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Ann Thorac Surg 1995;59:1345-1350
© 1995 The Society of Thoracic Surgeons
Department of Psychiatry and Behavioral Sciences, Community and Family Medicine, and Anesthesiology, and Duke Heart Center, Duke University Medical Center, Durham, North Carolina
Abstract
This report reviews critical issues facing investigators interested in neuropsychologic sequelae after cardiac operations: (1) experimental design; (2) selective attrition; (3) selection of instruments; (4) moderating factors; (5) definitions of cognitive decline; (6) statistical analysis; and (7) clinical significance. Implications for further research in the area are discussed.
Since its introduction in 1967, coronary artery bypass grafting (CABG) has become a common surgical method to treat patients with significant coronary artery disease. From 1983 to 1990, the number of operations increased from 191,000 to 392,000 [1]. Associated with this increase has been the progressive improvement over time in surgical outcome [2]. The dramatic improvement in successful results has been attributed to better myocardial protection, more complete coronary revascularization, improved operating technique resulting in enhanced graft patency rates, and better general patient support such as improved cardiac anesthesia and intensive care practices [3]. These developments are even more remarkable because CABG is now more likely to be performed on patients who are older, have more impaired cardiac function, and are more likely to have comorbid medical conditions [4].
Despite declines in overall mortality after CABG, deaths from neurologic complications have increased [5] and may account for as many as 20% of deaths [6, 7]. In addition, the prevalence of neuropsychologic impairment may be quite high, exceeding 60% in some reports [8, 9]. Because CABG and various alternative therapies including percutaneous transluminal coronary angioplasty (PTCA) and medical therapy (medication) have similar effects on survival for many patients with coronary artery disease [10], considerations other than survival need to be evaluated carefully. In particular, the quality of life of patients undergoing cardiac surgical procedures has recently received much attention, especially with respect to the effect of such procedures on cognitive and neuropsychologic outcomes.
The burgeoning interest in the relationship between CABG and neuropsychologic outcomes is reflected in the linear increase in published research in the area. A MEDLINE search for articles on this topic revealed that the number of published articles has increased fivefold from five in 1970 through 1974 to 25 in 1990 through 1994. The contributors to the literature come from such diverse backgrounds as psychology, nursing, anesthesiology, cardiology, and surgery. Investigators from these various backgrounds often approach the area from different theoretical perspectives and have their own unique expectations, objectives, and methodologies. As a result, it has been difficult to reach a consensus on the best method of assessing cognitive function in cardiac surgical patients. The purpose of this report is to discuss what we consider to be the most important methodological and conceptual issues currently facing investigators interested in the cognitive effects of cardiac surgery.
Experimental Design
Most studies typically assess patients at baseline prior to operation and at regular follow-up intervals. The most frequently studied intervals are the day prior to operation, 7 to 10 days after operation or immediately prior to discharge, 6 weeks, and 6 months after operation. Follow-up periods are less frequently extended beyond 1 year, and it is generally assumed that patients have achieved a stable level of cognitive function by 6 months postoperatively. Although studies comparing the cardioprotective effects of different pharmacologic agents or different surgical procedures (eg, different anesthetics, hypothermia, and rate of rewarming) may employ randomized controlled designs [11, 12], it is more common for studies to use each patient as his or her own control.
Many studies employ various comparison groups as nonrandom controls, such as other cardiac surgical patients, PTCA patients, or noncardiac surgical patients [12–16]. For example, in a recent study at Duke University Medical Center [13], patients undergoing PTCA tended to perform better on several neuropsychologic tests relative to patients receiving CABG or valve repair. The sample size was extremely small, however, and patients were not randomized to treatment groups.
Because randomized assignment is difficult in this population, most studies are observational without control groups [17–20]. However, at least one study [21] is underway to compare neuropsychologic outcomes in patients randomized to either CABG or PTCA as part of the Bypass Angioplasty Revascularization Investigation trial. A 5-year investigation of neuropsychologic performance in patients who underwent either CABG or PTCA is currently ongoing.
Selective Attrition
An important methodological consideration in assessing cognitive function after a cardiac operation is the problem of selective attrition. In most studies of neuropsychologic outcome after such a procedure, patients are followed serially over extended periods. Because patients do not randomly drop out of studies, reporting data only on the subset of patients who return for follow-up may yield an inaccurate picture of the true rate of impairment over time.
Examination of data from an ongoing study of neuropsychologic outcome and cardiac surgery at Duke University Medical Center, for example, clearly demonstrates the bias that can be introduced by considering only patients who return for follow-up visits. Table 1
shows that patients who drop out from the study after completing the baseline and predischarge assessments had greater neuropsychologic impairment at baseline than patients who completed testing at both the 6-week and 6-month follow-ups. Completers also were more likely to be better educated, male, white, married, and sicker as determined by ASA classification (anesthesiologists' subjective health ratings) and the number of occluded arteries. Thus, the 18% incidence of neuropsychologic decline (as defined by a decrease of 
1 standard deviation in at least two of nine measures) after CABG at 6 weeks may underestimate the true level of impairment because the more impaired patients were not available for follow-up.
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Selection of neuropsychologic instruments is a major concern for investigators in this area. Choosing neuropsychologic tests that are sensitive to subtle, as well as obvious, cognitive changes associated with cardiac surgery is important both for understanding how surgery can affect the brain and for advancing medical intervention and technological developments to reduce impairment.
Decisions regarding the selection of instruments are often guided by practical as well as theoretical considerations. Patients are usually available for only limited time periods; consequently, neuropsychologic test batteries are usually very brief. In addition, patients may be anxious, depressed, or fatigued, conditions limiting their ability to undergo extensive testing.
One of the obvious problems with using a limited neuropsychologic battery is that not all relevant domains of cognitive functioning are adequately assessed. Consequently, it is impossible to adequately identify specific areas that may be affected by a cardiac operation if only a few domains of cognitive function are assessed. Also, it is difficult to compare results of one study with another when each battery has a different set of instruments.
Typically, selection of a neuropsychologic battery is based on the following considerations: (1) reliability and validity of measures; (2) availability of normative data; (3) brevity; (4) sensitivity to relevant cognitive domains; (5) availability of alternative forms (for repeat testing); and (6) use in prior studies. In 1989, a National Institute of Mental Health–sponsored workshop developed a neuropsychologic test battery suitable for the early detection of neurologic complications in human immunodeficiency virus–positive asymptomatic individuals [22]. The following list is a modified version of this battery, which we believe would also be useful for assessing cognitive changes after cardiac surgical intervention.
Because this battery would likely require up to 10 hours of testing per patient and is expensive to administer and score, it is unlikely that such an extensive battery could be administered at a single site; rather, a multicenter trial would be needed to recruit the large number of patients required to thoroughly document neuropsychologic changes after cardiac operation.
For future studies, we recommend an abbreviated battery that assesses those functions most likely to be affected by cardiac surgical interventions. Such a battery should include both traditional neuropsychologic measures (eg, subtests of the Halstead-Reitan battery) and newer instruments derived from the experimental cognitive psychology literature (eg, Sternberg memory search procedure). Care should also be taken to retain a sufficient number of test items for a valid assessment if tests are modified for inclusion in a battery. A core set of instruments would greatly facilitate comparability between studies and permit greater generalization of results.
Moderating Factors
Evaluation of mood and psychiatric disturbance also should be included in the assessment battery. Emotional disturbance is prevalent among CABG patients. For example, recent data [23] from a series of 141 patients undergoing a cardiac operation at Duke University Medical Center indicated that 46% were at least mildly depressed at baseline (defined as achieving a score of >15 on the Center for Epidemiological Studies-depression scale), with a greater proportion of women being affected than men (66% versus 38%); after the operation, 60% were depressed (75% versus 54%, respectively). In addition, a large number of patients were clinically anxious and reported low levels of social support. These data are important because anxiety, depression, and other emotional problems can affect neuropsychologic performance and have important prognostic significance in patients with cardiac disease [14, 24–26].
In addition to emotional disturbance, there are other factors that can affect neuropsychologic performance and need to be considered in interpreting results of outcome studies. In addition to age [14, 17, 27] and education [17], medication use, medical status, and lack of uniform testing conditions all can influence cognitive performance. Blood pressure status may also be important; research has demonstrated that elevated blood pressure is associated with cognitive deficits in patients without cardiac disease [28–30].
Definitions of Cognitive Decline
Estimates of the extent of cognitive impairment (ie, decline in neuropsychologic performance) after cardiac surgical intervention have ranged from 24% [31] to 79% [9]. This wide discrepancy is due in part to the diversity of instruments, varying follow-up intervals, and differences in patient characteristics. More importantly, studies have used a variety of definitions of decline. The following definitions of impairment or change list the kinds of methods that can be used to classify patients as ``significantly declined:''
It is readily apparent that the prevalence of cognitive decline varies greatly as a function of the definition of decline that is used. For example, in the Duke series of 287 cardiac surgical patients who underwent neuropsychologic assessment at baseline and discharge, we examined the prevalence of decline using three different definitions: decline of one level in global impairment rating; decline of 1 standard deviation on 20% of tests; and 20% drop on 20% of tests. Comparison of these three methods revealed that there was agreement as to who declined in only 8% of cases and agreement as to who did not decline in only 30% of cases.
One seldom used method of defining decline, which may have particular promise in cardiac studies, involves IRs [32–34]. One approach with IRs involves converting raw scores to standardized T-scores and then using a priori criteria to rate the severity of impairment. Heaton and colleagues [33] have employed the following criteria, which may be useful for cardiac surgical studies, in studies of patients with neuropsychiatric impairment: IR 0 = T > 40 (no impairment); IR 1 = T 39–35 (mild impairment); IR 2 = T 34–30 (mild/moderate impairment); IR 3 = T 29–25 (moderate impairment); IR 4 = T 24–20 (moderate/severe impairment); and IR 5 = T < 20 (severe impairment). By employing such a system, investigators can consider scores that drop one level between testing sessions to be indicative of cognitive decline. This rating method also identifies patients who are impaired before operation, which could be useful for prognostic purposes.
Clinical ratings, another method of assessment, also has considerable utility in studies of neuropsychologic outcome in cardiac surgical patients. Most studies use one of the aforementioned definitions of decline or examine mean changes in performance over time. Although comparison of group means over time is useful, this procedure is limited when detecting subtle deficits in which there are different patterns of decline for subgroups of patients. If the affected functions are not consistent across individuals, changes may not be apparent in the group's mean score; that is, on any given measure, the ``normal'' performances of some individuals may mask the impaired scores of other, affected individuals.
To increase the likelihood that neuropsychologic tests will identify patients with impairment, patients' scores can be rated by trained neuropsychologists using standardized clinical criteria. These ratings represent global judgments regarding overall level of cognitive performance as well as specific areas of neurobehavioral functioning. Previous research has demonstrated the reliability and validity of clinical ratings in neuropsychology, both for diagnosing impairment and for documenting change in performance [34]. Thus, although investigators will likely continue to examine group means or use a definition of decline such as 1 standard deviation, clinical ratings also need to be considered. However, because these clinical ratings are more applicable to standardized than to experimental neuropsychologic instruments and because age, gender, and education affect performance, it may be problematic to develop well-defined criteria for judging the presence and severity of deficits.
Statistical Analysis
The main end point of studies of neuropsychologic function is change from preoperative baseline to postoperative condition. One way to report change is an analysis of categorical outcome data (ie, 1 standard deviation drop) using the method of logistic regression. This analysis examines what factors are associated with a change from one rating level to another. A shift in level may be more clinically meaningful than simply examining changes in raw scores. However, all steps are considered to be of equal size, and changes within a rating level are disregarded. A small decline may cause a person to cross the boundary between normal and ``impaired,'' or a large decline may occur within or entirely above such a boundary. A great deal of information about individuals may be lost when change in categories is assessed.
Alternatively, change can be considered on a continuum. Linear multivariate regression, a more powerful statistical method, can then be used to take advantage of all the information inherent in raw test scores. Such an analysis examines what factors are associated with the continuous, rather than categoric, amount of change in neuropsychologic function. Although the arbitrariness of categoric boundaries is avoided, it is difficult to ascertain with this type of analysis the clinical significance of change.
Clinical Significance
Although studies generally report statistically significant changes in neuropsychologic performance over time, relatively little attention has been given to the clinical importance of these changes. In addition to using clinical ratings and IRs to document the extent and severity of cognitive deficits, it is also important to understand how these changes affect activities of daily living. Previous studies [35] of psychiatric patients have shown that neuropsychologic test scores are related both to current level of everyday functioning and prognosis for long-term adjustment. Moreover, in studies of neurologic patient groups, typically after strokes, neuropsychologic test scores are related to current self-care abilities and may also predict improved self-care and ambulatory ability during recovery [35].
Available data further suggest that neuropsychologic performance is related to vocational functioning. Several reviews [36, 37] have concluded that cognitive levels in different occupational groups are strongly related to mean income levels and ratings of occupational prestige. Also, there is evidence that neuropsychologic performance is related to job performance and employment status in normal individuals [38, 39]. For example, Heaton and associates [39] administered a test battery consisting of the Halstead-Reitan battery and the Minnesota multiphasic personality inventory test to a diverse sample of patients referred for neuropsychologic testing. The unemployed group obtained significantly lower scores than the full-time employed group, whereas the part-time employed group obtained intermediate scores.
Similarly, Newman and co-workers [40] used the same test battery to predict future employment characteristics in a sample of 78 patients with stable neurologic conditions. The average IR was the single best predictor of employment status, as it correctly classified 78% of the sample over the 6-month follow-up.
In another study, Heaton and associates [41] assessed the relationship between neuropsychologic impairment and vocational adjustment in 289 human immunodeficiency virus–infected men in the San Diego area. Those patients who evidenced neuropsychologic impairment had a higher unemployment rate than their nonimpaired counterparts. Moreover, neuropsychologic impairment was strongly associated with subjective decreases in job-related abilities that could not be explained by either depression or medical symptoms.
However, few studies have examined the relationship between cognitive decline and vocational status in cardiac surgical patients. Results have been inconclusive [42], and further research is needed in this area.
Summary and Future Research Directions
Neuropsychologic impairment is generally believed to result from either chronic hypoperfusion during cardiac operations, embolism of air or particulate matter, or intracerebral hemorrhage. Further research is clearly needed to examine the mechanisms responsible for the neuropsychologic deficits observed after cardiac surgical procedures and to develop interventions designed to minimize neuropsychologic impairments. Recent research has taken advantage of new technologies to examine mechanisms of neuropsychologic impairment. For example, magnetic resonance imaging has been used in conjunction with neuropsychologic testing to pinpoint changes in brain structure and function after cardiac operations [43].
Most studies of patients after cardiac surgical interventions have used a very limited neuropsychologic test battery with a restricted range of test measures. The use of a broader set of instruments sensitive to a wider range of cognitive functions is a high priority. Moreover, few studies have examined the relationship between neuropsychologic test performance and everyday behaviors in cardiac surgical patients. To provide meaningful advice about the problems such patients experience, clinicians need more information about the likely impact of specific deficits and combinations of deficits on activities that have practical importance. For example, the kinds and degrees of deficits that make it unsafe for a patient to drive a car, manage finances, or return to work would have considerable practical impact. One study currently underway at Duke is examining the relationship between neuropsychologic outcome and self-report of everyday behaviors as assessed by the mental abilities questionnaire.
One of the problems encountered in addressing such issues is obtaining criterion information about patients' everyday functioning that is reliable, comparable to that of other patients being studied, and meaningful in terms of the requirements of living situations of different individuals. The most convenient and practical way of obtaining information about how patients are functioning during daily life is to question them. However, information obtained in this manner may not be accurate. Newman and colleagues [44] examined the relationship between patient self-report of cognitive abilities and actual cognitive ability as assessed by a neuropsychologic battery. They found that there was little agreement between the two and that self-report of impaired cognition was closely associated with depression.
Similarly, in another study, Heaton and associates [39] examined the relationship between neuropsychologic test performance, emotional functioning, and perceived abilities in a sample of 598 patients referred for clinical evaluations. These authors used self-ratings on the patient assessment of own functioning inventory, a 32-item questionnaire to obtain ratings of difficulties in various areas: cognition, memory, language and communication, and sensory-motor functioning. Self-ratings in each of these areas were more closely related to patients' Minnesota multiplasic personality inventory test results than to their neuropsychologic performance.
Another way to obtain criterion information is to use physician or family/spouse ratings. However, family ratings may be affected by their feelings about the patient and by their perception of the purpose of the assessment.
One way to obtain reliable criterion information free from bias may be to ask patients to perform in standardized laboratory situations that closely resemble relevant situations in everyday living. Examples might be driving simulators or other standardized tasks that are very like the kinds of activities that the patient might encounter during daily life. However, daily requirements for one person can be very different from those for others. For example, financial management can be quite different for people of different income levels.
It is unlikely that a single formula can be applied successfully to an entire group of patients. Clearly, more research is needed to demonstrate that performance on specific neuropsychologic instruments affects behaviors in certain areas of patients' everyday lives.
Acknowledgments
We thank Ms Catherine C. Craver, MEd, for assistance in the preparation of the manuscript.
We also thank R. Lloyd Smith, PhD, for statistical advice; Carolina P. Clancy for assistance in neuropsychologic testing; Judy B. Lewis, BSN, and Connie C. Sessions, RN, for assistance in patient recruitment; and Joseph G. Reves, MD.
This research was supported by grants, HL49572, AG09663, and MH49679 from the National Institutes of Health.
Footnotes
Presented at the Conference on CNS Dysfunction After Cardiac Surgery: Defining the Problem, Fort Lauderdale, FL, Dec 10–11, 1994. 
Address reprint requests to Dr Blumenthal, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box 3119, Durham, NC 27710.
* These instruments have been used in previous studies at Duke University Medical Center.
References
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|
|
|
|
 |
|
 F. D. Rubens, M. Boodhwani, and H. Nathan Interpreting studies of cognitive function following cardiac surgery: a guide for surgical teams Perfusion, May 1, 2007; 22(3): 185 - 192. [Abstract] [PDF]
|
|
|
|
 |
|
 B. K. Lal Cognitive Function After Carotid Artery Revascularization Vascular and Endovascular Surgery, February 1, 2007; 41(1): 5 - 13. [Abstract] [PDF]
|
|
|
|
|
|
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|
|
|
|
 |
|
 C. W. Hogue Jr, C. A. Palin, and J. E. Arrowsmith Cardiopulmonary bypass management and neurologic outcomes: an evidence-based appraisal of current practices. Anesth. Analg., July 1, 2006; 103(1): 21 - 37. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
 |
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
 D C Bellinger Cardiac surgery and the brain: differences between adult and paediatric studies Heart, April 1, 2003; 89(4): 365 - 366. [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
 D. Taggart About impaired minds and closed hearts BMJ, November 30, 2002; 325(7375): 1255 - 1256. [Full Text] [PDF]
|
|
|
|
 |
|
 D. Russell and R. Brucher Online Automatic Discrimination Between Solid and Gaseous Cerebral Microemboli With the First Multifrequency Transcranial Doppler Stroke, August 1, 2002; 33(8): 1975 - 1980. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
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|
|
|
|
 |
|
 M. F. Newman, J. L. Kirchner, B. Phillips-Bute, V. Gaver, H. Grocott, R. H. Jones, D. B. Mark, J. G. Reves, J. A. Blumenthal, and The Neurological Outcome Research Group and the Ca Longitudinal Assessment of Neurocognitive Function after Coronary-Artery Bypass Surgery N. Engl. J. Med., February 8, 2001; 344(6): 395 - 402. [Abstract] [Full Text] [PDF]
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|
|
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|
|
|
|
 |
|
 K. Millar, A. J. Asbury, and G. D. Murray Pre-existing cognitive impairment as a factor influencing outcome after cardiac surgery Br. J. Anaesth., January 1, 2001; 86(1): 63 - 67. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
O S Mortensen, J K Madsen, T Haghfelt, P Grande, K Saunamäki, S Haunsø, E Hjelms, H Arendrup, and t. D. study group Health related quality of life after conservative or invasive treatment of inducible postinfarction ischaemia Heart, November 1, 2000; 84(5): 535 - 540. [Abstract] [Full Text]
|
|
|
|
|
|
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|
|
|
|
|
|
D. van Dijk, A. M. A. Keizer, J. C. Diephuis, C. Durand, L. J. Vos, and R. Hijman Neurocognitive dysfunction after coronary artery bypass surgery: A systematic review J. Thorac. Cardiovasc. Surg., October 1, 2000; 120(4): 632 - 639. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
 |
|
 J. C. K. Fitch, S. Rollins, L. Matis, B. Alford, S. Aranki, C. D. Collard, M. Dewar, J. Elefteriades, R. Hines, G. Kopf, et al. Pharmacology and Biological Efficacy of a Recombinant, Humanized, Single-Chain Antibody C5 Complement Inhibitor in Patients Undergoing Coronary Artery Bypass Graft Surgery With Cardiopulmonary Bypass Circulation, December 21, 1999; 100(25): 2499 - 2506. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S NEWMAN and J STYGALL Changes in cognition following cardiac surgery Heart, November 1, 1999; 82(5): 541 - 542. [Full Text]
|
|
|
|
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S. Ashraf, K. Bhattacharya, Y. Tian, and K. Watterson Cytokine and S100B levels in paediatric patients undergoing corrective cardiac surgery with or without total circulatory arrest Eur. J. Cardiothorac. Surg., July 1, 1999; 16(1): 32 - 37. [Abstract] [Full Text] [PDF]
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S. Ashraf, K. Bhattacharya, S. Zacharias, P. Kaul, P. H. Kay, and K. G. Watterson Serum S100{beta} release after coronary artery bypass grafting: roller versus centrifugal pump Ann. Thorac. Surg., December 1, 1998; 66(6): 1958 - 1962. [Abstract] [Full Text] [PDF]
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E. P. Mahanna, J. A. Blumenthal, W. D. White, N. D. Croughwell, C. P. Clancy, L. R. Smith, and M. F. Newman Defining Neuropsychological Dysfunction After Coronary Artery Bypass Grafting Ann. Thorac. Surg., May 1, 1996; 61(5): 1342 - 1347. [Abstract] [Full Text]
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