Predictors of cognitive decline following coronary artery bypass graft surgery

Assessment of long-term cognitive dysfunction in older patients who undergo heart surgery

INTRODUCTION

Older patients are more likely to have cognitive dysfunction, and a great proportion of patients undergone surgical procedures are older adults. Postoperative cognitive dysfunction (POCD) has been shown as a consistent complication after major surgical procedures such as heart surgery.

AIM

To determine the presence of long-term POCD in ≥65-year-old patients undergoing coronary artery bypass grafting and aortic valve replacement, and to establish related risk factors.

METHODS

We prospectively and sequentially included 44 patients with coronary disease and aortic stenosis scheduled for heart surgery. Follow-up of all patients was standardized and a neurocognitive evaluation were performed preoperatively and at 1, 6 and 12 months after surgery.

RESULTS

Patients experienced a significantly postoperative cognitive dysfunction (33.5%, 63.4% and 38.9% at 1, 6 and 12 months, respectively) from baseline (20.5%). Patient-associated aspects such as age (p<0.01), history of smoking (p<0.01), arterial hypertension (p=0.022), diabetes mellitus (p=0.024), heart failure (p=0.036) and preoperative cognitive dysfunction (p<0.01), and surgery-associated aspects such as EuroSCORE (p<0.01) and operation time (p<0.01) were identified as related risk factors.

CONCLUSIONS

Older patients who underwent heart surgery had long-term POCD. Both patient- and surgery-related risk factors were established as related risk factors. These findings suggest that the prevalence of cognitive dysfunction after cardiac surgery in older patients could be related to a possible progression to dementia. In addition, many of the risk factors identified may be modifiable but in practice, these patients are not attended to for their possible cognitive impairment.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Predictors of cognitive dysfunction after cardiac surgery: a systematic review

AIMS

Postoperative cognitive dysfunction (POCD) is often experienced by cardiac surgery patients; however, it is not known if some groups of patients experience this more frequently or severely than others.The aim of this systematic review was to identify preoperative and postoperative predictors of cognitive dysfunction in adults following cardiac surgery.

METHODS AND RESULTS

Eight bibliographic databases were searched (January 2005 to March 2021) in relation to cardiac surgery and cognition. Studies including adult patients who had undergone open cardiac surgery and using a validated measurement of cognitive function were included. Full-text review for inclusion, quality assessment, and data extraction were undertaken independently by two authors.A total of 2870 papers were identified, of which 36 papers met the inclusion criteria and were included in the review. The majority were prospective observational studies [n = 28 (75.7%)]. In total, 61 independent predictors (45 preoperative and 16 postoperative) were identified as significant in at least one study; advancing age and education level appear important. Age has emerged as the most common predictor of cognitive outcome.

CONCLUSION

Although a number of predictors of POCD have been identified, they have inconsistently been reported as significantly affecting cognitive outcome. Consistent with previous research, our findings indicate that older patients and those with lower educational levels should be prioritized when developing and trialling interventions to improve cognitive function. These findings are less than surprising if we consider the methodological shortcomings of included studies. It is evident that further high-quality research exploring predictors of POCD is required.

The state of cognitive function in patients with stable coronary artery disease after coronary artery bypass grafting

Aim      To study the cognitive function (CF) state in patients with chronic ischemic heart disease (IHD) depending on the method of coronary bypass (CB), with extracorporeal circulation (EC) or on beating heart.Material and methods  Postoperative cognitive dysfunction (POCD) is a frequent complication of CB, and its development may depend on the method of surgery, with EC or on beating heart. This single-center, prospective, nonrandomized study included 196 patients with chronic IHD aged 61.0±5.1 years. Patients were divided into two groups based on the CB method: an EC group (n=11) and a beating heart surgery group (n=85). Mean follow-up period was 26±2.1 mos. The state of CF was evaluated before and after CB (at the hospital stage, at 3, 6, 12, and 24 mos.).Results The mean duration of CF recovery was 3 mos. only in the group of CB without EC (p&lt;0.05), whereas after CB with EC, CF parameters were similar to those during the hospital stage with somewhat reduced values. In 6 mos. after CB, CF normalized to baseline values in both groups (with and without EC). A possible CF decline in patients with chronic IHD after CB depended on the following factors: age older than 60 years (p&lt;0.05), diabetes mellitus with glycated hemoglobin &gt;7.5 % (p=0.001) and 6.5-7.5 % (p=0.03), smoking (p=0.04), atherosclerotic damage of the internal carotid artery (p&lt;0.05), and a Charlson comorbidity index &gt;5 (p=0.03). The CB surgery either with EC (p=0.04) or on beating heart (p=0.04) was associated with the development of CD.Conclusion      The results of the study allow identifying patients with chronic IHD and POCD-predisposing factors to recommend them beathing heart CB surgery.

Assessment of long-term cognitive dysfunction in older patients who undergo heart surgery

INTRODUCTION

Older patients are more likely to have cognitive dysfunction, and a great proportion of patients undergone surgical procedures are older adults. Postoperative cognitive dysfunction (POCD) has been shown as a consistent complication after major surgical procedures such as heart surgery.

AIM

To determine the presence of long-term POCD in ≥65-year-old patients undergoing coronary artery bypass grafting and aortic valve replacement, and to establish related risk factors.

METHODS

We prospectively and sequentially included 44 patients with coronary disease and aortic stenosis scheduled for heart surgery. Follow-up of all patients was standardized and a neurocognitive evaluation were performed preoperatively and at 1, 6 and 12 months after surgery.

RESULTS

Patients experienced a significantly postoperative cognitive dysfunction (33.5%, 63.4% and 38.9% at 1, 6 and 12 months, respectively) from baseline (20.5%). Patient-associated aspects such as age (p<0.01), history of smoking (p<0.01), arterial hypertension (p=0.022), diabetes mellitus (p=0.024), heart failure (p=0.036) and preoperative cognitive dysfunction (p<0.01), and surgery-associated aspects such as EuroSCORE (p<0.01) and operation time (p<0.01) were identified as related risk factors.

CONCLUSIONS

Older patients who underwent heart surgery had long-term POCD. Both patient- and surgery-related risk factors were established as related risk factors. These findings suggest that the prevalence of cognitive dysfunction after cardiac surgery in older patients could be related to a possible progression to dementia. In addition, many of the risk factors identified may be modifiable but in practice, these patients are not attended to for their possible cognitive impairment.

Postoperative cognitive change after cardiac surgery predicts long-term cognitive outcome

OBJECTIVES

Postoperative cognitive dysfunction (POCD) is a common consequence of coronary artery bypass grafting. However, domain-specific associations between postoperative changes and long-term performance are poorly known. The aim of this study was to investigate whether domain-specific cognitive changes after cardiac surgery predict long-term cognitive outcome.

MATERIALS AND METHODS

We assessed 100 patients (86 men, mean age 60) before coronary artery bypass grafting, with re-examinations after one week, three months, and a mean of 6.7 years. The extensive neuropsychological test battery was organized into seven functional cognitive domains. Cognitive decline and improvement were defined with the reliable change index derived from 17 matching healthy controls. Analyses were adjusted for baseline cognitive performance, age, gender, education and cardiovascular risks factors.

RESULTS

On group level, one week after surgery 71% patients showed cognitive decline and 9% improvement in any functional domain, as compared to preoperative results. Three months postsurgery, decline was observed in 47% and improvement in 25% of patients. Executive functioning was the most sensitive domain to both decline and improvement. Postoperative dysfunction predicted long-term cognitive deterioration six years after operation, particularly in the domain of executive functioning.

CONCLUSIONS

POCD after coronary artery bypass grafting is an essential risk factor for long-term deterioration and an indication for neuropsychological follow-up. Assessment of change in executive functioning after coronary artery bypass grafting may help to identify patients at risk for unfavorable long-term outcome.

Characteristics of Hospitalized Patients Screening Positive for Delirium

BACKGROUND

Delirium in the hospitals leads to worse outcomes for patients. There were no previous studies that characterize patients with delirium from multiple hospital locations.

OBJECTIVE

To describe patient characteristics screening positive for delirium and identify any correlations with hospital location and medication use.

DESIGN, SETTINGS, PATIENTS

Retrospective chart review of 227 hospitalized patients from a large, academic, tertiary referral, 2-campus health system. Patients were ≥18 years old and had delirium for at least ≥24 hours. Validated delirium screening tools were utilized.

MEASUREMENTS

Patients' demographics, inpatient stay information, delirium episodes characteristics, drugs, and palliative and psychiatry teams' involvement.

RESULTS

Most patients were older with a mean age of 64.1 years. The most common primary diagnoses were infection, cardiac, and pulmonary. Average length of delirium was 7.2 days (standard deviation [SD] = 8.2), and average length of stay (LOS) was 18.7 days (median = 10.5, SD = 35.1, 95% confidence interval = 14.1-23). Thirty-day readmission rate was 24.8% (65/262 hospitalizations); 12.8% of patients died in the hospital (29/227). Around one-third of hospitalizations had involvement of palliative care, palliative psychiatry, or general psychiatry team. There was a decrease in the number of medications administered 24 hours after the first recording of delirium compared to the immediate preceding 48 hours. Those hospitalizations where delirium first occurred in the intensive care unit (ICU) did have a longer LOS (average = 22.9, SD = 45.7) than those where delirium first occurred outside the ICU (average = 14.8, SD = 20.5). Patients were likely to have received an opioid within 48 hours in 51% of hospitalizations and to have received benzodiazepines in 16% of hospitalizations.

CONCLUSION

In our study, we found that delirium significantly impacted length of delirium episode, number of episodes of delirium, length of hospital admission, and mortality. The population most sensitive to the impacts of delirium were elderly patients.

Association of CT perfusion and postoperative cognitive dysfunction after off-pump coronary artery bypass grafting

OBJECTIVE

To investigate the relationship between an abnormal CT perfusion scan and postoperative cognitive dysfunction, as measured by changes in MoCA and MMSE scores, after off-pump coronary artery bypass grafting (OPCABG).

METHODS

Eight hundred and thirteen patients were selected who underwent OPCABG between August 2010 and September 2013. Cognitive function was assessed before operation and at seven days post-op. CT perfusion scan was obtained preoperatively and was used to divide patients into two groups: abnormal perfusion and normal perfusion groups.

RESULTS

(1) Logistic regression analysis showed that perfusion abnormalities (OR, 3.012; 95% CI, 1.660-5.463; P < 0.05) were an independent risk factor for postoperative cognitive dysfunction (POCD). (2) 556 patients with CT perfusion scans were divided into normal perfusion and abnormal perfusion groups: incidence of POCD in the abnormal perfusion group is significantly higher than the control group (21.6 vs 8.6%, P < 0.05); MMSE scores were significantly lower in patients with abnormal perfusion before and after surgery. MoCA scores demonstrated a significant drop after surgery for all patients with abnormal perfusion (P < 0.05). The abnormal perfusion group had a significant reduction in the visuospatial/executive and naming scores in the MoCA as compared to normal perfusion (P < 0.05).

CONCLUSION

Abnormal CT perfusion is a significant risk factor for postoperative cognitive dysfunction, and has the most impact on visuospatial/executive and naming functions.

Microembolization is associated with transient cognitive decline in patients undergoing carotid interventions

OBJECTIVE

Carotid interventions are important in helping to reduce the risk of stroke for patients with high-grade carotid artery stenosis; however, subclinical cerebral microemboli can occur during these procedures. Associations have been found between the incidence of microemboli and postoperative decline in memory. We therefore sought to determine whether this decline persisted long-term and to assess changes in other cognitive domains.

METHODS

Patients were prospectively recruited under an Institutional Review Board-approved protocol at a single academic center. Neuropsychological testing was administered preoperatively and at 1-month and 6-month intervals postoperatively. Cognitive domains that were evaluated included verbal memory, visual memory, psychomotor speed, dexterity, and executive function. Diffusion-weighted magnetic resonance imaging sequencing was performed preoperatively and ≤48 hours postoperatively to identify procedure-related microemboli. Univariate and multivariate regression models were used to identify relationships among microembolization, demographics, and cognition.

RESULTS

Included were 80 male patients with an average age of 69 years. Forty patients underwent carotid artery stenting and 40 underwent carotid endarterectomy. Comorbidities included diabetes in 45%, coronary artery disease in 50%, and prior neurologic symptoms in 41%. New postoperative microemboli were found in 45 patients (56%). Microembolization was significantly more common in the carotid artery stenting cohort (P < .005). Univariate analysis demonstrated that patients with procedurally related embolization showed decline 1 month postoperatively in verbal memory and Trail Making A measures. Multivariate analysis demonstrated that procedurally related embolization (odds ratio [OR], 2.8; P = .04) and preoperative symptomatic stenosis (OR, 3.2; P = .026) were independent predictors of decline for the Rey Auditory Verbal Learning Test Short Delay measure at 1 month. At 6 months, no significant relationship was found between emboli and decline on Rey Auditory Verbal Learning Test Short Delay, but age (OR, 1.1, P = .005) and chronic obstructive pulmonary disease (OR, 7.1, P = .018) were significantly associated with decline at 6 months after the intervention.

CONCLUSIONS

Microembolization that is associated with carotid artery intervention predicts short-term cognitive decline. However, some of these cognitive deficits persist at 6 months after the intervention, and further investigation is warranted to determine individual patient risk factors that may affect recovery.

Mind injuries after cardiac surgery

After cardiac surgery, delirium, cognitive dysfunction, depression, or anxiety disorders frequently occur, and profoundly affect patients' prognosis and quality of life. This narrative review focuses on the main clinical presentations of cognitive and psychological problems ('mind injuries') that occur postoperatively in absence of ascertainable focal neurologic deficits, exploring their pathophysiological mechanisms and possible strategies for prevention and treatment. Postoperative cognitive dysfunction is a potentially devastating complication that can involve several mechanisms and several predisposing, intraoperative, and postoperative risk factors, which can result in or be associated to cerebral microvascular damage. Postoperative depression is influenced by genetic or psychosocial predisposing factors, by neuroendocrine activation, and by the release of several pro-inflammatory factors. The net effect of these changes is neuroinflammation. These complex biochemical alterations, along with an aspecific response to stressful life events, might target the function of several brain areas, which are thought to represent a trigger factor for the onset of depression.

Genetic Polymorphisms Influence Cognition in Patients Undergoing Carotid Interventions

While carotid interventions help decrease the risk of stroke, nearly 40% of patients experience cognitive deterioration. Genetic polymorphism in apolipoprotein E (ApoE) and brain-derived neurotrophic factor (BDNF) have been implicated in cognitive impairment; however, it is unclear whether they may influence cognitive changes in patients undergoing carotid intervention. In this study, we seek to assess the role of genetic polymorphisms in carotid intervention-related cognitive change. Polymorphisms related to cognitive function were chosen for this preliminary analysis. Over 2 years, patients undergoing carotid interventions were prospectively recruited. Patients underwent neuropsychological testing 2 weeks prior to and at 1 month following their procedure. Saliva samples were collected for genetic analysis. Logistic regressions were used to identify associations between polymorphisms and cognitive measures. A total of 91 patients were included; all were male with an average age of 70 years. The majority of patients exhibited hypertension (95%) and a history of smoking (81%). Presence of ApoE 4 allele was associated with depression (p= 0.047). After correcting for age and genetic polymorphisms in BDNF and serotonin transporter (5-HTT), ApoE 4 allele was associated with depression (p= 0.044) and showed a trend with baseline cognitive impairment (p= 0.10). Age ≥ 70 years was associated with baseline cognitive impairment after adjusting for the three genetic polymorphisms (p= 0.03). Patients with ApoE 4 and BDNF A polymorphisms performed less well on the visual and verbal memory measures, respectively. Polymorphisms in ApoE and BDNF may provide insight on cognition in patients undergoing carotid interventions; however, the mechanism of this relationship remains unclear.

Intermediate- and Long-Term Cognitive Outcomes After Cardiovascular Procedures in Older Adults: A Systematic Review

BACKGROUND

Risks for intermediate- and long-term cognitive impairment after cardiovascular procedures in older adults are poorly understood.

PURPOSE

To summarize evidence about cognitive outcomes in adults aged 65 years or older at least 3 months after coronary or carotid revascularization, cardiac valve procedures, or ablation for atrial fibrillation.

DATA SOURCES

MEDLINE, Cochrane, and Scopus databases from 1990 to January 2015; ClinicalTrials.gov; and bibliographies of reviews and eligible studies.

STUDY SELECTION

English-language trials and prospective cohort studies.

DATA EXTRACTION

One reviewer extracted data, a second checked accuracy, and 2 independently rated quality and strength of evidence (SOE).

DATA SYNTHESIS

17 trials and 4 cohort studies were included; 80% of patients were men, and mean age was 68 years. Cognitive function did not differ after the procedure between on- and off-pump coronary artery bypass grafting (CABG) (n = 6; low SOE), hypothermic and normothermic CABG (n = 3; moderate to low SOE), or CABG and medical management (n = 1; insufficient SOE). One trial reported lower risk for incident cognitive impairment with minimal versus conventional extracorporeal CABG (risk ratio, 0.34 [95% CI, 0.16 to 0.73]; low SOE). Two trials found no difference between surgical carotid revascularization and carotid stenting or angioplasty (low and insufficient SOE, respectively). One cohort study reported increased cognitive decline after transcatheter versus surgical aortic valve replacement but had large selection and outcome measurement biases (insufficient SOE).

LIMITATIONS

Mostly low to insufficient SOE; no pertinent data for ablation; limited generalizability to the most elderly patients, women, and persons with substantial baseline cognitive impairment; and possible selective reporting and publication bias.

CONCLUSION

Intermediate- and long-term cognitive impairment in older adults attributable to the studied cardiovascular procedures may be uncommon. Nevertheless, clinicians counseling patients before these procedures should discuss the uncertainty in their risk for adverse cognitive outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Influence of intraoperative cerebral oximetry monitoring on neurocognitive function after coronary artery bypass surgery: a randomized, prospective study

OBJECTIVES

Postoperative cognitive decline is common after cardiac surgery, but it is often unrecognized at the time of hospital discharge. However, it has a great impact on patient's quality of life. Cerebral oximetry with the INVOS (IN Vivo Optical Spectroscopy) system provides the possibility of non-invasive, continuous measurement of regional cerebral oxygen saturation (rSO2), which can improve patients' outcome. The aim of this study was to examine whether cerebral oximetry can decrease the incidence of cognitive decline after coronary artery bypass grafting.

METHODS

We have performed a prospective, randomized study with 200 patients enrolled. Patients were divided into INVOS interventional group and CONTROL group without monitoring of cerebral oximetry. A standardized interventional protocol was performed in the INVOS group to maintain rSO2 above 80% of the patient's baseline value or above 50% of the absolute value. Cognitive evaluation was performed in all patients before and 7 days after surgery. Logistic regression was used to reveal predictors of cognitive decline.

RESULTS

The incidence of cognitive decline 7 days after surgery was significantly lower (P = 0.002) in the INVOS interventional group (28%) than in the CONTROL group (52%). Intraoperative use of INVOS monitoring was associated with lower incidence of cognitive decline (odds ratio 0.21). In addition, predictors of cognitive decline revealed by multivariate logistic regression were older age, higher EuroSCORE and SAPS II (Simplified Acute Physiology Score) values, lower educational level and persistence of preoperative atrial fibrillation. Patients with prolonged rSO2 desaturation, defined as rSO2 area under the curve (AUC) of more than 150 min% for desaturation below 20% of baseline or AUC of more than 50 min% for desaturation below 50% absolute value, had an increased risk of cognitive decline.

CONCLUSION

Postoperative cognitive outcome was significantly better in patients with intraoperative cerebral oximetry monitoring. Prolonged rSO2 desaturation is a predictor of cognitive decline and has to be avoided.

Inflammatory Response in Patients under Coronary Artery Bypass Grafting Surgery and Clinical Implications: A Review of the Relevance of Dexmedetomidine Use

Despite the fact that coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB) prolongs life and reduces symptoms in patients with severe coronary artery diseases, these benefits are accompanied by increased risks. Morbidity associated with cardiopulmonary bypass can be attributed to the generalized inflammatory response induced by blood-xenosurfaces interactions during extracorporeal circulation and the ischemia/reperfusion implications, including exacerbated inflammatory response resembling the systemic inflammatory response syndrome (SIRS). The use of specific anesthetic agents with anti-inflammatory activity can modulate the deleterious inflammatory response. Consequently, anti-inflammatory anesthetics may accelerate postoperative recovery and better outcomes than classical anesthetics. It is known that the stress response to surgery can be attenuated by sympatholytic effects caused by activation of central (α-)2-adrenergic receptor, leading to reductions in blood pressure and heart rate, and more recently, that they can have anti-inflammatory properties. This paper discusses the clinical significance of the dexmedetomidine use, a selective (α-)2-adrenergic agonist, as a coadjuvant in general anesthesia. Actually, dexmedetomidine use is not in anesthetic routine, but this drug can be considered a particularly promising agent in perioperative multiple organ protection.

Drug-eluting stents: from evidence to policy

Drug-eluting stents are a major breakthrough in cardiology, with the Cypher (Cordis Corporation) and Taxus (Boston Scientific) stents preventing 60-70% of repeat coronary revascularizations, compared with bare metal stents. Both evidence- and risk-based application of drug-eluting stents is expected to create relevant financial and equity problems to most public hospitals, as the cost of drug-eluting stents is over 1000 higher than traditional stents. In the perspective of third-party payers, drug-eluting stents are cost-effective revascularization strategies for a large portion of patients actually undergoing stenting. However, adequate guidelines and reimbursement strategies are still awaited in several countries.

Coronary artery bypass graft surgery: the past, present, and future of myocardial revascularisation

The development of the heart-lung machine ushered in the era of modern cardiac surgery. Coronary artery bypass graft surgery (CABG) remains the most common operation performed by cardiac surgeons today. From its infancy in the 1950s till today, CABG has undergone many developments both technically and clinically. Improvements in intraoperative technique and perioperative care have led to CABG being offered to a more broad patient profile with less complications and adverse events. Our review outlines the rich history and promising future of myocardial revascularization.

Preexisting depressive symptoms are associated with long-term cognitive decline in patients after cardiac surgery

OBJECTIVE

To examine whether preoperative psychological dysfunctions rather than intraoperative factors may differentially predict short- and long-term postoperative cognitive decline (POCD) in patients after cardiac surgery.

METHOD

Forty-two patients completed a psychological evaluation, including the Trail Making Test Part A and B (TMT-A/B), the memory with 10/30-s interference, the phonemic verbal fluency and the Center for Epidemiological Studies of Depression (CES-D) scale for cognitive functions and depressive symptoms, respectively, before surgery, at discharge and at 18-month follow-up.

RESULTS

Ten (24%) and 11 (26%) patients showed POCD at discharge and at 18-month follow-up, respectively. The duration of cardiopulmonary bypass significantly predicted short-term POCD [odds ratio (OR)=1.04, P<.05], whereas preoperative psychological factors were unrelated to cognitive decline at discharge. Conversely, long-term cognitive decline after cardiac surgery was significantly predicted by preoperative scores in the CES-D (OR=1.26, P<.03) but not by intraoperative variables (all Ps >.23).

CONCLUSIONS

Our findings showed that preexisting depressive symptoms rather than perioperative risk factors are associated with cognitive decline 18 months after cardiac surgery. This study suggests that a preoperative psychological evaluation of depressive symptoms is essential to anticipate which patients are likely to show long-term cognitive decline after cardiac surgery.

Pulsatile versus non-pulsatile flow to reduce cognitive decline after coronary artery bypass surgery: A randomized prospective clinical trial

BACKGROUND

In this prospective study, we aimed to compare the effect of pulsatile and non-pulsatile flow on the cognitive functions in patients undergoing coronary artery bypass surgery.

METHODS

Patients scheduled for their first coronary artery bypass surgery (n = 148) were randomly assigned to the pulsatile flow group (Group A, n = 75) or non-pulsatil group (Group B, n = 73). Cognitive performance was assessed with (MoCA) montreal cognitive assessment test performed by psychologists before coronary artery bypass surgery and 1 month after the operation.

RESULTS

Mild cognitive impairment was seen in 12 (16%) patients and serious cognitive impairment was seen in 1 (1.33%) patient in the pulsatile flow group. In the other group, mild cognitive impairment was detected in 23 (31.50%) patients and serious cognitive decline was found in 3 (4.10%) patients. Mean MoCA scores were 25.86 ± 2.62 in group A and 22.12 ± 2.20 in group B. The difference between two groups was statistically significant (P = 0.041).

CONCLUSIONS

We suggest that pulsatile flow has beneficial effects to decrease cognitive dysfunction in patients undergoing on-pump coronary artery bypass surgery.

Delirium in the cardiovascular ICU: exploring modifiable risk factors

OBJECTIVE

Delirium, an acute organ dysfunction, is common among critically ill patients leading to significant morbidity and mortality; its epidemiology in a mixed cardiology and cardiac surgery ICU is not well established. We sought to determine the prevalence and risk factors for delirium among cardiac surgery ICU patients.

DESIGN

Prospective observational study.

SETTING

Twenty-seven-bed medical-surgical cardiac surgery ICU.

PATIENTS

Two hundred consecutive patients with an expected cardiac surgery ICU length of stay >24 hrs.

INTERVENTIONS

None.

MEASUREMENTS

Baseline demographic data and daily assessments for delirium using the validated and reliable Confusion Assessment Method for the ICU were recorded, and quantitative tracking of delirium risk factors were conducted. Separate analyses studied the role of admission risk factors for occurrence of delirium during the cardiac surgery ICU stay and identified daily occurring risk factors for the development of delirium on a subsequent cardiac surgery ICU day.

MAIN RESULTS

Prevalence of delirium was 26%, similar among cardiology and cardiac surgical patients. Nearly all (92%) exhibited the hypoactive subtype of delirium. Benzodiazepine use at admission was independently predictive of a three-fold increased risk of delirium (odds ratio 3.1 [1, 9.4], p = 0.04) during the cardiac surgery ICU stay. Of the daily occurring risk factors, patients who received benzodiazepines (2.6 [1.2, 5.7], p = 0.02) or had restraints or devices that precluded mobilization (2.9 [1.3, 6.5], p < 0.01) were more likely to have delirium the following day. Hemodynamic status was not associated with delirium.

CONCLUSIONS

Delirium occurred in one in four patients in the cardiac surgery ICU and was predominately hypoactive in subtype. Chemical restraints via use of benzodiazepines or the use of physical restraints/restraining devices predisposed patients to a greater risk of delirium, pointing to areas of quality improvement that would be new to the vast majority of cardiac surgery ICUs.

Clinical impact of neurocognitive deficits after cardiac surgery

OBJECTIVES

Postoperative neurocognitive deficits (POCDs) have been found to occur frequently after cardiac surgery. Although POCDs have received significant attention in the medical literature and public media, the true clinical impact of these deficits on patient outcomes and quality of life (QOL) is not well defined.

METHODS

Neuropsychometric testing was performed on 696 patients undergoing coronary artery bypass surgery using a battery of tests divided into 4 domains; memory, attention, speed, and psychomotor function. These were performed preoperatively, at hospital discharge, and at 3 months postoperatively. POCDs were defined as a drop in scores by 1 standard deviation in 1 domain or more. QOL was assessed using Short Form 36 and clinical outcomes were recorded.

RESULTS

POCDs were identified in 265 (38%) patients at discharge and in 132 (19%) at 3 months. There was no observed difference in mortality or major morbidity in patients with or without POCDs. Predictors of POCDs at discharge were elevated preoperative creatinine (P = .04), increased cardiopulmonary bypass time (P = .005), and diabetes (P = .003). At 3 months, patients had improvements in both physical and mental components of QOL, independent of the occurrence of POCDs (P > .5). Independent predictors of improved QOL included younger age, severe preoperative anginal symptoms, normal left ventricular function, absence of postoperative wound infection, but not POCDs.

CONCLUSIONS

Neurocognitive deficits can be frequently detected on comprehensive neuropsychometric testing after cardiac surgery. However, they are not associated with any clinically important differences in patient outcome or in QOL after surgery.

Clinical, methodological and theoretical issues in the assessment of cognition after anaesthesia and surgery: a review

As people live longer, the burden of cognitive impairment to elderly patients, their families and society becomes increasingly common and important. The loss of independence, a reduction in the quality of life and increased mortality are possible correlates to the mental disintegration. Cognitive dysfunction following major surgery on the elderly is a significant problem which adds to other cognitive impairments caused by neurodegeneration, cerebrovascular impairments and other causes. There are challenges in reviewing the literature because of many methodological concerns. There is no standard definition; the diagnosis is made only by the results of neuropsychological tests which are not standardised for this purpose; test results are analysed by different statistical methods (some of them inappropriate); controls are often absent or poorly matched; and pre-existing mild cognitive impairment, which affects 10 to 20% of people older than 65 years and is similar to the subtle cognitive impairment following surgery, is not sought for and recognised. Reviews of the subject have varied from descriptions such as 'a well recognised and significant problem' to 'a hypothetical phenomenon for which there is no International Statistical Classification of Disease (ICD-9) code, and no Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) code'. This article examines both sides of the spectrum in a detailed review which explains the necessary psychological 'jargon', discusses the methods used and points to areas of future research.

Attrition in longitudinal randomized controlled trials: home visits make a difference

Background

Participant attrition in longitudinal studies can introduce systematic bias, favoring participants who return for follow-up, and increase the likelihood that those with complications will be underestimated. Our aim was to examine the effectiveness of home follow-up (Home F/U) to complete the final study evaluation on potentially “lost” participants by: 1) evaluating the impact of including and excluding potentially “lost” participants (e.g., those who required Home F/U to complete the final evaluation) on the rates of study complications; 2) examining the relationship between timing and number of complications on the requirement for subsequent Home F/U; and 3) determining predictors of those who required Home F/U.

Methods

We used data from a randomized controlled trial (RCT) conducted from 1991–1994 among coronary artery bypass graft surgery patients that investigated the effect of High mean arterial pressure (MAP) (intervention) vs. Low MAP (control) during cardiopulmonary bypass on 5 complications: cardiac morbidity/mortality, neurologic morbidity/mortality, all-cause mortality, neurocognitive dysfunction and functional decline. We enhanced completion of the final 6-month evaluation using Home F/U.

Results

Among 248 participants, 61 (25%) required Home F/U and the remaining 187 (75%) received Routine F/U. By employing Home F/U, we detected 11 additional complications at 6 months: 1 major neurologic complication, 6 cases of neurocognitive dysfunction and 4 cases of functional decline. Follow-up of 61 additional Home F/U participants enabled us to reach statistical significance on our main trial outcome. Specifically, the High MAP group had a significantly lower rate of the Combined Trial Outcome compared to the Low MAP group, 16.1% vs. 27.4% (p=0.032). In multivariate analysis, participants who were ≥ 75 years (OR=3.23, 95% CI 1.52-6.88, p=0.002) or on baseline diuretic therapy (OR=2.44, 95% CI 1.14-5.21, p=0.02) were more likely to require Home F/U. In addition, those in the Home F/U group were more likely to have sustained 2 or more complications (p=0.05).

Conclusions

Home visits are an effective approach to reduce attrition and improve accuracy of study outcome reporting. Trial results may be influenced by this method of reducing attrition. Older participants, those with greater medical burden and those who sustain multiple complications are at higher risk for attrition.

Epidemiology and risk factors for delirium across hospital settings

Delirium is one of the most common causes of acute end-organ dysfunction across hospital settings, occurring in as high as 80% of critically ill patients that require intensive care unit (ICU) care. The implications of this acute form of brain injury are profound. Across many hospital settings (emergency department, general medical ward, postoperative and ICU), a patient who experiences delirium is more likely to experience increased short- and long-term mortality, decreases in long-term cognitive function, increases in hospital length of stay and increased complications of hospital care. With the development of reliable setting-specific delirium-screening instruments, researchers have been able to highlight the predisposing and potentially modifiable risk factors that place patients at highest risk. Among the large number of risk factors discovered, administration of potent sedative medications, most notably benzodiazepines, is most consistently and strongly associated with an increased burden of delirium. Alternatively, in both the hospital and ICU, delirium can be prevented with the application of protocols that include early mobility/exercise. Future studies must work to understand the epidemiology across settings and focus upon modifiable risk factors that can be integrated into existing delirium prevention and treatment protocols.

The influence of preoperative serum anticholinergic activity and other risk factors for the development of postoperative cognitive dysfunction after cardiac surgery

OBJECTIVE

Patients undergoing cardiac surgery are at risk for postoperative cognitive dysfunction (POCD). Evaluating preoperative risk factors represents 1 possible way to minimize the postoperative risk of cognitive dysfunction. We investigated marked deterioration in cholinergic neurotransmission as 1 such potential risk factor for transient and long-lasting POCD. Serum anticholinergic activity (SAA) has already been described as a risk factor for developing delirium in an elderly study population. However, the role of SAA for long-lasting POCD is unknown.

METHODS

Following local ethics board approval and written informed consent, we recruited a cohort of patients aged ≥ 55 years undergoing cardiac surgery. Before surgery, levels of SAA were measured and a battery of neuropsychologic tests (NPTs) was applied. S100 calcium binding protein ß concentration was measured intraoperatively. Pre-, intra-, and postoperative patient-specific characteristics were recorded. The NPTs were repeated 3 months after hospital discharge to evaluate 3-month POCD. A group of nonsurgical patients (n = 34) was recruited as control subjects to adjust NPT scores, using reliable methods for the change index. Logistic multivariate regression was used to evaluate independent predictors of POCD.

RESULTS

One hundred fifty-four patients were screened before surgery, and 117 completed the second NPT. POCD was identified in 25.6% of patients. In contrast to intraoperatively increased S100 calcium binding protein ß, preoperative SAA was not associated with POCD following adjustment for covariates.

CONCLUSIONS

Preoperatively increased SAA did not predict POCD 3 months after cardiac surgery.

Cognitive trajectories after postoperative delirium

BACKGROUND

Delirium is common after cardiac surgery and may be associated with long-term changes in cognitive function. We examined postoperative delirium and the cognitive trajectory during the first year after cardiac surgery.

METHODS

We enrolled 225 patients 60 years of age or older who were planning to undergo coronary-artery bypass grafting or valve replacement. Patients were assessed preoperatively, daily during hospitalization beginning on postoperative day 2, and at 1, 6, and 12 months after surgery. Cognitive function was assessed with the use of the Mini-Mental State Examination (MMSE; score range, 0 to 30, with lower scores indicating poorer performance). Delirium was diagnosed with the use of the Confusion Assessment Method. We examined performance on the MMSE in the first year after surgery, controlling for demographic characteristics, coexisting conditions, hospital, and surgery type.

RESULTS

The 103 participants (46%) in whom delirium developed postoperatively had lower preoperative mean MMSE scores than those in whom delirium did not develop (25.8 vs. 26.9, P<0.001). In adjusted models, those with delirium had a larger drop in cognitive function (as measured by the MMSE score) 2 days after surgery than did those without delirium (7.7 points vs. 2.1, P<0.001) and had significantly lower postoperative cognitive function than those without delirium, both at 1 month (mean MMSE score, 24.1 vs. 27.4; P<0.001) and at 1 year (25.2 vs. 27.2, P<0.001) after surgery. With adjustment for baseline differences, the between-group difference in mean MMSE scores was significant 30 days after surgery (P<0.001) but not at 6 or 12 months (P=0.056 for both). A higher percentage of patients with delirium than those without delirium had not returned to their preoperative baseline level at 6 months (40% vs. 24%, P=0.01), but the difference was not significant at 12 months (31% vs. 20%, P=0.055).

CONCLUSIONS

Delirium is associated with a significant decline in cognitive ability during the first year after cardiac surgery, with a trajectory characterized by an initial decline and prolonged impairment. (Funded by the Harvard Older Americans Independence Center and others.).

Circulação extracorpórea e complicações no período pós-operatório imediato de cirurgias cardíacas

OBJETIVO: Comparar a frequência de complicações apresentadas pelos pacientes, durante o pós-operatório imediato (POI), de cirurgias cardíacas de acordo com o tempo de circulação extra-corpórea (CEC). MÉTODOS: Estudo de natureza quantitativa, descritivo e correlacional com 83 pacientes adultos divididos em dois grupos de acordo com o tempo de CEC. RESULTADOS: Do total de pacientes, 44 (53%) tiveram o tempo de duração da CEC de até 85 minutos e 39 (47 %) tiveram o tempo acima de 85 minutos. As complicações foram comuns para ambos os grupos, sendo as mais frequentes dor e oligúria. No entanto, hemotórax, pneumotórax e infarto agudo do miocárdio ocorreram apenas no grupo com maior tempo de CEC. CONCLUSÃO: A maioria das complicações ocorridas no POI apresentou frequencia semelhante para os pacientes, independente do tempo de CEC.

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.

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.

Neuropsychological outcomes after coronary artery bypass grafting

Short- and long-term cognitive declines after cardiac surgery with cardiopulmonary bypass have been reported, but the frequency, severity, nature, and etiology of postoperative cognitive changes have been difficult to quantify. Current studies have corrected the principal methodological shortcoming of earlier studies by including control groups, and have shown that while early postoperative cognitive decline does occur in some patients, it is generally mild and reversible by 3 months after surgery. Late cognitive changes do occur, but comparison with patients undergoing off-pump surgery or those being treated medically suggests that these changes are not specific to CABG or more specifically to the use of cardiopulmonary bypass.

Executive function (capacity for behavioral self-regulation) and decline predicted mortality in a longitudinal study in Southern Colorado

OBJECTIVE

To assess the relationship between mortality and impairment and decline in a specific executive cognitive function, the capacity for behavioral self-regulation.

STUDY DESIGN AND SETTING

This study examined the association between mortality and baseline and 22-month decline in the capacity for behavioral self-regulation, as measured by the Behavioral Dyscontrol Scale, among 1,293 participants of the San Luis Valley Health and Aging Study (SLVHAS), a population-based longitudinal study. The Behavioral Dyscontrol Scale and a measure of overall mental status, the Mini-Mental State Examination, were administered at baseline and follow-up interviews. Cox regression was used to examine baseline and decline in capacity for behavioral self-regulation as possible predictors of mortality.

RESULTS

Baseline Behavioral Dyscontrol Scale score was predictive of mortality, independent of demographics and comorbidity count (hazard ratio [HR]=1.07; 95% confidence interval [CI]: 1.04, 1.09). It remained a significant predictor with further adjustment for Mini-Mental State Examination score. Decline in this specific executive cognitive function was associated with mortality after adjustment for covariates and baseline cognitive scores (HR=1.09; 95% CI: 1.04, 1.13).

CONCLUSION

Thus, both baseline capacity for behavioral self-regulation and its decline over time predicted mortality in the SLVHAS cohort. These associations may partly be attributed to maintaining the ability for self-care. Understanding how specific forms of impairment contribute to mortality may help identify patients who could benefit from early intervention.