Cognition 6 years after surgical or medical therapy for coronary artery disease

Dissecting the possible influences of anesthesia and surgery on Alzheimer’s disease

SUMMARY Alzheimer’s disease (AD) is a neurodegenerative disease with late onset leading to significant morbidity and, ultimately, mortality. The prevalence of dementia in developed countries for individuals aged 65 years or over is approximately 10% currently, and the number of people with dementia is projected to increase by 350% by 2050. Older people frequently require anesthesia and surgery, such that by 2050 it is anticipated that 50% of all anesthetics will be administered to people aged 65 years or over. Anesthesia is known to be associated with neuropathological changes that mirror AD neuropathology in animal studies, and also with clinical cognitive changes known as postoperative cognitive dysfunction. This article will consider the evidence to date and whether we are able to dissect the possible influences of anesthesia and surgery. Identifying associations between postoperative cognitive dysfunction, dementia and AD is essential for developing strategies that will limit injury, and defer or prevent this disease. As a first step, preoperative cognitive assessment as part of routine perioperative management should become routine practice.

Surgery and brain atrophy in cognitively normal elderly subjects and subjects diagnosed with mild cognitive impairment

BACKGROUND

Structural magnetic resonance imaging is used to longitudinally monitor the progression of Alzheimer disease from its presymptomatic to symptomatic phases. Using magnetic resonance imaging data from the Alzheimer's Disease Neuroimaging Initiative, we tested the hypothesis that surgery would impact brain parameters associated with progression of dementia.

METHODS

Brain images from the neuroimaging initiative database were used to study normal volunteer subjects and patients with mild cognitive impairment for the age group 55 to 90 inclusive. We compared changes in regional brain anatomy for three visits that defined two intervisit intervals for a surgical cohort (n = 41) and a propensity matched nonsurgical control cohort (n = 123). The first interval for the surgical cohort contained the surgical date. Regional brain volumes were determined with Freesurfer and quantitatively described with J-image software (University of California at San Francisco, San Francisco, California). Statistical analysis used Repeated Measures ANCOVA (SPSS, v.18.0; Chicago, IL).

RESULTS

We found that surgical patients, during the first follow-up interval (5-9 months), but not subsequently, had increased rates of atrophy for cortical gray matter and hippocampus, and lateral ventricle enlargement, as compared with nonsurgical controls. A composite score of five cognitive tests during this interval showed reduced performance for surgical patients with mild cognitive impairment.

CONCLUSIONS

Elderly subjects after surgery experienced an increased rate of brain atrophy during the initial evaluation interval, a time associated with enhanced risk for postoperative cognitive dysfunction. Although there was no difference in atrophy rate by diagnosis, subjects with mild cognitive impairment suffered greater subsequent cognitive effects.

Cardiac output, blood pressure variability, and cognitive decline in geriatric cardiac patients

OBJECTIVE

To prospectively investigate whether baseline findings on specific cardiovascular indices are predictive of subsequent rate of decline in Attention-Executive-Psychomotor function in a cohort of ambulatory older adults with cardiovascular diseases (CVDs).

METHODS

One hundred seventy-two older adults with CVD were administered a neuropsychological battery of executive functions tests at study entry, and at 12 and 36 months thereafter. At study entry, they also underwent vascular assessments including cardiac output, ejection fraction, blood pressure (BP), brachial artery reactivity, and carotid intima media thickness. Random coefficient regressions were used to investigate the effect of these cardiac indices on rate of decline in Attention-Executive-Psychomotor function.

RESULTS

Cardiac output, systolic BP variability, and diastolic BP variability predicted decline in Attention-Executive-Psychomotor function. Specifically, lower cardiac output, reduced variability in systolic BP, and increased variability in diastolic BP were associated with a faster rate of decline in Attention-Executive-Psychomotor function. Mean resting systolic and diastolic blood pressure did not predict decline in Attention-Executive-Psychomotor function.

CONCLUSIONS

Decline in frontal-subcortical cognitive functions among patients with CVDs appears to be mediated by systemic hypoperfusion and variability in blood pressure. The precise nature of these relationships, especially with regard to blood pressure variability, is complex and demands continued investigation.

Two-year course of cognitive function and mood in adults with congestive heart failure and coronary artery disease: the Heart-Mind Study

BACKGROUND

Congestive heart failure (CHF) has been associated with impaired cognitive function, but it is unclear if these changes are specific to CHF and if they get worse with time. We designed this study to determine if adults with CHF show evidence of cognitive decline compared with adults with and without coronary artery disease (CAD).

METHODS

A longitudinal study was carried out of 77 adults with CHF (ejection fraction, EF < 0.4), 73 adults with a clinical history of CAD and EF > 0.6, and 81 controls with no history of CAD. The Cambridge Cognitive Examination of the Elderly (CAMCOG) was the primary outcome measure. Secondary measures included the California Verbal Learning Test (CVLT), digit coding and copying, Hospital Anxiety and Depression Scale (HADS), and the short form health survey (SF36). Endpoints were collected at baseline and after 12 and 24 months.

RESULTS

The adjusted CAMCOG scores of CHF participants declined 0.9 points over two years (p = 0.022) compared with controls without CAD. There were no differences between the groups on other cognitive measures. Participants with CHF and with CAD experienced similar changes in cognitive function over two years. Left ventricular EF and six-minute walk test results could not explain the observed associations.

CONCLUSIONS

The changes in cognitive function and mood associated with CHF over two years are subtle and not specific to CHF.

Molecular approaches to improving general anesthetics

Over the last several decades, the average age of patients has steadily increased, whereas the use of general anesthesia and deep sedation has grown largely outside the operating room environment. Currently available general anesthetics and delivery models represent limitations in addressing these trends. At the same time, research has tremendously expanded the knowledge of how general anesthetics produce their beneficial effects and also revealed evidence of previously unappreciated general anesthetic toxicities. The goal of this review is to highlight these important developments and describe translational research on new general anesthetics with the potential to improve and reshape clinical care.

Iatrogenic risk factors for Alzheimer's disease: surgery and anesthesia

Increasing evidence indicates that patients develop post-operative cognitive decline (POCD) following surgery. POCD is characterized by transient short-term decline in cognitive ability evident in the early post-operative period. This initial decline might be associated with increased risk of a delayed cognitive decline associated with dementia 3 to 5 years post-surgery. In some studies, the conversion rates to dementia are up to 70% in patients who are 65 years or older. The factors responsible for the increased risk of dementia are unclear; however, clinical studies investigating the prevalence of POCD and dementia following surgery do not show an association with the type of anesthesia or duration of surgery. Epidemiological studies from our group support this observation. The adjusted Hazard Ratios for developing dementia (or AD specifically) after prostate or hernia surgery were 0.65 (95% CI, 0.51 to 0.83, prostate) and 0.65 (95% CI, 0.49 to 0.85, hernia) for cohorts of subjects exposed to general anesthesia compared to those exposed only to local anesthesia. Animal studies suggest that prolonged exposure to some volatile-inhalational anesthetics increase production of amyloid-β and vulnerability to neurodegeneration, but these results are weakened by the absence of clinical support. Inflammation and a maladaptive stress response might also contribute to the pathophysiology of this disorder. Future research needs to identify predisposing factors, and then strategies to protect against POCD and subsequent dementia. The field also needs to adopt a more rigorous approach to codifying the frequency and extent of early and delayed post-operative cognitive decline.

Sex, aging, and preexisting cerebral ischemic disease in patients with aortic stenosis

BACKGROUND

Patients undergoing cardiac surgery have a high frequency of preexisting cerebral ischemic lesions, the presence of which appears to predict cognitive sequelae. Patients undergoing aortic valve replacement for aortic stenosis (AS) incur an exceptionally high risk for perioperative cerebral ischemia. The extreme risk in this subgroup may arise from the preexisting burden of cerebral ischemic disease. We tested the hypotheses that increasing age, female sex, coronary artery disease, and the severity of AS are predictive of the severity of preexisting cerebral ischemic lesions.

METHODS

A total of 95 subjects were included in this study. Subjects were imaged on 1.5 Tesla magnetic resonance imaging scanners to obtain multimodal image sets which were used for the automatic segmentation of cerebral lesion volume. The dependence of lesion volume upon age, sex, coronary artery disease, and the severity of AS were tested.

RESULTS

The results demonstrate a strong correlation between aging, female sex, and white matter and ischemia-like lesion volume in patients with aortic stenosis.

CONCLUSIONS

Women and those of advanced age presenting for aortic valve replacement for AS may incur a particularly high risk for postoperative neurologic sequelae due to an exceptional preexisting burden of cerebral ischemic disease.

Acute anemia elicits cognitive dysfunction and evidence of cerebral cellular hypoxia in older rats with systemic hypertension

BACKGROUND

Postoperative cognitive dysfunction occurs frequently after cardiac, major vascular, and major orthopedic surgery. Aging and hypertensive cerebrovascular disease are leading risk factors for this disorder. Acute anemia, common to major surgery, has been identified as a possible contributor to postoperative cognitive dysfunction. The effect of hypoxia upon cognition and the cellular and molecular processes involved in learning and memory has been well described. Cerebrovascular changes related to chronic hypertension may expose cells to increased hypoxia with anemia.

METHODS

Young to aged spontaneously hypertensive rats underwent testing for visuospatial memory and learning in the Morris water maze, measurement of cerebral tissue oxygenation via tissue oxygen probe, and measurement of hypoxia-sensitive genes and proteins, under conditions of sham and experimental isovolemic anemia.

RESULTS

Acute isovolemic anemia elicited evidence of aging-dependent visuospatial working memory and learning impairment. Isovolemic anemia did not result in cerebral tissue hypoxia, when measured via tissue oxygen probe. Evidence of cellular hypoxia was, however, identified in response to the anemic challenge, as hypoxia-sensitive genes and proteins were up-regulated. Importantly, cellular hypoxic gene responses were increased with anemia in an age-dependent manner in this model of aging with chronic hypertension.

CONCLUSIONS

In a translational model of chronic hypertension, clinically relevant levels of acute anemia were associated with an age-dependent visuospatial working memory and learning impairment that was matched by an age-dependent cellular sensitivity to anemic hypoxia. These data offer support for a possible link between anemic hypoxia and postoperative cognitive dysfunction in humans.

Association between hypotension, low ejection fraction and cognitive performance in cardiac patients

BACKGROUND AND PURPOSE

Impaired cardiac function can adversely affect the brain via decreased perfusion. The purpose of this study was to determine if cardiac ejection fraction (EF) is associated with cognitive performance, and whether this is modified by low blood pressure.

METHODS

Neuropsychological testing evaluating multiple cognitive domains, measurement of mean arterial pressure (MAP), and measurement of EF were performed in 234 individuals with coronary artery disease. The association between level of EF and performance within each cognitive domain was explored, as was the interaction between low MAP and EF.

RESULTS

Adjusted global cognitive performance, as well as performance in visuoconstruction and motor speed, was significantly directly associated with cardiac EF. This relationship was not entirely linear, with a steeper association between EF and cognition at lower levels of EF than at higher levels. Patients with low EF and low MAP at the time of testing had worse cognitive performance than either of these alone, particularly for the global and motor speed cognitive scores.

CONCLUSIONS

Low EF may be associated with worse cognitive performance, particularly among individuals with low MAP and for cognitive domains typically associated with vascular cognitive impairment. Further care should be paid to hypotension in the setting of heart failure, as this may exacerbate cerebral hypoperfusion.

Neurocognitive dysfunction following cardiac surgery

Postoperative neurocognitive decline (POCD) is the most frequently reported form of brain injury in the cardiac surgery setting. Even though most patients recover over a period of several months, recovery is variable and often transient, and early decline may be a marker of neurocognitive dysfunction after several years. Recent studies, however, suggest that late neurocognitive decline after coronary artery bypass graft surgery may not be specific to the use of cardiopulmonary bypass. Large prospective, longitudinal trials with appropriate controls remain necessary to identify how patient characteristics, disease progression, and surgical and anesthetic technique contribute to aging-related neurocognitive decline. This article reviews the current literature on the etiology of POCD following cardiac surgery, discusses strategies to reduce patient risk, and provides some insight into some controversies that merit continued investigation.

Longitudinal trajectories of cognitive decline among older adults with cardiovascular disease

BACKGROUND

The long-term course of cognitive impairments secondary to cardiovascular disease (CVD) is unclear. In this study, we prospectively investigated the temporal pattern, rate and hierarchy of cognitive decline attributable to CVD--a risk factor for the development of vascular cognitive impairment (VCI)--and examined the influence of cardiac surgery and heart failure on cognitive decline.

METHODS

A total of 172 older adults with CVD were administered a comprehensive battery of neuropsychological tests at study entry, and at 12 and 36 months thereafter. Random coefficient regressions were used to investigate the temporal course, rate and hierarchy of cognitive decline, as well as to examine the effect of heart failure (reported by 21% of the sample) and cardiac surgery (reported by 44% of the sample) on trajectories of cognitive change.

RESULTS

The course of decline in cognition was linear for language and attention-executive function-psychomotor speed, and curvilinear for visuospatial abilities, memory and overall cognition. The decline in attention-executive function-psychomotor speed was smaller than the decline in other domains. The greatest decline occurred in visuospatial abilities. The rate of decline in cognition was not altered by a history of heart failure. Patients who had undergone cardiac surgery exhibited slower deceleration in their rates of decline in overall cognition. At baseline, patients with a history of heart failure had comparatively poorer attention-executive function-psychomotor speed, overall cognition and, to a lesser extent, visuospatial scores.

CONCLUSION

There is measurable decline in neurocognitive function among patients with CVD. This decline is linear in some cognitive domains and curvilinear in others and is not attributable to the normal aging process. Cardiac surgery, but not heart failure, significantly affects the trajectory of cognitive decline. Because most vascular risk factors are modifiable, preventive measures such as lifestyle changes may be useful in retarding cognitive decline among patients with CVD, thus preventing the onset of VCI.

Measurement of post-operative cognitive dysfunction after cardiac surgery: a systematic review

Post-operative cognitive dysfunction (POCD) is a decline in cognitive function from pre-operative levels, which has been frequently described after cardiac surgery. The purpose of this study was to examine the variability in the measurement and definitions for POCD using the framework of a 1995 Consensus Statement on measurement of POCD. Electronic medical literature databases were searched for the intersection of the search terms 'thoracic surgery' and 'cognition, dementia, and neuropsychological test.' Abstracts were reviewed independently by two reviewers. English articles with >50 participants published since 1995 that performed pre-operative and post-operative psychometric testing in patients undergoing cardiac surgery were reviewed. Data relevant to the measurement and definition of POCD were abstracted and compared with the recommendations of the Consensus Statement. Sixty-two studies of POCD in patients undergoing cardiac surgery were identified. Of these studies, the recommended neuropsychological tests were carried out in less than half of the studies. The cognitive domains measured most frequently were attention (n=56; 93%) and memory (n=57; 95%); motor skills were measured less frequently (n=36; 60%). Additionally, less than half of the studies examined anxiety and depression, performed neurological exam, or accounted for learning. Four definitions of POCD emerged: per cent decline (n=15), standard deviation decline (n=14), factor analysis (n=13), and analysis of performance on individual tests (n=12). There is marked variability in the measurement and definition of POCD. This heterogeneity may impede progress by reducing the ability to compare studies on the causes and treatment of POCD.

The (Un)Importance of Cerebral Microemboli

Background: The use of cardiopulmonary bypass (CPB) is associated with cerebral microemboli. Cognitive decline after cardiac surgery has therefore always been attributed to the use of CPB. However, randomized studies comparing coronary bypass surgery with and without CPB failed to establish a clear cognitive benefit of avoiding CPB. The aim of this analysis was to systematically review the studies that directly assessed the association between cerebral microemboli and cognitive decline after cardiac surgery. Methods: The electronic database of PubMed of the National Library of Medicine from 1980 until 2009 was searched to identify relevant literature. Search terms related to “cardiac surgery,” “microemboli,” and “cognitive decline” were used. Studies were reviewed independently by 2 reviewers and relevant articles were included completely if they matched the selection criteria. This review included studies in adult cardiac surgical patients reporting both a measure of cerebral embolic load and cognitive outcomes. Results: The literature search yielded 423 different titles, of which 22 met the selection criteria. All 22 studies used neuropsychological tests to determine cognitive outcome. Seven studies used postoperative (diffusion-weighted) magnetic resonance imaging (MRI) to detect cerebral emboli and 15 studies used intraoperative transcranial Doppler imaging. In 1 MRI study and 5 Doppler studies, an association was found between the number of cerebral emboli and the risk of postoperative cognitive decline. In 15 studies, such an association could not be established. One study did not assess the direct relation between microemboli and cognitive decline. Conclusion: This systematic review could neither confirm nor rule out a causal link between emboli from CPB and postoperative cognitive decline.

Patterns of cognitive change in elderly patients during and 6 months after hospitalisation: a prospective cohort study

BACKGROUND

The extent and patterns of cognitive change regularly occurring in elderly patients who experience prolonged hospitalisation have not been well examined.

OBJECTIVE

To describe patterns of cognitive change during and 6 months after hospitalisation and to identify prognostic factors associated with different patterns of changes.

DESIGN

A prospective cohort study.

SETTING

Five med-surgical units at a tertiary hospital in Taipei, Taiwan.

PARTICIPANTS

Patients ≥65 years old without preexisting profound cognitive impairment (Mini-Mental State Examination score ≥20) and with an expected hospital length of stay >5 days were drawn from consecutive admissions. Of 351 patients, 82.9% (138 women, 153 men, mean age=71.6 years) completed all four scheduled assessments.

METHODS

Cognition was measured by the Mini-Mental State Examination at 4 times: admission, discharge, and 3 and 6 months post-discharge. Possible prognostic factors at admission included demographics, comorbidities, number of medications, serum haemoglobin, length of hospital stay, and surgery.

RESULTS

Four cognitive-change patterns with a high prevalence of decline were identified by cluster analysis. The worsening then improve group (n=47) had a deep V-shape with a mean fluctuation of 3.9 points on the Mini-Mental State Examination, and the low continuous group (n=83) had little change. Both the start high and decline (n=66) and start low and decline (n=95) groups showed persistent and accelerated declines, with baseline cognitive scores of 29.1 and 25.5 points, respectively. Predictor variables at admission for different patterns of cognitive change were age, total education (years), cardiovascular comorbidities, number of medications, functional and nutritional status, depressive symptoms, surgical treatment, and haemoglobin level <12 g/dL.

CONCLUSIONS

Cognitive decline during and after hospitalisation shows four heterogeneous patterns of change. Different patterns of change were predicted by age, education, cardiovascular comorbidities, number of medications, functional and nutritional status, depressive symptoms, surgical treatment, and haemoglobin level <12 g/dL, most of which are potentially modifiable factors.

A Prospective 1-Year Study of Changes in Neuropsychological Functioning After Implantable Cardioverter-Defibrillator Surgery

Background—The testing of the implantable cardioverter-defibrillator (ICD), through the induction of repeated episodes of ventricular fibrillation, has been associated with disturbances in cerebral activity and increased levels of cytoplasmic enzymes. However, the neuropsychological outcomes of cerebral changes and their quality-of-life implications are unknown.

Methods and Results—Fifty-two ICD recipients completed standardized validated neuropsychological tests 1 to 3 days before ICD surgery and then 6 weeks, 6 months, and 12 months after surgery. They also completed psychometric tests measuring anxiety, depression, and quality of life. Between 31% and 39% of patients showed a significant neuropsychological impairment from their baseline function 6 weeks, 6 months, and 12 months after surgery. Ten percent of patients had late-onset deficits at 12 months only. Frequent areas of impairment were auditory and visual memory and attention. Neuropsychological impairment was not related to mood or quality of life at follow-up, although anxiety and depression predicted reduced quality of life.

Conclusions—ICD implantation is associated with neuropsychological impairment that dissipates for the majority of recipients after 12 months. Short-term memory function and attention are particularly vulnerable to changes in oxygen during ICD testing. Although anxiety and depression are prevalent, there is little evidence for the direct impact of mood on cognition, and deficits appear not to be associated with reduced quality of life. These results provide evidence for longitudinal outcomes of ICD surgery and have implications for patient rehabilitation and adjustment.

Delirium: an independent predictor of functional decline after cardiac surgery

OBJECTIVES

To determine whether patients who developed delirium after cardiac surgery were at risk of functional decline.

DESIGN

Prospective cohort study.

SETTING

Two academic hospitals and a Veterans Affairs Medical Center.

PARTICIPANTS

One hundred ninety patients aged 60 and older undergoing elective or urgent cardiac surgery.

MEASUREMENTS

Delirium was assessed daily and was diagnosed according to the Confusion Assessment Method. Before surgery and 1 and 12 months postoperatively, patients were assessed for function using the instrumental activities of daily living (IADL) scale. Functional decline was defined as a decrease in ability to perform one IADL at follow-up.

RESULTS

Delirium occurred in 43.1% (n=82) of the patients (mean age 73.7+/-6.7). Functional decline occurred in 36.3% (n=65/179) at 1 month and in 14.6% (n=26/178) at 12 months. Delirium was associated with greater risk of functional decline at 1 month (relative risk (RR)=1.9, 95% confidence interval (CI)=1.3-2.8) and tended toward greater risk at 12 months (RR=1.9, 95% CI=0.9-3.8). After adjustment for age, cognition, comorbidity, and baseline function, delirium remained significantly associated with functional decline at 1 month (adjusted RR=1.8, 95% CI=1.2-2.6) but not at 12 months (adjusted RR=1.5, 95% CI=0.6-3.3).

CONCLUSION

Delirium was independently associated with functional decline at 1 month and had a trend toward association at 12 months. These findings provide justification for intervention trials to evaluate whether delirium prevention or treatment strategies might improve postoperative functional recovery.

Differences in brain volume, hippocampal volume, cerebrovascular risk factors, and apolipoprotein E4 among mild cognitive impairment subtypes

OBJECTIVES

To evaluate demographics, magnetic resonance imaging (MRI) measures, and vascular risk among mild cognitive impairment (MCI) subtypes.

DESIGN

Cross-sectional study.

SETTING

Both clinics and the community.

PARTICIPANTS

A total of 153 subjects with MCI, 218 cognitively normal older individuals (controls), and 68 patients with Alzheimer disease.

MAIN OUTCOME MEASURES

Classification of subjects with MCI according to current subtype diagnostic convention based on neuropsychological performance, estimates of vascular risk based on medical history, research MRI unless there was a specific contraindication, and apolipoprotein E genotype.

RESULTS

Of the 153 subjects with MCI, 65 were diagnosed with amnestic single-domain, 46 with amnestic multiple-domain, 27 with nonamnestic single-domain, and 15 with nonamnestic multiple-domain MCI. Analyses of control, MCI, and Alzheimer disease cases revealed significant differences in brain and hippocampal volumes between each group. Post hoc analyses of MRI measures among the MCI subtypes found that patients with amnestic single-domain MCI had significantly less brain atrophy and that hippocampal volume differed significantly from controls for the 2 amnestic forms of MCI. Apolipoprotein E genotype prevalence was significantly greater in the amnestic and nonamnestic subtypes of MCI. Conversely, the nonamnestic subtypes were more likely to have increased vascular risk and to be African American.

CONCLUSIONS

Amnestic forms of MCI appear to have demographic, genetic, and MRI findings suggestive of Alzheimer disease pathology, whereas the nonamnestic forms of MCI have findings suggestive of vascular disease. Importantly, however, all subjects with MCI showed evidence of brain injury, and the biological differences among subtypes are relatively subtle beyond the memory vs nonmemory groupings.

Long-term cognitive decline in older subjects was not attributable to noncardiac surgery or major illness

BACKGROUND

Persistent postoperative cognitive decline is thought to be a public health problem, but its severity may have been overestimated because of limitations in statistical methodology. This study assessed whether long-term cognitive decline occurred after surgery or illness by using an innovative approach and including participants with early Alzheimer disease to overcome some limitations.

METHODS

In this retrospective cohort study, three groups were identified from participants tested annually at the Washington University Alzheimer's Disease Research Center in St. Louis, Missouri: those with noncardiac surgery, illness, or neither. This enabled long-term tracking of cognitive function before and after surgery and illness. The effect of surgery and illness on longitudinal cognitive course was analyzed using a general linear mixed effects model. For participants without initial dementia, time to dementia onset was analyzed using sequential Cox proportional hazards regression.

RESULTS

Of the 575 participants, 214 were nondemented and 361 had very mild or mild dementia at enrollment. Cognitive trajectories did not differ among the three groups (surgery, illness, control), although demented participants declined more markedly than nondemented participants. Of the initially nondemented participants, 23% progressed to a clinical dementia rating greater than zero, but this was not more common after surgery or illness.

CONCLUSIONS

The study did not detect long-term cognitive decline independently attributable to surgery or illness, nor were these events associated with accelerated progression to dementia. The decision to proceed with surgery in elderly people, including those with early Alzheimer disease, may be made without factoring in the specter of persistent cognitive deterioration.

Neuropsychological function 5 years after cardiac surgery and the effect of psychological distress

Research has shown conflicting results with regard to the influence of depression and anxiety on neuropsychological performance following coronary artery bypass graft (CABG) surgery. Notably, the independent effects of depression and anxiety have not been examined among CABG candidates in the longer term where it is has been suggested that these patients show marked cognitive deterioration. A neuropsychological test battery and measures of psychological distress were completed by 86 CABG patients and 50 nonsurgical control participants at baseline and 6 months, whereas 75 patients and 36 controls, respectively, completed a 5-year follow-up. In CABG patients, cognitive and affective depressive symptoms were independently associated with lower and worse performance on the Boston Naming Test, Purdue Peg Board, and Digit Symbol Coding 6 months after surgery, whereas at 5-year follow-up an effect for Digit Symbol persisted, and an association was also observed for the Trail Making Test (TMT). On average, CABG patients performed worse on TMT and Digit Symbol at 6 months, whereas at 5-year follow-up their performance was worse on short-term delayed verbal recall. The results among the CABG patients did not show a consistent pattern of association between psychological distress and those neuropsychological domains that were on average significantly lower than a nonsurgical control group. The results here also support the use of nonbiased statistical methodology to document dysfunction among heterogeneous cognitive domains after CABG surgery.

Preconditioning and tolerance against cerebral ischaemia: from experimental strategies to clinical use

Neuroprotection and brain repair in patients after acute brain damage are still major unfulfilled medical needs. Pharmacological treatments are either ineffective or confounded by adverse effects. Consequently, endogenous mechanisms by which the brain protects itself against noxious stimuli and recovers from damage are being studied. Research on preconditioning, also known as induced tolerance, over the past decade has resulted in various promising strategies for the treatment of patients with acute brain injury. Several of these strategies are being tested in randomised clinical trials. Additionally, research into preconditioning has led to the idea of prophylactically inducing protection in patients such as those undergoing brain surgery and those with transient ischaemic attack or subarachnoid haemorrhage who are at high risk of brain injury in the near future. In this Review, we focus on the clinical issues relating to preconditioning and tolerance in the brain; specifically, we discuss the clinical situations that might benefit from such procedures. We also discuss whether preconditioning and tolerance occur naturally in the brain and assess the most promising candidate strategies that are being investigated.

Treatment of depression after coronary artery bypass surgery: a randomized controlled trial

CONTEXT

There has been little research on the treatment of depression after coronary artery bypass surgery.

OBJECTIVE

To test the efficacy of 2 nonpharmacological interventions for depression after coronary artery bypass surgery compared with usual care.

DESIGN

A 12-week, randomized, single-blind clinical trial with outcome evaluations at 3, 6, and 9 months.

SETTING

Outpatient research clinic at Washington University School of Medicine, St Louis, Missouri.

PATIENTS

One hundred twenty-three patients who met the DSM-IV criteria for major or minor depression within 1 year after surgery.

INTERVENTION

Twelve weeks of cognitive behavior therapy or supportive stress management. Approximately half of the participants were taking nonstudy antidepressant medications.

MAIN OUTCOME MEASURE

Remission of depression, defined as a score of less than 7 on the 17-item Hamilton Rating Scale for Depression.

RESULTS

Remission of depression occurred by 3 months in a higher proportion of patients in the cognitive behavior therapy (71%) and supportive stress-management (57%) arms than in the usual care group (33%) (chi(2)(2) = 12.22, P = .002). Covariate-adjusted Hamilton scores were lower in the cognitive behavior therapy (mean [standard error], 5.5 [1.0]) and the supportive stress-management (7.8 [1.0]) arms than in the usual care arm (10.7 [1.0]) at 3 months. The differences narrowed at 6 months, but the remission rates differed again at 9 months (73%, 57%, and 35%, respectively; chi(2)(2) = 12.02, P = .003). Cognitive behavior therapy was superior to usual care at most points on secondary measures of depression, anxiety, hopelessness, stress, and quality of life. Supportive stress management was superior to usual care only on some of the measures.

CONCLUSIONS

Both cognitive behavior therapy and supportive stress management are efficacious for treating depression after coronary artery bypass surgery, relative to usual care. Cognitive behavior therapy had greater and more durable effects than supportive stress management on depression and several secondary psychological outcomes.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00042198.

Randomized, double-blinded, placebo controlled study of neuroprotection with lidocaine in cardiac surgery

BACKGROUND AND PURPOSE

Cognitive decline after cardiac surgery remains common and diminishes patients' quality of life. Based on experimental and clinical evidence, this study assessed the potential of intravenously administered lidocaine to reduce postoperative cognitive dysfunction after cardiac surgery using cardiopulmonary bypass.

METHODS

After IRB approval, 277 patients undergoing cardiac surgery were enrolled into this prospective, randomized, double-blinded placebo controlled clinical trial. Subjects were randomized to receive: (1) Lidocaine as a 1 mg/kg bolus followed by a continuous infusion through 48 hours postoperatively, or (2) Placebo bolus and infusion. Cognitive function was assessed preoperatively and again at 6 weeks and 1 year postoperatively. The effect of lidocaine on postoperative cognition was tested using multivariable regression modeling; P<0.05 was considered significant.

RESULTS

Among the 241 allocated subjects (Lidocaine: n=114; Placebo: n=127), the incidence of cognitive deficit in the lidocaine group was 45.5% versus 45.7% in the placebo group (P=0.97). Multivariable analysis revealed a significant interaction between treatment group and diabetes, such that diabetic subjects receiving lidocaine were more likely to suffer cognitive decline (P=0.004). Secondary analysis identified total lidocaine dose (mg/kg) as a significant predictor of cognitive decline and also revealed a protective effect of lower dose lidocaine in nondiabetic subjects.

CONCLUSIONS

Lidocaine administered during and after cardiac surgery does not reduce the high rate of postoperative cognitive dysfunction. Higher doses of lidocaine and diabetic status were independent predictors of cognitive decline. Protective effects of lower dose lidocaine in nondiabetic subjects need to be further evaluated.

Subjective memory symptoms in surgical and nonsurgical coronary artery patients: 6-year follow-up

BACKGROUND

Self-reported cognitive and memory complaints after coronary artery bypass graft (CABG) operations are common. Several studies have attempted to quantify the incidence of such complaints and to examine the relationship between subjective and objective cognitive functioning, but the etiology and longitudinal course of these self-reports remain unclear.

METHODS

Measures of subjective memory complaints were compared in two groups: 220 CABG patients and 92 nonsurgical cardiac patients at 3 months, and 1, 3, and 6 years. At 6 years, additional measures were used to quantify memory self-assessment. The frequency of subjective complaints at each time point was determined, and associations with objective cognitive performance as well as depression were examined.

RESULTS

At early (3-month or 1-year) follow-up, subjective memory complaints were reported more often by the CABG than the nonsurgical group (45.5% vs 17.0%, p < 0.0001). By 6 years, the frequency of complaints was similar (52%) in both groups. Subjective memory ratings were significantly correlated with performance on several memory tests at 6 years. This relationship was not confounded by depression.

CONCLUSIONS

Subjective memory complaints are more frequent early in follow-up in patients undergoing CABG than in controls, but are similar by 6 years. The increase in subjective complaints over time may be related to progression of underlying cerebrovascular disease. Unlike previous studies, we found that subjective memory assessments were correlated with objective performance on several memory tests. Although subjective memory complaints are more common in patients with depression, they cannot be explained by depression alone.