Effect of open heart surgery on intellectual performance

Cognitive Outcomes After Heart Valve Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

To summarize evidence on cognitive outcomes after heart valve surgery; secondary aim, to examine whether aortic and mitral valve surgery are associated with different cognitive outcomes.

DESIGN

Preferred Reporting Items for Systematic Reviews and Meta-Analyses systematic review and meta-analysis.

SETTING

Cardiac surgery.

PARTICIPANTS

Individuals undergoing heart valve surgery.

MEASUREMENTS

We searched MEDLINE, EMBASE, and PsycINFO for peer-reviewed reports of individuals undergoing heart valve surgery who underwent pre- and postoperative cognitive assessment. Our initial search returned 1,475 articles, of which 12 were included. Postoperative cognitive results were divided into those from 1 week to 1 month (early outcomes, n_pooled  = 450) and from 2 to 6 months (intermediate outcomes; n_pooled  = 722). No studies with longer-term outcomes were identified.

RESULTS

Subjects had moderate early cognitive decline from baseline (Becker mean gain effect size (ES)=-0.39 ± 0.27) that improved slightly by 2 to 6 months (ES=-0.25 ± 0.38). Individuals undergoing aortic valve surgery-who were older on average than those undergoing mitral valve surgery (68 vs 57)-had greater early cognitive decline than those undergoing mitral valve surgery (ES=-0.68 vs -0.12), but both cohorts had similar decline 2 to 6 months postoperatively (ES=-0.27 vs -0.20).

CONCLUSIONS

Heart valve surgery is associated with cognitive decline over the 6 months after surgery, but outcomes beyond 6 months are unclear. These findings highlight the cognitive vulnerability of this population, especially older adults with aortic stenosis. © 2018 American Geriatrics Society and Wiley Periodicals, Inc. J Am Geriatr Soc 66:2327-2334, 2018.

[Postoperative cerebral dysfunction]

AIM

To study the structure, risk factors and methods of prevention of postoperative brain dysfunction on the example of coronary artery bypass surgery with cardiopulmonary bypass.

MATERIAL AND METHODS

The study included 77 patients who undergone elective coronary artery bypass surgery at the beating heart (22 patients) or with cardiopulmonary bypass (55 patients, including 24 patients, who received cerebroprotective treatment with cytoflavin in the preoperative period). All patients underwent dynamic (pre- and postoperative) neurological, neuropsychological, instrumental examinations.

RESULTS

The postoperative cerebral dysfunction was diagnosed in 34 (44,2%) patients. The frequency of the clinical types of postoperative cerebral dysfunction significantly differed: perioperative stroke - 3 (3,9%) cases, symptomatic delirium of the early postoperative period - 11 (14,3%) cases, delayed cognitive impairment - 28 (36,4%) cases. The risk factors of postoperative cerebral dysfunction after the coronary artery bypass surgery with cardiopulmonary bypass were identified. Preventive preoperative use of the neuroprotective drug cytoflavin reduces the severity of delayed cognitive impairment after the coronary artery bypass surgery with cardiopulmonary bypass and has a good safety profile.

CONCLUSION

An analysis of the literature data and the results of our own studies show that postoperative cerebral dysfunction is the nosological entity with various etiological factors, pathogenetic mechanisms and the characteristic clinical types, which has an effect on the outcome of surgical treatment.

Cerebral dysfunction after cardiopulmonary bypass: aetiology, manifestations and interventions

Central nervous system dysfunction following cardiac surgery remains a significant cause of morbidity and mortality, with the reported incidence of dysfunction varying widely between studies. Microemboli and global cerebral hypoperfusion are implicated as the major aetiologies of CNS impairment. Preoperative and intraoperative variables influencing the patient's risk of complications remain controversial. Based on a review of previous studies, this paper outlines the major causes and manifestations of CNS impairment as well as the intraoperative interventions currently advocated to improve the cerebral outcome of cardiac patients.

Prevalence and risk factors of postoperative delirium in patients undergoing open heart surgery in northwest of iran

INTRODUCTION

Delirium as a relatively common complication following cardiac surgery remains a contributory factor in postoperative mortality and an obstacle to early discharge of patients.

METHODS

In the present study 329 patients who underwent open heart surgery between 1st January 2008 to 1st January 2009 in Shahid Madani Heart Center, Tabriz, Iran were enrolled.

RESULTS

Overall 4.9% of patients developed delirium after cardiac surgery. We found atrial fibrillation (P = 0.005), lung diseases (P = 0.04) and hypertension (P = 0.02) to be more common in patients who develop delirium postoperatively. Furthermore, the length of intensive care unit (ICU) stay, cardiopulmonary bypass (CPB) time, and ventilation period were also significantly increased. Also a statistically meaningful relationship between the female gender and development of delirium was also noted (P = 0.02). On the other hand no meaningful relationship was detected between diabetes, history of cerebral vascular diseases, peripheral vascular diseases, myocardial infarction, development of pneumonia following surgery, and laboratory levels of sodium, potassium, glucose, and complete blood cell count (CBC) including white blood cells, red blood cells, platelets in the blood-hemoglobin and hematocrits. Also environmental factors like presence of other patients or companion with the patient, and objects like clock, window and calendar in the patient's room did not affect prevention of delirium.

CONCLUSION

Based on this and other investigations, it can be suggested to use MMPI test to recognize pathologic elements to prevented delirium after surgery and complementary treatment for coping with delirium.

Brain SPECT imaging and neuropsychological testing in coronary artery bypass patients: single photon emission computed tomography

BACKGROUND

Cognitive deficits appear frequently after cardiac operation. While the etiology remains unclear, alterations in cerebral perfusion during cardiopulmonary bypass may be causative. Single photon emission computed tomography (SPECT) scanning utilizes a radiopharmaceutical to provide images of cerebral perfusion. We proposed to study the cerebral circulation of patients during coronary artery bypass operation employing cardiopulmonary bypass.

METHODS

Thirty-five neurologically normal patients underwent preoperative SPECT brain scanning and neuropsychological testing. A second SPECT brain perfusion scan was obtained by administering the radioisotope during cardiopulmonary bypass, with subsequent scanning upon completion of the procedure. Postoperative neuropsychological testing was performed prior to discharge.

RESULTS

Fourteen (40%) of patients demonstrated significant neuropsychological decline. Patients who suffered cognitive impairment were no different in demographic, general health, or surgical variables. Patients who demonstrated neuropsychological decline had significantly poorer cerebral perfusion both at baseline and during operation.

CONCLUSIONS

Impaired cerebral perfusion at baseline may identify patients at risk for cognitive injury after cardiac operation. Alterations in cerebral perfusion during cardiopulmonary bypass is common, and may be a factor in neuropsychological deficits seen after cardiac operation.

Neurobehavioural sequelae of cardiopulmonary bypass

The development of coronary artery bypass grafting (CABG) and its effect on angina is the product of a series of technical and scientific advances. Despite these advances, however, adverse neurobehavioural outcomes continue to occur. Stroke is the most serious complication of CABG, but studies that have identified demographic and medical risk factors available before surgery are an important advance. Short-term cognitive deficits are common after CABG, but may not be specific to this procedure. However, deficits in some cognitive areas such as visuoconstruction persist over time, and may reflect parieto-occipital watershed area injury secondary to hypoperfusion or embolic factors. Risk factors for cognitive decline may be time dependent, with short-term studies identifying factors that differ from those of long-term studies. Patients with depression before surgery are likely to have persistent depression afterwards. However, depression does not account for the cognitive decline after CABG. Since CABG is increasingly done in older patients with more comorbidity, the challenge is to identify patients at risk of adverse neurocognitive outcomes and to protect them by modification of the surgical procedure or by effective medical therapy.

Head and Heart: Neuropsychological Reaction and Arterial Line Filtration during Cardiopulmonary Bypass

As part of a prospective study of neuropsychologic reactions after cardiopulmonary bypass and their relation to arterial line filters, 44 patients who underwent elective cardiac operations were randomized into two groups. Group A had a 40-micron nylon screen filter in the arterial line. No arterial filter was used in group B. Neuropsychological examinations of all patients were conducted before and at a mean of 8 days after the operation on a double blind basis by a single trained psychologist. The tests included the Wechsler Memory Scale, the trail-making test, the Hamilton Anxiety Rating Scale, and the Hamilton Rating Scale for Depression. The 2 groups were otherwise similar with respect to preoperative neurologic and intellectual status, anesthetic methods, duration of operation, operative procedures performed, and the time spent in the intensive care unit. Surprisingly, there was a highly significant improvement in all four test scores after surgery. There were no statistically significant differences in the test scores between the two groups but considerable inter-patient performance variability was noted. The arterial line filter did not appear to have an effect on test scores. Routine use of an arterial filter remains questionable.

Cognitive outcome after coronary artery bypass: a one-year prospective study

BACKGROUND

Cognitive deficits have been reported in patients after coronary artery bypass grafting, but the incidence of these deficits varies widely. We studied prospectively the incidence of cognitive change and whether the changes persisted over time.

METHODS

Cognitive testing was done preoperatively and 1 month and 1 year postoperatively in 127 patients undergoing coronary artery bypass grafting. Tests were grouped into eight cognitive domains. A change of 0.5 standard deviation or more at 1 month and 1 year from patient's preoperative Z score was the outcome measure.

RESULTS

We identified four main outcomes for each cognitive domain: no decline; decline and improvement; persistent decline; and late decline. Only 12% of patients showed no decline across all domains tested; 82% to 90% of patients had no decline in visual memory, psychomotor speed, motor speed, and executive function; 21% and 26% had decline and improvement in verbal memory and language; approximately 10% had persistent decline in the domains of verbal memory, visual memory, attention, and visuoconstruction; and 24% had late decline (between 1 month and 1 year) in visuoconstruction.

CONCLUSIONS

This study establishes that the incidence of cognitive decline varies according to the cognitive domain studied and that some patients have persistent and late cognitive changes in specific domains after coronary artery bypass grafting.

Delirium and cognitive disorders after cardiac operations: relationship to pre- and intraoperative quantitative electroencephalogram

We examined the incidence of delirium and cognitive disorders after cardiac operations and the related risk factors. The value of pre- and intraoperative QEEG was determined. Using the Mini-Mental State Examination and the Saskatoon Delirium Checklist, 321 patients were tested during the immediate postoperative period. Forty-four patients (14%) showed delirium, 68 (23%) cognitive disorders and 26 (9%) both. Significant risk factors for the development of cognitive disorders were age > or = 70 yr, female gender, duration of cardiopulmonary bypass > or = 2.5 h and aorta-cross-clamping > 70 min. Risk factors for delirium were age > or = 70 yr, female gender and Hb < 5 mmol 1(-1) intraoperatively. The preoperative QEEG showed significant differences between the groups with and without a cognitive disorder, while the intraoperative QEEG showed significant differences between the groups with and without delirium. Different risk factors for delirium and cognitive disorders are a possible explanation for the controversies in the literature, where neuropsychologic complications were grouped together. A low intraoperative Hb is an important risk factor for the development of delirium and can be treated. The preoperative QEEG may have prognostic significance in the occurrence of cognitive disorders, while the intraoperative QEEG may have prognostic significance in the occurrence of delirium.

Cognitive function after open-heart surgery: are postoperative neuropsychological deficits caused by cardiopulmonary bypass?

Despite the many technological developments in arterial perfusion and cardiac surgical procedures, open-heart surgery is still believed to pose a significant risk for cerebral injury. There are several potential causes of brain damage during open-heart surgery, including prolonged or severe arterial hypotension, as well as emboli emanating from the cardiopulmonary bypass circuit or the operative field. This article reviews the available neuropsychological studies of outcome following cardiac valve replacement and coronary artery bypass grafting. Because both procedures are life-saving operations, the research in this area has been quasi-experimental and fraught with methodological problems. Nonetheless, the findings converge to suggest that cognitive dysfunction occurs after open-heart surgery, and that the deficits are attributable, at least in part, to factors specific to the operation or to the patient being maintained on cardiopulmonary bypass. Preliminary findings suggest that embolization is the primary cause of perioperative deficits in uncomplicated operations. Studies have also consistently found preoperative deficits in this population, suggesting that neuropsychological dysfunction is caused by severe chronic cardiac disease as well as open-heart surgery.

Thoracic aortic operations in patients aged 70 years or older

Thirty-one patients over the age of 70 years (group A) and 72 patients less than 69 years (group B) underwent a variety of thoracic aortic surgical procedures. Early and long-term results and cerebral function were compared between the two groups. Preoperative and postoperative cerebral function was evaluated using mini mental state-Himeji and Wechsler adult intelligence scale tests. The operative mortality of groups A and B was 12.9% and 11.1%, respectively (not significant). There were no significant differences in postoperative complications between the two groups. The late mortality rates of groups A and B were 11.1% and 9.3%, respectively (not significant). There were no significant differences between the two groups in the mini mental state-Himeji test, digit symbol, vocabulary, and total Wechsler adult intelligence scale scores before and after operation. We conclude that thoracic aortic surgical procedures in patients over 70 years of age can be performed with acceptable mortality and morbidity risks. Most patients showed symptomatic improvement.

Cognitive function in patients with symptomatic dilated cardiomyopathy before and after cardiac transplantation

Pre- and postoperative cognitive performance of candidates for heart transplantation was examined by means of an extensive battery of neuropsychological measures. A total of 54 patients completed the preoperative cognitive protocol, 20 of whom also completed postoperative testing. Age (less than 50 or greater than or equal to 50 years of age) and the primary cause of cardiac deterioration (idiopathic, ischemic disease or rheumatic/congenital defects) were the major classification variables. The main findings of this study were: 1) Preoperative neuropsychological measures revealed a high frequency of impaired performance, particularly in measures of memory, higher level processing of information and motor speed. A pattern consistent with diffuse rather than focal or lateralized cerebral deficits was observed. Significant differences were not found on the basis of the cause of cardiac disease, but some were observed for age (the older group was more impaired). 2) A comparison of pre- and postoperative cognitive scores failed to show significant cognitive improvement despite greatly improved physical health. The cause of cardiac deterioration was not differentially associated with postoperative cognitive performance, and there was equivocal evidence for age effects. These findings may have implications for the selection of transplant recipients and the timing of transplantation surgery.

Psychosomatic aspects of coronary artery bypass graft surgery. A prospective study of 101 male patients

101 consecutive male patients were examined by means of clinical interviews and depression, anxiety, personality, psychometric and life stress tests. The examinations took place preoperatively, on the 9th postoperative day (average) and 7.5 months after surgery. The mean age of the patients was 52.2 years and the mean duration of CHD was 6.7 years. Prior to surgery 77% had experienced myocardial infarction and 85% belonged to NYHA class III or IV. 74% had a 3-vessel disease. When the NYHA classification was used as criterion for rehabilitation the result was excellent. Postoperatively 80% belonged to NYHA class I or II. Hospital mortality rate was 4% and one patient died from myocardial infarction prior to the final follow-up. Preoperatively 17% of the study group were working. 87% of the patients experienced negative effects on work life, caused by CHD. Postoperatively 33% worked regularly. The postoperative work situation correlated with the duration of preoperative unemployment (p less than 0.0001), the patient's own opinion about work return (willingness/unwillingness to return to work) (p less than 0.01), as well as with the amount of negative life stress experienced preoperatively (p less than 0.01). Only 13% of the series experienced positive effects on work life, caused by CABG surgery. The majority of the patients had experienced negative effects on social and economic life (51%), as well as on sexual life (70%), caused by CHD. After surgery improvements were noted by 36% on social life and by 27% on sexual life. 15% experienced impairment of sexual life postoperatively. According to the Beck Depression Inventory 29% showed depression preoperatively, and 10% postoperatively. The difference is significant (p less than 0.0001). Clinically the figures tended to be higher. The same tendency holds for anxiety scores as measured by the Hamilton anxiety scale. The incidence of postoperative psychoses was 35%. Higher age (p less than 0.01) and/or absence of psychosomatic diseases (p less than 0.05) correlated with higher frequency of psychoses. Even though cardiological rehabilitation according to the NYHA classification was excellent, 22% of the series did not think their expectations were fulfilled. Psychic and social rehabilitation was in several aspects unsatisfactory, and the patients did not seem prepared for this. The importance to consider rehabilitation from a psychosomatic standpoint is clearly shown. To predict the result of rehabilitation preoperatively is not possible.

Long-term cerebral outcome after open-heart surgery. A five-year neuropsychological follow-up study

A prospective 5 years' neuropsychological, neurological, cardiological and electroencephalographical follow-up study was carried out in 44 patients who had undergone open-heart surgery for valve replacement. A distinct interrelationship was found between the clinical outcome immediately after operation and the neuropsychological long-term course despite the rapid recovery of occasional clinical disorders related to operative procedures. In fact, the psychometric performance scores of those who did not develop clinical signs of cerebral dysfunction induced in operation showed a significant difference only years after operation. Similarly, the harmful effects of long perfusion time (extracorporeal circulation) in operation were reflected in the long-term neuropsychological performance. Some evidence seemed to suggest that the correction of the prolonged circulatory disorder might possibly afford real enhancement of higher cerebral functions. The long-term results not only emphasize the importance of a careful clinical evaluation but also emphasize the necessity of considering the subclinical level of events both before and after operation when assessing the overall outcome and cerebral safety of cardiac surgery patients.

Five-year neurological and EEG outcome after open-heart surgery

A five-year neurological and EEG follow-up was carried on 55 patients who had undergone open-heart surgery for valve replacement in order to investigate the long-term results of the treatment. The five-year survival rate was 89%. The prevalence of permanent neurological abnormalities after operation was 9%. Transient ischaemic attacks occurred in five patients but no more severe cerebrovascular accidents were encountered. The rate of embolic events was 2.8 per 100 patient-years. Various subjective symptoms and complaints showed a highly beneficial outcome. Also the five-year EEG outcome was encouraging; the prevalence of abnormal EEG had fallen from the value before operation of 45% to 25%. The harmful influence of long perfusion time (extracorporeal circulation) during operation was found to be reflected in the long-term EEG outcome and, significantly, not only in the patients who had, but also in those who had not developed clinical abnormalities complicating the immediate course after operation. Although a valvular surgery patient faces a number of CNS problems before, during and after operation, the overall long-term outcome of successful surgery seems highly beneficial in neurological terms.

Prediction of cerebral outcome after extracorporeal circulation

50 open-heart patients were investigated using simultaneous clinical, electroencephalographical (EEG) and neuropsychological evaluation in order to assess the possibilities of predicting the postoperative outcome with preoperative measures. The presence of one or more of the following indices was prognostically unfavourable: a history of cerebrovascular diseases or syncope; delta or sharp wave EEG abnormalities or low quantitative EEG mean frequency; a poor performance score in one of the psychometric tests (colour naming). Using these measures, 28 cases with presumably high risks were indicated, and 24 (86%) sustained cerebral complications attributable to the operation. The observations contrast clearly with previous studies whose predictions, using only one single criterion, have proved invalid. A significant level of prediction seems to be obtainable, but only by the simultaneous consideration of several different cerebral functions. The prognostic approach may offer one way of achieving the necessarily needed improved cerebral safety in cardiac surgery.