Neurocognitive outcomes are not improved by 17beta-estradiol in postmenopausal women undergoing cardiac surgery

Targeted temperature management in cardiac surgery: a systematic review and meta-analysis on postoperative cognitive outcomes

BACKGROUND

Postoperative cognitive decline occurs commonly after cardiac surgery. The available literature is inconclusive on the role of intraoperative causal or protective factors.

METHODS

We systematically reviewed studies evaluating delayed neurocognitive recovery (DNR), postoperative neurocognitive disorder (NCD), stroke, and the mortality rates among patients undergoing hypothermic or normothermic cardiopulmonary bypass (CPB). We further performed a subgroup analysis for age, surgery type (coronary artery bypass grafting [CABG], valve surgery, or combined), and the mean arterial blood pressure (MAP) during CPB, and conducted a proportion meta-analysis after calculation of single proportions and confidence intervals (CIs).

RESULTS

We included a total of 58 studies with 9609 patients in our analysis. Among these, 1906 of 4010 patients (47.5%) had DNR, and 2071 of 7160 (28.9%) had postoperative NCD. Ninety of 4625 patients (2.0%) had a stroke, and 174 of 7589 (2.3%) died. There was no statistically significant relationship between the considered variables and DNR, NCD, stroke, and mortality. In the subgroup analysis comparing hypothermic with normothermic CPB, we found higher NCD rates after combined surgery; for normothermic CPB cases only, the rates of DNR and NCD were lower after combined surgery compared with CABG surgery. A MAP >70 mm Hg compared with MAP=50-70 mm Hg during CPB was associated with a lower rate of DNR.

CONCLUSIONS

Temperature, MAP during cardiopulmonary bypass age, and surgery type were not associated with neurocognitive disorders, stroke, and mortality in cardiac surgery. Normothermic cardiopulmonary bypass, particularly when performed with MAP >70 mm Hg, may reduce the risk of postoperative neurocognitive decline after cardiac surgery.

PROSPERO REGISTRATION NUMBER

CRD42019140844.

Preoperative Anemia and Risk for Perioperative Neurocognitive Dysfunction in Cardiac Surgery Patients: A Retrospective Analysis

OBJECTIVES

To evaluate whether there is a relationship between preoperative anemia and domain-specific cognitive performance in patients undergoing cardiac surgery.

DESIGN

Retrospective analysis of data collected from a randomized study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

A total of 436 patients age ≥55 years undergoing cardiac surgery.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Neuropsychological testing was performed before and one month after surgery, using a standard battery. Individual Z-scores calculated from the mean and standard deviation of tests at baseline were combined into domain-specific scores. Anemia (hemoglobin <130 g/L for men, <120 g/L for women) was present in 41% of patients. Preoperative anemia had little impact on preoperative cognition. There were no differences in the change in cognitive performance one month after surgery from baseline between patients with and without preoperative anemia. However, in a sensitivity analysis using multiple imputation for missing cognitive test scores, significant associations were observed between preoperative anemia and change in postoperative processing speed (p = 0.016), change in executive function (p = 0.049), and change in fine motor speed (p = 0.016). Nadir hemoglobin during cardiopulmonary bypass, which was lower in anemic than nonanemic patients, was associated with decrements in performance on tests of verbal fluency (p = 0.007), processing speed (p = 0.042), and executive function (p = 0.10) one month after surgery but not delayed neurocognitive recovery (p = 0.06).

CONCLUSIONS

Preoperative anemia may be associated with impairment of selective cognitive domains after surgery. Any effect of preoperative anemia may have on cognition after surgery might be related to lower nadir hemoglobin during cardiopulmonary bypass.

Genistein: mechanisms of action for a pleiotropic neuroprotective agent in stroke

Genistein is a plant estrogen promoted as an alternative to post-menopausal hormone therapy because of a good safety profile and its promotion as a natural product. Several preclinical studies of cerebral ischemia and other models of brain injury support a beneficial role for genistein in protecting the brain from injury whether administered chronically or acutely. Like estrogen, genistein is a pleiotropic molecule that engages several different mechanisms to enhance brain health, including reduction of oxidative stress, promotion of growth factor signaling, and immune suppression. These actions occur in endothelial, glial, and neuronal cells to provide a coordinated beneficial action to ischemic challenge. Though many of these protective actions are associated with estrogen-like actions of genistein, additional activities on other receptors and intracellular targets suggest that genistein is more than a mere estrogen-mimic. Importantly, genistein lacks some of the detrimental effects associated with post-menopausal estrogen treatment and may provide an alternative to hormone therapy in those patients at risk for ischemic events.

Risk Factors Associated with Cognitive Decline after Cardiac Surgery: A Systematic Review

Modern day cardiac surgery evolved upon the advent of cardiopulmonary bypass machines (CPB) in the 1950s. Following this development, cardiac surgery in recent years has improved significantly. Despite such advances and the introduction of new technologies, neurological sequelae after cardiac surgery still exist. Ischaemic stroke, delirium, and cognitive impairment cause significant morbidity and mortality and unfortunately remain common complications. Postoperative cognitive decline (POCD) is believed to be associated with the presence of new ischaemic lesions originating from emboli entering the cerebral circulation during surgery. Cardiopulmonary bypass was thought to be the reason of POCD, but randomised controlled trials comparing with off-pump surgery show contradictory results. Attention has now turned to the growing evidence that perioperative risk factors, as well as patient-related risk factors, play an important role in early and late POCD. Clearly, identifying the mechanism of POCD is challenging. The purpose of this systematic review is to discuss the literature that has investigated patient and perioperative risk factors to better understand the magnitude of the risk factors associated with POCD after cardiac surgery.

Continuous-combined oral estradiol/drospirenone has no detrimental effect on cognitive performance and improves estrogen deficiency symptoms in early postmenopausal women: a randomized placebo-controlled trial

OBJECTIVE

This study aimed to explore the effects of continuous-combined estradiol 1 mg/drospirenone 2 mg (E2D) on cognitive performance in healthy, recently postmenopausal women.

METHODS

A 6-month randomized, double-blind, placebo-controlled study was carried out in a university research center. Participants were 23 healthy postmenopausal women aged 49 to 55 years. Cognitive performance was assessed with a computerized cognitive battery administered to all participants on 0, 12, and 26 weeks. Functional magnetic resonance imaging was performed on 13 participants before and after treatment using tasks of verbal fluency and mental rotation.

RESULTS

E2D was not associated with an overall effect on cognitive performance. Functional magnetic resonance imaging results showed no difference between the groups for verbal fluency or mental rotation task performance at baseline. The mental rotation task was associated with increased blood oxygen level-dependent signalling in the placebo group in both occipital lobes and in the left superior parietal lobe after 26 weeks (P < 0.05), with no changes over time seen in the treatment group. The total menopausal symptom and sexual function domain scores improved after treatment in women randomized to E2D compared with the placebo group (both P < 0.05). Similarly, systolic blood pressure, weight, and body mass index were significantly lower in women randomized to E2D at 26 weeks (P < 0.05).

CONCLUSIONS

E2D has no detrimental effect on cognitive performance in early postmenopausal women. E2D significantly improves menopausal symptoms, sexual function, systolic blood pressure, and weight.

Neurocognitive outcomes after cardiac surgery

PURPOSE OF REVIEW

To summarize recent studies of neurocognitive dysfunction after cardiac surgery, as well as to outline efforts and approaches toward advancing the field.

RECENT FINDINGS

Observational studies have improved our understanding of the incidence and the trajectory of cognitive decline after cardiac surgery; however, the magnitude of this neurocognitive change remains controversial because of the inconsistent definitions and the lack of a gold-standard diagnostic modality. Nonetheless, physicians commonly see patients with functional and cognitive impairments after cardiac surgery, which utilize healthcare resources and impact quality of life. Novel approaches have utilized advanced neuroimaging techniques as well as innovative monitoring modalities to improve the efficiency of neuroprotective strategies during cardiac surgery.

SUMMARY

Adverse cognitive and neurologic outcomes following cardiac surgery range from discrete neurocognitive deficits to severe neurologic injury such as stroke and even death. The elderly are at higher risk of suffering these outcomes and the public health dimension of this problem is expected to accelerate. Future studies should combine advanced neuroimaging with genomic, transcriptional, proteomic, and metabolomic profiling to improve our understanding of the pathophysiologic mechanisms and optimize the diagnosis, prevention, and treatment of neurocognitive injury.

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.

Is There a Future for Neuroprotective Agents in Cardiac Surgery?

This article gives an overview of neuroprotective drugs that were recently tested in clinical trials in cardiac surgery. Also, recommendations are given for successful translational research and considerations for management during cardiac surgery.

Prognostic value of troponin I levels for predicting adverse cardiovascular outcomes in postmenopausal women undergoing cardiac surgery

BACKGROUND

Adverse cardiac events that follow cardiac surgery are an important source of perioperative morbidity and mortality for women. Troponin I provides a sensitive measure of cardiac injury, but the levels after cardiac surgery may vary between sexes. Our purpose in this study was to evaluate the prognostic value of troponin I levels for predicting cardiovascular complications in postmenopausal women undergoing cardiac surgery.

METHODS

The cohort of this study were women enrolled in a previously reported clinical trial evaluating the neuroprotective potential of 17beta-estradiol in elderly women. In that study, 175 postmenopausal women not receiving estrogen replacement therapy and scheduled to undergo coronary artery bypass graft (with or without valve surgery) were prospectively randomized to receive 17beta-estradiol or placebo in a double-blind manner beginning the day before surgery and continuing for 5 days postoperatively. Serial 12-lead electrocardiograms were performed and serum troponin I concentrations were measured before surgery, after surgery on arrival in the intensive care unit, and for the first four postoperative days. The primary end-point of the present study was major adverse cardiovascular events (MACE) defined as a Q-wave myocardial infarction, low cardiac output state or death within 30 days of surgery. The diagnosis of Q-wave myocardial infarction was made independently by two physicians blinded to treatment and patient outcomes with the final diagnosis requiring consensus. Low cardiac output state was defined as cardiac index <2.0 L x min(-1) x m(-2) for >8 h regardless of treatment.

RESULTS

Troponin I levels on postoperative day 1 were predictive of MACE (area under the receiver operator curve = 0.862). A cutoff point for troponin I of >7.6 ng/mL (95% confidence interval, 6.4-10.8) provided the optimal sensitivity and specificity for identifying patients at risk for MACE. The negative predictive value of a troponin I level for identifying a patient with a composite cardiovascular outcome was high (96%) and the positive predictive value moderate (40%). Postoperative troponin I levels were not different between women receiving perioperative 17beta-estradiol treatment compared with placebo and the frequency of MACE was not influenced by 17beta-estradiol treatment.

CONCLUSIONS

In postmenopausal women, elevated troponin I levels on postoperative day 1 are predictive of MACE. Monitoring of perioperative troponin I levels might provide a means for stratifying patients at risk for adverse cardiovascular events.

The role of postoperative neurocognitive dysfunction on quality of life for postmenopausal women 6 months after cardiac surgery

BACKGROUND

Women are prone to neurological complications after cardiac surgery. We have previously reported that treatment perioperatively with the neuroprotectant steroid 17beta-estradiol did not improve neurocognitive end-points 4 to 6 wk after surgery for elderly women. In this study, we evaluated the influence of early postoperative neurocognitive dysfunction on quality of life in postmenopausal women undergoing cardiac surgery and whether it is impacted by perioperative 17beta-estradiol treatment.

METHODS

One hundred seventy-four postmenopausal women randomly received 17beta-estradiol or placebo in a double-blind manner beginning the day before surgery and continued until the fifth postoperative day. The patients underwent psychometric testing using a standard battery before surgery and again 4 to 6 wk and 6 mo postoperatively. Quality of life was assessed at baseline and 6 mo after surgery with the SF-36 questionnaire and the Lawton instrumental activities of daily living scale.

RESULTS

Complete data were available from 108 women of whom 13% demonstrated postoperative neurocognitive dysfunction. Based on multiple logistic regression analysis, a neurocognitive deficit 4 to 6 wk after surgery was an independent predictor of a lower SF-36 physical component score (P = 0.004) and lower Lawton instrumental activities of daily living scale 6 mo postoperatively (P = 0.026). Treatment with 17beta-estradiol (P = 0.003) and smoking status (P = 0.015) were predictors of worse SF-36 mental health component rating. Preoperative lower scores were independently associated with low quality of life postoperatively for all measurements.

CONCLUSIONS

Postoperative neurocognitive dysfunction is associated with impaired quality of life in women after cardiac surgery. Perioperative treatment with 17beta-estradiol provides no benefits to postoperative quality of life. The relationship between low preoperative and postoperative self-rated health status suggests that some aspects of quality of life in postmenopausal women are not amenable to improvements with cardiac surgery.

Risk factors for neurocognitive dysfunction after cardiac surgery in postmenopausal women

BACKGROUND

Women are at higher risk than men for neurologic complications from cardiac operations. This study identified risk factors for neurocognitive dysfunction after cardiac operations in elderly women.

METHODS

One hundred thirteen postmenopausal women undergoing primary coronary artery bypass grafting, with or without valve operation, underwent psychometric testing and neurologic evaluation the day before operation and 4 to 6 weeks postoperatively. Risk factors assessed for neurologic complications included atherosclerosis of the ascending aorta and apolipoprotein epsilon4 genotype. Postoperative neurocognitive dysfunction was defined as the composite end point of a one standard deviation decrement from baseline on two or more psychometric tests or a new neurologic deficit.

RESULTS

Neurocognitive dysfunction was present in 25% of the women 4 to 6 weeks postoperatively. Women with a neurocognitive deficit tended to be older than those without a deficit (72.1 +/- 8.1 vs 69.4 +/- 8.9 years, p = 0.144) and were more likely to have mild atherosclerosis of the ascending aorta, a history of congestive heart failure, longer duration of cardiopulmonary bypass (CPB) and aortic cross-clamping, lower nadir blood pressure during CPB, higher rates of postoperative atrial fibrillation, and longer postoperative hospitalization. Mild atherosclerosis of the ascending aorta, duration of CPB, duration of aortic cross-clamping (p = 0.051), and length of postsurgical hospitalization were independently associated with postoperative neurocognitive dysfunction.

CONCLUSIONS

Mild atherosclerosis of the ascending aorta, duration of CPB, aortic cross-clamping time, and length of hospitalization, but not apolipoprotein epsilon4 genotype, identified risk for neurocognitive dysfunction after cardiac operation in postmenopausal women.