Association of neurocognitive function and quality of life 1 year after coronary artery bypass graft (CABG) surgery

Predictors of cognitive recovery after cardiac surgery

BACKGROUND

Postoperative neurocognitive decline occurs frequently. Although predictors of cognitive injury have been well examined, factors that modulate recovery have not. We sought to determine the predictors of cognitive recovery after initial injury following cardiac surgery.

METHODS

Two hundred eighty-one patients previously enrolled in cognitive studies who experienced cognitive decline 6 weeks after cardiac surgery were retrospectively evaluated. Eligible patients completed a battery of neurocognitive measures and quality-of-life assessments at baseline, 6 weeks, and 1 year after surgery. Factor analysis was conducted to calculate the cognitive index (CI), a unified, continuous measure of cognitive function. Cognitive recovery was defined as 1-year CI greater than baseline CI. Potential predictors of cognitive recovery including patient characteristics, quality-of-life factors, comorbidities, medications, and intraoperative variables were assessed with multivariable regression modeling; P<0.05 was considered significant.

RESULTS

Of the 229 patients in our final data set, 103 (45%) demonstrated cognitive recovery after initial decline in CI at 6 weeks. Multivariable analyses revealed that more education (odds ratio [OR] 1.332 [1.131-1.569], P<0.001), baseline CI (OR 0.987 [0.976-0.998], P=0.02), less decline in CI at 6 weeks (OR 1.044 [1.014-1.075], P=0.004), and greater activities of daily living at 6 weeks (OR 0.891 [0.810-0.981], P=0.02) were significant predictors of cognitive recovery.

CONCLUSION

Cognitive recovery occurred in approximately one half of the cardiac surgical patients experiencing early decline. The association between cognitive recovery and Instrumental Activities of Daily Living scores at 6 weeks merits further investigation as it is the only potentially modifiable predictor of recovery.

Depressive symptoms after CABG surgery: a meta-analysis

LEARNING OBJECTIVES

After participating in this educational activity, the reader should be better able to measure the risk of depression before and after coronary artery bypass graft (CABG) surgery; examine the course of depression after CABG; and apply the results of the study to the treatment of patients.

OBJECTIVE

Depression is highly comorbid with coronary artery disease. Clinicians face the question of whether patients' depressive symptoms will improve after coronary artery bypass graft surgery (CABG). The objective of this meta-analysis is to determine the course of depressive symptoms after CABG.

METHODS

EMBASE, PubMed, and PsycINFO were searched for studies assessing depression before and after CABG. Meta-analyses were performed for depression at early (1-2 weeks), recovery (>2 weeks to 2 months), mid (>2 months to 6 months), and late (>6 months) postoperative time points. Heterogeneity and publication bias were analyzed.

RESULTS

Thirty-nine studies were included in the meta-analysis. Twelve reported dichotomous outcomes; 18 reported continuous outcomes; and 9 reported both. Risk of depression was increased early (relative risk [RR] = 1.27; 95% confidence interval [CI], 1.01-1.61). There was a significantly decreased risk of depression at recovery (RR = 0.78; 95% CI, 0.67-0.90), mid (RR = 0.64; 95% CI, 0.58-0.70), and late (RR = 0.68; 95% CI, 0.58-0.79) time points without heterogeneity. All studies reporting continuous depression scales had significant heterogeneity.

CONCLUSIONS

The risk of depression decreased post-CABG when depression was measured dichotomously. While depression improves overall and remits for some patients after CABG, the majority of patients will not experience remission of depression. Preoperative and postoperative depression monitoring is important.

Postoperative cognitive dysfunction in geriatric patients

Postoperative cognitive dysfunction (POCD) is a severe long-term complication after surgical procedures. POCD is mainly seen among geriatric patients. Hospitalization, extent of surgery, and systemic inflammatory response might contribute to POCD. The possible influence of the type of anesthesia is discussed. POCD is often not recognized; thus, incidence rates are likely to be underestimated (19-40%). POCD is associated with major consequences for the individual patient, e.g., delayed long-term recovery, reduced quality of life, and an increased mortality rate. Multiple risk factors have been identified over the last decade. However, the exact etiology is still unknown. This mini-review summarizes the recent developments concerning POCD prevention, diagnosis, and treatment.

Attrition in longitudinal randomized controlled trials: home visits make a difference

Background

Participant attrition in longitudinal studies can introduce systematic bias, favoring participants who return for follow-up, and increase the likelihood that those with complications will be underestimated. Our aim was to examine the effectiveness of home follow-up (Home F/U) to complete the final study evaluation on potentially “lost” participants by: 1) evaluating the impact of including and excluding potentially “lost” participants (e.g., those who required Home F/U to complete the final evaluation) on the rates of study complications; 2) examining the relationship between timing and number of complications on the requirement for subsequent Home F/U; and 3) determining predictors of those who required Home F/U.

Methods

We used data from a randomized controlled trial (RCT) conducted from 1991–1994 among coronary artery bypass graft surgery patients that investigated the effect of High mean arterial pressure (MAP) (intervention) vs. Low MAP (control) during cardiopulmonary bypass on 5 complications: cardiac morbidity/mortality, neurologic morbidity/mortality, all-cause mortality, neurocognitive dysfunction and functional decline. We enhanced completion of the final 6-month evaluation using Home F/U.

Results

Among 248 participants, 61 (25%) required Home F/U and the remaining 187 (75%) received Routine F/U. By employing Home F/U, we detected 11 additional complications at 6 months: 1 major neurologic complication, 6 cases of neurocognitive dysfunction and 4 cases of functional decline. Follow-up of 61 additional Home F/U participants enabled us to reach statistical significance on our main trial outcome. Specifically, the High MAP group had a significantly lower rate of the Combined Trial Outcome compared to the Low MAP group, 16.1% vs. 27.4% (p=0.032). In multivariate analysis, participants who were ≥ 75 years (OR=3.23, 95% CI 1.52-6.88, p=0.002) or on baseline diuretic therapy (OR=2.44, 95% CI 1.14-5.21, p=0.02) were more likely to require Home F/U. In addition, those in the Home F/U group were more likely to have sustained 2 or more complications (p=0.05).

Conclusions

Home visits are an effective approach to reduce attrition and improve accuracy of study outcome reporting. Trial results may be influenced by this method of reducing attrition. Older participants, those with greater medical burden and those who sustain multiple complications are at higher risk for attrition.

The effects of isoflurane and desflurane on cognitive function in humans

BACKGROUND

The etiology of postoperative cognitive decline (POCD) remains to be determined. Anesthetic isoflurane, but not desflurane, may induce neurotoxicity. However, the functional consequences of these effects have not been assessed. We therefore performed a pilot study to determine the effects of isoflurane and desflurane on cognitive function in humans.

METHODS

The subjects included patients who had lower extremity or abdominal surgery under spinal anesthesia alone (S, n = 15), spinal plus desflurane anesthesia (SD, n = 15), or spinal plus isoflurane anesthesia (SI, n = 15) by randomization. Each of the subjects received cognitive tests immediately before and 1 week after anesthesia and surgery administered by an investigator who was blinded to the anesthesia regimen. POCD was defined using the scores from each of these tests.

RESULTS

We studied 45 subjects, 24 males and 21 females. The mean age of the subjects was 69.0 ± 1.9 years. There was no significant difference in age and other characteristics among the treatment arms. The mean number of cognitive function declines in the S, SD, and SI groups was 1.13, 1.07, and 1.40, respectively. POCD incidence after SI (27%), but not SD (0%), anesthesia was higher than that after S (0%), P = 0.028 (3-way comparison).

CONCLUSION

These findings from our pilot study suggest that isoflurane and desflurane may have different effects on postoperative cognitive function, and additional studies with a larger sample size and longer times of follow-up testing are needed.

Multimodal brain monitoring reduces major neurologic complications in cardiac surgery

OBJECTIVE

Although adverse neurologic outcomes are common complications of cardiac surgery, intraoperative brain monitoring has not received adequate attention. The aim of the present study was to evaluate the effectiveness of multimodal brain monitoring in the prevention of major brain injury and reducing the duration of mechanical ventilation, intensive care unit, and postoperative hospital stays after cardiac surgery.

DESIGN

A retrospective, observational, controlled study.

SETTING

A single-center regional hospital.

PARTICIPANTS

One thousand seven hundred twenty-one patients who had undergone cardiac surgery with cardiopulmonary bypass from July 2007 to July 2010. One hundred sixty-six patients with multimodal brain monitoring and a control group without brain monitoring (N = 1,555) were compared retrospectively.

INTERVENTIONS

Multimodal brain monitoring was performed for 166 patients, consisting of intraoperative recordings of somatosensory-evoked potentials, electroencephalography, and transcranial Doppler.

MEASUREMENTS AND MAIN RESULTS

The incidence of major neurologic complications and the duration of mechanical ventilation, intensive care unit, and postoperative hospital stays were considered. Patients with brain monitoring had a significantly lower incidence of perioperative major neurologic complications (0%) than those without monitoring (4.06%, p = 0.01) and required significantly shorter periods of mechanical ventilation (p = 0.001) and intensive care unit stays (p = 0.01) than controls. The length of postoperative hospital stays did not differ significantly between the 2 groups (p = 0.57).

CONCLUSIONS

This preliminary study suggests that multimodal brain monitoring can reduce the incidence of neurologic complications as well as hospital costs associated with post-cardiac surgery patient care. Furthermore, intraoperative brain monitoring provides useful information about brain functioning, blood flow velocity, and metabolism, which may guide the anesthesiologist during surgery.

Elevated postoperative inflammatory biomarkers are associated with short- and medium-term cognitive dysfunction after coronary artery surgery

PURPOSE

We tested the hypothesis that elevated postoperative interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations are associated with short- and medium-term impairment of cognitive functions in patients after coronary artery surgery using cardiopulmonary bypass.

METHODS

Eighty-six age- and education-balanced patients ≥55 years of age undergoing elective coronary artery bypass surgery with cardiopulmonary bypass and 28 nonsurgical controls with coronary artery disease were enrolled. Recent verbal and nonverbal memory and executive functions were assessed before surgery and at 1 week and 3 months after surgery using a cognitive test battery. IL-6 concentrations were measured before surgery and 4 h after cardiopulmonary bypass, and CRP concentrations were measured before surgery and at 24 and 72 h after anesthetic induction. Overall cognitive function between high and low biomarker concentration groups was analyzed by the Wilcoxon rank-sum test.

RESULTS

Recent memory was at least 1 standard deviation (SD) impaired at 1 week and 3 months in the high-CRP compared with low-CRP and in the high-IL-6 compared with low-IL-6 concentration groups. Overall cognitive function was significantly (P = 0.04 and P = 0.01, respectively) different between the high- and low-CRP concentration groups (CRP assayed 24 h after anesthetic induction) at both 1 week and 3 months. Overall cognitive function was also significantly (P = 0.04) different between the high and low-IL-6 concentration groups at 1 week after surgery.

CONCLUSION

The results suggest that elevated postoperative IL-6 and CRP concentrations are associated with the subsequent development of short- and medium-term impairment of cognitive functions after coronary artery surgery.

RNA interference-mediated silencing of BACE and APP attenuates the isoflurane-induced caspase activation

Background

β-Amyloid protein (Aβ) has been shown to potentiate the caspase-3 activation induced by the commonly used inhalation anesthetic isoflurane. However, it is unknown whether reduction in Aβ levels can attenuate the isoflurane-induced caspase-3 activation. We therefore set out to determine the effects of RNA interference-mediated silencing of amyloid precursor protein (APP) and β-site APP-cleaving enzyme (BACE) on the levels of Aβ and the isoflurane-induced caspase-3 activation.

Methods

H4 human neuroglioma cells stably transfected to express full-length human APP (H4-APP cells) were treated with small interference RNAs (siRNAs) targeted at silencing BACE and APP for 48 hours. The cells were then treated with 2% isoflurane for six hours. The levels of BACE, APP, and caspase-3 were determined using Western blot analysis. Sandwich Enzyme-linked immunosorbent assay (ELISA) was used to determine the extracellular Aβ levels in the conditioned cell culture media.

Results

Here we show for the first time that treatment with BACE and APP siRNAs can decrease levels of BACE, full-length APP, and APP c-terminal fragments. Moreover, the treatment attenuates the Aβ levels and the isoflurane-induced caspase-3 activation. These results further suggest a potential role of Aβ in the isoflurane-induced caspase-3 activation such that the reduction in Aβ levels attenuates the isoflurane-induced caspase-3 activation.

Conclusion

These findings will lead to more studies which aim at illustrating the underlying mechanism by which isoflurane and other anesthetics may affect Alzheimer's disease neuropathogenesis.

Postoperative cognitive deficit after cardiopulmonary bypass with preserved cerebral oxygenation: a prospective observational pilot study

Background

Neurologic deficits after cardiac surgery are common complications. Aim of this prospective observational pilot study was to investigate the incidence of postoperative cognitive deficit (POCD) after cardiac surgery, provided that relevant decrease of cerebral oxygen saturation (cSO2) is avoided during cardiopulmonary bypass.

Methods

cSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80% of baseline and above 55% during anesthesia including cardiopulmonary bypass. POCD was tested by trail making test, digit symbol substitution test, Ray's auditorial verbal learning test, digit span test and verbal fluency test the day before and 5 days after surgery. POCD was defined as a decline in test performance that exceeded - 20% from baseline in two tests or more. Correlation of POCD with lowest cSO2 and cSO2 - threshold were determined explorative.

Results

POCD was observed in 43% of patients. Lowest cSO2 during cardiopulmonary bypass was significantly correlated with POCD (p = 0.015, r2 = 0.44, without Bonferroni correction). A threshold of 65% for cSO2 was able to predict POCD with a sensitivity of 86.7% and a specificity of 65.0% (p = 0.03, without Bonferroni correction).

Conclusions

Despite a relevant decrease of cerebral oxygen saturation was avoided in our pilot study during cardiopulmonary bypass, incidence of POCD was comparable to that reported in patients without monitoring. A higher threshold for cSO2 may be needed to reduce the incidence of POCD.

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.

Delirium as a predictor of long-term cognitive impairment in survivors of critical illness

OBJECTIVE

To test the hypothesis that duration of delirium in the intensive care unit is an independent predictor of long-term cognitive impairment after critical illness requiring mechanical ventilation.

DESIGN

Prospective cohort study.

SETTING

Medical intensive care unit in a large community hospital in the United States.

PATIENTS

Mechanically ventilated medical intensive care unit patients who were assessed daily for delirium while in the intensive care unit and who underwent comprehensive cognitive assessments 3 and 12 mos after discharge.

MEASUREMENTS AND MAIN RESULTS

Of 126 eligible patients, 99 survived>or=3 months after critical illness; long-term cognitive outcomes were obtained for 77 (78%) patients. Median age was 61 yrs, 51% were admitted with sepsis/acute respiratory distress syndrome, and median duration of delirium was 2 days. At 3-mo and 12-mo follow-up, 79% and 71% of survivors had cognitive impairment, respectively (with 62% and 36% being severely impaired). After adjusting for age, education, preexisting cognitive function, severity of illness, severe sepsis, and exposure to sedative medications in the intensive care unit, increasing duration of delirium was an independent predictor of worse cognitive performance-determined by averaging age-adjusted and education-adjusted T-scores from nine tests measuring seven domains of cognition-at 3-mo (p=.02) and 12-mo follow-up (p=.03). Duration of mechanical ventilation, alternatively, was not associated with long-term cognitive impairment (p=.20 and .58).

CONCLUSIONS

In this study of mechanically ventilated medical intensive care unit patients, duration of delirium (which is potentially modifiable) was independently associated with long-term cognitive impairment, a common public health problem among intensive care unit survivors.

Cognitive function after major noncardiac surgery, apolipoprotein E4 genotype, and biomarkers of brain injury

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a significant cause of morbidity after noncardiac surgery. Identified risk factors are largely limited to demographic characteristics. We hypothesized that POCD was associated with apolipoprotein E4 (APOE4) genotype and plasma biomarkers of brain injury and inflammation.

METHODS

Three hundred ninety-four patients older than 55 yr undergoing major elective noncardiac surgery were enrolled in this prospective observational study. Apolipoprotein E genotyping was performed at baseline. Plasma was collected at baseline and end of surgery and at 4.5, 24, and 48-h postoperatively. Six protein biomarkers were assayed (B-type natriuretic peptide, C-reactive protein, D-dimer, matrix metalloproteinase-9, neuron-specific enolase, and S-100B). Neurocognitive testing was conducted at baseline and at 6 weeks and 1 yr after surgery; scores were subjected to factor analysis. The association of APOE4 and biomarkers with POCD was tested using multivariable regression modeling.

RESULTS

Three hundred fifty patients (89%) completed 6-week neurocognitive testing. POCD occurred in 54.3% of participants at 6 weeks and 46.1% at 1 yr. There was no difference in POCD between patients with or without the APOE4 allele (56.6 vs. 52.6%; P = 0.58). The continuous cognitive change score (mean +/- SD) was similar between groups (APOE4: 0.05 +/- 0.27 vs. non-APOE4: 0.07 +/- 0.28; P = 0.53). Two hundred ninety-one subjects (74%) completed testing at 1 yr. POCD occurred in 45.9% of APOE4 subjects versus 46.3% of non-APOE4 subjects (P = 0.95). The cognitive score was again similar (APOE4: 0.08 +/- 0.27 vs. non-APOE4: 0.05 +/- 0.25; P = 0.39). Biomarker levels were not associated with APOE4 genotype or cognition at 6 weeks or 1 yr.

CONCLUSION

Cognitive decline after major noncardiac surgery is not associated with APOE4 genotype or plasma biomarker levels.

Off-pump coronary artery revascularization in octogenarians: is it better?

PURPOSE OF REVIEW

Octogenarians are the fastest growing stratum of the population and have the highest prevalence of coronary artery disease. In the past, physicians have been reluctant to provide these patients with optimal care. Seniors are frequently excluded from large randomized trials and generally not included in published guidelines. The purpose of this review is to revisit the demography and epidemiology of coronary artery disease in this population as well as therapeutic strategies used.

RECENT FINDINGS

Recent publications have shown significant advancement in medical and invasive treatment of coronary artery disease in elderly, with special focus on the potential benefit of off-pump coronary artery bypass (OPCAB) surgery.

SUMMARY

Although OPCAB surgery has gained popularity over the past 15 years, its benefit regarding operative mortality and major complications has not been clearly defined in the general population. There is a body of literature supporting its benefit in the elderly population. OPCAB surgery has the potential of decreasing operative mortality and major postoperative complications such as stroke, delirium, atrial fibrillation, and decline in neurocognitive functions in these patients. Off-pump surgery is technically more demanding and has been blamed for providing less complete revascularization and lower graft patency rate, especially in less experienced hands. However, with the upcoming demographic explosion of senior citizens in western societies, OPCAB surgery has definitely to be a part of the armamentarium of modern cardiac surgeons.

Postoperative Delirium is Associated with Postoperative Cognitive Dysfunction at One Week after Cardiac Surgery with Cardiopulmonary Bypass

Postoperative delirium with cognitive impairment frequently occurs after cardiac surgery. It was hypothesized that delirium is associated with residual postoperative cognitive dysfunction in patients after surgery using cardiopulmonary bypass. Male cardiac surgical patients ( M age = 66 yr., SD = 8; M education = 13 yr., SD = 2) and nonsurgical controls ( M age = 62, SD = 7; M education = 12, SD = 2) 55 years of age or older were balanced on age and education. Delirium was assessed by the Intensive Care Delirium Screening Checklist preoperatively and for up to 5 days postoperatively. Recent verbal and nonverbal memory and executive functions were assessed (as scores on particular tests) before and 1 wk. after surgery. In 56 patients studied ( n = 28 Surgery; n=28 Nonsurgery), nine patients from the Surgery group developed delirium. In the Surgery group, the proportion of patients having postoperative cognitive dysfunction was significantly greater in those who experienced delirium (89%) compared with those who did not (37%). The odds of developing this dysfunction in patients with delirium were 14 times greater than those who did not. Postoperative delirium is associated with scores for residual postoperative cognitive dysfunction 1 wk. after cardiac surgery.

Neuropsychological function 5 years after cardiac surgery and the effect of psychological distress

Research has shown conflicting results with regard to the influence of depression and anxiety on neuropsychological performance following coronary artery bypass graft (CABG) surgery. Notably, the independent effects of depression and anxiety have not been examined among CABG candidates in the longer term where it is has been suggested that these patients show marked cognitive deterioration. A neuropsychological test battery and measures of psychological distress were completed by 86 CABG patients and 50 nonsurgical control participants at baseline and 6 months, whereas 75 patients and 36 controls, respectively, completed a 5-year follow-up. In CABG patients, cognitive and affective depressive symptoms were independently associated with lower and worse performance on the Boston Naming Test, Purdue Peg Board, and Digit Symbol Coding 6 months after surgery, whereas at 5-year follow-up an effect for Digit Symbol persisted, and an association was also observed for the Trail Making Test (TMT). On average, CABG patients performed worse on TMT and Digit Symbol at 6 months, whereas at 5-year follow-up their performance was worse on short-term delayed verbal recall. The results among the CABG patients did not show a consistent pattern of association between psychological distress and those neuropsychological domains that were on average significantly lower than a nonsurgical control group. The results here also support the use of nonbiased statistical methodology to document dysfunction among heterogeneous cognitive domains after CABG surgery.

Randomized, double-blinded, placebo controlled study of neuroprotection with lidocaine in cardiac surgery

BACKGROUND AND PURPOSE

Cognitive decline after cardiac surgery remains common and diminishes patients' quality of life. Based on experimental and clinical evidence, this study assessed the potential of intravenously administered lidocaine to reduce postoperative cognitive dysfunction after cardiac surgery using cardiopulmonary bypass.

METHODS

After IRB approval, 277 patients undergoing cardiac surgery were enrolled into this prospective, randomized, double-blinded placebo controlled clinical trial. Subjects were randomized to receive: (1) Lidocaine as a 1 mg/kg bolus followed by a continuous infusion through 48 hours postoperatively, or (2) Placebo bolus and infusion. Cognitive function was assessed preoperatively and again at 6 weeks and 1 year postoperatively. The effect of lidocaine on postoperative cognition was tested using multivariable regression modeling; P<0.05 was considered significant.

RESULTS

Among the 241 allocated subjects (Lidocaine: n=114; Placebo: n=127), the incidence of cognitive deficit in the lidocaine group was 45.5% versus 45.7% in the placebo group (P=0.97). Multivariable analysis revealed a significant interaction between treatment group and diabetes, such that diabetic subjects receiving lidocaine were more likely to suffer cognitive decline (P=0.004). Secondary analysis identified total lidocaine dose (mg/kg) as a significant predictor of cognitive decline and also revealed a protective effect of lower dose lidocaine in nondiabetic subjects.

CONCLUSIONS

Lidocaine administered during and after cardiac surgery does not reduce the high rate of postoperative cognitive dysfunction. Higher doses of lidocaine and diabetic status were independent predictors of cognitive decline. Protective effects of lower dose lidocaine in nondiabetic subjects need to be further evaluated.

Coronary artery bypass grafting is associated with excellent long-term survival and quality of life: a prospective cohort study

BACKGROUND

We investigated the long-term outcome of coronary artery bypass grafting both in terms of survival and quality of life.

METHODS

Ten-year postsurgery survival was collated on patients undergoing coronary artery bypass grafting from 1994 to 1996, and quality of life was assessed using EQ-5D and a quality-of-life thermometer. We analyzed data from 1,180 patients. Mean age was 61 years, and 79% had triple-vessel disease.

RESULTS

Thirty-day mortality was 3.3% (1.8% elective). Mean time to censorship for survivors was 9.9 years (range, 8.1 to 12.3 years). Ten-year survival was 66% across all patients, 70% for elective patients. Ten-year cardiac survival was 82%. Percutaneous intervention was required in 25 patients in the subsequent 10 years (2%), and only 4 required redo coronary artery bypass grafting (0.3%); 59% of patients reported no angina, and 88% of patients had grade II angina or better. Of 621 patients who were assessed for quality of life at 10 years, 530 (85%) had a quality of life within a 95% confidence interval of the score found in the general population with similar age. Poor quality of life was reported in 91 patients (14.7%). Significant predictors of poor long-term quality of life were current smoking, Canadian Cardiovascular Society grade III or IV, redo operation, female sex, diabetes, peripheral vascular disease, more than 2 days in intensive care, and chronic obstructive pulmonary disease. Twenty-five percent of patients with poor EQ-5D outcome had grade IV angina. Interestingly, age did not correlate with poor outcome, and administration of blood, arterial revascularization, left mainstem disease, or cross-clamp fibrillation had no impact on survival or outcome.

CONCLUSIONS

Coronary artery bypass grafting is associated with excellent 10-year survival and quality of life.

Neuroprotection during cardiac surgery

Cardiac surgery continues to be associated with significant adverse cerebral outcomes, ranging from stroke to cognitive decline. The underlying mechanism of the associated cerebral injury is incompletely understood but is believed to be primarily caused by cerebral embolism and hypoperfusion, exacerbated by ischemia/reperfusion injury. Extensive research has been undertaken in an attempt to minimize the incidence of perioperative cerebral injury, and both pharmacological and nonpharmacological strategies have been investigated. Although many agents demonstrated promise in preclinical studies, there is currently insufficient evidence from clinical trials to recommend the routine administration of any pharmacological agents for neuroprotection during cardiac surgery. The nonpharmacological strategies that can be recommended on the basis of evidence include transesophageal echocardiography and epiaortic ultrasound-guided assessment of the atheromatous ascending aorta with appropriate modification of cannulation, clamping or anastomotic technique and optimal temperature management. Large-scale randomized controlled trials are still required to address further the issues of optimal pH management, glycemic control, blood pressure management and hematocrit during cardiopulmonary bypass. Past, present and future directions in the field of neuroprotection in cardiac surgery will be discussed.

Neuropsychologic and quality-of-life outcomes after coronary artery bypass surgery with and without cardiopulmonary bypass: a prospective randomized trial

OBJECTIVES

The objective of this study was to compare neuropsychologic and quality-of-life outcomes of patients undergoing off-pump coronary artery bypass surgery to those undergoing coronary artery bypass graft surgery using conventional cardiopulmonary bypass.

DESIGN

A prospective randomized trial of coronary artery bypass graft surgery with and without the use of cardiopulmonary bypass.

SETTING

A cardiothoracic surgery unit at a tertiary hospital.

PARTICIPANTS

Sixty-six patients undergoing coronary artery bypass graft surgery and a control group of 50 participants not undergoing cardiac surgery.

INTERVENTIONS

Patients were randomized to receive coronary artery bypass graft surgery with cardiopulmonary bypass or randomized to coronary artery bypass graft surgery without the use of cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

The proportions of neuropsychologic deficits and improvement in quality-of-life were comparable regardless of whether patients were randomized to receive off-pump coronary artery bypass graft surgery or conventional coronary artery graft surgery with cardiopulmonary bypass.

CONCLUSIONS

Patients receiving coronary artery bypass grafts without cardiopulmonary bypass did not show fewer cognitive deficits or greater improvement in quality of life.

Molecular physiology of preconditioning-induced brain tolerance to ischemia

Ischemic tolerance describes the adaptive biological response of cells and organs that is initiated by preconditioning (i.e., exposure to stressor of mild severity) and the associated period during which their resistance to ischemia is markedly increased. This topic is attracting much attention because preconditioning-induced ischemic tolerance is an effective experimental probe to understand how the brain protects itself. This review is focused on the molecular and related functional changes that are associated with, and may contribute to, brain ischemic tolerance. When the tolerant brain is subjected to ischemia, the resulting insult severity (i.e., residual blood flow, disruption of cellular transmembrane gradients) appears to be the same as in the naive brain, but the ensuing lesion is substantially reduced. This suggests that the adaptive changes in the tolerant brain may be primarily directed against postischemic and delayed processes that contribute to ischemic damage, but adaptive changes that are beneficial during the subsequent test insult cannot be ruled out. It has become clear that multiple effectors contribute to ischemic tolerance, including: 1) activation of fundamental cellular defense mechanisms such as antioxidant systems, heat shock proteins, and cell death/survival determinants; 2) responses at tissue level, especially reduced inflammatory responsiveness; and 3) a shift of the neuronal excitatory/inhibitory balance toward inhibition. Accordingly, an improved knowledge of preconditioning/ischemic tolerance should help us to identify neuroprotective strategies that are similar in nature to combination therapy, hence potentially capable of suppressing the multiple, parallel pathophysiological events that cause ischemic brain damage.

Central nervous system injury associated with cardiac surgery

Millions of individuals with coronary artery or valvular heart disease have been given a new chance at life by heart surgery, but the potential for neurological injury is an Achilles heel. Technological advancements and innovations in surgical and anaesthetic technique have allowed us to offer surgical treatment to patients at the extremes of age and infirmity-the group at greatest risk for neurological injury. Neurocognitive dysfunction is a complication of cardiac surgery that can restrict the improved quality of life that patients usually experience after heart surgery. With a broader understanding of the frequency and effects of neurological injury from cardiac surgery and its implications for patients in both the short term and the long term, we should be able to give personalised treatments and thus preserve both their quantity and quality of life. We describe these issues and the controversies that merit continued investigation.

Health related quality of life trajectories and predictors following coronary artery bypass surgery

BACKGROUND

Many studies have demonstrated that health related quality of life (HRQoL) improves, on average, after coronary artery bypass graft surgery (CABGS). However, this average improvement may not be realized for all patients, and it is possible that there are two or more distinctive groups with different, possibly non-linear, trajectories of change over time. Furthermore, little is known about the predictors that are associated with these possible HRQoL trajectories after CABGS.

METHODS

182 patients listed for elective CABGS at The Royal Melbourne Hospital completed a postal battery of questionnaires which included the Short-Form-36 (SF-36), Profile of Mood States (POMS) and the Everyday Functioning Questionnaire (EFQ). These data were collected on average a month before surgery, and at two months and six months after surgery. Socio-demographic and medical characteristics prior to surgery, as well as surgical and post-surgical complications and symptoms were also assessed. Growth curve and growth mixture modelling were used to identify trajectories of HRQoL.

RESULTS

For both the physical component summary scale (PCS) and the mental component summary scale (MCS) of the SF-36, two groups of patients with distinct trajectories of HRQoL following surgery could be identified (improvers and non-improvers). A series of logistic regression analyses identified different predictors of group membership for PCS and MCS trajectories. For the PCS the most significant predictors of non-improver membership were lower scores on POMS vigor-activity and higher New York Heart Association dyspnoea class; for the MCS the most significant predictors of non-improver membership were higher scores on POMS depression-dejection and manual occupation.

CONCLUSION

It is incorrect to assume that HRQoL will improve in a linear fashion for all patients following CABGS. Nor was there support for a single response trajectory. It is important to identify characteristics of each patient, and those post-operative symptoms that could be possible targets for intervention to improve HRQoL outcomes.

Outcomes of coronary artery bypass graft surgery

This review article summarizes the major studies that have investigated the outcomes of coronary artery bypass graft surgery (CABG). The article includes a review of the literature in the areas of: history of CABG; indications for CABG; and measurement of quality of life following CABG, including prolongation of life, physical functioning (ie, relief from angina and dyspnea, physical activity, as well as complications of surgery and re-hospitalization), psychological functioning, and social functioning. Overall, the literature demonstrates that the outcomes of CABG have historically been measured in terms of mortality and morbidity; however, it has now been well recognized that adjustment to CABG is a multidimensional phenomenon that is not fully explained by medical factors. Therefore, in addition to studying mortality and morbidity outcomes following CABG many recent studies have identified that it is important to investigate various physical, psychological, and social variables that have a significant impact on post-operative adjustment to CABG.