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

High prevalence of obstructive sleep apnea in a surgical aortic valve replacement cohort: an observational study

Study Objectives

A high prevalence of sleep apnea has been reported among transcatheter aortic valve replacement (AVR) patients; however, the prevalence of sleep apnea in the younger and relatively healthier population of surgical AVR (SAVR) patients is unknown.

Methods

We assessed the prevalence of sleep apnea and overall sleep quality in patients having SAVR. Participants aged 50-89 were eligible for recruitment. All participants completed type II HST before SAVR. Sleep apnea was defined as an apnea-hypopnea index (AHI) ≥ 5 events/hour. The current use of positive airway pressure was exclusionary.

Results

The 46 participants (32 males/14 females) had a mean age of 66.6 years, body mass index of 30, AHI of 23.5, and obstructive AHI of 22.0. Only four participants had a prior sleep apnea diagnosis, yet all but one had sleep apnea on type II sleep testing. Two-thirds of sleep apnea was moderate or severe (AHI ≥ 15). A quarter of respiratory events were defined by arousals without desaturations. Whereas most sleep parameters resembled those of similarly aged community cohorts, mean percentage of N3 was reduced, accounting for only 3.8% of total sleep time.

Conclusions

Type II home sleep testing (HST) revealed a 97.8% prevalence of sleep apnea in this sample, most of which was undiagnosed obstructive sleep apnea. Roughly two-thirds of sleep apnea was moderate or severe. Such a high impact of obstructive sleep apnea among patients with severe aortic valve disease deserves further investigation on potential underlying mechanisms and clinical implications.

Patient-Reported Postoperative Neuropsychological Deterioration After Heart Valve Replacement and Coronary Artery Bypass Grafting

Background

Postoperative cognitive decline (POCD) after cardiosurgical interventions are well described through objective psychometric tests. However, a patient's subjective perception is essential to clinical assessment and quality of life. This study systematically evaluated patient-reported POCD between subjects undergoing coronary artery bypass grafting and heart valve replacement.

Methods

This study was a multicentre, prospective questionnaire survey conducted at the cardiac surgery departments at the Kerckhoff Clinic in Bad Nauheim and the University Hospital in Giessen, Germany. We included patients undergoing elective coronary artery bypass grafting (CABG), aortic valve replacement (AVR), mitral valve replacement or reconstruction (MVR), and combined surgery (CABG + valve replacement [VR]) with extracorporeal circulation. The Hospital Anxiety and Depression Scale, the Cognitive Failures Questionnaire (CFQ) for Self-assessment (CFQ-S), and the external assessment (CFQ-foreign [F]) were completed preoperatively, as well as at 3 and 12 months postoperatively.

Results

A total of 491 patients were available for analyses (CABG = 182, AVR = 134, MVR = 93, CABG + VR = 82). POCD and postoperative depression increase (PODI) were observed for each surgical procedure. (At the 3-month follow-up: CFQ-S [CABG = 7.1%, AVR = 3.7%, MVR = 9.7%, CABG + VR = 9.8%]; CFQ-F [CABG = 9.9%, AVR = 9.7%, MVR = 9.7%, CABG + VR = 15.9%]; PODI [CABG = 7.7%, AVR = 9.7%, MVR = 6.5%, CABG + VR = 8.5%]. At the 12-month follow-up: CFQ-S [CABG = 6.6%, AVR = 7.5%, MVR = 15.1%, CABG + VR = 7.3%]; CFQ-F [CABG = 7.1%, AVR = 14.9%, MVR = 10.8%, CABG + VR = 9.8%]; PODI [CABG = 10.4%, AVR = 11.2%, MVR = 6.5%, CABG + VR = 4.9%]). No significant between-group effects were observed for the CFQ-S, CFQ-F, or the Hospital Anxiety and Depression Scale.

Conclusions

For clinicians, paying attention to patients' self-reported experiences of reduced cognitive function and symptoms of depression following cardiac surgery is important. Such reporting is an indication that interventions such as cognitive training or psychotherapy should be considered.

Cognitive Impairment in Patients With Cardiac Disease: Implications for Clinical Practice

Cognitive impairment is common in patients with cardiovascular disease. One in 3 patients presenting at cardiology clinics have some degree of cognitive impairment, depending on the cardiac condition, comorbidities, and age. In up to half of these cases cognitive impairment may go unrecognized; however, it may affect self-management and treatment adherence. The high prevalence of cognitive impairment in patients with cardiac disease is likely due to shared risk factors, as well as direct consequences of cardiac dysfunction on the brain. Moreover, cardiac interventions may have beneficial as well as adverse effects on cognitive functioning. In this review, we describe prevalence and risk factors for cognitive impairment in patients with several common cardiac conditions: heart failure, coronary artery disease, and aortic valve stenosis. We discuss the potential effects of guideline-based treatments on cognition and identify open questions and unmet needs. Given the high prevalence of unrecognized cognitive impairment in cardiac patients, we recommend a stepwise approach to improve detection and management of cognitive impairment.

Difference in GFAP Levels in POCD and Non-POCD Patients After on Pump CABG

Introduction

On-pump, coronary artery bypass grafting (CABG) is the most common cause of postoperative cognitive dysfunction (POCD) after cardiac surgery. Previous studies showed that the incidence of POCD after cardiac surgery was 60%, higher than non-cardiac surgery with 11.7%. Glial fibrillary acid protein (GFAP) is one of the sensitive biomarkers of brain damage. Previous studies have found that elevated GFAP serum is associated with cognitive impairment. This study aims to measure the difference in GFAP levels in POCD and non-POCD patients after CABG on-pump surgery.

Methods

This study is a retrospective cohort design study. The data were obtained from 56 subjects undergoing elective CABG on the pump surgery enrolled into two groups consisting of 28 POCD as a case group and 28 non-POCD as a control group. In this study, the ELISA method measured the levels of GFAP biomarkers within 24 hours after surgery. After 72 hours, the patient received a MoCA-INA examination to determine cognitive impairment. Data analysis was carried out by SPSS 23.00 software.

Results

The mean age of patients in both groups was 60 years and was dominated by males (>85%). POCD patients were found to have a significantly longer duration of cardiopulmonary bypass (CPB) and cross-clamp surgery than non-POCD patients (p = 0.002 and p = 0.004). Postoperative GFAP levels in POCD patients were significantly higher than in non-POCD patients (12.95 ± 7.47 vs 3.80 ± 2.77, p < 0.001). There was a significant increase in GFAP levels compared with non-POCD (8.28 ± 7.24 vs -1.5 ± 3.03, p < 0.001). The area under the curve (AUC) value of GFAP against POCD was 0.887, cut-off GFAP 4.750 with a sensitivity of 92.9% and a specificity of 71.4%.

Conclusion

POCD patients had higher GFAP levels than non-POCD patients. There are differences in GFAP levels in patients with POCD and non-POCD post-CABG surgery.

Preoperative Risk Factors and Early Outcomes of Delirium in Valvular Open-Heart Surgery

BACKGROUND

 Compared with coronary artery bypass grafting surgery, data regarding postoperative delirium are scant in valvular open-heart surgery. Therefore, the goal of this retrospective study was to investigate the incidence, preoperative risk factors, and early outcomes of delirium in a large group of patients undergoing valvular open-heart surgery.

METHODS

 In 13,229 patients with isolated valvular or combined valvular and bypass surgery, the incidence of postoperative delirium was assessed until discharge. Independent risk factors of delirium were evaluated by multivariable logistic regression analysis. Moreover, we assessed the multivariable-adjusted risk of prolonged intensive care unit (ICU) stay (>48 hours) and in-hospital mortality in patients with delirium.

RESULTS

 Overall, the incidence of postoperative delirium was 8.4%. The incidence in patients experiencing a postoperative stroke or seizure was 23.1 and 29.7%, respectively. Twelve preoperative risk factors, mostly nonmodifiable, were independently associated with the risk of delirium, including advanced age, renal impairment, stroke, the need for emergency surgery, and severe preoperative anemia (hemoglobin < 9 g/dL). Postoperative delirium was associated with an adjusted odds ratio (OR) of prolonged ICU stay of 9.48 (95% confidence interval [CI]: 7.96-11.30). Adjusted in-hospital mortality was, however, significantly lower in patients with delirium versus patients without delirium (OR, 0.56; 95% CI: 0.38-0.83).

CONCLUSION

 In valvular open-heart surgery, postoperative delirium is a frequent neurological complication that is associated with other postoperative neurological complications and several, mostly nonmodifiable, preoperative risk factors. Although postoperative delirium was associated with a significantly increased risk of prolonged ICU stay, this did not translate into an increased short-term mortality.

An Association Between C-Reactive Protein Levels and the Occurrence of Cognitive Dysfunction After Heart Valve Replacement

Background

Postoperative cognitive dysfunction (POCD) is defined as cognitive dysfunction related to inflammation after surgical procedures, which is common following cardiac surgery. Cognitive deficits are thought to result from a systemic inflammatory response. C-reactive protein (CRP) and other proinflammatory cytokines, which are released in response to inflammation, disrupt the blood–brain barrier and neurotransmission, resulting in POCD. This study aimed to determine the correlation between POCD and increased levels of CRP in patients who had undergone heart valve replacement.

Methods

This study comprised 32 patients with normal cognitive function undergoing heart valve replacement. The CRP levels were measured before surgery and on the second postoperative day, and cognitive function was examined via the Indonesian-adapted Montreal Cognitive Assessment (MOCA-INA) on the third postoperative day. Data were analyzed using Spearman correlation test.

Results

Of the 32 patients, 28 (87.5%) experienced POCD. The median level of CRP was 6.6 mg/dL (interquartile range: 4.0, 8.3 g/dL). According to Spearman correlation test, increased levels of CRP were significantly related to POCD following heart valve replacement (p = 0.003, r = 0.501). The receiver operating characteristic curve indicated that the CRP cutoff level was 3.345 mg/dL, and the sensitivity and specificity were 89.3% and 75%, respectively.

Conclusion

High expression level of CRP was correlated with POCD following heart valve replacement.

Patient-Reported Cognitive Outcomes Following Cardiac Surgery: A Descriptive Review

A descriptive review was conducted to evaluate the evidence of cognitive patient-reported outcome measures (PROMs) following cardiac surgery. The search of electronic databases resulted in 400 unique manuscripts. Nine studies met the criteria to be part of the final review. Results of the review suggest that there are few validated PROMs that assess cognitive function in the cardiac surgical population. Furthermore, PROMs have not been used to assess overall cognitive function following cardiac surgery within the past decade. However, one domain of cognitive function—memory—was described, with up to half of patients reporting a decline postoperatively. Perceived changes in cognitive function may impact health-related quality of life and a patient’s overall view of the success of their surgery. Early identification of cognitive changes measured with PROMs may encourage earlier intervention and improve patient-centered care. In clinical practice, nurses may be in the best position to administer PROMs preoperatively and postoperatively.

Delirium in older patients undergoing aortic valve replacement: incidence, predictors, and cognitive prognosis

Background

Transcatheter aortic valve replacement is increasingly performed in frail older patients who were previously ineligible for a standard surgical procedure. The objectives of this study are to determine delirium incidence, predictors, and relationship with cognitive performance at 3-month follow-up in older patients undergoing aortic valve replacement (AVR).

Methods

Patients (N = 93) aged 70 years and older, undergoing transcatheter (TAVR, N = 66) or surgical (SAVR, N = 27) aortic valve replacement in an academic medical center were enrolled in this prospective cohort study. Delirium was assessed using the Confusion Assessment Method (CAM) on postoperative days 1, 2, 3, and 7. Data on patients’ socio-demographics, functional status (including instrumental activities of daily living (IADL), and surgical risk scores (including Society of Thoracic Surgeons (STS) risk score), were collected at baseline. Cognitive status was assessed with the Mini-Mental Status Exam (MMSE) and the Clock Drawing Test (CDT) at baseline and 3 months after AVR.

Results

Delirium occurred in 21 (23%) patients, within the first three postoperative days in 95% (20/21) of the cases. Delirium incidence was lower in TAVR (13/66 = 20%) than SAVR (8/27 = 30%) patients, but this difference was not statistically significant (p = .298). Patients with delirium had lower baseline cognitive performance (median MMSE score 27.0 ± 3.0 vs 28.0 ± 3.0, p = .029), lower performance in IADL (7.0 vs 8.0, p = .038), and higher STS risk scores (4.7 ± 2.7 vs 2.9 ± 2.3, p = .020). In multivariate analyses, patients with intermediate (score > 3 to ≤8) and high (score > 8) STS risk scores had 4.3 (95%CI 1.2–15.1, p = .025) and 16.5 (95%CI 2.0–138.2, p = .010), respectively, higher odds of incident delirium compared to patients with low (score ≤ 3) STS risk scores. At 3-month follow-up (N = 77), patients with delirium still had lower MMSE score (27.0 ± 8.0 vs 28.0 ± 2.0, p = .007) but this difference did not remain significant once adjusting for baseline MMSE (β-coefficient 1.11, 95%CI [− 3.03–0.80], p = .248).

Conclusions

Delirium occurred in about one in five older patients undergoing AVR, almost essentially within the first three postoperative days. Beside cognitive performance, STS risk score could enhance the identification of high-risk older patients to better target preventative interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02100-5.

Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline

This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfusion originates from chronically reduced cardiac output which progresses as heart failure worsens. Other left ventricular heart parts, including atrium, valves, myocardium, and aorta can contribute to the physiological shortfall of cardiac output. It follows that hemodynamic instability and perfusion changes occurring from the aging heart's blood pumping deficiency will, in time, damage vulnerable brain cells linked to specific cognitive regulatory sites, diminishing neuronal energy metabolism to a level where progressive cognitive impairment is the outcome. Could cognitive impairment progress be reversed with a heart transplant? Evidence is presented detailing the errant hemodynamic pathways leading to cognitive impairment during aging as an offshoot of inefficient structural and functional heart parts and their contribution to heart failure.

Prevalence of Depression in Coronary Artery Bypass Surgery: A Systematic Review and Meta-Analysis

Coronary artery bypass graft surgery (CABG) might adversely affect the health status of the patients, producing cognitive deterioration, with depression being the most common symptom. The aim of this study is to analyse the prevalence of depression in patients before and after coronary artery bypass surgery. A systematic review and meta-analysis was carried out, involving a study of the past 10 years of the following databases: CINAHL, LILACS, MEDLINE, PsycINFO, SciELO, Scopus, and Web of Science. The total sample comprised n = 16,501 patients. The total number of items was n = 65, with n = 29 included in the meta-analysis. Based on the different measurement tools used, the prevalence of depression pre-CABG ranges from 19-37%, and post-CABG from 15-33%. There is a considerable presence of depression in this type of patient, but this varies according to the measurement tool used and the quality of the study. Systematically detecting depression prior to cardiac surgery could identify patients at potential risk.

Adjunct Pharmacotherapy After Transcatheter Aortic Valve Replacement: Current Status and Future Directions

Transcatheter aortic valve replacement (TAVR) is a validated treatment option for severe aortic stenosis. Ischemic and thrombotic complications remain important and strongly correlate with mortality. The optimal postprocedural antithrombotic strategy for prevention of thrombotic events remains unclear. The international guidelines for medical management following TAVR are discordant, allowing for significant variance in prescribing habits. The optimal treatment strategy has yet to be delineated. Clinical trials are ongoing to assess the risks and benefits of various strategies. We discuss the pathobiology and rationale for antithrombotic therapy after TAVR, review current evidence and guidelines, and offer a concise evidence-based approach to this subject.

The value of screening for cognition, depression, and frailty in patients referred for TAVI

Background: Current surgical risk assessment tools fall short of appreciating geriatric risk factors including cognitive deficits, depressive, and frailty symptoms that may worsen outcomes post-transcatheter aortic valve implantation (TAVI). This study hypothesized that a screening tool, SMARTIE, would improve detection of these risks pre-TAVI, and thus be predictive of postoperative delirium (POD) and 30-day mortality post-TAVI. Design: Prospective observational cohort study, using a historical cohort for comparison. Participants: A total of 234 patients (age: 82.2±6.7 years, 59.4% male) were included. Half were screened using SMARTIE. Methods: The SMARTIE cohort was assessed for cognitive deficits and depressive symptoms using the Mini-Cog test and PHQ-2, respectively. Measures of frailty included activities of daily living inventory, the Timed Up and Go test and grip strength. For the pre-SMARTIE cohort, we extracted cognitive deficits, depression and frailty symptoms from clinic charts. The incidence of POD and 30-day mortality were recorded. Bivariate chi-square analysis or t-tests were used to report associations between SMARTIE and pre-SMARTIE groups. Multivariable logistic regression models were employed to identify independent predictors of POD and 30-day mortality. Results: More patients were identified with cognitive deficits (χ2=11.73, p=0.001), depressive symptoms (χ2=8.15, p=0.004), and physical frailty (χ2=5.73, p=0.017) using SMARTIE. Cognitive deficits were an independent predictor of POD (OR: 8.4, p<0.01) and 30-day mortality (OR: 4.04, p=0.03). Conclusion: This study emphasized the value of screening for geriatric risk factors prior to TAVI by demonstrating that screening increased identification of at-risk patients. It also confirmed findings that cognitive deficits are predictive of POD and mortality following TAVI.