Psychopathology and cognitive dysfunction five years after open-heart surgery

Does Dexmedetomidine Ameliorate Postoperative Cognitive Dysfunction? A Brief Review of the Recent Literature

PURPOSE OF REVIEW

Postoperative cognitive dysfunction (POCD) occurs in 20-50% of postsurgical patients with a higher prevalence in elderly patients and patients with vascular disease and heart failure. In addition, POCD has been associated with many negative outcomes, such as increased hospital length of stay, increased rates of institutionalization, and higher patient mortality. This brief review discusses select evidence suggesting an association between neuroinflammation and POCD and whether the use of dexmedetomidine, a short-acting alpha 2 agonist, may ameliorate the incidence of POCD. We review the recent evidence for neuroinflammation in POCD, dexmedetomidine's properties in reducing inflammatory-mediated brain injury, and clinical studies of dexmedetomidine and POCD.

RECENT FINDINGS

There is evidence to support the anti-inflammatory and immunomodulatory effects of dexmedetomidine in animal models. Several clinical investigations have demonstrated favorable outcomes using dexmedetomidine over placebo for the reduction of postoperative delirium. Few studies have used high-quality endpoints for the assessment of POCD and no demonstrable evidence supports the use of dexmedetomidine for the prevention of POCD. While evidence exists for the neural anti-inflammatory properties of dexmedetomidine, human trials have yielded incomplete results concerning its use for the management of POCD. Dexmedetomidine may reduce acute postoperative delirium, but further studies are needed prior to recommending the use of dexmedetomidine for the direct reduction of POCD.

[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.

Statistical and conceptual issues in defining post-operative cognitive dysfunction

The occurrence of post-operative cognitive dysfunction is a distressing complication following surgery. In an effort to gain a more complete understanding of patients' cognitive recovery following surgical procedures common neuropsychological assessment tools have been adopted in a repeated measures design. It is widely regarded that this represents the most comprehensive method of determining cognitive status in this population but it has resulted in a number of statistical and conceptual difficulties in attempting to infer significant change. The current paper outlines these core difficulties and provides some potential methods to overcome these.

Neuropsychologic dysfunction after cardiac surgery: what is the problem?

Twenty years ago Aberg published his seminal studies on the neuropsychologic consequences of cardiopulmonary bypass (CPB). Twenty years later, what is the state of current research on the problem of post-CPB neurologic injury, and what different management techniques have been employed to influence this outcome? This article reviews the definition and assessment of postoperative neuropsychologic dysfunction; epidemiologic data and associated risk factors assessing post-CPB neuropsychologic dysfunction are critically appraised.

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.

The Conceptual Level Analogy Test: internal consistency and relationship to demographic variables

The Conceptual Level Analogy Test is a recently developed test of abstract reasoning predictive of morbidity and mortality following cardiac surgery. The present study examined the relationship of test scores with demographic variables and the internal consistency of the test for a non-clinical sample. Analysis indicated that the test is a unidimensional scale. Significant effects were found for age, occupation, and education on total score. Corrections for these demographic factors in future work with surgical populations may improve the prediction of post-surgical status.

Diffuse cerebral symptoms in convalescents from cerebral infarction and myocardial infarction

In order to evaluate occurrence and cause of a number of diffuse cerebral symptoms (DCS), such as impaired memory, inability to concentrate, emotional instability, irritability, etc., 44 survivors of cerebral infarction (CI) and 40 survivors of myocardial infarction (MI) were seen 6-26 months after onset for psychometric testing and an interview about DCS. Although surprisingly common in both groups, DCS were significantly more frequent in CI patients than in MI patients. 1/2 of the former and 1/3 of the latter complained of 5 or more symptoms. In contrast, a significant difference in test performance was demonstrated in only 1 of 4 tests. There was no significant correlation between the number of DCS and test performance. In both groups, DCS occurrence was independent of age, whereas in the MI group, but not in the CI group, test performance was inversely related to age. In the CI group, DCS occurrence was not significantly related to size or site of the infarction. The results indicate that an organic brain damage cannot be the sole cause of DCS, and it is suggested that some of the symptoms are manifestations of a stress response syndrome provoked by insufficient coping with the consequences of the disease.

[Delirium following heart surgery with extracorporeal circulation: clinical aspects and observations in a specialized center]

Delirium following heart surgery with extra-corporeal circulation recently has been the subject of several studies that show a syndrome with variable diagnostic criteria and incidence which tend to confuse the entity. The diagnostic criteria proposed by the recent DSM-III of the American Psychiatric Association allow a better circumscription of the syndrome but exclude a group of patients manifesting visual hallucinations, sometimes paranoid features and cognitive functions that are less disturbed. Heller's and Kornfeld's less rigid criteria, on the other hand, have the disadvantage of including functional psychotic states that can arise after surgery without a true delirium with organic brain syndrome. We suggest the use of standard criteria that could include only delirium following cardiac surgery with E.C.C. and subdivision of the patients following the kind of surgery. In a retrospective study of the last four years at the Montreal Heart Institute, our clinical observations show an incidence of delirium after heart surgery with E.C.C. of 3%. a finding much lower than that reported in other centres which show an incidence between 13 and 67%. The more important factors found, were the kind of surgery (valve replacement more than coronary bypass), the age of the patients, and the degree of sickness after surgery during the stay in the intensive care unit. Those risk factors were also found in other recent studies. We describe the clinical syndrome and discuss its etiology in reviewing the more common risk factors before, during and after surgery. We underline the importance of the quality of the relationship with the patient before and after surgery in discussing prevention and treatment.

Assessment of recovery: with special reference to a study with post-operative cardiac patients

The recovery process is dependent on many psychological and physical factors. In this paper recovery refers to major, short-term illness often treated by surgery, which is not expected to result in permanent disability or handicap. Research reviewed which attempts to identify influences on recovery also shows how many patients are left with a degree of disability, usually for psychological reasons. It is suggested that the stress and impact of severe illness and surgery may have a long lasting, previously unrecognized effect. Nursing which studies the interaction of physical and psychological aspects of illness and care is seen as the most suitable discipline from which to assess recovery and identify risk factors. A study reported here with patients after coronary artery grafting, provides information on recovery and illustrates how many aspects of a patients' experience may help or hinder this process. Data is obtained from patients' interviews to give a wider, more humanistic evaluation of outcome than is usually employed for this type of surgery.

[Delirium after surgery with extra-corporeal circulation]

The recent literature still reports a high incidence of delirium in patients operated with extracorporeal circulation. This syndrome is found more often in patients over 50 years and in patients with a previous history of delirium, alcoholism, drug addiction or cerebral damage and is more frequent after valvular than after coronary surgery. It is also often observed in patients who present major post-operative complications. Attention and concentration capacity are characteristically modified (diminished most of the time) with or without faulty perception (hallucinations), sleep alterations, incoherent language, apathy or agitation. Disorientation and memory troubles are common. Delirium appears within a few hours or a few days of the surgery, its evolution is fluctuant and generally benign. A retrospective study at the Montreal Heart Institute showed an incidence of 2.98 per cent (84 cases/2811 open heart surgery cases) over the last four years. The mean age of these patients was 57.5 years (versus 50.4 for patients without delirium). Major post-operative complications were found in 37 (44 per cent) of these 84 patients. The incidence was lower (1.45 per cent) in coronary than in valvular (4.6 per cent) surgery cases. Several explanations are presented to explain this low incidence.