.9 to 23.0 ± 4.4; p = 0.001). Particularly, significant improvements were identified in the executive function (p < 0.001) and memory (p = 0.008). In addition, linear regression analysis demonstrated a significant collinearity of improvement between executive function as well as memory and increased CO (ρ = 0.695; p < 0.001 and ρ = 0.628; p < 0.001, respectively). The walked distance and QOL also improved significantly 3 months after TTVI.

CONCLUSION

Cognitive impairment is highly prevalent in HFpEF patients with severe TR. TTVI results in an improved CF, especially with regard to executive function and memory. These improvements also correlate with more efficient hemodynamics reflected by increased CO.

Causal Association of Cardiac Function by Magnetic Resonance Imaging with Frailty Index: A Mendelian Randomization Study

Owing to the susceptibility of conventional observational studies to confounding factors and reverse causation, the causal association between cardiac function and frailty is unclear. We aimed to investigate whether cardiac function has causal effects on frailty. In this study, a two-sample Mendelian randomization (MR) study was conducted using genetic variants associated with cardiac function assessed by magnetic resonance imaging phenotypes as instrumental variables. Genetic variants associated with cardiac function by magnetic resonance imaging (including seven cardiac function phenotypes) and the frailty index (FI) were obtained from two large genome-wide association studies. MR estimates from each genetic instrument were combined using inverse variance weighted (IVW), weighted median, and MR‒Egger regression methods. We found that the increase in genetically determined stroke volume (beta - 0.13, 95% CI - 0.16 to - 0.10, p = 1.39E-6), rather than other cardiac phenotypes, was associated with lower FI in MR analysis of IVW after Bonferroni correction. Sensitivity analyses examining potential bias caused by pleiotropy or reverse causality revealed similar findings (e.g., intercept [SE], - 0.008 [0.011], p = 0.47 by MR‒Egger intercept test). The leave-one-out analysis indicated that the association was not driven by single nucleotide polymorphisms. No evidence of heterogeneity was found among the genetic variants (e.g., MR‒Egger: Q statistic = 14.4, p = 0.156). In conclusion, we provided evidence that improved cardiac function could contribute to reducing FI. These findings support the hypothesis that enhancing cardiac function could be an effective prevention strategy for frailty.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00072-z.

Clinical Trials of New Drugs for Vascular Cognitive Impairment and Vascular Dementia

Population aging has challenged the treatment of cognitive impairment or dementia. Vascular dementia is the second leading cause of dementia after Alzheimer’s disease. Cognitive consequences after ischemic brain injury have been recognized as a preferred target for therapeutic strategies, prompting the search for potential agents. The keyword “vascular dementia” was used to search ClinicalTrials.gov to determine agents represented in phases I, II, III, and IV. The agents were classified on the basis of their mechanisms. Of the 17 randomized controlled trials meeting our inclusion criteria, 9 were completed in the past 10 years, and 8 are ongoing or in the planning stages. We also identified one trial in phase I, nine in phase II, six in phase III, and one in phase IV. Fewer trials of new drugs for improving cognition or ameliorating the behavioral and psychological symptoms of dementia target vascular dementia than Alzheimer’s dementia. Drug trials on vascular dementia overlap with drug trials targeting functional outcomes in cerebrovascular disease. International pharmaceutical companies’ investment in new drugs targeting VCI and vascular dementia remains insufficient.

The interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases: Implications for therapy

Microtubules, a highly dynamic cytoskeleton, participate in many cellular activities including mechanical support, organelles interactions, and intracellular trafficking. Microtubule organization can be regulated by modification of tubulin subunits, microtubule-associated proteins (MAPs) or agents modulating microtubule assembly. Increasing studies demonstrate that microtubule disorganization correlates with various cardiocerebrovascular diseases including heart failure and ischemic stroke. Microtubules also mediate intracellular transport as well as intercellular transfer of mitochondria, a power house in cells which produce ATP for various physiological activities such as cardiac mechanical function. It is known to all that both microtubules and mitochondria participate in the progression of cancer and Parkinson's disease. However, the interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases remain unclear. In this paper, we will focus on the roles of microtubules in cardiocerebrovascular diseases, and discuss the interplay of mitochondria and microtubules in disease development and treatment. Elucidation of these issues might provide significant diagnostic value as well as potential targets for cardiocerebrovascular diseases.

Education level may modify the association between cardiac index and cognitive function among elders with normal ejection function

Background

Lower cardiac index (CI) in elders has been associated with incident dementia, and higher CI has protectively effect with brain aging. In the present study, we investigated the modulating effects of education level and arterial stiffness on the association between CI and cognitive function among older adults.

Methods

A total of 723 elders (≥60 years, 50.1% women) with normal left ventricular ejection fraction (≥50%) were identified from the Cardiovascular Diseases Risk Factor Two-Township Study. CI was calculated from the Doppler-derived stroke volume. We evaluated arterial stiffness by measuring carotid-femoral pulse wave velocity (CFPWV) and global cognitive function by using the Mini-Mental Short Examination (MMSE). Education level was determined by years of formal education.

Results

In linear regression analysis adjusting for age, sex, formal years of education, and CFPWV, CI was significantly positively associated with MMSE (BETA=0.344±0.130, P = 0.0082). In logistic regression analysis adjusting for age, sex, formal years of education, and CFPWV, subjects with a CI≥75 percentile had a significantly lower risk of low MMSE (<26) (OR = 0.495, 95% CI = 0.274–0.896, P = 0.02). In subgroup analysis, higher CI was significantly associated with higher MMSE and lower risk of low MMSE only in elders with ≤ 9 years of formal education. Causal mediation analysis suggests that higher CI maintains higher MMSE in elders with lower education levels whereas higher CFPWV causes lower MMSE in all the elders.

Conclusion

In elders with normal ejection fraction, a higher CI was associated with a lower risk of cognitive function impairment, independent of arterial stiffness, mainly in subjects with a lower education level and possibly a smaller cognitive reserve.

Dynamics of Cognitive Function in Patients with Heart Failure Following Transcatheter Mitral Valve Repair

Aims: Interventional transcatheter edge-to-edge mitral valve repair (TMVR) is an established treatment option for patients with severe mitral regurgitation (MR) and high operative risk. Cognitive impairment is one of the most common conditions among often extensive comorbidities in these patients. The specific patterns of cognitive decline and particularly the effect of TMVR are not well described. Thus, this study aimed to investigate into the impact of TMVR on cognitive impairment, exercise capacity, and quality of life. Methods: Cognitive function (executive, naming, memory, attention, language, abstraction, and orientation) was assessed with the standardized Montreal Cognitive Assessment test (MoCA; range between 0 and 30 points) before and 3 months after TMVR in 72 consecutive patients alongside echocardiographic examination and assessment of exercise capacity (six-minute walk test) as well as quality-of-life questionnaires (Minnesota living with heart failure questionnaire, MLHF-Q). Results: Patients’ median age was 81 [76.0; 84.5] years, 39.7% were female with a median EuroScore II of 4.4% [2.9; 7.7]. The assessment of cognitive function showed a significant improvement of the cumulative MoCA-Test result (from 22.0 [19.0; 24.5] to 24 [22.0; 26.0]; p < 0.001) with significant changes in the subcategories executive (p < 0.001), attention (p < 0.001), abstraction (p < 0.001), and memory (p < 0.001). In addition, quality of life (from 47.5 [25.0; 69.3] to 24.0 [12.0; 40.0]; p < 0.001) and exercise capacity (from 220.0 m [160.0; 320.0] to 280.0 m [200.0; 380.0]; p = 0.003) increased significantly 3 months after the TMVR procedure. Conclusions: TMVR leads to a significant improvement of cognitive function, exercise capacity, and quality of life in patients with chronic heart failure in 3 months follow up and again highlights the benefit of the evermore established TMVR procedure for patients with high operative risk.

The Relationship Between Pre-existing Coronary Heart Disease and Cognitive Impairment Is Partly Explained by Reduced Left Ventricular Ejection Fraction in the Subjects Without Clinical Heart Failure: A Cross-Sectional Study

Background

Coronary heart disease (CHD) is closely associated with cognitive impairment, especially in severe cases of heart failure. However, it is unclear whether cardiac systolic function plays a role in the relationship between pre-existing CHD and cognitive impairment in subjects without clinical heart failure.

Methods

In total, 208 subjects from the First Affiliated Hospital of Xi’an Jiaotong University were recruited from June 2014 to January 2015, and were divided into CHD (n = 118) and non-CHD (n = 90) groups according to the inclusion and exclusion criteria. The global cognitive function of all subjects was assessed by the Mini-Mental State Examination (MMSE) and cognitive impairment was defined as the score lower than the cutoff value. Left ventricular ejection fraction (LVEF) was measured using transthoracic echocardiograms. The relationship among pre-existing CHD, LVEF, and cognitive impairment was analyzed by multivariate logistic regression.

Results

In total, 34 subjects met the criteria of cognitive impairment. Univariate analysis showed that the cognitive impairment prevalence in the CHD group was significantly higher than that in the non-CHD group (22.0 vs. 8.9%, p = 0.011). Multivariate logistic analysis revealed that CHD was significantly associated with a higher risk of cognitive impairment (odds ratio [OR] = 3.284 [95% CI, 1.032–10.450], p = 0.044) after adjusting for confounds except for LVEF. However, the OR of CHD decreased (OR = 2.127 [95% CI, 0.624–7.254], p = 0.228) when LVEF was further corrected as a continuous variable, and LVEF was negatively associated with the risk of cognitive impairment (OR = 0.928 [95% CI, 0.882–0.976], p = 0.004).

Conclusion

Pre-existing CHD is associated with a higher risk of cognitive impairment, and such an association can be considerably explained by reduced LVEF. An impaired cardiac systolic function may play a key role in the relationship between CHD and cognitive impairment among patients with pre-heart failure conditions.

Alzheimer's disease and related dementias and heart failure: A community study

BACKGROUND

Cognitive function is essential to effective self-management of heart failure (HF). Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) can coexist with HF, but its exact prevalence and impact on health care utilization and death are not well defined.

METHODS

Residents from 7 southeast Minnesota counties with a first-ever diagnosis code for HF between January 1, 2013 and December 31, 2018 were identified. Clinically diagnosed AD/ADRD was ascertained using the Centers for Medicare and Medicaid (CMS) Chronic Conditions Data Warehouse algorithm. Patients were followed through March 31, 2020. Cox and Andersen-Gill models were used to examine associations between AD/ADRD (before and after HF) and death and hospitalizations, respectively.

RESULTS

Among 6336 patients with HF (mean age [SD] 75 years [14], 48% female), 644 (10%) carried a diagnosis of AD/ADRD at index HF diagnosis. The 3-year cumulative incidence of AD/ADRD after HF diagnosis was 17%. During follow-up (mean [SD] 3.2 [1.9] years), 2618 deaths and 15,475 hospitalizations occurred. After adjustment, patients with AD/ADRD before HF had nearly a 2.7 times increased risk of death, but no increased risk of hospitalization compared to those without AD/ADRD. When AD/ADRD was diagnosed after the index HF date, patients experienced a 3.7 times increased risk of death and a 73% increased risk of hospitalization compared to those who remain free of AD/ADRD.

CONCLUSIONS

In a large, community cohort of patients with incident HF, the burden of AD/ADRD is quite high as more than one-fourth of patients with HF received a diagnosis of AD/ADRD either before or after HF diagnosis. AD/ADRD markedly increases the risk of adverse outcomes in HF underscoring the need for future studies focused on holistic approaches to improve outcomes.

The interaction and pathogenesis between cognitive impairment and common cardiovascular diseases in the elderly

Both cognitive impairment and cardiovascular diseases have a high incidence in the elderly population, increasing the burden of care and reducing the quality of life. Studies have suggested that cognitive impairment interacts with cardiovascular diseases such as coronary heart disease, abnormal blood pressure, heart failure, and arrhythmia. On one hand, cognitive impairment in the elderly influences the progression and self-management of cardiovascular diseases and increases the risk of cardiovascular-related adverse events. On the other hand, coronary heart disease, heart failure, higher blood pressure variability, orthostatic hypotension, and atrial fibrillation may aggravate cognitive impairment. The role of blood pressure levels on cognition remains controversial. Several shared biological pathways have been proposed as the underlying mechanism for the association. Cardiovascular diseases may lead to cognitive decline even dementia through cerebral perfusion damage, brain structural changes, inflammation, β-amyloid deposition, and neuroendocrine disorders. It is of great significance to study the interaction and put forward effective interventions in an overall perspective to reduce care burden and improve the quality of life of the elderly patients.

Cognitive Impairment in Heart Failure—A Review

Simple Summary

Compared to the general population, patients with heart failure have reduced cognition and increased dementia risk. Brain changes have been observed in these individuals, including reduced brain volumes and abnormal areas suggestive of ischaemia (lack of blood and hence oxygen supply to tissues). Patients with heart failure who have cognitive impairment have poorer self-care and are at increased risk of rehospitalisation and death. Causes of cognitive impairment in heart failure have been suggested, including reduced blood supply to the brain, inflammatory processes, protein abnormalities and thromboembolic disease (formation of blood clots which may travel to the brain and impede blood flow). In this article, we discuss these potential causes linking heart failure and cognitive impairment, and discuss the recognition and management of cognitive impairment in patients with heart failure.

Abstract

Cognitive impairment (CI) is common in heart failure (HF). Patients with HF demonstrate reduced global cognition as well as deficits in multiple cognitive domains compared to controls. Degree of CI may be related to HF severity. HF has also been associated with an increased risk of dementia. Anatomical brain changes have been observed in patients with HF, including grey matter atrophy and increased white matter lesions. Patients with HF and CI have poorer functional independence and self-care, more frequent rehospitalisations as well as increased mortality. Pathophysiological pathways linking HF and CI have been proposed, including cerebral hypoperfusion and impaired cerebrovascular autoregulation, systemic inflammation, proteotoxicity and thromboembolic disease. However, these mechanisms are poorly understood. We conducted a search on MEDLINE, Embase and Scopus for original research exploring the connection between HF and CI. We then reviewed the relevant literature and discuss the associations between HF and CI, the patterns of brain injury in HF and their potential mechanisms, as well as the recognition and management of CI in patients with HF.

Association of autosomal dominant polycystic kidney disease with cerebral small vessel disease

Cilia dysfunction in autosomal-dominant polycystic kidney disease (ADPKD) may impair the integrity of glymphatic system and be implicated in the progression of cerebral small vessel disease (SVD), although the link between the two diseases has not been investigated. We evaluated the association of ADPKD pathology with SVD pattern and severity. Overall, 304 individuals in an ADPKD (chronic kidney disease stage ≤4 and age ≥50 years) cohort and their age, sex, and estimated glomerular filtration rate (eGFR)-matched controls were retrospectively included. ADPKD severity was classified into 1 A-B, 1 C, and 1 D-E, according to age and height-adjusted total kidney volume. SVD parameters included white-matter hyperintensity (WMH) severity scale, enlarged perivascular space (ePVS) score, and degree of lacunes or cerebral microbleeds (CMBs). After adjustments for age, sex, eGFR, and cerebrovascular risk factor parameters, ADPKD was associated with higher ePVS scores (P < 0.001), but not with the WMH severity or degree of lacunes or CMBs. In the ADPKD subgroup, higher ADPKD severity class was associated with higher ePVS scores (P < 0.001), WMH severity (P = 0.003), and degree of lacunes (P = 0.002). ADPKD associated cilia dysfunction may induce chronic cerebral glymphatic system dysfunction, which may contribute to the specific progression of ePVS compared with other SVD markers.

Abnormal amyloid beta metabolism in systemic abnormalities and Alzheimer's pathology: Insights and therapeutic approaches from periphery

Alzheimer's disease (AD) is an age-associated, multifactorial neurodegenerative disorder that is incurable. Despite recent success in treatments that partially improve symptomatic relief, they have failed in most clinical trials. Re-holding AD for accurate diagnosis and treatment is widely known as a challenging task. Lack of knowledge of basic molecular pathogenesis might be a possible reason for ineffective AD treatment. Historically, a majority of therapy-based studies have investigated the role of amyloid-β (Aβ peptide) in the central nervous system (CNS), whereas less is known about Aβ peptide in the periphery in AD. In this review, we provide a comprehensive summary of the current understanding of Aβ peptide metabolism (anabolism and catabolism) in the brain and periphery. We show that the abnormal metabolism of Aβ peptide is significantly linked with central-brain and peripheral abnormalities; the interaction between peripheral Aβ peptide metabolism and peripheral abnormalities affects central-brain Aβ peptide metabolism, suggesting the existence of significant communication between these two pathways of Aβ peptide metabolism. This close interaction between the central brain and periphery in abnormal Aβ peptide metabolism plays a key role in the development and progression of AD. In conclusion, we need to obtain a full understanding of the dynamic roles of Aβ peptide at the molecular level in both the brain and periphery in relation to the pathology of AD. This will not only provide new information regarding the complex disease pathology, but also offer potential new clues to improve therapeutic strategies and diagnostic biomarkers for the successful treatment of AD.

Brain age estimation at tract group level and its association with daily life measures, cardiac risk factors and genetic variants

Brain age can be estimated using different Magnetic Resonance Imaging (MRI) modalities including diffusion MRI. Recent studies demonstrated that white matter (WM) tracts that share the same function might experience similar alterations. Therefore, in this work, we sought to investigate such issue focusing on five WM bundles holding that feature that is Association, Brainstem, Commissural, Limbic and Projection fibers, respectively. For each tract group, we estimated brain age for 15,335 healthy participants from United Kingdom Biobank relying on diffusion MRI data derived endophenotypes, Bayesian ridge regression modeling and 10 fold-cross validation. Furthermore, we estimated brain age for an Ensemble model that gathers all the considered WM bundles. Association analysis was subsequently performed between the estimated brain age delta as resulting from the six models, that is for each tract group as well as for the Ensemble model, and 38 daily life style measures, 14 cardiac risk factors and cardiovascular magnetic resonance imaging features and genetic variants. The Ensemble model that used all tracts from all fiber groups (FG) performed better than other models to estimate brain age. Limbic tracts based model reached the highest accuracy with a Mean Absolute Error (MAE) of 5.08, followed by the Commissural ([Formula: see text]), Association ([Formula: see text]), and Projection ([Formula: see text]) ones. The Brainstem tracts based model was the less accurate achieving a MAE of 5.86. Accordingly, our study suggests that the Limbic tracts experience less brain aging or allows for more accurate estimates compared to other tract groups. Moreover, the results suggest that Limbic tract leads to the largest number of significant associations with daily lifestyle factors than the other tract groups. Lastly, two SNPs were significantly (p value [Formula: see text]) associated with brain age delta in the Projection fibers. Those SNPs are mapped to HIST1H1A and SLC17A3 genes.

Inflammatory markers and tract-based structural connectomics in older adults with a preliminary exploration of associations by race

Peripheral inflammation has been implicated in cognitive dysfunction and dementia. While studies outline the relationship between elevated inflammation and individual gray or white matter alterations, less work has examined inflammation as related to connectivity between gray and white matter or variability in these associations by race. We examined the relationship between peripheral inflammation and tract-based structural connectomics in 74 non-demented participants (age = 69.19 ± 6.80 years; 53% female; 45% Black) who underwent fasting venipuncture and MRI. Serum was assayed for C-reactive protein, interleukin-6, and interleukin-1β. Graph theory analysis integrated T1-derived gray matter volumes and DTI-derived white matter tractography into connectivity matrices analyzed for local measures of nodal strength and efficiency in a priori regions of interest associated with cardiovascular disease risk factors and dementia. Linear regressions adjusting for relevant covariates showed associations between inflammatory markers and nodal strength in the isthmus, posterior and caudal anterior cingulate (p's ≤ .042). Adding an inflammatory marker*race term showed race-modified associations between C-reactive protein and efficiency in the thalamus and amygdala, and nodal strength in the putamen (p's ≤ .048), between interleukin-6 and efficiency in the pars triangularis and amygdala (p's ≤ .024), and between interleukin-1β and nodal strength in the pars opercularis (p = .048). Higher levels of inflammation associated with lower efficiency and higher strength for White participants but higher efficiency and lower strength for Black participants. Results suggest inflammation is associated with tract-based structural connectomics in an older diverse cohort and that differential relationships may exist by race within prefrontal and limbic brain regions.

Exercise and the Risk of Dementia in Patients with Newly Diagnosed Atrial Fibrillation: A Nationwide Population-Based Study

BACKGROUND

It is unclear whether exercise would reduce dementia in patients with a new diagnosis of atrial fibrillation (AF). Therefore, we aimed to evaluate the association between the change in physical activity (PA) before and after new-onset AF and the risk of incident dementia.

METHODS

Using the Korean National Health Insurance Service database, we enrolled a total of 126,555 patients with newly diagnosed AF between 2010 and 2016, who underwent health examinations within two years before and after their diagnosis of AF. The patients were divided into four groups: persistent non-exercisers, exercise starters, exercise quitters, and exercise maintainers.

RESULTS

Based on a total of 396,503 person-years of follow-up, 5943 patients were diagnosed with dementia. Compared to persistent non-exercisers, exercise starters (adjusted hazard ratio (aHR) 0.87; 95% confidence interval (CI) 0.81-0.94), and exercise maintainers (aHR 0.66; 95% CI 0.61-0.72) showed a lower risk of incident dementia; however, the risk was similar in exercise quitters (aHR 0.98; 95% CI 0.92-1.05) (p-trend < 0.001). There was a J-shaped relationship between the dose of exercise and the risk of dementia, with the risk reduction maximized at 5-6 times per week of moderate-to-vigorous PA among exercise starters.

CONCLUSION

Patients who initiated or continued regular exercise after diagnosis of AF were associated with a lower risk of dementia than persistent non-exercisers, with no risk reduction associated with exercise cessation. Our findings may provide evidence for the benefit of exercise prescription to patients with new-onset AF to prevent incident dementia regardless of their current exercise status.

Cognitive impairment in myocardial infarction and heart failure

Myocardial infarction (MI) occurs when coronary blood flow is decreased due to an obstruction/occlusion of the vessels, leading to myocardial death and progression to heart failure (HF). Cognitive impairment, anxiety, depression and memory loss are the most frequent mental health problems among patients with HF. The most common cause of cognitive decline is cardiac systolic dysfunction, which leads to reduced cerebral perfusion. Several in vivo and clinical studies provide information regarding the underlying mechanisms of HF in brain pathology. Neurohormonal activation, oxidative stress, inflammation, glial activation, dendritic spine loss and brain programmed cell death are all proposed as contributors of cognitive impairment in HF. Furthermore, several investigations into the effects of various medications on brain pathology utilizing MI models have been reported. In this review, potential mechanisms involving HF-associated cognitive impairment, as well as neuroprotective interventions in HF models, are discussed and summarized. In addition, gaps in the surrounding knowledge, including the types of brain cell death and the effects of cell death inhibitors in HF, are presented and discussed. This review provides valuable information that will suggest the potential therapeutic strategies for cognitive impairment in patients with HF.

Lower Left Ventricular Ejection Fraction Relates to Cerebrospinal Fluid Biomarker Evidence of Neurodegeneration in Older Adults

BACKGROUND

Subclinical cardiac dysfunction is associated with decreased cerebral blood flow, placing the aging brain at risk for Alzheimer's disease (AD) pathology and neurodegeneration.

OBJECTIVE

This study investigates the association between subclinical cardiac dysfunction, measured by left ventricular ejection fraction (LVEF), and cerebrospinal fluid (CSF) biomarkers of AD and neurodegeneration.

METHODS

Vanderbilt Memory & Aging Project participants free of dementia, stroke, and heart failure (n = 152, 72±6 years, 68% male) underwent echocardiogram to quantify LVEF and lumbar puncture to measure CSF levels of amyloid-β42 (Aβ42), phosphorylated tau (p-tau), and total tau (t-tau). Linear regressions related LVEF to CSF biomarkers, adjusting for age, sex, race/ethnicity, education, Framingham Stroke Risk Profile, cognitive diagnosis, and apolipoprotein E ɛ4 status. Secondary models tested an LVEF x cognitive diagnosis interaction and then stratified by diagnosis (normal cognition (NC), mild cognitive impairment (MCI)).

RESULTS

Higher LVEF related to decreased CSF Aβ42 levels (β= -6.50, p = 0.04) reflecting greater cerebral amyloid accumulation, but this counterintuitive result was attenuated after excluding participants with cardiovascular disease and atrial fibrillation (p = 0.07). We observed an interaction between LVEF and cognitive diagnosis on CSF t-tau (p = 0.004) and p-tau levels (p = 0.002), whereas lower LVEF was associated with increased CSF t-tau (β= -9.74, p = 0.01) and p-tau in the NC (β= -1.41, p = 0.003) but not MCI participants (p-values>0.13).

CONCLUSIONS

Among cognitively normal older adults, subclinically lower LVEF relates to greater molecular evidence of tau phosphorylation and neurodegeneration. Modest age-related changes in cardiovascular function may have implications for pathophysiological changes in the brain later in life.

Mind your heart: the epigenetic consequences of heart failure on brain function

The bidirectional link between heart and brain has intrigued scientists for ages, but little is known on the underlying mechanism. In their recent study, Fischer and colleagues (Islam et al, 2021) propose a mechanism by which heart failure-induced cognitive decline is linked to epigenetic changes that affect gene expression in neurons of hippocampus.

Neurological complications of heart failure

Heart failure (HF) is a major global cause of death with increasing absolute worldwide numbers of HF patients. HF results from the interaction between cardiovascular aging with specific risk factors, comorbidities, and disease modifiers. The failing heart and neuronal injury have a bidirectional interaction requiring specific management strategies. Decreased cardiac output has been associated with lower brain volumes. Cerebral blood flow (CBF) may normalize following heart transplantation among severe HF patients. Stroke and cognitive impairment remain the main neurologic conditions associated with HF. However, HF patients may also suffer from chronic cerebral hypoperfusion. It seems likely that HF-related ischemic strokes are primarily the result of cardiac embolism. Atrial fibrillation (AF) is present in half of stroke patient with HF. The increased risk of hemorrhagic strokes is less well characterized and likely multifactorial, but may in part reflect a higher use of long-term antithrombotic therapy. The steady improvement of neuroimaging techniques has demonstrated an increased prevalence of silent ischemic lesions among HF patients. The populations most likely to benefit from long-term anticoagulant therapy are HF patients with AF. Cognitive impairment in HF can have a variety of clinical manifestations from mild memory problems to dementia.

New Avenues for Optimal Treatment of Atrial Fibrillation and Stroke Prevention

One in 3 individuals free of atrial fibrillation (AF) at index age 55 years is estimated to develop AF later in life. AF increases not only the risk of ischemic stroke but also of dementia, even in stroke-free patients. In this review, we address recent advances in the heart-brain interaction with focus on AF. Issues discussed are (1) the timing of direct oral anticoagulants start following an ischemic stroke; (2) the comparison of direct oral anticoagulants versus vitamin K antagonists in early secondary stroke prevention; (3) harms of bridging with heparin before direct oral anticoagulants; (4) importance of appropriate direct oral anticoagulants dosing; (5) screening for AF in high-risk populations, including the role of wearables; (6) left atrial appendage occlusion as an alternative to oral anticoagulation; (7) the role of early rhythm-control therapy; (8) effect of lifestyle interventions on AF; (9) AF as a risk factor for dementia. An interdisciplinary approach seems appropriate to address the complex challenges posed by AF.

Impact of Cardiovascular Hemodynamics on Cognitive Aging

[Figure: see text].

Arterial Stiffness in Aging: Does It Have a Place in Clinical Practice?: Recent Advances in Hypertension

Aortic stiffness increases markedly with age and is associated with excess risk for various adverse clinical outcomes, including heart disease, dementia, and kidney disease. Although evidence for adverse effects of aortic stiffening is overwhelming, integration of direct and indirect measures of aortic stiffness into routine clinical assessment has lagged behind the science. This brief review will examine recent evidence supporting the value of stiffness as an important new risk factor for hypertension and cardiovascular disease and will offer suggestions for incorporating stiffness measures into routine clinical practice.

Associations between left ventricular function, vascular function and measures of cerebral small vessel disease: a cross-sectional magnetic resonance imaging study of the UK Biobank

OBJECTIVES

Impaired cardiovascular function has been associated with cognitive deterioration; however, to what extent cardiovascular dysfunction plays a role in structural cerebral changes remains unclear. We studied whether vascular and left ventricular (LV) functions are associated with measures of cerebral small vessel disease (cSVD) in the middle-aged general population.

METHODS

In this cross-sectional analysis of the UK Biobank, 4366 participants (54% female, mean age 61 years) underwent magnetic resonance imaging to assess LV function (ejection fraction [EF] and cardiac index [CI]) and cSVD measures (total brain volume, grey and white matter volumes, hippocampal volume and white matter hyperintensities [WMH]). Augmentation index (AIx) was used as a measure of arterial stiffness. Linear and non-linear associations were evaluated using cardiovascular function measures as determinants and cSVD measures as outcomes.

RESULTS

EF was non-linearly associated with total brain volume and grey matter volume, with the largest brain volume for an EF between 55 and 60% (both p < 0.001). EF showed a negative linear association with WMH (- 0.23% [- 0.44; - 0.02], p = 0.03), yet no associations were found with white matter or hippocampal volume. CI showed a positive linear association with white matter (β 3194 mm³ [760; 5627], p = 0.01) and hippocampal volume (β 72.5 mm³ [23.0; 122.0], p = 0.004). No associations were found for CI with total brain volume, grey matter volume or WMH. No significant associations were found between AIx and cSVD measures.

CONCLUSIONS

This study provides novel insights into the complex associations between the heart and the brain, which could potentially guide early interventions aimed at improving cardiovascular function and the prevention of cSVD.

KEY POINTS

• Ejection fraction is non-linearly and cardiac index is linearly associated with MRI-derived measures of cerebral small vessel disease. • No associations were found for arterial stiffness with cSVD measures.

Association of Risk of Dementia With Direct Oral Anticoagulants Versus Warfarin Use in Patients With Non-valvular Atrial Fibrillation: A Systematic Review and Meta-analysis

ABSTRACT

Atrial fibrillation (AF) is associated with an increased risk of dementia. Studies have shown the beneficial effects of anticoagulants in preventing dementia in this population. However, evidence around the use of direct oral anticoagulants (DOACs) versus warfarin in AF-related dementia prevention remains sparse. This systematic review and meta-analysis aimed to evaluate the use of DOACs versus warfarin in dementia prevention in this population. MEDLINE, EMBASE, PsycINFO, and the CENTRAL databases were systematically searched from its inception until May 2020. Nine studies (n = 611,069) were included for quantitative meta-analysis. DOACs use was associated with a lower risk of composite dementia outcomes compared with warfarin use [odds ratio (OR) 0.56, 95% confidence interval (CI) 0.34-0.94, P = 0.03]. No significant difference was found in subtypes of dementia (vascular dementia, Alzheimer's disease, and cognitive disorder) between both groups. No significant difference in the risk of composite dementia outcomes between the dabigatran and warfarin groups (OR 0.97, 95% CI 0.88-1.08, P = 0.61). Apixaban (OR 0.58, 95% CI 0.50-0.67, P < 0.00001) and rivaroxaban (OR 0.67, 95% CI 0.61-0.75, P < 0.00001) use were both associated with a significantly lower risk of composite dementia outcomes compared with warfarin use. Findings need to be interpreted with caution because of low certainty of evidence. In conclusion, this systematic review and meta-analysis of 9 comparative studies demonstrated the superiority of DOACs over warfarin in prevention of dementia in AF. Future prospective trials with adequate follow-up period are warranted to ascertain its causal relationship.

The relationship between heart disease and cognitive impairment

Neurodegenerative dementias, such as Alzheimer's disease, and vascular cognitive impairment were once considered unrelated processes. Emerging evidence, however, shows that both conditions often coexist and that vascular risk factors in midlife predispose to the development of cognitive decline later in older adults. In addition, recent advanced in basic science research have elucidated key underpinnings of this association. In this chapter, we review the clinical and basic science data that explain the relationship between vascular risk factors, heart disease, and cognitive decline.

Lower Cardiac Output Relates to Longitudinal Cognitive Decline in Aging Adults

Background

Subclinical reductions in cardiac output correspond to lower cerebral blood flow (CBF), placing the brain at risk for functional changes.

Objectives

This study aims to establish the consequences of reduced cardiac output on longitudinal cognitive outcomes in aging adults.

Methods

Vanderbilt Memory and Aging Project participants free of clinical dementia and heart failure (n = 306, 73 ± 7, 58% male) underwent baseline echocardiography to assess cardiac output (L/min) and longitudinal neuropsychological assessment at baseline, 18 months, 3 and 5 years. Linear mixed-effects regressions related cardiac output to trajectory for each longitudinal neuropsychological outcome, adjusting for age, sex, race/ethnicity, education, body surface area, Framingham Stroke Risk Profile score, apolipoprotein E (APOE) ε4 status and follow-up time. Models were repeated, testing interactions with cognitive diagnosis and APOE-ε4 status.

Results

Lower baseline cardiac output related to faster declines in language (β = 0.11, p = 0.01), information processing speed (β = 0.31, p = 0.006), visuospatial skills (β = 0.09, p = 0.03), and episodic memory (β = 0.02, p = 0.001). No cardiac output x cognitive diagnosis interactions were observed (p > 0.26). APOE-ε4 status modified the association between cardiac output and longitudinal episodic memory (β = 0.03, p = 0.047) and information processing speed outcomes (β = 0.55, p = 0.02) with associations stronger in APOE-ε4 carriers.

Conclusion

The present study provides evidence that even subtle reductions in cardiac output may be associated with more adverse longitudinal cognitive health, including worse language, information processing speed, visuospatial skills, and episodic memory performances. Preservation of healthy cardiac functioning is important for maintaining optimal brain aging among older adults.

Association of Ventricular Arrhythmias With Dementia: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

We performed a cross-sectional analysis to determine whether nonsustained ventricular tachycardia (NSVT) and premature ventricular contractions (PVCs) were associated with dementia in a population-based study.

METHODS

We included 2,517 (mean age 79 years, 26% Black) participants who wore a 2-week ambulatory continuous ECG recording device in 2016 to 2017. NSVT was defined as a wide-complex tachycardia ≥4 beats with a rate >100 bpm. We calculated NSVT and PVC burden as the number of episodes per day. Dementia was adjudicated by experts. We used logistic regression to assess the associations of NSVT and PVCs with dementia.

RESULTS

The mean recording time of the Zio XT Patch was 12.6 ± 2.6 days. There were 768 (31%) participants with NSVT; prevalence was similar in White and Black participants. There were 134 (6.5%) dementia cases (5% in White, 10% in Black participants). After multivariable adjustment, there was no overall association between NSVT and dementia; however, there was a significant race interaction (p < 0.001). In Black participants, NSVT was associated with a 3.67 times higher adjusted odds of dementia (95% confidence interval [CI] 1.92-7.02) compared to those without NSVT, whereas in White participants NSVT was not associated with dementia (odds ratio [95% CI] 0.64 [0.37-1.10]). In Black participants only, a higher burden of PVCs was associated with dementia.

CONCLUSIONS

Presence of NSVT and a higher burden of NSVT and PVCs are associated with dementia in elderly Black people. Further research to confirm this novel finding and to elucidate the underlying mechanisms is warranted.

Multi-time-point data preparation robustly reveals MCI and dementia risk factors

Introduction

Conflicting results on dementia risk factors have been reported across studies. We hypothesize that variation in data preparation methods may partially contribute to this issue.

Methods

We propose a comprehensive data preparation approach comparing individuals with stable diagnosis over time to those who progress to mild cognitive impairment (MCI)/dementia. This was compared to the often-used "baseline" analysis. Multivariate logistic regression was used to evaluate both methods.

Results

The results obtained from sensitivity analyses were consistent with those from our multi-time-point data preparation approach, exhibiting its robustness. Compared to analysis using only baseline data, the number of significant risk factors identified in progression analyses was substantially lower. Additionally, we found that moderate depression increased healthy-to-MCI/dementia risk, while hypertension reduced MCI-to-dementia risk.

Discussion

Overall, multi-time-point-based data preparation approaches may pave the way for a better understanding of dementia risk factors, and address some of the reproducibility issues in the field.

Vascular contributions to cognitive impairment and dementia (VCID): A report from the 2018 National Heart, Lung, and Blood Institute and National Institute of Neurological Disorders and Stroke Workshop

Vascular contributions to cognitive impairment and dementia (VCID) are characterized by the aging neurovascular unit being confronted with and failing to cope with biological insults due to systemic and cerebral vascular disease, proteinopathy including Alzheimer's biology, metabolic disease, or immune response, resulting in cognitive decline. This report summarizes the discussion and recommendations from a working group convened by the National Heart, Lung, and Blood Institute and the National Institute of Neurological Disorders and Stroke to evaluate the state of the field in VCID research, identify research priorities, and foster collaborations. As discussed in this report, advances in understanding the biological mechanisms of VCID across the wide spectrum of pathologies, chronic systemic comorbidities, and other risk factors may lead to potential prevention and new treatment strategies to decrease the burden of dementia. Better understanding of the social determinants of health that affect risks for both vascular disease and VCID could provide insight into strategies to reduce racial and ethnic disparities in VCID.

The central nervous system and heart failure

The view that chronic heart failure was exclusively a disease of the heart dominated the cardiovascular literature until relatively recently. However, over the last 40 years it has increasingly come to be seen as a multisystem disease. Aside from changes in the sympathetic and parasympathetic nervous systems and the renin-angiotensin-aldosterone system, adaptations to the lungs, muscles and gastrointestinal tract have been clearly documented. It is clear that the brain and CNS are also affected in patients with heart failure, although this is often under recognized. The purpose of this review is to summarize the changes in the structure and biochemical function of the CNS in patients with chronic heart failure and to discuss their potential importance.

Prevention and Treatment of Alzheimer's Disease: Biological Mechanisms of Exercise

Alzheimer's disease (AD) is the most common form of dementia. With an aging population and no disease modifying treatments available, AD is quickly becoming a global pandemic. A substantial body of research indicates that lifestyle behaviors contribute to the development of AD, and that it may be worthwhile to approach AD like other chronic diseases such as cardiovascular disease, in which prevention is paramount. Exercise is an important lifestyle behavior that may influence the course and pathology of AD, but the biological mechanisms underpinning these effects remain unclear. This review focuses on how exercise can modify four possible mechanisms which are involved with the pathology of AD: oxidative stress, inflammation, peripheral organ and metabolic health, and direct interaction with AD pathology. Exercise is just one of many lifestyle behaviors that may assist in preventing AD, but understanding the systemic and neurobiological mechanisms by which exercise affects AD could help guide the development of novel pharmaceutical agents and non-pharmacological personalized lifestyle interventions for at-risk populations.