Heart and brain interconnection - clinical implications of changes in brain function during heart failure

Association between heart failure and cerebral collateral flow in large vessel occlusive ischemic stroke

BACKGROUND

Cerebral collateral circulation plays a crucial role in determining the extent of brain ischemia in large vessel occlusive (LVO) stroke. Heart failure (HF) is known to cause cerebral hypoperfusion, yet the relationship between HF and robustness of collateral flow has not been well described.

METHODS

Consecutive patients with middle cerebral and/or internal carotid LVO who underwent endovascular thrombectomy (EVT) between 2012 and 2020 were included. Single-phase head CTA prior to EVT was used to assess collateral status (poor <50 % filling; good ≥50 %). Classification of HF by left ventricular ejection fraction (LVEF) on echocardiogram was used where HF with reduced ejection fraction (HFrEF) had LVEF ≤40 %, HF with preserved EF (HFpEF) had LVEF ≥50 % with evidence of structural heart disease, and no HF had LVEF≥50 % without structural heart disease. Multivariable logistic regression analyses were performed to evaluate the association between HF and poor collaterals.

RESULTS

We identified 235 patients, mean age was 69 ± 15 years; initial NIHSS was 18 ± 7. Of these, 107 (45.5 %) had HF and 105 (44.7 %) had poor collaterals. Those with HF were likely to have poor collaterals compared to those without HF (56.1 % vs 35.2 %, P = 0.001). There was a dose-dependent relationship between EF and poor collaterals: adjusted odds of poor collaterals were 1.63 and 2.45 in HFpEF and HFrEF, compared to those without HF (trend P = .018).

CONCLUSION

Patients with HFrEF are more likely to have poor cerebral collaterals. Further study is needed to explore the pathomechanisms. Optimization of HF may improve cerebral collaterals and enhance EVT outcomes.

Cardiac output-mediated regulation of cerebral blood flow during exercise: Clinical perspectives on the indirect impact of muscle metaboreflex

The muscle metaboreflex stimulates the elevation of arterial blood pressure, aiming to rectify the oxygen deficit by enhancing oxygen delivery to support muscle activity. Moreover, activating the muscle metaboreflex significantly increases cardiac output (CO) by increasing factors such as heart rate, ventricular contractility, preload, stroke volume and mobilization of central blood volume. Previous studies indicate that ageing and cardiovascular diseases modify the muscle metaboreflex during exercise, limiting the ability to increase CO during physical activity. Alongside reduced exercise capacity, the attenuated rise in CO due to abnormal muscle metaboreflex in these patients impedes the increase in cerebral blood flow during exercise. Considering that CO plays a pivotal role in regulating cerebral blood flow adequately during exercise, this occurrence might contribute to an elevated risk of cerebral diseases, and it could also, at least, reduce the effective role of exercise in preventing cerebral disease and dementia among elderly individuals and patients with cardiovascular conditions. Therefore, it is important to consider this phenomenon when optimizing the effectiveness of exercise rehabilitation in patients with cardiovascular disease to prevent cerebral diseases and dementia.

The effect of preexisting heart failure and coronary artery disease on motor function recovery in cerebral infarct patients: A retrospective observational study

Less is known about the impact of heart failure (HF) and coronary artery disease (CAD) on motor recovery after cerebral infarction although previous studies have reported that preexisting HF and CAD were associated with increased mortality in stroke patients as well as unfavorable functional outcomes. In this study, we aimed to accurately evaluate the impact of HF and CAD on motor recovery after cerebral infarction by including only patients with corona radiata using diffusion tensor tractography. A total of 110 patients were recruited, and diffusion tensor tractography was performed within 7 to 30 days of infarct onset. Motor function on the affected side was evaluated for each patient using the upper myocardial infarction (MI), lower MI, modified Brunnstrom classification, and the functional ambulation category at the onset of stroke and 6 months after the onset of stroke. The influence of preexisting HF and CAD on the recovery of motor function were analyzed, adjusting for critical factors for motor recovery after stroke, namely the corticospinal tract condition, lesion location, age, and upper and lower MIs at the onset of stroke. No significant difference was found in motor outcomes according to the presence of HF, while poorer outcomes in motor function of the lower extremities and gait ability were observed in patients with CAD compared to patients without CAD. Motor function of the lower extremities and gait ability in cerebral infarct patients with CAD is more impaired than those without CAD.

Mechanical thrombectomy in patients with heart failure: the Italian registry of Endovascular Treatment in Acute Stroke

BACKGROUND

Heart failure (HF) is the second most important cardiac risk factor for stroke after atrial fibrillation (AF). Few data are available on mechanical thrombectomy (MT) in acute ischemic stroke (AIS) patients with HF.

METHODS

The source of data is the multicentre Italian Registry of Endovascular Treatment in Acute Stroke (IRETAS). All AIS patients ≥ 18 years receiving MT were categorised in two groups: HF and no-HF. Baseline clinical and neuroradiological findings on admission were analysed.

RESULTS

Of 8924 patients, 642 (7.2%) had HF. Compared to the no-HF group, HF patients had higher prevalence of cardiovascular risk factors. Rate of complete recanalisation (TICI 2b-3) was 76.9% in HF vs 78.1% in no-HF group (p = 0.481). Rate of symptomatic intracerebral haemorrhage at 24-h non-contrast computed tomography (NCCT) was 7.6% in HF vs 8.3% in no-HF patients (p = 0.520). At 3 months, 36.4% of HF patients and 48.2% of no-HF patients (p < 0.001) had mRS 0-2, and mortality was, respectively, 30.7% and 18.5% (p < 0.001). In multivariate logistic regression, HF was independently associated with mortality at 3 months (OR 1.53, 1.24-1.88 95% CI, p < 0.001). In multivariate ordinal regression, HF patients had a probability of transitioning to a higher mRS level of 1.23 (1.05-1.44 95% CI, p = 0.012). The propensity score analysis of two groups matched for age, sex, and NIHSS at admission yielded the same results.

CONCLUSION

MT is safe and effective in HF patients with AIS. Patients with HF and AIS suffered from higher 3-month mortality and unfavourable outcome regardless of acute treatments.

Long-Term Outcome in Patients With Acute Ischemic Stroke and Heart Failure

BACKGROUND

This study aimed to identify the association between long term functional outcomes and acute ischemic stroke (AIS) in patients with heart failure (HF) in Japan and whether 1-year event risks can be related to these patients.

METHODS AND RESULTS

This was a prospective observational study, and 651 patients registered in the Tokyo Women's Medical University Stroke Registry were classified into the HF and non-HF groups. Functional outcome at 1 year after stroke onset was defined as either good (modified Rankin Scale [mRS] score of 0-2) or poor (mRS score of 3-6). The primary outcome was a composite of major adverse cardiovascular events (MACE), including non-fatal stroke, non-fatal acute coronary syndrome, and vascular death. Patients with HF had a higher poor functional outcome rate at 1 year than those without HF (54.7% vs. 28.2%, P<0.001). Multivariate logistic regression analysis also demonstrated the prevalence of HF was an independent predictor of an mRS score of ≥3 at 1 year after stroke onset (odds ratio, 1.05; 95% confidence interval, 1.00-1.10; P=0.036). Furthermore, patients with HF tended to have a higher risk of MACE and all-cause mortality than those without HF.

CONCLUSIONS

AIS patients with HF were associated with poor functional outcome at the 1-year follow up. Further multicenter studies involving a larger number of patients are warranted to verify these results.

The Vascular-Immune Hypothesis of Alzheimer's Disease

Alzheimer's disease (AD) is a devastating and irreversible neurodegenerative disorder with unknown etiology. While its cause is unclear, a number of theories have been proposed to explain the pathogenesis of AD. In large part, these have centered around potential causes for intracerebral accumulation of beta-amyloid (βA) and tau aggregates. Yet, persons with AD dementia often exhibit autopsy evidence of mixed brain pathologies including a myriad of vascular changes, vascular brain injuries, complex brain inflammation, and mixed protein inclusions in addition to hallmark neuropathologic lesions of AD, namely insoluble βA plaques and neurofibrillary tangles (NFTs). Epidemiological data demonstrate that overlapping lesions diminish the βA plaque and NFT threshold necessary to precipitate clinical dementia. Moreover, a subset of persons who exhibit AD pathology remain resilient to disease while other persons with clinically-defined AD dementia do not exhibit AD-defining neuropathologic lesions. It is increasingly recognized that AD is a pathologically heterogeneous and biologically multifactorial disease with uncharacterized biologic phenomena involved in its genesis and progression. Here, we review the literature with regard to neuropathologic criteria and incipient AD changes, and discuss converging concepts regarding vascular and immune factors in AD.

Altered brain networks and connections in chronic heart failure patients complicated with cognitive impairment

Objective

Accumulating evidence shows that cognitive impairment (CI) in chronic heart failure (CHF) patients is related to brain network dysfunction. This study investigated brain network structure and rich-club organization in chronic heart failure patients with cognitive impairment based on graph analysis of diffusion tensor imaging data.

Methods

The brain structure networks of 30 CHF patients without CI and 30 CHF patients with CI were constructed. Using graph theory analysis and rich-club analysis, changes in global and local characteristics of the subjects' brain network and rich-club organization were quantitatively calculated, and the correlation with cognitive function was analyzed.

Results

Compared to the CHF patients in the group without CI group, the CHF patients in the group with CI group had lower global efficiency, local efficiency, clustering coefficient, the small-world attribute, and increased shortest path length. The CHF patients with CI group showed lower nodal degree centrality in the fusiform gyrus on the right (FFG.R) and nodal efficiency in the orbital superior frontal gyrus on the left (ORB sup. L), the orbital inferior frontal gyrus on the left (ORB inf. L), and the posterior cingulate gyrus on the right (PCG.R) compared with CHF patients without CI group. The CHF patients with CI group showed a smaller fiber number of edges in specific regions. In CHF patients with CI, global efficiency, local efficiency and the connected edge of the orbital superior frontal gyrus on the right (ORB sup. R) to the orbital middle frontal gyrus on the right (ORB mid. R) were positively correlated with Visuospatial/Executive function. The connected edge of the orbital superior frontal gyrus on the right to the orbital inferior frontal gyrus on the right (ORB inf. R) is positively correlated to attention/calculation. Compared with the CHF patients without CI group, the connection strength of feeder connection and local connection in CHF patients with CI group was significantly reduced, although the strength of rich-club connection in CHF patients complicated with CI group was decreased compared with the control, there was no statistical difference. In addition, the rich-club connection strength was related to the orientation (direction force) of the Montreal cognitive assessment (MoCA) scale, and the feeder and local connection strength was related to Visuospatial/Executive function of MoCA scale in the CHF patients with CI.

Conclusion

Chronic heart failure patients with CI exhibited lower global and local brain network properties, reduced white matter fiber connectivity, as well as a decreased strength in local and feeder connections in key brain regions. The disrupted brain network characteristics and connectivity was associated with cognitive impairment in CHF patients. Our findings suggest that impaired brain network properties and decreased connectivity, a feature of progressive disruption of brain networks, predict the development of cognitive impairment in patients with chronic heart failure.

Assessment of cerebral glucose metabolism in patients with heart failure by 18F-FDG PET/CT imaging

BACKGROUND

To evaluate the cerebral metabolism in patients with heart failure (HF).

METHODS

One hundred and two HF patients were prospectively enrolled, who underwent gated 99mTc-sestamibi single photon emission computed tomography (SPECT)/CT, cardiac and cerebral 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. Fifteen healthy volunteers served as controls. Patients were stratified by extent of hibernating myocardium (HM) and left ventricular ejection fraction (LVEF) into 4 groups where Group1: HM < 10% (n = 33); Group2: HM ≥ 10%, LVEF < 25% (n = 34); Group3: HM ≥ 10%, 25% ≤ LVEF ≤ 40% (n = 16) and Group 4: LVEF > 40% (n = 19). The standardized uptake value (SUV) in the whole brain (SUVwhole-brain) and the SUV ratios (SUVR) in 24 cognition-related brain regions were determined. SUVwhole-brain and SUVRs were compared between the 4 patient groups and the healthy controls.

RESULTS

SUVwhole-brain (r = 0.245, P = 0.013) and SUVRs in frontal areas, hippocampus, and para-hippocampus (r: 0.213 to 0.308, all P < 0.05) were correlated with HM. SUVwhole-brain differed between four patient groups and the healthy volunteers (P = 0.016) and SUVwhole-brain in Group 1 was lower than that in healthy volunteers (P < 0.05). SUVRs of Group 3 in frontal areas were the highest among four patient subgroups (P < 0.05).

CONCLUSIONS

Cerebral metabolism in the whole brain was reduced but maintained in cognition-related frontal areas in HF patients with HM and moderately impaired global left ventricular function.

Comparison of Cognitive Performance and Cardiac Function Between Three Different Rat Models of Vascular Dementia

PURPOSE

Establishing an ideal animal model is essential for studying the pathogenesis, prevention and treatment of vascular dementia (VD). The present study was designed to compare the differences of behavior, cerebral blood flow (CBF), cardiac output and the levels of myocardial enzyme of three different VD rat models.

METHODS

The rats were randomly divided into sham-operated group (SHAM), permanent bilateral common carotid artery occlusion group (BCCAO), BCCAO combined with sodium nitroprusside (2.0mg·kg^-1) group (BCCAO+2.0SNP) and BCCAO combined with sodium nitroprusside (2.5mg·kg^-1) group (BCCAO+2.5SNP). After operation, Morris water maze test, echocardiographic evaluation and the measurement of CBF were performed, then the levels of myocardial enzymes in serum were assessed during euthanasia.

RESULTS

Compared with SHAM rats, the three VD model rats showed different degrees of cognitive impairment, lower cardiac output and CBF, and BCCAO rats showed higher levels of myocardial enzymes. Compared with BCCAO rats, the spatial learning ability of BCCAO+2.0SNP rats and BCCAO+2.5SNP rats was more severely impaired, while the levels of myocardial enzymes of BCCAO+2.0SNP rats were lower. Compared with BCCAO+2.0SNP rats, BCCAO+2.5SNP rats showed no significant difference in cognitive function and cardiac function.

CONCLUSION

Our present study demonstrated that all of the three different VD rat models exhibited cognitive and cardiac function impairment. The BCCAO+2.0SNP model and BCCAO+2.5SNP model damaged the spatial learning ability more seriously. The BCCAO+2.5SNP model caused more comprehensive cognitive impairment. In addition, the BCCAO+2.0SNP model and BCCAO+2.5SNP model might cause more serious damage to cardiac function.

Cognitive Impairment in Acute Heart Failure: Narrative Review

Cognitive impairment (CI) represents a common but often veiled comorbidity in patients with acute heart failure (AHF) that deserves more clinical attention. In the AHF setting, it manifests as varying degrees of deficits in one or more cognitive domains across a wide spectrum ranging from mild CI to severe global neurocognitive disorder. On the basis of the significant negative implications of CI on quality of life and its overwhelming association with poor outcomes, there is a compelling need for establishment of detailed consensus guidelines on cognitive screening methods to be systematically implemented in the population of patients with heart failure (HF). Since limited attention has been drawn exclusively on the field of CI in AHF thus far, the present narrative review aims to shed further light on the topic. The underlying pathophysiological mechanisms of CI in AHF remain poorly understood and seem to be multifactorial. Different pathophysiological pathways may come into play, depending on the clinical phenotype of AHF. There is some evidence that cognitive decline closely follows the perturbations incurred across the long-term disease trajectory of HF, both along the time course of stable chronic HF as well as during episodes of HF exacerbation. CI in AHF remains a rather under recognized scientific field that poses many challenges, since there are still many unresolved issues regarding cognitive changes in patients hospitalized with AHF that need to be thoroughly addressed.

Risk of dementia in patients with atrial fibrillation: Short versus long follow-up. A systematic review and meta-analysis

BACKGROUND

No previous meta-analyses have compared the risk of dementia, due to an underlying atrial fibrillation (AF), in the short-term versus the long-term period.

AIM

To perform an update meta-analysis of studies examining the association between AF and dementia and the relative impact of follow-up period.

METHODS

Data were obtained searching MEDLINE and Scopus for all investigations published between 1 January 2000 and March 1, 2021 reporting the risk of dementia in AF patients. The following MeSH terms were used for the search: "Atrial Fibrillation" AND "Dementia" OR "Alzheimer's disease". From each study, the adjusted hazard ratio (aHR) with the related 95% confidence interval (CI) was pooled using a random effect model.

RESULTS

The analysis was carried out on 18 studies involving 3.559.349 subjects, of which 902.741 (25.3%) developed dementia during follow-up. A random effect model revealed an aHR of 1.40 (95% CI: 1.27-1.54, p < 0.0001; I2  = 93.5%) for dementia in subjects with AF. Stratifying the studies according to follow-up duration, those having a follow-up ≥10 years showed an aHR for dementia of 1.37 (95% CI: 1.21-1.55, p < 0.0001, I2  = 96.6%), while those with a follow-up duration <10 years has a slightly higher aHR for dementia (HR: 1.59, 95%CI: 1.51-1.67, p < 0.0001, I2  = 49%). Nine studies showed that the aHR for Alzheimer's disease (AD) in AF patients was 1.30 (95%CI: 1.12-1.51, p < 0.0001, I2  = 87.6%).

CONCLUSIONS

Evidence suggests that patients with AF have an increased risk of developing dementia and AD. The risk of dementia was slightly higher when the follow-up was shorter than 10 years.

Cognitive Dysfunction after Heart Disease: A Manifestation of the Heart-Brain Axis

The functions of the brain and heart, which are the two main supporting organs of human life, are closely linked. Numerous studies have expounded the mechanisms of the brain-heart axis and its related clinical applications. However, the effect of heart disease on brain function, defined as the heart-brain axis, is less studied even though cognitive dysfunction after heart disease is one of its most frequently reported manifestations. Hypoperfusion caused by heart failure appears to be an important risk factor for cognitive decline. Blood perfusion, the immune response, and oxidative stress are the possible main mechanisms of cognitive dysfunction, indicating that the blood-brain barrier, glial cells, and amyloid-β may play active roles in these mechanisms. Clinicians should pay more attention to the cognitive function of patients with heart disease, especially those with heart failure. In addition, further research elucidating the associated mechanisms would help discover new therapeutic targets to intervene in the process of cognitive dysfunction after heart disease. This review discusses cognitive dysfunction in relation to heart disease and its potential mechanisms.

Heart and brain interactions in heart failure: Cognition, depression, anxiety, and related outcomes

BACKGROUND

Cognitive impairment, anxiety and depression are common in heart failure (HF) patients and its evolution is not fully understood.

OBJECTIVES

To assess the cognitive status of HF patients over time, its relation to anxiety and depression, and its prognostic impact.

METHODS

Prospective, longitudinal, single center study including patients enrolled in a structured program for follow-up after hospital admission for HF decompensation. Cognitive function, anxiety/depression state, HF-related quality of life (QoL) were assessed before discharge and during follow-up (between 6^th and 12^th month) using Montreal Cognitive Assessment (MoCA), Hospital Anxiety and Depression Scale (HADS) and Kansas City Cardiomyopathy Questionnaire, respectively. HF related outcomes were all cause readmissions, HF readmissions and the composite endpoint of all-cause readmissions or death.

RESULTS

43 patients included (67±11.3 years, 69% male); followed-up for 8.2±2.1 months. 25.6% had an abnormal MoCA score that remained stable during follow-up (22.6±4.2 vs. 22.2±5.5; p=NS). MoCA score <22 at discharge conferred a sixfold greater risk of HF readmission [HR=6.42 (1.26-32.61); p=0.025], also predicting all-cause readmissions [HR=4.00 (1.15-13.95); p=0.03] and death or all-cause readmissions [HR=4.63 (1.37-15.67); p=0.014]. Patients with higher MoCA score showed a greater ability to deal with their disease (p=0.038). At discharge, 14% and 18.6% had an abnormal HADS score for depression and anxiety, respectively, which remained stable during follow-up and was not related to MoCA.

CONCLUSIONS

Cognitive function, anxiety and depressive status remain stable in HF patients despite optimized HF therapy. Cognitive status shall be routinely screened to adopt attitudes that improve management as it has an impact on HF-related QoL and prognosis.

Cerebral blood flow impairment and cognitive decline in heart failure

BACKGROUND AND PURPOSE

Cognitive decline is an important contributor to disability in patients with chronic heart failure, affecting 25%-50% of patients. The aim of this review is to stress the importance of understanding pathophysiological mechanisms of heart failure involved in cognitive decline.

METHODS

An extensive PubMed search was conducted for the literature on the basic mechanisms of cerebral blood flow regulation, the effect of cardiac dysfunction on cerebral blood flow, and possible mechanisms underlying the association between cardiac dysfunction and cognitive decline.

RESULTS

Published literature supports the thesis that cardiac dysfunction leads to cerebral blood flow impairment and predisposes to cognitive decline. One of the postulated mechanisms underlying cognitive decline in chronic heart failure is chronic regional hypoperfusion of critical brain areas. Cognitive function may be further compromised by microvascular damage due to cardiovascular risk factors. Furthermore, it is implied that cerebral blood flow assessment could enable early recognition of patients at risk and help guide appropriate therapeutic strategies.

CONCLUSION

Interdisciplinary knowledge in the fields of neurology and cardiology is essential to clarify heart and brain interconnections in chronic heart failure. Understanding and identifying the basic neuropathophysiological changes in chronic heart failure could help with developing methods for early recognition of patients at risk, followed by institution of therapeutic actions to prevent or decrease cognitive decline.

Heart and brain interactions in heart failure: Cognition, depression, anxiety, and related outcomes

BACKGROUND

Cognitive impairment, anxiety and depression are common in heart failure (HF) patients and its evolution is not fully understood.

OBJECTIVES

To assess the cognitive status of HF patients over time, its relation to anxiety and depression, and its prognostic impact.

METHODS

Prospective, longitudinal, single center study including patients enrolled in a structured program for follow-up after hospital admission for HF decompensation. Cognitive function, anxiety/depression state, HF-related quality of life (QoL) were assessed before discharge and during follow-up (between 6^th and 12^th month) using Montreal Cognitive Assessment (MoCA), Hospital Anxiety and Depression Scale (HADS) and Kansas City Cardiomyopathy Questionnaire, respectively. HF related outcomes were all cause readmissions, HF readmissions and the composite endpoint of all-cause readmissions or death.

RESULTS

43 patients included (67±11.3 years, 69% male); followed-up for 8.2±2.1 months. 25.6% had an abnormal MoCA score that remained stable during follow-up (22.6±4.2 vs. 22.2±5.5; p=NS). MoCA score <22 at discharge conferred a sixfold greater risk of HF readmission [HR=6.42 (1.26-32.61); p=0.025], also predicting all-cause readmissions [HR=4.00 (1.15-13.95); p=0.03] and death or all-cause readmissions [HR=4.63 (1.37-15.67); p=0.014]. Patients with higher MoCA score showed a greater ability to deal with their disease (p=0.038). At discharge, 14% and 18.6% had an abnormal HADS score for depression and anxiety, respectively, which remained stable during follow-up and was not related to MoCA.

CONCLUSIONS

Cognitive function, anxiety and depressive status remain stable in HF patients despite optimized HF therapy. Cognitive status shall be routinely screened to adopt attitudes that improve management as it has an impact on HF-related QoL and prognosis.

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.

Atrial fibrillation and cognitive disorders: An overview on possible correlation

Atrial Fibrillation is the most common cardiac arrhythmia affecting people of all ages, principally the elderly. Cognitive decline and dementia are also prevalent diseases in elderly. The scientific community always showed interest in the possible association between these two pathological entities, both implicating social and economic burden. This has been confirmed by several longitudinal population-based studies. Some studies also revealed that the association between atrial fibrillation and dementia may be not related to history of stroke. Therefore, other pathophysiological mechanisms are likely implicated, so far unclear or undefined. The aim of the present review is to analyse the possible mechanisms underlying the frequent association between atrial fibrillation and cognitive impairment.

Heart Failure in Ischemic Stroke

Background and Purpose—

Heart failure (HF) in patients with acute ischemic stroke constitutes the source of various detrimental pathophysiologic mechanisms including prothrombotic and proinflammatory states, worsening of cerebral tissue oxygenation, and hemodynamic impairment. In addition, HF might affect the safety and efficacy of the acute recanalization stroke therapies.

Methods—

Patients treated with intravenous recombinant tissue-type plasminogen activator or mechanical recanalization at a universitary stroke center were included into a prospective registry. Patients received cardiological evaluation, including echocardiography, during acute care. Functional outcome was assessed after 90 days by structured telephone interviews. Safety and efficacy of intravenous thrombolysis and mechanical thrombectomy were investigated among patients with HF and compared with patients with normal cardiac function after propensity score matching.

Results—

One thousand two hundred nine patients were included. HF was present in 378 patients (31%) and an independent predictor of unfavorable functional outcome. Recanalization rates were equal among patients with HF after intravenous thrombolysis and after mechanical recanalization or combined treatment. The rate of secondary intracranial hemorrhage was not different (7% versus 8%; P =0.909 after thrombolysis and 15% versus 20%, P =0.364 after mechanical recanalization or combined therapy). Early mortality within 48 hours after admission was equal (<1.5% in both groups).

Conclusions—

In this real-world cohort of patients with stroke, HF was an independent predictor of unfavorable functional long-term outcome, while the safety and efficacy of intravenous thrombolysis and mechanical recanalization appeared unaffected.

Potential Applications of Remote Limb Ischemic Conditioning for Chronic Cerebral Circulation Insufficiency

Chronic cerebral circulation insufficiency (CCCI) refers to a chronic decrease in cerebral blood perfusion, which may lead to cognitive impairment, psychiatric disorders such as depression, and acute ischemic stroke. Remote limb ischemic conditioning (RLIC), in which the limbs are subjected to a series of transient ischemic attacks, can activate multiple endogenous protective mechanisms to attenuate fatal ischemic injury to distant organs due to acute ischemia, such as ischemic stroke. Recent studies have also reported that RLIC can alleviate dysfunction in distant organs caused by chronic, non-fatal reductions in blood supply (e.g., CCCI). Indeed, research has indicated that RLIC may exert neuroprotective effects against CCCI through a variety of potential mechanisms, including attenuated glutamate excitotoxicity, improved endothelial function, increased cerebral blood flow, regulation of autophagy and immune responses, suppression of apoptosis, the production of protective humoral factors, and attenuated accumulation of amyloid-β. Verification of these findings is necessary to improve prognosis and reduce the incidence of acute ischemic stroke/cognitive impairment in patients with CCCI.

Dynamic cerebral autoregulation is impaired during submaximal isometric handgrip in patients with heart failure

The incidence of neurological complications, including stroke and cognitive dysfunction, is elevated in patients with heart failure (HF) with reduced ejection fraction. We hypothesized that the cerebrovascular response to isometric handgrip (iHG) is altered in patients with HF. Adults with HF and healthy volunteers were included. Cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery) and arterial blood pressure (BP; Finometer) were continuously recorded supine for 6 min, corresponding to 1 min of baseline and 3 min of iHG exercise, at 30% maximum voluntary contraction, followed by 2 min of recovery. The resistance-area product was calculated from the instantaneous BP-CBV relationship. Dynamic cerebral autoregulation (dCA) was assessed with the time-varying autoregulation index estimated from the CBV step response derived by an autoregressive moving-average time-domain model. Forty patients with HF and 23 BP-matched healthy volunteers were studied. Median left ventricular ejection fraction was 38.5% (interquartile range: 0.075%) in the HF group. Compared with control subjects, patients with HF exhibited lower time-varying autoregulation index during iHG, indicating impaired dCA ( P < 0.025). During iHG, there were steep rises in CBV, BP, and heart rate in control subjects but with different temporal patterns in HF, which, together with the temporal evolution of resistance-area product, confirmed the disturbance in dCA in HF. Patients with HF were more likely to have impaired dCA during iHG compared with age-matched control subjects. Our results also suggest an impairment of myogenic, neurogenic, and metabolic control mechanisms in HF. The relationship between impaired dCA and neurological complications in patients with HF during exercise deserves further investigation. NEW & NOTEWORTHY Our findings provide the first direct evidence that cerebral blood flow regulatory mechanisms can be affected in patients with heart failure during isometric handgrip exercise. As a consequence, eventual blood pressure modulations are buffered less efficiently and metabolic demands may not be met during common daily activities. These deficits in cerebral autoregulation are compounded by limitations of the systemic response to isometric exercise, suggesting that patients with heart failure may be at greater risk for cerebral events during exercise.

Detecting and Managing Cognitive Impairment to Improve Engagement in Heart Failure Self-Care

PURPOSE OF THE REVIEW

The purpose of this review was to examine the recent literature on detecting cognitive impairment in patients with heart failure (HF) and the evidence indicating any ramifications of cognitive impairment on patient engagement in HF self-care.

RECENT FINDINGS

Mild cognitive impairment (MCI) is common in HF and impacts on patients' engagement in self-care, yet it is frequently not detected. The use of screening tools, even when brief, improves detection of MCI. However, the most sensitive, specific and feasible screening measure to use in practice is yet to be identified. A full neuropsychological assessment is required to determine a diagnosis of cognitive impairment and to identify the specific areas of cognitive deficit. In patients with HF, there appears to be differing clusters of cognitive deficits. Identification of these deficits may help inform the application of specific cognitive training strategies to ameliorating cognitive changes in HF patients and potentially enhance engagement in self-care. Screening for cognitive impairment is crucial in the management of HF patients to ensure that potential self-care deficits are prevented. The optimal screening tool is yet to be identified.

Cerebral hypoperfusion is not associated with an increase in amyloid β pathology in middle-aged or elderly people

INTRODUCTION

It is hypothesized that cerebral hypoperfusion promotes the development of Alzheimer pathology. We therefore studied whether longstanding cerebral hypoperfusion is associated with Alzheimer pathology in nondemented humans.

METHODS

Cerebral blood flow and amyloid β (¹⁸F-Flutemetamol) positron emission tomography retention were assessed in eleven patients with unilateral occlusion of precerebral arteries resulting in chronic and uneven hypoperfusion. A subset of patients underwent tau (¹⁸F-AV-1451) positron emission tomography.

RESULTS

The blood flow was significantly reduced on the affected side of the brain in patients with unilateral occlusion of the internal carotid artery or stenosis of the middle cerebral artery. However, the cortical uptake of ¹⁸F-Flutemetamol or ¹⁸F-AV-1451 was not altered.

DISCUSSION

Our results suggest that longstanding cerebral hypoperfusion in humans does not result in accumulation of amyloid β fibrils or tau aggregates.

Exercise training to reduce sympathetic nerve activity in heart failure patients. A systematic review and meta-analysis

OBJECTIVE

To determine the effects of exercise training on sympathetic nerve activity in heart failure patients.

METHODS

A systematic review was performed. An electronic search of MEDLINE, ProQuest, SciELO, SPORTDiscus, Rehabilitation and Sport Medicine Source, Cumulative Index to Nursing and Allied Health Literature, Tripdatabase, Science Direct and PEDrO was performed from their inception to February 2017. Clinical trials and quasi-experimental studies were considered for primary article selection. The studies should include patients diagnosed with chronic heart failure that performed exercise training for at least 4 weeks. Sympathetic nerve activity should be measured by microneurography before and after the intervention. The Cochrane Collaboration's Risk of Bias Tool was used to evaluate risk of bias, and the quality of evidence was rated following the GRADE approach. Standardized mean differences (SMD) were calculated for control and experimental groups. Meta-analysis was performed using the random effects model.

RESULTS

Five trials were included. Overall, the trials had moderate risk of bias. The experimental group indicated a significant decrease in the number of bursts per minute (SMD -2.48; 95% CI -3.55 to -1.41) when compared to the control group. Meanwhile, a significant decrease was also observed in the prevalence of bursts per 100 beats in the experimental group when compared to the control group (SMD -2.66; 95% CI -3.64 to -1.69).

CONCLUSION

Exercise training could be effective in reducing sympathetic nerve activity in patients with heart failure. The quality of evidence across the studies was moderate. Future studies are necessary to confirm these results.

Reversible Motor Paralysis and Early Cardiac Rehabilitation in Patients With Advanced Heart Failure Receiving Left Ventricular Assist Device Therapy

Advanced heart failure (HF) is sometimes complicated with brain impairment because of a microthrombosis caused by decreased left ventricular contraction or reduced brain circulation. Some patients may recover after left ventricular assist device (LVAD) implantation. However, little is known about the perioperative therapeutic strategy in patients suffering from such complications, particularly from a cardiac rehabilitation viewpoint. We report on a 58-year-old male patient with a previous history of poliomyelitis and a light paralysis in the left upper extremity, who suffered left hemiplegia with no evidence of stroke after hemodynamic deterioration. The combination therapy of perioperative cardiac rehabilitation and LVAD therapy improved his left hemiplegia as well as activities of daily living, and the patient was discharged on foot on postoperative day 72 after briefing the family on LVAD home management. Early initiation of cardiac rehabilitation before LVAD implantation may be a key for the smooth discharge and resocialization of patients suffering from brain impairment complicated with advanced HF.

Identification of cardiac-related circulating microRNA profile in human chronic heart failure

BACKGROUND

During chronic heart failure, levels of circulating miRNAs endued with characteristics of diseased cells could be identified as biomarkers. In this study, we sought to identify cardiac-related circulating miRNAs as biomarkers of failing heart.

METHODS

Total RNA of plasma and heart samples was extracted from 10 normal controls and 14 patients with chronic heart failure. Microarray was applied for miRNA profiles. Validation and organ/tissue distribution analysis was performed by qRT-PCR. In addition, bioinformatics analysis was performed to understand the critical roles of these cardiac-related circulating miRNAs in heart failure.

RESULTS

Results showed that levels of more than half of the miRNAs dysregulated in heart failed to show any differences in plasma. Meanwhile, more than 90% of the miRNAs dysregulated in plasma remained stable in heart. Four cardiac fibroblast-derived miRNAs (miR-660-3p, miR-665, miR-1285-3p and miR-4491) were found significantly upregulated in heart and plasma during heart failure. These 4 miRNAs strongly discriminated patients from controls, and 3 of them showed significant correlations with LVEF.

CONCLUSIONS

This study provides global profiles of miRNAs changes in plasma and failing heart, and using a circulation-tissue miRNA profiling comparison model, we successfully identify 3 cardiac-related circulating miRNAs as potential biomarkers for diagnosis of heart failure.

Differential activation of c‑Fos in the paraventricular nuclei of the hypothalamus and thalamus following myocardial infarction in rats

Proto-oncogene c-Fos (c-Fos) is frequently used to detect a pathogenesis in central nervous system disorders. The present study examined changes in the immunoreactivity of c-Fos in the paraventricular nucleus of the hypothalamus (PVNH) and paraventricular nucleus of the thalamus (PVNT) following myocardial infarction (MI) in rats. Infarction in the left ventricle was examined by Masson's trichrome staining. Neuronal degeneration was monitored for 56 days after MI using crystal violet and Fluoro-Jade B histofluorescence staining. Changes in the immunoreactivity of c-Fos were determined using immunohistochemistry for c-Fos. The average infarct size of the left ventricle circumference was ~44% subsequent to MI. Neuronal degeneration was not detected in PVNH and PVNT following MI. c-Fos immunoreactive (⁺) cells were infrequently observed in the nuclei of the sham-group. However, the number of c-Fos⁺ cells was increased in the nuclei following MI and peaked in the PVNH and PVNT at 3 and 14 days, respectively. The number of c-Fos⁺ cells were comparable with the sham group at 56 days after MI. Therefore, MI may induce c-Fos immunoreactivity in PVNH and PVNT, this increase of c-Fos expression levels may be associated with the stress that occurs in the brain following MI.

Hippocampal Blood Flow Abnormality Associated With Depressive Symptoms and Cognitive Impairment in Patients With Chronic Heart Failure

BACKGROUND

Depressive symptoms and memory impairment are prevalent in patients with chronic heart failure (CHF). Although the mechanisms remain to be elucidated, the hippocampus (an important brain area for emotion and memory) may be a possible neural substrate for these symptoms.

METHODS AND RESULTS

We prospectively enrolled 40 Stage C patients, who had past or current CHF symptoms, and as controls 40 Stage B patients, who had structural heart disease but had never had CHF symptoms, in Brain Assessment and Investigation in Heart Failure Trial (B-HeFT) (UMIN000008584). As the primary index, we measured cerebral blood flow (CBF) in the 4 anterior-posterior segments of the hippocampus, using brain MRI analysis. Depressive symptoms, immediate memory (IM) and delayed memory (DM) were assessed using Geriatric Depression Scale (GDS), and Wechsler Memory Scale-revised (WMS-R), respectively. Hippocampus CBF in the most posterior segment was significantly lower in Stage C than in Stage B group (P=0.029 adjusted for Holm's method). Multiple regression analysis identified significant association between hippocampus CBF and GDS or DM score in Stage C group (all P<0.05). GDS score was significantly higher, and IM and DM scores were lower in Stage C patients with hippocampus CBF below the median than those with hippocampus CBF above the median (all P<0.05).

CONCLUSIONS

Hippocampus abnormalities are associated with depressive symptoms and cognitive impairment in CHF patients. (Circ J 2016; 80: 1773-1780).

Atrial Fibrillation, Cognitive Decline And Dementia

Atrial fibrillation (AF) is a common cardiac arrhythmia. Growing evidence supports a role for AF as a risk factor for cognitive decline and dementia. In this review, we summarize epidemiologic observations linking AF with cognitive outcomes, describe potential mechanisms, and explore the impact of AF treatments on cognitive decline and dementia. Community-based, observational studies show a consistent higher rate of cognitive decline and risk of dementia in persons with AF. These associations are partly due to the increased risk of clinical stroke in AF, but other mechanisms, including incidence of silent cerebral infarcts, microbleeds, and cerebral hypoperfusion, are likely additional contributors. Adequate oral anticoagulation and improved management of the overall cardiovascular risk profile in persons with AF offer the promise of reducing the impact of AF on cognitive decline and dementia.