Analysis and interpretation of neuropsychologic tests in cardiac surgery

doi:10.1016/0003-4975(95)00215-7

The Annals of Thoracic Surgery

Volume 59, Issue 5, May 1995, Pages 1351-1355

https://doi.org/10.1016/0003-4975(95)00215-7 Get rights and content

Neuropsychologic assessment in the context of cardiac surgery is constrained by the clinical time available to see patients, and as such test selection needs to be carefully planned. Besides the time limitations, it differs from clinical neuropsychologic assessment primarily because it tends to involve at least two assessments, a comparison with performance before operation, and a limited number of tests. The analysis and design issues involved in both incidence studies and intervention studies are discussed in this article. Incidence studies customarily involve a single group assessed on at least two occasions and are designed to identify the numbers of individuals who show clear evidence of neuropsychologic changes after a cardiac operation. Intervention studies involve at least two groups where one factor (eg, surgical equipment) is varied systematically. The research on neuropsychologic deficits after cardiac operations has progressed from incidence studies, which involve a conventional definition of deficit, to intervention studies, in which specific test performance can be compared.

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Cited by (79)

Measuring and monitoring cognition in the postoperative period
2020, Best Practice and Research: Clinical Anaesthesiology
It is common for patients of all ages to experience some degree of cognitive disturbance following surgery. In most cases, impairment appears mild and is restricted to the acute post-operative period, resolving steadily and speedily. In a small number of cases, however, deficits may be more pronounced and/or endure for longer periods, significantly delaying recovery and increasing the risk of serious clinical complications. The ability to accurately measure postoperative cognition, and track recovery of function, is an important clinical task. This review explores practical and methodological issues that may confound this process, examining how best to obtain reliable and meaningful measures of cognition before and after surgery. It considers neuropsychological test selection, administration, analysis and interpretation and offers evidence-based practice points for clinicians and researchers.
Cognitive outcomes following coronary artery bypass grafting: A systematic review and meta-analysis of 91,829 patients
2019, International Journal of Cardiology
Citation Excerpt :
When categorized by the 1SD method (where the pre-surgery cognition score of a patient is ≥1SD below study population/control patients/published norms) the presence of cognitive impairment was higher than when classified utilising a cut-off method (such as Mini-Mental State Examination (MMSE) ≤ 24) with rates of 32% and 14% respectively. This likely occurred as the 1SD method involves more comprehensive testing (neuropsychological test battery) allowing the assessment of subtle changes, compared to the commonly used screening tests administered in the cut-off method [16,29–31]. It is therefore likely that a third of patients present with cognitive impairment pre-operatively.
Cognitive impairments, including delirium, are common after coronary artery bypass grafting (CABG) surgery, as described in over three decades of research. Our aim was to pool estimates across the literature for the first-time, relative to time (from pre- to post-CABG) and diagnosis (cognitive impairment, delirium and dementia).
A systematic search of four databases was undertaken. 215 studies incorporating data from 91,829 patients were used to estimate the prevalence of cognitive impairments pre- and post-CABG, including delirium and dementia post-CABG, using random effects meta-analyses.
Pre-surgical cognitive impairment was seen in 19% of patients. Post-operatively, cognitive impairment was seen in around 43% of patients acutely; this resolved to 19% at 4–6 months and then increased to 25% of patients between 6-months to 1-year post-operatively. In the long term, between 1 and 5-years post-operatively, cognitive impairment increased and was seen in nearly 40% of patients. Post-operative delirium was apparent in 18% of CABG patients which increased to 24% when a diagnostic instrument was utilized alongside clinical criteria. Dementia was present in 7% of patients 5–7 years post-surgery.
The results of this meta-analysis demonstrate that cognitive impairment and delirium are major issues in CABG patients which require specific attention. It is imperative that appropriate methods for investigating cognitive impairment, and screening for delirium using a diagnostic instrument, occur in both pre-and post-CABG settings.
Brain volume and cognitive function in patients with revascularized coronary artery disease
2017, International Journal of Cardiology
The pathogenesis of cognitive dysfunction in patients with CAD remains unclear. CAD is associated with brain atrophy and specific lesions. Detailed knowledge about the association of brain volume measured with MRI, and cognitive function in patients with CAD is lacking. We therefore investigated brain volume and cognitive function in patients with revascularized coronary artery disease (CAD), and controls without CAD.
Brain MRI scans and cognitive tests from patients with CAD were compared with data from control subjects without CAD. Cognitive performance was assessed with the Rey Auditory Verbal Learning (short term memory) and Trailmaking (divided attention) tests. Multivariable regression analysis was used to study associations between CAD, brain volume and cognitive function.
A total of 102 patients with CAD and 48 control subjects were included. Level of education and age were comparable between the groups. Compared with controls, patients with CAD had smaller total brain volume (expressed as fraction of intracranial volume) [%ICV, mean (SD), 0.78 (0.03) vs 0.80 (0.02), P = 0.001] and larger volume of non-ventricular cerebrospinal fluid [%ICV, median (IQR) 0.19 (0.18 to 0.21) vs 0.18 (0.17 to 0.20), P = 0.001]. Patients in the CAD group had poorer cognitive function [mean (SD) Z-score − 0.16 (0.72) vs 0.41 (0.69), P < 0.01]. Multivariable regression showed that CAD, higher age, lower level of education and greater cerebrospinal fluid volume were independent predictors of poorer cognitive function.
CAD patients had a smaller total brain volume and poorer cognitive function than controls. Greater volume of cerebrospinal fluid was an independent predictor of poorer cognitive function.
Postoperative cognitive dysfunction after total joint arthroplasty in the elderly: A meta-analysis
2014, Journal of Arthroplasty
Citation Excerpt :
Unfortunately, these studies only used a small number of comparable measures and so it is not known whether practice effects counteracted any decline on other measures. It is also possible that cognitive decline occurred in a subset of individuals but was masked when group data was analysed [41,48,49]. This is illustrated in a recent meta-analysis of cognitive outcomes after cardiac surgery [24] which, based on group data, concluded that there was either no change or small improvements in performance following surgery.
This meta-analysis consolidated the research on postoperative cognitive dysfunction (POCD) following total joint arthroplasty (TJA). Data from 17 studies that assessed cognition pre- and post-surgery in TJA patients alone (15 studies) or matched TJA and control groups (2 studies) were analysed. Results were grouped by cognitive domain (memory, attention, language, speed, general cognition) and follow-up interval (pre-discharge, 3-6 months post-surgery). The TJA data revealed small declines in reaction time and general cognition pre-discharge, but no evidence of decline 3–6 months post-surgery. Very limited TJA and Control data indicated no group differences in the changes to performance over time; however, the TJA group was cognitively compromised pre- and post-surgery compared to Controls. Further appropriately controlled research is required to clarify whether POCD commonly occurs after TJA.
A preliminary study of the effects of ulinastatin on early postoperative cognition function in patients undergoing abdominal surgery
2013, Neuroscience Letters
Citation Excerpt :
Parallel forms of tests were used in sequential testing in a randomized way, when available, to minimize any practice effect. A postoperative deficit in any test was defined by a decline of 20% or more from the preoperative value of that test [17]. Any patient demonstrating a deficit in 2 or more tests was considered as having POCD.
Ulinastatin, a urinary trypsin inhibitor, is widely used to treat acute systemic inflammatory disorders. However, its effects on early postoperative cognitive function have not been fully elucidated. The objective of this study was to investigate the effect of ulinastatin on serum IL-6, TNF-α, CRP and S100β protein concentration and early postoperative cognitive function in patients after abdominal surgery.
Eighty ASAI-II patients older than 65 years, scheduled for elective abdominal surgery were randomly divided into 2 groups (n = 40 each): ulinastatin and control. After induction of anesthesia, the ulinastatin group received 10,000 units/kg of ulinastatin intravenously before surgical incision and 5000 units/kg on post-op days 1–3. Cognitive function was assessed preoperatively and on post-op day 7 using a battery of nine neuropsychological tests. Serum IL-6, TNF-α, CRP and S100β protein levels were determined preoperatively, at the end of surgery and on post-op days 1–3.
There were significant decrements in each neuropsychological test, except for the Digit Span Backward Test between groups. Based on neuropsychological testing, the ulinastatin group had a lower incidence of postoperative cognitive dysfunction (POCD) than the control group (2.5% versus 27.5%, p < 0.05). In the control group, serum S100β protein and IL-6 concentrations increased at the end of surgery and on post-op days 1 and 2. The ulinastatin group had lower serum S100β protein and IL-6 concentrations than those in the control group (p < 0.05).
Ulinastatin may be effective in reducing the incidence of early postoperative cognitive dysfunction.
Neurodevelopmental Outcomes in Children with Congenital Heart Disease
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View all citing articles on Scopus

: Presented at the Conference on CNS Dysfunction After Cardiac Surgery: Defining the Problem, Fort Lauderdale, FL, Dec 10–11, 1994.

View full text

Analysis and interpretation of neuropsychologic tests in cardiac surgery

Evaluation of the efficacy of coronary bypass surgery. II

Am J Cardiol

The diminishing mortality of coronary bypass grafting for myocardial infarction

NC Med J

The UK Cardiac Surgical Register 1977–1982

Br Med Bull

Acute neuropsychological consequences of coronary artery bypass surgery

Curr Psych Res Rev

The persistence of neuropsychological deficits twelve months after coronary artery bypass surgery

Neuropsychological and psychological changes

Cognitive function after coronary surgery

Effects of decreased cerebral blood flow

Am J Psychiat

Perceptual and cognitive deficit following coronary artery bypass surgery

Stress Med

The incidence and nature of neuropsychological morbidity following cardiac surgery

Perfusion

Two-year follow-up study of coronary bypass surgery

J Thorac Cardiovasc Surg

Persistance of neuropsychological deficits following CABG

Anaesthesiology

Cerebral consequences of cardiopulmonary bypass

Lancet

Focal neurological lesions and diffuse brain damage in open-heart surgery patients

Neuropsychological dysfunction following elective cardiac operation I. Early assessment

J Thorac Cardiovasc Surg

The effects of arterial filtration during open heart surgery on cerebral function

Circulation

Evidence for involvement of hypocapnia and hypotension in aetiology of neurological deficit after cardiopulmonary bypass

Lancet

Neurologic and neuropsychological morbidity following major surgery: comparison of coronary artery bypass surgery and peripheral vascular surgery

Stroke

Neuropsychological functioning following cardiopulmonary bypass

Cabbages and CABG

Br Med Bull

Neuropsychologic outcome after open-heart surgery

Arch Neurol

Neuropsychological dysfunction following elective cardiac operation. II. A six month reassessment

J Thorac Cardiovasc Surg

Effects of extracorporeal circulation upon behaviour, personality and brain function. Part II. Hemodynamic, metabolic and psychomotor correlations

Ann Surg

Long-term intellectual dysfunction following coronary artery bypass surgery: a six month follow up study

Q J Med

Neuropsychiatric complications following cardiac surgery

Semin Thorac Cardiovasc Surg

Neurological, cognitive and psychiatric sequale associated with the surgical management of cardiac disease

Long-term cerebral outcome after open-heart surgery: a five year neuropsychological follow-up study

Stroke

Cerebral protection during open heart surgery

Thorax