Neurocognitive Function in Patients with Ventricular Assist Devices: A Comparison of Pulsatile and Continuous Blood Flow Devices

Heart-brain interactions: clinical evidence and mechanisms based on critical care medicine

In this review paper, we search the recent literature regarding the application of the heart-brain interaction theories in the field of intensive care unit. Simultaneously, we methodically summarize the clinical evidence supporting its application in intensive care unit treatment, based on clinical randomized trials and clinical case studies. We delve into how it's applied in treating severely ill patients and in researching animal models for cardio-cerebral comorbidities, aiming to supply benchmarks for subsequent clinical trials and studies on mechanisms.

Echocardiographic measures of the left heart and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: The CABLE study

INTRODUCTION

This study delineated the interrelationships between subclinical alterations in the left heart, cerebrospinal fluid (CSF), Alzheimer's disease (AD) biomarkers, and cognition.

METHODS

Multiple linear regressions were conducted in 1244 cognitively normal participants (mean age = 65.5; 43% female) who underwent echocardiography (left atrial [LA] and left ventricular [LV] morphologic or functional parameters) and CSF AD biomarkers measurements. Mediating effects of AD pathologies were examined. Differences in cardiac parameters across ATN categories were tested using analysis of variance (ANOVA) and logistic regressions.

RESULTS

LA or LV enlargement (characterized by increased diameters and volumes) and LV hypertrophy (increased interventricular septal or posterior wall thickness and ventricular mass) were associated with higher CSF phosphorylated (p)-tau and total (t)-tau levels, and poorer cognition. Tau pathologies mediated the heart-cognition relationships. Cardiac parameters were higher in stage 2 and suspected non-Alzheimer's pathology groups than controls.

DISCUSSION

These findings suggested close associations of subclinical cardiac changes with tau pathologies and cognition.

HIGHLIGHTS

Various subclinical alterations in the left heart related to poorer cognition. Subclinical cardiac changes related to tau pathologies in cognitively normal adults. Tau pathologies mediated the heart-cognition relationships. Subclinical cardiac changes related to the AD continuum, especially to stage 2. The accumulation of cardiac alterations magnified their damage to the brain.

Cognitive Impairment in Heart Failure: A Heart Failure Society of America Scientific Statement

Cognitive impairment is common among adults with heart failure (HF), as both diseases are strongly related to advancing age and multimorbidity (including both cardiovascular and noncardiovascular conditions). Moreover, HF itself can contribute to alterations in the brain. Cognition is critical for a myriad of self-care activities that are necessary to manage HF, and it also has a major impact on prognosis; consequently, cognitive impairment has important implications for self-care, medication management, function and independence, and life expectancy. Attuned clinicians caring for patients with HF can identify clinical clues present at medical encounters that suggest cognitive impairment. When present, screening tests such as the Mini-Cog, and consideration of referral for comprehensive neurocognitive testing may be indicated. Management of cognitive impairment should focus on treatment of underlying causes of and contributors to cognitive impairment, medication management/optimization, and accommodation of deficiencies in self-care. Given its implications on care, it is important to integrate cognitive impairment into clinical decision making. Although gaps in knowledge and challenges to implementation exist, this scientific statement is intended to guide clinicians in caring for and meeting the needs of an increasingly complex and growing subpopulation of patients with HF.

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.

Relation Between Frailty and 1-Year Outcomes After Implantation of a Left Ventricular Assist Device

Frailty has been associated with morbidity and mortality in patients with heart failure and those who underwent cardiac surgery. We aimed to study the effect of frailty on cardiovascular outcomes and the reversibility of frailty after the left ventricular assist device (LVAD) implantation. A total of 51 consecutive patients (44 men; aged 54 ± 10 years) scheduled to undergo LVAD implantation were assessed for frailty (Fried's phenotype, frail ≥3/5), cognitive function (using Mini-Cog), and depression (utilizing Patient Health Questionnaire-9) before the surgery and 3 months afterward. Patients were observed for mortality and adverse events [all-cause readmission, bleeding, renal dysfunction, and ventricular fibrillation (VF)/sustained ventricular tachycardia (VT)] for 12 months. More than half of the patients (54%) were designated as frail. Although there was no statistical difference in mortality among frail and nonfrail patients, frail ones were more likely to have a prolonged length of stay [adjusted odds ratio (AOR) 14.9, 95% confidence interval 1.6 to 132.5, p = 0.01]. At the 3-month reassessment after operation, frailty and cognition rates were better (frailty score [lower is better]: 3 vs 1.5, p <0.0001; cognition score [higher is better]: 4.5 vs 5, p = 0.001), and patients had less depression (Patient Health Questionnaire-9 score [lower is better]: 8 vs 4, p <0.0001). Of the secondary outcomes, only postoperative VF/sustained VT reached statistical significance in being more common among frail patients than nonfrail ones (p = 0.02). Although frailty was not associated with mortality at 1 year, prolonged length of stay occurred more with frail LVAD patients. Frailty status, cognitive function, and depressive mood all improved in most patients after LVAD.

Cognitive Impairment in Heart Failure: Landscape, Challenges, and Future Directions

Heart failure (HF) is a major global healthcare problem accounting for substantial deterioration of prognosis. As a complex clinical syndrome, HF often coexists with multi-comorbidities of which cognitive impairment (CI) is particularly important. CI is increasing in prevalence among patients with HF and is present in around 40%, even up to 60%, of elderly patients with HF. As a potent and independent prognostic factor, CI significantly increases the hospitalization and mortality and decreases quality of life in patients with HF. There has been a growing awareness of the complex bidirectional interaction between HF and CI as it shares a number of common pathophysiological pathways including reduced cerebral blood flow, inflammation, and neurohumoral activations. Research that focus on the precise mechanism for CI in HF is still ever insufficient. As the tremendous adverse consequences of CI in HF, effective early diagnosis of CI in HF and interventions for these patients may halt disease progression and improve prognosis. The current clinical guidelines in HF have begun to emphasize the importance of CI. However, nearly half of CI in HF is underdiagnosed, and few recommendations are available to guide clinicians about how to approach CI in patients with HF. This review aims to synthesize knowledge about the link between HF and cognitive dysfunction, issues pertaining to screening, diagnosis and management of CI in patients with HF, and emerging therapies for prevention. Based on data from current studies, critical gaps in knowledge of CI in HF are identified, and future research directions to guide the field forward are proposed.

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.

Cognitive impairment in heart failure: clinical implications, tools of assessment, and therapeutic considerations

Cognitive impairment (CI) is an important comorbidity in patients with heart failure (HF). Its prevalence parallels the severity of heart failure, while it is an independent prognostic marker of adverse events. Various factors contribute to cognitive decline in HF, influencing self-care. There are no standardized screening methods for the diagnosis and management of these patients. The aim of the present manuscript is to provide an overview of the impact of cognitive impairment in HF, describe the utility of assessment tools and imaging methods for the evaluation of CI, and propose a comprehensive diagnostic and management approach.

Congestive nephropathy: a neglected entity? Proposal for diagnostic criteria and future perspectives

Venous congestion has emerged as an important cause of renal dysfunction in patients with cardiorenal syndrome. However, only limited progress has been made in differentiating this haemodynamic phenotype of renal dysfunction, because of a significant overlap with pre-existing renal impairment due to long-term hypertension, diabetes, and renovascular disease. We propose congestive nephropathy (CN) as this neglected clinical entity. CN is a potentially reversible subtype of renal dysfunction associated with declining renal venous outflow and progressively increasing renal interstitial pressure. Venous congestion may lead to a vicious cycle of hormonal activation, increased intra-abdominal pressure, excessive renal tubular sodium reabsorption, and volume overload, leading to further right ventricular (RV) stress. Ultimately, renal replacement therapy may be required to relieve diuretic-resistant congestion. Effective decongestion could preserve or improve renal function. Congestive acute kidney injury may not be associated with cellular damage, and complete renal function restoration may be a confirmatory diagnostic criterion. In contrast, a persistently low renal perfusion pressure might induce renal dysfunction and histopathological lesions with time. Thus, urinary markers may differ. CN is mostly seen in biventricular heart failure but may also occur secondary to pulmonary arterial hypertension and elevated intra-abdominal pressure. An increase in central venous pressure to >6 mmHg is associated with a steep decrease in glomerular filtration rate. However, the central venous pressure range that can provide an optimal balance of RV and renal function remains to be determined. We propose criteria to identify cardiorenal syndrome subgroups likely to benefit from decongestive or pulmonary hypertension-specific therapies and suggest areas for future research.

More continuous flow, better learning? The effect of aortic valve opening in patients with left ventricular assist device

PURPOSE

The aim of this study was to analyze neurocognitive function in patients who underwent continuous flow left ventricular assist device (LVAD) implantation.

MATERIAL AND METHOD

This cross-sectional study included three groups: LVAD (n = 31), heart failure patients (n = 26), and healthy volunteers (n = 27). The Rey Auditory-Verbal Learning Test (RAVLT), Judgement of Line Orientation Test (JLOT), Trail Making Test (TMT), Stroop Color-Word Interference Test (SCWIT), Verbal Fluency Test (VFT), Symbol-Digit Modality Test (SDMT) were used to assess the neurocognitive functions. Data were analyzed at a median 12 (3-47) months after LVAD implantation. The LVAD patients were also divided by aortic valve opening (AVO) into three subgroups as "closed" (n = 9), "1-6" (n = 8) and "7-10" (n = 14) opening per ten beats and data were re-analyzed accordingly.

RESULTS

There was no significant difference among the groups according to SCWIT, JLOT, SDMT, TMT, and VFT scores. Post-hoc analyzes of RAVLT scores showed significant differences between the LVAD and the other two groups in favor of the LVAD group. Also, the patients with AVO "7-10" the response times were longer and learning scores were found to be lower than those without AVO.

CONCLUSION

With continuous-flow LVAD, neurocognitive functions were not impaired. The learning performance was better in cases where there was no AVO and flow was completely device dependent. We may speculate that neurocognitive functions are not worsening with continuous cerebral blood flow and even it may improve learning performance.

Longitudinal Effects of Left Ventricular Assist Device Implantation on Global and Domain-Specific Cognitive Function

BACKGROUND

Left ventricular assist devices (LVADs) are a common treatment of advanced heart failure, but cognitive dysfunction, which is common in heart failure, could limit the ability to perform postimplantation LVAD care. Implantation of an LVAD has been associated with improved cerebral perfusion and may improve cognitive function post implantation.

OBJECTIVE

The aim of this study was to quantify longitudinal change in cognitive function after LVAD implantation.

METHODS

A secondary analysis of data on 101 adults was completed to evaluate cognitive function before implantation and again at 1, 3, and 6 months post implantation of an LVAD. Latent growth curve modeling was conducted to characterize change over time. Serial versions of the Montreal Cognitive Assessment were used to measure overall (total) cognitive function and function in 6 cognitive domains.

RESULT

There was moderate, nonlinear improvement from preimplantation to 6 months post implantation in Montreal Cognitive Assessment total score (Hedges' g = 0.50) and in short-term memory (Hedges' g = 0.64). There also were small, nonlinear improvements in visuospatial ability, executive function, and attention from preimplantation to 6 months post implantation (Hedges' g = 0.20-0.28). The greatest improvements were observed in the first 3 months after implantation and were followed by smaller, sustained improvements or no additional significant change.

CONCLUSIONS

Implantation of an LVAD is associated with significant, nonlinear improvement in short-term memory and global cognitive function, with the most significant improvements occurring in the first 3 months after implantation. Clinicians should anticipate improvements in cognitive function after LVAD implantation and modify postimplantation education to maximize effectiveness of LVAD self-care.

Motor outcome, executive functioning, and health-related quality of life of children, adolescents, and young adults after ventricular assist device and heart transplantation

OBJECTIVE

The aim of the current study is to measure long-term executive function, motor outcome, and QoL in children, adolescents, and young adults after VAD and Htx.

METHODS

Patients were examined during routine follow-up. Investigation tools were used as follows: Examination for MND of motor outcomes, Epitrack^® for attention and executive functioning, and Kidscreen-52 and EQ-5D-5L questionnaires for QoL. Additional data were retrospectively obtained by an analysis of patient medical records.

RESULTS

Out of 145 heart transplant recipients at the department of pediatric cardiology of the University Hospital Munich, 39 were implanted with a VAD between 1992 and 2016. Seventeen (43.6%) patients died before or after Htx; 22 (56.4%) patients were included in our study. Mean age at transplant was 9.52 years (range: 0.58-24.39 years, median 9), and the mean follow-up time after Htx was 6.18 years (range: 0.05-14.60 years, median 5.82). MND examination could be performed in 13 patients (normal MND: n = 11, simple MND: n = 1, complex MND: n = 1). Executive functioning was tested in 15 patients. Two (13.3%) patients had good results, six (40%) average results, three (20%) borderline results, and four (26.7%) impaired results. QoL (Kidscreen n = 7, EQ-5D-5L n = 8) was similar to a healthy German population.

CONCLUSION

Motor outcome, executive functioning and QoL in survivors of VAD bridging therapy and Htx can be good, though underlying diseases and therapies are associated with a high risk of cerebral ischemic or hemorrhagic complications.

Impact of chronic kidney disease on in-hospital outcomes following left ventricular assist device placement: A national perspective

BACKGROUND

Left ventricular assist devices (LVADs) are being increasingly utilized for the treatment of stage-D heart failure. A LVAD is a battery-operated, mechanical pump that assists in pumping blood out of the left ventricle (LV) into the aorta, thereby lowering left ventricular burden. Prevalence of chronic kidney disease (CKD) is increasing in patients receiving LVAD.

OBJECTIVES

The purpose of this study was to compare in-hospital mortality and hospitalization expenditure associated with CKD in patients receiving LVAD implantation.

METHODS

Using the National Inpatient Sample from January 2012 through September 2015, index hospitalizations for LVAD were identified. Based on kidney function, LVAD recipients were divided into three groups: Group 1 included patients with normal renal function or CKD stages I-III. Groups 2 and 3 comprised of patients with CKD stage IV/V, and end-stage renal disease on dialysis respectively.

RESULTS

A total of 20,656 patients received LVAD during the study period. Mean age was 56.1 years; 76.8% were men. In a fully adjusted model, in-hospital mortality was higher in group 2 (OR: 1.33, CI: 1.16-1.50) and highest in group 3 (OR: 8.95, CI: 6.90-11.61). Similarly, the length of hospitalization, and hospitalization cost were higher in group 2 and highest in group 3.

CONCLUSION

Despite improving outcomes in patients receiving LVAD, CKD remained a significant health problem. Worsening in-hospital outcomes paralleling the degree of kidney dysfunction were observed in patients receiving LVADs in this study.

Cognitive decline in heart failure

Cognitive impairment (CI) is common in older adults with heart failure (HF). The prevalence of CI is higher among patients with HF than in those without. The spectrum of CI in HF is similar to that observed in the general population and may range from delirium to isolated memory or non-memory-related deficits to dementia. Both HF with reduced ejection fraction and HF with preserved ejection fraction have been associated with defects in different domains of cognition. Numerous risk factors have been shown to contribute to CI in HF. Additionally, various pathophysiological mechanisms related to HF can contribute to cognitive decline. These conditions are not routinely screened for in clinical practice settings with HF populations, and guidelines on optimal assessment strategies are lacking. Validated tools and criteria should be used to differentiate acute cognitive decline (delirium) from chronic cognitive decline such as mild cognitive impairment and dementia. CI in HF has been associated with higher rates of disability and impairment in self-care activities that may in turn increase healthcare cost, hospital readmission and mortality. Early detection of CI may improve clinical outcomes in older adults with HF. Appropriate HF management strategies may also help to reduce CI in patients with HF, and future research is needed to develop and test newer and more effective interventions to improve outcomes in patients with HF and CI.

[Artificial organs]

Research has been fighting against organ failure and shortage of donations by supplying artificial organs for many years. With the raise of new technologies, tissue engineering and regenerative medicine, many organs can benefit of an artificial equivalent: thanks to retinal implants some blind people can visualize stimuli, an artificial heart can be proposed in case of cardiac failure while awaiting for a heart transplant, artificial larynx enables laryngectomy patients to an almost normal life, while the diabetic can get a glycemic self-regulation controlled by smartphones with an artificial device. Dialysis devices become portable, as well as the oxygenation systems for terminal respiratory failure. Bright prospects are being explored or might emerge in a near future. However, the retrospective assessment of putative side effects is not yet sufficient. Finally, the cost of these new devices is significant even if the advent of three dimensional printers may reduce it.

Debate: creating adequate pulse with a continuous flow ventricular assist device: can it be done and should it be done? Probably not, it may cause more problems than benefits!

PURPOSE OF REVIEW

The feasibility and benefits of creating adequate pulsatility with continuous flow left ventricular assist devices (LVADs) have long been debated. This review discusses recent technical and clinical findings to answer whether such intervention should be implemented in the standard patient management.

RECENT FINDINGS

Only a limited amount of pulsatility can be generated by periodic speed steps, both considerably smaller in flow increase and in pace rate than the natural circulation. Organ systems are not impeded in their normal function and even not in recovery by a continuous flow. Known problems such as gastrointestinal bleeding are not necessarily due to pulsatility per se, or not important for therapeutic progress, such as minor modifications of the arterial walls.

SUMMARY

The speculative benefits of augmented pulsatility with continuous flow LVADs could be overrated and are still incompletely evaluated. Potential risks that might arise from this strategy should be carefully weighed before implementing extensive pulsatility as standard patient management.

The use of therapeutic magnesium for neuroprotection during global cerebral ischemia associated with cardiac arrest and cardiac surgery in adults: a systematic review

BACKGROUND

Global cerebral ischemia occurs due to reduced blood supply to the brain. This is commonly caused by a cessation of myocardial activity associated with cardiac arrest and cardiac surgery. Survival is not the only important outcome because neurological dysfunction impacts on quality of life, reducing independent living. Magnesium has been identified as a potential neuroprotective agent; however, its role in this context is not yet clear.

OBJECTIVES

The objective of this review was to present the best currently available evidence related to the neuroprotective effects of magnesium during a period of global cerebral ischemia in adults with cardiac arrest or cardiac surgery.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

The current review considered adults aged over 18 years who were at risk of global cerebral ischemia associated with cardiac arrest or cardiac surgery. Studies of patients with existing neurological deficits or under the age of 18 years were excluded from the review.

TYPES OF INTERVENTION(S)/PHENOMENA OF INTEREST

The intervention of interest was magnesium administered in doses of at least of 2 g compared to placebo to adult patients within 24 hours of cardiac arrest or cardiac surgery.

TYPES OF STUDIES

The current review considered experimental designs including randomized controlled trials, non-randomized controlled trials and quasi-experimental designs.

OUTCOMES

The outcome of interest were neurological recovery post-cardiac arrest or cardiac surgery, as measured by objective scales, such as but not limited to, cerebral performance category, brain stem reflexes, Glasgow Coma Score and independent living or dependent living status. To enable assessment of the available data, neuroprotection was examined by breaking down neurological outcomes into three domains - functional neurological outcomes, neurophysiological outcomes and neuropsychological outcomes.

SEARCH STRATEGY

The search strategy aimed to find both published and unpublished studies between January 1980 and August 2014, utilizing the Joanna Briggs Institute (JBI) three-step search strategy. Databases searched included PubMed, Embase, CINAHL, Cochrane Central Register of Controlled Trials, Australian Clinical Trials Register, Australian and New Zealand Clinical Trials Register, Clinical Trials, European Clinical Trials Register and ISRCTN Registry.

METHODOLOGICAL QUALITY

The studies included in this review were of moderate-to-good-quality randomized controlled trials. Studies included measured neurological outcome using functional neurological assessment, neuropsychiatric assessment or neurophysiological assessment.

DATA EXTRACTION

Data were extracted using standardized templates provided by the JBI Meta-analysis of Statistics Assessment and Review Instrument software.

DATA SYNTHESIS

Quantitative data were, where possible, pooled in statistical meta-analysis using Review Manager 5.3 (The Nordic Cochrane Centre, Cochrane; Copenhagen, Denmark). Where statistical pooling was not possible, the findings were presented in narrative form, including tables and figures, to aid in data presentation, where appropriate.

RESULTS

Seven studies with a total of 1164 participants were included in this review. Neurological outcome was categorized into three domains: functional neurological, neurophysiological and neuropsychological outcomes. Meta-analysis of three studies assessing the neuroprotective properties of magnesium administration post cardiac arrest found improved functional neurological outcome (odds ratio 0.44; 95% confidence interval 0.24-0.81).

CONCLUSION

Magnesium may improve functional neurological outcome in patients who suffer global cerebral ischemia associated with cardiac surgery and cardiac arrest. Magnesium does not decrease neuropsychological decline.Further testing of neurological outcomes in the domains of functional outcomes, neurophysiological markers and neuropsychological tests are required to further understanding of the neuroprotective effects of magnesium. Suitable dosing regimens should be investigated prior to introduction into clinical practice. Further research is required to investigate the optimal magnesium dose.

Biventricular mechanical support devices--clinical perspectives

Cardiac transplantation remains the optimal treatment for end stage heart failure in selected patients. However, the shortage of donor hearts, rigorous eligibility criteria and long waiting lists have increased the demand for alternative treatment strategies such as mechanical circulatory support. While many patients are adequately supported with left ventricular assist devices, frequently there is right heart failure or involvement of the right ventricle, requiring biventricular support. Pulsatile flow biventricular devices and total artificial hearts approved for temporary biventricular support have limitations including size, high rates of adverse events and restricted mobility which makes them unsuitable for long term support. A number of centres have reported dual continuous flow left ventricular assist devices as a means of supporting the left and right heart. This review will summarise the literature on the outcomes and complications from current biventricular support devices and assess the role of dual continuous flow VAD therapy, and the new continuous flow total heart replacement devices.

Physiological impact of continuous flow on end-organ function: clinical implications in the current era of left ventricular assist devices

The clinical era of continuous-flow left ventricular assist devices has debunked many myths about the dire need of a pulse for human existence. While this therapy has been documented to provide a clear survival benefit in end-stage heart failure patients, we are now faced with certain morbidity challenges that as of yet have no easy mechanistic physiological explanation. The effect of physiological changes on end-organ function in patients supported by continuous-flow ventricular assist devices may offer insight into some of these morbidities. We therefore present a review of current evidence documenting the impact of continuous flow on end-organ function.

Possible neurocognitive benefits of exercise in persons with heart failure

More than 6 million Americans have heart failure (HF) and more than 500,000 are diagnosed each year. In addition to its many adverse medical consequences, HF is also a significant risk factor for neurological disorders like Alzheimer's disease and associated with cognitive impairment long prior to the onset of these conditions. Converging bodies of literature suggest cognitive dysfunction in HF may be at least partially modifiable. One key mechanism for cognitive improvement is improved cerebral blood flow, which may be possible with exercise in patients with HF. This brief review provides a model for the likely neurocognitive benefits of exercise in HF and encourages further work in this area.

Incidence and predictors of cognitive decline in patients with left ventricular assist devices

BACKGROUND

After left ventricular assist device (LVAD) placement for advanced heart failure, increased cerebral perfusion should result in improved cognitive function. However, stroke (a well-known LVAD complication) and subclinical cerebral ischemia may result in transient or permanent cognitive decline. We sought to describe the incidence and predictors of cognitive decline after LVAD using a valid, sensitive assessment tool.

METHODS AND RESULTS

Among 4419 patients in the Interagency Registry for Mechanically Assisted Circulatory Support who underwent LVAD implantation between May 2012 and December 2013, cognitive function was assessed in 1173 patients with the Trail Making B Test before LVAD and at 3, 6, and 12 months. The test detects several forms of cognitive impairment, including subclinical stroke. Cognitive decline was defined as a clinically important increase during follow-up using a moderate Cohen d effect size of 0.5×baseline SD (32 s). The cumulative incidence of cognitive decline in the year after LVAD implantation, treating death and transplantation as competing risks, was 29.2%. In adjusted analysis, older age (≥70 versus <50 years; hazard ratio, 2.24; 95% confidence interval 1.46-3.44; P(trend)<0.001) and destination therapy (hazard ratio, 1.42; 95% confidence interval, 1.05-1.92) were significantly associated with greater risk of cognitive decline.

CONCLUSIONS

Cognitive decline occurs commonly in patients in the year after LVAD and is associated with older age and destination therapy. These results could have important implications for patient selection and improved communication of risks before LVAD implantation. Additional studies are needed to explore the association between cognitive decline and subsequent stroke, health status, and mortality in patients after LVAD.

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

Heart failure (HF) is a highly prevalent disorder worldwide and, consequently, a burden on the healthcare systems of many nations. Although the effects of HF are systemic, many therapeutic targets are focused on cardiac dysfunction. The brain is closely related to the heart, but there are few reports on the relationship between these organs. We describe the effects of the brain on HF progression. Specific brain regions control sympathetic drive and neurohumoral factors, which play an important role in disease exacerbation. In addition, we review some of our previous studies on deranged cerebral metabolism and reduced cerebral blood flow during HF. Although the reasons underlying these effects during HF remain uncertain, we propose plausible mechanisms for these phenomena. In addition, the clinical implications of such conditions in terms of predicting prognosis are discussed. Finally, we investigate cognitive impairment in patients with HF. Cognitive impairment through cerebral infarction or hypoperfusion is associated with adverse outcomes, including death. This brief review of brain function during the development of HF should assist with future strategies to better manage patients with this condition.

Cognitive impairment and cardiovascular diseases in the elderly. A heart-brain continuum hypothesis

The aging population is increasing and, therefore, a higher prevalence of cardiac disease is emerging; including hypertension, coronary artery disease, atrial fibrillation and chronic heart failure. Large cohort studies have revealed a relationship among increased risk for cognitive impairment and dementia in cardiovascular diseases probably due to embolic stroke or chronic cerebral hypoperfusion. Thus, the aim of the present review is to overview the studies that investigate the presence and/or the development of cognitive impairments and dementia in patients with varied types of cardiovascular disease. Finally, a continuum among hypertension, coronary artery disease, atrial fibrillation and chronic heart failure with to the development of cognitive impairment and progression to dementia has been hypothesized.

Minimized extracorporeal circulation does not impair cognitive brain function after coronary artery bypass grafting

OBJECTIVES

Objective evaluation of the impact of minimized extracorporeal circulation (MECC) on perioperative cognitive brain function in coronary artery bypass grafting (CABG) by electroencephalogram P300 wave event-related potentials and number connection test (NCT) as metrics of cognitive function.

METHODS

Cognitive brain function was assessed in 31 patients in 2013 with a mean age of 65 years [standard deviation (SD) 10] undergoing CABG by the use of MECC with P300 auditory evoked potentials (peak latencies in milliseconds) directly prior to intervention, 7 days after and 3 months later. Number connection test, serving as method of control, was performed simultaneously in all patients.

RESULTS

Seven days following CABG, cognitive P300 evoked potentials were comparable with preoperative baseline values [vertex (Cz) 376 (SD 11) ms vs 378 (18) ms, P = 0.39; frontal (Fz) 377 (11) vs 379 (21) ms, P = 0.53]. Cognitive brain function at 3 months was compared with baseline values [(Cz) 376 (11) ms vs 371 (14 ms) P = 0.09; (Fz) 377 (11) ms vs 371 (15) ms, P = 0.04]. Between the first postoperative measurement and 3 months later, significant improvement was observed [(Cz) 378 (18) ms vs 371 (14) ms, P = 0.03; (Fz) 379 (21) vs 371 (15) ms, P = 0.02]. Similar clearly corresponding patterns could be obtained via the number connection test. Results could be confirmed in repeated measures analysis of variance for Cz (P = 0.05) and (Fz) results (P = 0.04).

CONCLUSIONS

MECC does not adversely affect cognitive brain function after CABG. Additionally, these patients experience a substantial significant cognitive improvement after 3 months, evidentiary proving that the concept of MECC ensures safety and outcome in terms of brain function.

Cognitive performance is associated with left ventricular function in older chronic hemodialysis patients: result of a pilot study

BACKGROUND

Cognitive impairment is a common finding in end-stage renal disease patients on chronic hemodialysis, but data on the associated factors are still scanty.

AIMS

The present study evaluated the association between cognitive function and left ventricular systolic function in hemodialysis patients.

METHODS

We enrolled 72 patients admitted to the Hemodialysis Unit of the Catholic University, Rome. Cognitive performance was evaluated using the Mini Mental State Examination (MMSE); a cutoff of 24 was used to diagnose cognitive impairment. Left ventricular ejection fraction (LVEF) was assessed by echocardiography. Multivariable linear and logistic regressions were adopted to assess the adjusted association between cognitive performance and LVEF. Also, linear discriminant analysis was performed to ascertain the cutoff level of LVEF which best predicted cognitive impairment.

RESULTS

Cognitive impairment was found in 37 (51 %) patients. According to linear regression, MMSE was independently associated with LVEF (B = 0.06; 95 % CI = 0.01-0.12; P = 0.040). Logistic regression confirmed the inverse association between LVEF and cognitive impairment (OR = 0.87; 95 % CI = 0.78-0.98; P = 0.022). In linear discriminant analysis, the LVEF cutoff level that best predicted cognitive impairment was ≤51 %.

CONCLUSION

Cognitive impairment is a common finding in hemodialysis patients. Even mildly depressed LVEF is independently associated with cognitive impairment. This association and its potential therapeutic implications should be assessed in dedicated studies.

Ventricular Assist Devices - Evolution of Surgical Heart Failure Treatment

End-stage heart failure represents a substantial worldwide problem for the healthcare system. Despite significant improvements (medical heart failure treatment, implantable cardioverters, cardiac resyschronisation devices), long-term survival and quality of life of these patients remains poor. Heart transplantation has been an effective therapy for terminal heart failure, but it remains limited by an increasing shortage of available donor organs along with strict criteria defining acceptable recipients. For the last 50 years, mechanical alternatives to support the circulation have been investigated; however, during the early years device development has been marked in general by slow progress. However, in the past two decades, the technology has evolved dramatically. The purpose of this review is to give a short summary on the evolution of ventricular assist device (VAD) therapy and to give perspectives for future treatment of heart failure.

Rotary blood pumps as definitive treatment for severe heart failure

Rotary blood pumps are increasingly recognized as mainstream therapy for severely symptomatic heart failure. Carefully targeted refinements in patient selection and postoperative care have substantially reduced the adverse event burden. These improvements translate into better survival and quality of life in comparison with medical management. Medium-term outcomes now compete favorably with cardiac transplantation, although evidence-based outcome data indicate that transplant and ‘lifetime’ left ventricular-assist device (LVAD) candidates are fundamentally different. Significant challenges remain in relation to neurological injury and right heart failure, which may continue to limit exercise capacity. In the meantime, both physician awareness and patient access to LVAD technology remain limited. The debate is rarely between cardiac transplant or lifetime LVAD. It should focus on the choice between pump versus palliative care for the thousands of patients of all age groups who are judged ineligible for transplantation. Comprehensive healthcare systems must consider contemporary evidence and provide the most symptomatic of heart failure patients with effective care. Cardiac resynchronization therapy is no longer the ceiling for this.

Past and present of cardiocirculatory assist devices: a comprehensive critical review

During the last 20 years, the management of heart failure has significantly improved by means of new pharmacotherapies, more timely invasive treatments and device assisted therapies. Indeed, advances in mechanical support, namely with the development of more efficient left ventricular assist devices (LVADs), and the total artificial heart have reduced mortality and morbidity in patients awaiting transplantation, so much so, that LVADs are now approved of as a strategy for destination therapy. In this review, the authors describe in detail the current basic indications, functioning modalities, main limitations of surgical LAVDs, total artificial heart development, and percutaneous assist devices, trying to clarify this complex, but fascinating topic.

The pharmacotherapy implications of ventricular assist device in the patient with end-stage heart failure

Advances in mechanical circulatory support, such as the use of ventricular assist devices (VADs), have become a means for prolonging survival in end-stage heart failure (HF). VADs decrease the symptoms of HF and improve quality of life by replacing some of the work of a failing heart. They unload the ventricle to provide improved cardiac output and end-organ perfusion, resulting in improvement in cardiorenal syndromes and New York Heart Association functional class rating. VADs are currently used asa bridge to heart transplantation, a bridge to recovery of cardiac function, or as destination therapy. Complications of VAD include bleeding, infections, arrhythmias, multiple organ failure, right ventricular failure, and neurological dysfunction. Patients with VAD have unique pharmacotherapeutic requirements in terms of anticoagulation, appropriate antibiotic selection, and continuation of HF medications. Pharmacists in acute care and community settings are well prepared to care for the patient with VAD. These patients require thorough counseling and follow-up with regard to prevention and treatment of infections, appropriate levels of anticoagulation, and maintenance of fluid balance. A basic understanding of this unique therapy can assist pharmacists in attending to the needs of patients with VAD.

Pulsed or continuous flow in long-term assist devices: a debated topic

The end-stage cardiomyopathy is an increasing worldwide problem. Cardiac transplantation lacks sufficient donors to treat all patients, and there is thus debate about alternative strategies. The use of left ventricular assist devices for long-term support is increasing with a positive impact on patient survival. Although there is an ongoing debate regarding the risks and benefits of maintaining pulsatile flow during long-term ventricular assist device support, there has been a significant move towards implantation of continuous flow devices due to the lower surgical morbidity and better long-term reliability of these pumps. The following is a review of the literature on continuous and pulsatile flow for long-term support. Starting from the definition of flow, we analyze the current evidence and consider gastrointestinal complications.

Alteration of LV end-diastolic volume by controlling the power of the continuous-flow LVAD, so it is synchronized with cardiac beat: development of a native heart load control system (NHLCS)

There are many reports comparing pulsatile and continuous-flow left ventricular assist devices (LVAD). But continuous-flow LVAD with the pulsatile driving technique had not been tried or discussed before our group's report. We have previously developed and introduced a power-control unit for a centrifugal LVAD (EVAHEART®; Sun Medical), which can change the speed of rotation so it is synchronized with the heart beat. By use of this unit we analyzed the end-diastolic volume (EDV) to determine whether it is possible to change the native heart load. We studied 5 goats with normal hearts and 5 goats with acute LV dysfunction because of micro-embolization of the coronary artery. We used 4 modes, "circuit-clamp", "continuous", "counter-pulse", and "co-pulse", with the bypass rate (BR) 100%. We raised the speed of rotation of the LVAD in the diastolic phase with the counter-pulse mode, and raised it in the systolic phase with the co-pulse mode. As a result, the EDV decreased in the counter-pulse mode and increased in the co-pulse mode, compared with the continuous mode (p < 0.05), in both the normal and acute-heart-failure models. This result means it may be possible to achieve favorable EDV and native heart load by controlling the rotation of continuous-flow LVAD, so it is synchronized with the cardiac beat. This novel driving system may be of great benefit to patients with end-stage heart failure, especially those with ischemic etiology.

Long-term continuous flow left ventricular assist device support and end-organ function: prospects for destination therapy

Pulsatile flow left ventricular assist devices (PF-LVADs) have successfully supported patients with severe heart failure for bridge-to-transplant (BTT) and destination therapy (DT). End-organ dysfunction is often reversed, optimizing the patient's condition to enhance survival, and quality of life. Questions have been raised regarding the potential for continuous flow LVADs (CF-LVADs) to provide the same quality of circulatory support. Prior research showing that PF is superior to continuous, non-PF does not appear to be relevant with CF-LVADs for BTT and DT. Under most clinical conditions, arterial pulsatility is present during CF-LVAD support, and this type of support should not be termed "nonpulsatile." Clinical studies have shown that renal, hepatic, and neurocognitive function is either maintained within a normal range, or is significantly improved, during CF-LVAD support for durations up to 15 months. Results of the randomized clinical trial between the CF HeartMate II and the pulsatile HeartMate XVE (both by Thoratec Corp, Pleasanton, CA, USA) are pending final US Food and Drug Administration (FDA) review and are not yet published. Studies of microcirculation during CF-LVAD support indicate that capillary blood flow is adequate to support cellular function. There are anecdotal cases of patients being supported with a CF-LVAD for over seven years with preserved end-organ function. Presently, there are no clinical reports indicating that end-organ function is not well maintained. Current clinical evidence indicates that end-organ perfusion and function can be well maintained for extended durations of support with a CF-LVAD.

Cardiac resynchronization therapy: a pilot study examining cognitive change in patients before and after treatment

BACKGROUND

Cardiovascular patients with reduced cardiovascular output and capacity such as those with congestive heart failure (CHF) have demonstrated cognitive-related dysfunction. The use of cardiac resynchronization therapy (CRT) is considered standard care for CHF patients who do not improve despite optimal medical therapy. Cardiac resynchronization therapy may improve neurocognitive and psychosocial functioning in patients by increasing cardiac output and cerebral perfusion.

METHODS

A total of 20 patients were examined before and 3 months after CRT device implantation, via administration of standard neurocognitive and psychosocial testing measures.

RESULTS

Significant improvements in neurocognitive measures of attention (Digit Span: t[20] = - 2.695 [55.94+/-9.27-62.31+/-10.05], P = 0.015) and information processing (Digit Symbol: t[20] = - 4.577, P < 0.001; Controlled Oral Word Association Test: t[20] = - 3.338, P = 0.004) were demonstrated. Improvements in cardiac-specific quality of life were also significant (Minnesota Living with Heart Failure Questionnaire: t[16] = 3.544, P = 0.005 [55.17+/-18.23-36.75+/-18.00]; The Left Ventricular Dysfunction Questionnaire: t[16] = 3.544, P = 0.003 [63.43+/-23.35-43.29+/-21.62]).

CONCLUSION

These results represent clinically significant, qualitative, and quantitative cognitive functional benefits for patients from a neurocognitive and psychosocial perspective. Results suggest that biventricular pacing improves cardiovascular outcome and psychosocial functioning in patients with CHF. The future investigation of a larger sample would be beneficial in establishing the depth and breadth of this improvement.

The current status of heart transplantation and the development of "artificial heart systems"

BACKGROUND

In view of the major technical advances in ventricular assist devices (VAD) in recent years, the authors discuss the question whether these "artificial hearts" are still no more than a temporary measure for patients awaiting heart transplantation (HTx), or whether they can already be used as an independent form of long-term treatment.

METHODS

Statistics from Eurotransplant regarding heart transplantations and transplant waiting lists in Germany are presented. Technical developments in cardiac support systems, the variation in results depending on the indication, and the findings with respect to quality of life are all discussed on the basis of a selective review of the literature and the authors' own clinical experience.

RESULTS

The waiting list for heart transplantation in Germany has grown to a record size of nearly 800 patients, while fewer than 400 hearts are transplanted each year. Technical advances have improved outcomes in VAD therapy, but the outcome depends on the patient's preoperative condition. The physical performance of patients who have received VAD is comparable to that of HTx patients; nonetheless, HTx patients have a better quality of life.

CONCLUSIONS

Chronic VAD therapy has become a clinical reality. Because of the greater number of patients awaiting HTx, many will not receive their transplants in time. When the decision to treat with VAD is made early, it can be used as an alternative form of treatment with a comparable one-year survival (>75%).