Differential effects of advanced age on neurologic and cardiac risks of coronary artery operations

Acute stroke in patients undergoing coronary artery bypass grafting surgery in acute coronary syndrome: Predictors and outcomes

OBJECTIVES

Coronary artery bypass grafting (CABG) surgery in patients with acute coronary syndrome (ACS) remains a high-risk procedure and is associated with adverse outcomes. The risk factors of acute stroke in the above-mentioned patients stay unclear and some appropriate data is lacking in the literature. Thus, we aimed to investigate the predictors of acute stroke in patients undergoing CABG surgery in ACS.

METHODS

The retrospective single-centre cohort analysis was conducted. All patients (n = 1344) who suffered from acute coronary syndrome and underwent CABG procedure at the University hospital Cologne from June 2011 until October 2019 were included in our study. In order to find the risk factors of acute stroke after bypass surgery, patients were divided into two groups (non-stroke group (n = 1297) and stroke group (n = 47)). In order to even above-mentioned groups propensity score matching (PSM) analysis was performed (non-stroke group (n = 46) and stroke group (n = 46).

RESULTS

Duration of cardiopulmonary bypass (p = .015) and cross clamp time (p = .006) were significantly longer in patients who suffered stroke. Perioperative myocardial infarction was significantly higher (p = .030) in the stroke group. Likewise, the duration of intensive care unit stay (p < .001) and in-hospital stay (p < .001) were significantly longer in patients with stroke. However, the mortality rate did not differ significantly (p = .131) between above-mentioned groups. Univariate and multivariate analysis showed cardiogenic shock (p = .003), peripheral vascular disease (PVD, p = .025) and previous stroke (p = .045) as relevant independent predictors for acute stroke after CABG procedure in patients with ACS.

CONCLUSION

Based on our findings, acute stroke after bypass surgery in patients with ACS is associated with increased mortality and adverse outcomes. Cardiogenic shock, peripheral vascular disease and previous stroke were independent predictors of stroke after CABG procedure. Therefore, preoperative evaluation of potential risk factors may be crucial to improve postoperative results.

Role of Intraoperative Electroencephalography in Predicting Postoperative Delirium in Patients Undergoing Cardiovascular Surgeries

OBJECTIVE

To determine the utility of electroencephalography (EEG) in predicting postoperative delirium (POD) in patients who underwent cardiovascular surgeries with EEG monitoring.

METHODS

A total of 1161 patients who underwent cardiovascular surgeries with EEG monitoring were included in the study, and their data were retrospectively reviewed. POD assessment was done utilizing Intensive Care Delirium Screening Checklist (ICDSC). Patients with a score of > 4 on ICDSC were diagnosed with POD.

RESULTS

Of 1161 patients, 131 patients had EEG changes and 56 (42.74%) of 131 patients experienced POD. Of 1030 patients without EEG changes, 219 (21.26%) experienced POD. EEG showed specificity of 91.5% and negative predictive value of 78.7% in detecting POD. On multivariable analysis, EEG changes showed a strong association with POD (ORadj 1.97 CI (1.30-2.99), p = 0.001) with persistent EEG changes showing even a higher risk of developing POD (ORadj 2.65 (1.43-4.92), p = 0.002).

CONCLUSION

EEG change has specificity of 91.5% emphasizing the need for its implementation as a diagnostic tool for predicting POD. Patients with POD are two times more likely to experience significant EEG changes, especially persistent EEG changes when undergoing cardiovascular surgeries.

SIGNIFICANCE

Intraoperative EEG can detect POD, and EEG changes based therapeutic interventions can mitigate POD.

Aortic repair following initial decompressive craniectomy for acute type A aortic dissection complicated with extensive hemorrhagic cerebral infarction: a case report

A 69-year-old woman presented with acute type A aortic dissection complicated by extensive hemorrhagic cerebral infarction due to brain malperfusion. Emergency decompressive craniectomy was initially performed, with an initial diagnosis of hemorrhagic cerebral infarction. The patient was referred for surgical management following a diagnosis of acute type A aortic dissection. After stabilizing the neurological condition with medical treatment for nine weeks, hemiarch replacement was performed electively. The postoperative course was uneventful, with no new neurological disorders. Subsequently, she recovered sufficiently to have daily conversations and attend hospital appointments using a wheelchair.

Prediction of stroke reconvalescence after coronary bypass surgery indicated by CT scan parameters

BACKGROUND

Stroke in the postoperative time course after heart surgery remains a serious risk. Cranial computer tomography (CCT) is the first line option to detect severe intracranial damage. However, only few data are available to predict neurological outcome. Using visual rating scales (VRSs), this study addresses reliability and effectivity to indicate neurological status and likelyhood of improvement.

METHODS

In a single-center retrospective evaluation, 3719 patients underwent coronary bypass surgery. Because of a delayed recovery phase and neurologic deficits after cardiac surgery 109 patients had a cranial CT scan in the early postoperative period. The incidence of clinically relevant findings within the imaging was rated by an experienced neuroradiologist using two VRS, that is, the age-related white matter changes (ARWMCs) and the Mendes-Ribeiro visual rating scale (MRVRS). Both are computer-assisted measurement schemes to detect stroke-related intracranial damage. Follow-up was investigated with regard to clinical outcome and patient-related risk profiles.

RESULTS

Of 109 patients with postoperative cranial CT scans due to prolonged recovery phases or proven neurological damage 44.5% had one cerebral defect in CCT imaging scans only. The others showed multiple defects. During hospital stay, 92.3% experienced neurological improvement exposing reduced ARWMC, while 7.1% had no improvement and correlating high scores. Of both scales, the ARWMC-VRS demonstrated superior accuracy and discrimination. The preoperative ejection fraction (EF), arteriosclerotic degeneration of carotid arteries, and reduced glomerular filtration rate were found to have a high correlation (r = 0.0005) with the latter group. In-hospital mortality of this cohort was 8.18%.

CONCLUSION

Both the ARWMC and MRVRS were found to be appropriate. They reliably discriminate the groups of stroke patients after coronary artery bypass grafting (CABG)  in the analysis of CCT images. When applied at the onset of neurological symptoms both scales are able to predict neurological reconvalescence upon hospital dismission. The ARWMC scale appeared superior as it demonstrated better accuracy and discrimination. The use of both VRS in patients with suspected stroke after CABG surgery can give insightful information toward a progression of neurological dysfunction or postoperative improvement.

Impact of sex on outcomes after cardiac surgery: A systematic review and meta-analysis

BACKGROUND

Despite advances in cardiac surgery, observational studies suggest that females have poorer post-operative outcomes than males. This study is the first to review sex related outcomes following both coronary artery bypass graft (CABG) and valve surgery with or without combined CABG.

METHODS

We identified 30 primary research articles reporting either short-term mortality (in-hospital/30 day), long-term mortality, and post-operative stroke, sternal wound infection and myocardial infarction (MI) in both sexes following CABG and valve surgery with or without combined CABG. Reported adjusted odds/hazard ratio were pooled using an inverse variance model.

RESULTS

Females undergoing CABG and combined valve and CABG surgery were at higher risk of short-term mortality (odds ratio (OR) 1.40; 95% confidence interval (CI) 1.32-1.49; I² = 79%) and post-operative stroke (OR 1.2; CI 1.07-1.34; I² = 90%) when compared to males. However, for isolated AVR, there was no difference found (OR 1.19; 95% CI 0.74-1.89). There was no increased risk in long-term mortality (OR 1.04; 95% CI: 0.93-1.16; I² = 82%), post-operative MI (OR 1.22; 95%CI: 0.89-1.67; I² = 60%) or deep sternal wound infection (OR 0.92; 95%CI: 0.65-1.03, I² = 87%). No evidence of publication bias or small study effect was found.

CONCLUSION

Females are at a greater risk of short-term mortality and post-operative stroke than males following CABG and valve surgery combined with CABG. However, there is no difference for Isolated AVR. Long-term mortality is equivalent in both sexes. PROSPERO Registration: CRD42021244603.

Trends in Utilization and Safety of In-Hospital Coronary Artery Bypass Grafting During a Non-ST-Segment Elevation Myocardial Infarction

Up to 10% of non-ST-segment elevation myocardial infarction (NSTEMI) patients require coronary artery bypass graft (CABG) surgery during their hospitalization. Contemporary, real-world, data regarding CABG utilization and safety in NSTEMI patients are lacking. Our objectives were to investigate the contemporary trends in utilization and outcomes of CABG in patients admitted for NSTEMI. Using the 2003 to 2015 National Inpatient Sample data, we identified hospitalizations for NSTEMI, during which a CABG was performed. Patients' sociodemographic and clinical characteristics, incidence of surgical complications, length of stay, and mortality were analyzed. Multivariate analyses were performed to identify predictors of in-hospital complications and mortality. An estimated total of 440,371 CABG surgeries, during a hospitalization for NSTEMI, were analyzed. The utilization of CABG was steady over the years. The data show increasing prevalence of individual co-morbidities as well as cases with Deyo Co-morbidity Index ≥2 (p <0.001). High, 26.4%, complication rate was driven mainly by cardiac and pulmonary complications. The mortality rate declined from 3.6% in 2003 to an average of 2.4% during 2010 to 2015. Older age, female gender, heart failure, and delayed CABG timing were independent predictors of adverse outcomes. In conclusion, utilization of in-hospital CABG as the primary revascularization strategy in patients with NSTEMI remained steady over the years. These data reveal the raising prevalence of co-morbidities during the study. High complication rate was recorded; however, the mortality declined over the years to about 2.4%. Delaying CABG was associated with small but statistically significant worsening in outcomes.

Exogenous hydrogen sulfide alleviates surgery-induced neuroinflammatory cognitive impairment in adult mice by inhibiting NO signaling

Background

To investigate the effect and mechanisms of exogenous hydrogen sulfide in surgery-induced neuroinflammatory cognitive dysfunction.

Methods

C57BL/6 J male mice (n = 140) were used and randomly divided into seven groups: the sham group, surgery group, GYY4137 group, L-NAME group, surgery+GYY4137 group, surgery +L-NAME group, and surgery+GYY4137 + L-NAME group. After the interventions, open field tests (OFT) and the Morris water maze (MWM) test were conducted to evaluate learning and memory abilities in the mice. ELISAs, nitrate reductase assays, and Western blots (WB) were conducted to evaluate interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase (SOD) levels. Furthermore, the expression level of microglial marker ionized calcium binding adaptor molecule 1 (IBA) in the hippocampal CA1 and CA3 areas was detected by an immunohistochemical (IHC) assay and apoptotic cells were observed using terminal deoxynucleotidyl transferase dUTP end-labeling (TUNEL) staining kits.

Results

We found that surgery induced neuroinflammatory cognitive dysfunction, oxidative stress, microglial activation, and cell apoptosis in the hippocampus. Moreover, following surgery, NO and iNOS levels were elevated in the hippocampus. Notably, all the effects caused by surgery were reversed by the H₂S donor GYY4137 or the iNOS inhibitor N(gamma)-nitro-L-arginine methyl ester (L-NAME). However, the combined application of GYY4137 and L-NAME was not superior to treatment with either agent alone and the effect of GYY4137 was similar to that of L-NAME.

Conclusion

The long-acting hydrogen sulfide donor GYY4137 had an ability to reversed the cognitive deficits and inflammation caused by carotid artery exposure surgery. This implies that NO signaling pathways might participate in this process. These results indicate that exogenous H₂S may be a promising therapy for POCD.

Entropy Measures as Descriptors to Identify Apneas in Rheoencephalographic Signals

Rheoencephalography (REG) is a simple and inexpensive technique that intends to monitor cerebral blood flow (CBF), but its ability to reflect CBF changes has not been extensively proved. Based on the hypothesis that alterations in CBF during apnea should be reflected in REG signals under the form of increased complexity, several entropy metrics were assessed for REG analysis during apnea and resting periods in 16 healthy subjects: approximate entropy (ApEn), sample entropy (SampEn), fuzzy entropy (FuzzyEn), corrected conditional entropy (CCE) and Shannon entropy (SE). To compute these entropy metrics, a set of parameters must be defined a priori, such as, for example, the embedding dimension m, and the tolerance threshold r. A thorough analysis of the effects of parameter selection in the entropy metrics was performed, looking for the values optimizing differences between apnea and baseline signals. All entropy metrics, except SE, provided higher values for apnea periods (p-values < 0.025). FuzzyEn outperformed all other metrics, providing the lowest p-value (p = 0.0001), allowing to conclude that REG signals during apnea have higher complexity than in resting periods. Those findings suggest that REG signals reflect CBF changes provoked by apneas, even though further studies are needed to confirm this hypothesis.

Varenicline reduces DNA damage, tau mislocalization and post surgical cognitive impairment in aged mice

Postoperative cognitive dysfunction (POCD) occurs more frequently in elderly patients undergoing major surgery. Age associated cholinergic imbalance may exacerbate postoperative systemic and neuroinflammation, but the effect nicotinic acetylcholine receptor (nAchR) stimulation on the development of POCD remains unclear. Aged male C57BL/6N mice (18 months old) underwent a midline laparotomy or were exposed to sevoflurane anesthesia alone (4-5%), with or without concomitant varenicline, a partial nAchR, at 1 mg/kg/day. Laparotomy increased pro-inflammatory cytokines in the liver and hippocampus (IL-1β and MCP-1) and induced a decline in cognitive performance, indicated by lower discrimination index in the Novel Object Recognition test, greater error number and longer escape latency in the Y-maze test. Glia activation, aberrant tau phosphorylation (AT8) and accumulation of phosphorylated H2AX in the hippocampus were detectable up to postoperative day 14, with neuronal apoptosis seen in the hippocampus. Perioperative varenicline attenuated the cognitive decline and associated tau protein mislocalization, DNA damage and neuronal apoptosis. The modulation of JAK2/STAT3 signaling may play a critical role in this process. Neuroinflammation, tau phosphorylation and DNA damage contribute to the development of cognitive dysfunction following laparotomy. Cholinergic stimulation by varenicline attenuated these changes through preventing the mislocalization of phosphorylated tau and DNA damage.

Long-Term Outcomes for Patients With Stroke After Coronary and Valve Surgery

BACKGROUND

Postoperative stroke is one of the most devastating complications of cardiac surgery. When life-threatening situations such as large infarction and hemorrhage occur, neurosurgical procedures may be performed. In this study, we analyzed the long-term medical and surgical outcomes of stroke after cardiac surgery.

METHODS

We conducted a retrospective, nationwide, population-based study. All enrolled patients underwent first-time cardiac surgery and were further divided into the subgroups of nonstroke, stroke with medical treatment, and stroke with neurosurgical treatment. All-cause mortality, recurrent stroke, and readmission were analyzed.

RESULTS

We included 67,051 patients in this study. Patients with postoperative stroke (2.6%, n = 1,731) exhibited an in-hospital mortality rate of 12.3% (n = 213) and a 5-year mortality rate of 49.1% (n = 850). Unprecedentedly, the 83 patients who underwent neurosurgical procedures exhibited an in-hospital mortality of 16.9%; this rate increased to 65.1% at the 5-year follow-up. This neurosurgical subgroup exhibited the highest rate of long-term mortality (p < 0.001). In the neurosurgical subgroup, age was the risk factor for all-cause mortality (hazard ratio, 2.60; 95% confidence interval, 1.60-4.24; p < 0.001).

CONCLUSIONS

Postoperative stroke often leads to high mortality and poor long-term outcomes. Patients who experienced a severe stroke and underwent neurosurgical procedures also exhibited poor outcomes. Patients and their families should be informed of relatively high mortality and poor long-term outcomes before neurosurgical operation.

Strategies to Protect the Brain During Cardiac Surgery

Despite significant advances in cardiopulmonary by pass (CPB) technology, surgical techniques, and anes thetic management, central nervous system (CNS) com plications remain a common and costly problem after CPB. Stroke is often considered a rare and unprevent able complication of cardiac surgery. Recent studies have shown that through the use of echocardiography and historical risk stratification strategies, we can de fine which patients are at substantially greater risk for CNS injury. Through enhanced understanding of the etiology of stroke and perioperative factors, which are associated with potential for neuroprotection or injury extension, there now exists a greater potential than ever to substantially reduce neurological injury associ ated with cardiac surgery. Strategies and theories of stratifying patients at risk and secondarily reducing that risk are described, as well as consideration for early postoperative assessment to allow treatment when events occur.

Orthopedic Surgery and Post-Operative Cognitive Decline in Idiopathic Parkinson's Disease: Considerations from a Pilot Study

BACKGROUND

Post-operative cognitive dysfunction (POCD) demarks cognitive decline after major surgery but has been studied to date in "healthy" adults. Although individuals with neurodegenerative disorders such as Parkinson's disease (PD) commonly undergo elective surgery, these individuals have yet to be prospectively followed despite hypotheses of increased POCD risk.

OBJECTIVE

To conduct a pilot study examining cognitive change pre-post elective orthopedic surgery for PD relative to surgery and non-surgery peers.

METHODS

A prospective one-year longitudinal design. No-dementia idiopathic PD individuals were actively recruited along with non-PD "healthy" controls (HC) undergoing knee replacement surgery. Non-surgical PD and HC controls were also recruited. Attention/processing speed, inhibitory function, memory recall, animal (semantic) fluency, and motor speed were assessed at baseline (pre-surgery), 3 weeks, 3 months, and 1 year post- orthopedic surgery. Reliable change methods examined individual changes for PD individuals relative to control surgery and control non-surgery peers.

RESULTS

Over two years we screened 152 older adult surgery or non-surgery candidates with 19 of these individuals having a diagnosis of PD. Final participants included 8 PD (5 surgery, 3 non-surgery), 47 Control Surgery, and 21 Control Non-Surgery. Eighty percent (4 of the 5) PD surgery declined greater than 1.645 standard deviations from their baseline performance on measures assessing processing speed and inhibitory function. This was not observed for the non-surgery PD individuals.

CONCLUSION

This prospective pilot study demonstrated rationale and feasibility for examining cognitive decline in at-risk neurodegenerative populations. We discuss recruitment and design challenges for examining post-operative cognitive decline in neurodegenerative samples.

A Systematic Approach to the Understanding and Redesigning of Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) is a highly complex process. We developed a system to capture and study detailed information during cardiac surgery that serves as a framework for understanding variation that occurs during CPB. The system allows the surgical team to link unwanted variation (ie, hypotension) and unwanted events (ie, the production of microemboli) to the processes of care. A more thorough understanding of embolic activity and hemodynamic aberrations, precursors to both stroke and subtle neurologic injury, that occur during CPB, will allow the surgical team to identify high leverage, modifiable aspects of care and abate these precursors to patient injury. Multimodality simultaneous monitoring and recording of physiologic parameters, emboli in the CPB circuit and in the middle cerebral arteries, and cerebral NIRS during surgery was carried out in patients undergoing open heart surgery with CPB. A system was designed that captures physiologic data from the patient monitors and the heart-lung machine at 20-second intervals and time synchronizes all measures with a video recording of the surgical procedure. Emboli counts count in the CPB circuit and right and left middle cerebral arteries were continuously recorded. Video recordings depicting various surgical and perfusion techniques with associated embolic activity were provided to the surgical team. Wide variation in embolic counts, cerebral blood flow velocity, and physiologic parameters were observed. Periods of embolic activity and cerebral desaturation could be related to surgical and CPB processes of care. We have identified increased emboli counts in the CPB circuit and in the middle cerebral arteries related to the method of venous drainage, manipulation of the aorta, and anastomotic techniques. se of this model provides the surgical team detailed information about these precursors to neurologic injury. This system provides a systematic approach to the understanding and redesigning of CPB.

Optimal Temperature Management During Cardiopulmonary Bypass: Warm, Cold, or Tepid?

Hypothermia permitted the advent of cardiac surgery and is considered by many the mainstay of cerebral protection during cardiopulmonary bypass (CPB). How ever, some clinicians have questioned the importance of reduced temperatures during CPB and advocate "normo thermic" heart surgery. Hypothermia (mild, moderate, and profound) provides protection during periods of inadequate oxygen delivery by at least two mecha nisms. First, metabolic rate is directly related to tempera ture ; therefore, reduced temperatures increase toler ance to inadequate oxygen delivery. Q10 values (the ratio of metabolic rates at temperature X°C and tempera ture X°C - 10°C) are controversial and are reported as varying between 2.0 and 5.0. During profound hypother mia (temperature = 17°C), metabolic requirements are 10% to 15% of normothermic values. Second, reduced temperatures (even minimal reductions [34°C to 35°C]) attenuate the release of glutamate and other excitatory amines from ischemic neuronal cells. This phenomenon is thought to play an important role in hypothermic cerebral protection. Many investigators have assessed the impact of normothermic temperatures on cerebral outcomes in cardiac surgery patients. Although seem ingly conflicting conclusions are reported, this much is clear: cerebral temperatures in excess of 37°C exacer bate ischemic injury and even mild hypothermia re duces central nervous system damage in the ischemic brain.

Management of the Ascending Aorta in Routine Cardiac Surgery

It is well known that subtle neurologic and neuropsychologic adverse effects are associated with cardiac surgery. Microgaseous emboli may arise from the cardiac pulmonary bypass apparatus; however, most particulate emboli arise from the ascending aorta. Atherosclerosis of the ascending aorta may effect up to 38% of cardiac surgical patients greater than 50 years of age. In addition to avoiding cardiopulmonary bypass with off-pump procedures, avoiding manipulation of the ascending aorta in any way is also associated with a reduction in embolic complications. Epiaortic scanning is the most accurate way to assess the location and severity of atheromata in the ascending aorta. Management of the atheromatous ascending aorta may include changes to cannulation options for cardiopulmonary bypass, such as femoral or axillary cannulation. Complete avoidance of the cross-clamp may be entertained. Aorta cannulae incorporate a number of filtration and deflection devices that may offer some protection to the brachiocephalic vessels. In some cases, replacement of the ascending aorta under deep hypothermic circulatory arrest is appropriate. Avoidance of the ascending aorta by using arterial revascularization as sequential or Y grafts, or placing proximal anastomoses on the subclavian arteries, may allow for complete revascularization without touching the ascending aorta. A full appreciation of the information obtained with epiaortic scanning or transesophageal echocardiography allows for decisions to be made to tailor each procedure to the patient's unique needs and circumstances for optimal outcomes.

Pharmacologic Management of Acute Heart Failure: A Review

Because of improved social and medical standards in the western world, the average age of the population continues to increase. This altering demographic profile has its impact on the surgical population, resulting in a dramatic increase in the number of patients with exten sive cardiovascular disease, presenting for either car diac or noncardiac surgery. As a result, the incidence of perioperative acute congestive heart failure (CHF) is a major clinical problem at the present time. For the pharmacologic management of acute CHF, the β-adreno ceptor agonists continue to be the mainstay of therapy, due to their short duration of action and hemodynamic controlability by continuous intravenous infusion. Mono therapy with the phosphodiesterase type III (PDE) inhibi tors appears to be the treatment of choice in selected patients with high systemic vascular resistance or re sidual β-adrenoceptor blockade. Combination therapy especially deserves attention, because this approach allows the enhancement of contractile force, possibly without the side effects associated with the administra tion of high concentrations of one agent alone. New developments including ultrashort-acting PDE inhibi tors, calcium-dependent calcium sensitizers, and cal cium promotors are anxiously awaited.

Strategies and Techniques for Neuroprotection in Coronary Artery Surgery

Patients undergoing coronary artery bypass grafting are at higher risk of neurologic events than demographi cally similar patients undergoing noncardiac surgery. Postoperative stroke has been shown to occur two to three times more frequently than in age-, gender-, and education-matched patients undergoing noncardiac vas cular or thoracic surgery. The incidence of more subtle brain syndromes, giving rise to symptoms of memory loss and cognitive deterioration as documented in up to 79% of coronary bypass patients, varies depending on whether prospective or retrospective data are analyzed, and whether or not serial cognitive testing is used, and is also significantly higher in coronary bypass patients. Various factors have been identified as causative in the genesis of perioperative neurologic injury in these pa tients. Although there is evidence that microgaseous and microparticulate emboli are instrumental in the production of postoperative cognitive impairment, the role of ascending aortic atherosclerosis is increasingly recognized as being the greatest single risk factor for postoperative stroke.

Genetic Predictors of Perioperative Neurologic and Neuropsychological Injury and Recovery

Central nervous system (CNS) dysfunction after cardio pulmonary bypass represents a continuum from coma and focal stroke to cognitive deficits after surgery. Despite the marked increase in investigation of neuro logic and neurocognitive deficits after cardiac surgery, causative factors fail to predict the majority of the variance in the observed incidence of both early and late neurocognitive decline pointing to some inherent indi vidual susceptibility to injury. The authors' investigative team recently discovered a genetic association be tween late-onset Alzheimer's disease and the apolipo protein E (APOE, gene; apoE, protein) ∈-4 gene. This finding triggered many recent studies that have shown an important role of apoE in the determination of neurologic injury and recovery following a variety of acute ischemic insults including intracerebral hemor rhage, closed-head injury, as well as acute stroke and dementia pugilistica. Most important to the current discussion is the authors' recent report documenting preliminary evidence of an association of APOE4 with neurocognitive decline after cardiac surgery. This re view discusses the authors' hypothesis that the bio chemical products coded by this gene are not available to protect and repair the neurons of the CNS during cardiac surgery resulting in deficits of memory, atten tion, and concentration. Potential mechanisms of apoE's association with acute neurologic injury are discussed including regulation of the inflammatory response. The authors have recently determined that apoE, in vivo, modulates the release of nitric oxide and tumor necro sis factor a. This may compound the autonomic dysreg ulation recently reported in the aging population. The authors' preliminary data associating APOE4 with cogni tive impairment after cardiac surgery support this hy pothesis. The different potential mechanisms of apoE function in neuronal injury and recovery are not mutu ally exclusive, and it is likely that apoE modulates the CNS injury response at several functional levels.

Hypothermia-induced platelet aggregation and cognitive decline in coronary artery bypass surgery: a pilot study

Hypothermia-induced platelet aggregation (HIPA) was previously reported in whole blood exposed to synthetic surfaces at 24°-32°C in one-third of normal subjects tested. Cardiopulmonary bypass, conducted with hypothermia, may lead to such aggregation, resulting in microvascular occlusion contributing to cognitive impairment. This pilot study was conducted to explore the relationship between HIPA and cognitive outcome at hospital discharge in patients undergoing coronary artery bypass graft (CABG) surgery as a first step toward a longer-term study.

Patients (n=45) undergoing mild to moderate hypothermia (32°-28°8C) during CABG surgery underwent cognitive testing preoperatively and prior to hospital discharge. Tests included: visual and verbal memory, mental processing speed, executive function, language, and intellectual function. HIPA was identified using an in vitro assay in which blood flowing in polyvinychloride tubing was subjected to hypothermia, and platelet aggregates were detected using microscopy and passing the exiting blood through a 20-μm pore filter.

Forty-four percent of patients exhibited HIPA. The entire cohort exhibited significant postoperative cognitive decline in verbal memory, mental processing speed and executive function. There was greater cognitive decline in the group with HIPA compared with the group not exhibiting this phenomenon. The patients with HIPA showed significant decline in four of five cognitive measures whereas patients not exhibiting this phenomenon declined in only two of five cognitive measures.

HIPA appears to be associated with an added risk of cognitive decline immediately following CABG surgery employing mild to moderate hypothermia. The findings of our study suggest the long-term cognitive effects of hypothermia-induced platelet aggregation need to be explored.

Off-Pump Coronary Artery Bypass Surgery

Off-pump coronary artery bypass surgery has been adopted enthusiastically worldwide. However, despite more than 6 years’ experience and refinement, many surgeons use it only sporadically and some hardly at all. This reluctance persists despite support for the procedure because of the lack of properly designed risk models and/or randomized studies. Although it has not been overwhelmingly shown that off-pump surgery is superior to the conventional on-pump procedure, the technique has its place in our specialty. It has been shown to be better for noncritical end points in selected patients in the hands of selected surgeons. That there are differences in surgical skill among surgeons is something we all know but rarely discuss in public. Until now, disparities in skill have been most salient with uncommon and extraordinarily challenging operations. Perhaps the off-pump procedure should be regarded as the “challenging” aspect of coronary artery bypass surgery, and self-restraint may need to remain in force if we are to continue to achieve the highest level of clinical excellence.

Troubleshooting during a challenging high-risk pacemaker lead extraction: a case report and review of the literature

BACKGROUND

The use of cardiac implantable electrical devices continues to increase with the validation of new beneficial indications. While the risks of device implantation decreased significantly over time, significant risk remains associated with their extraction when indicated. A high-risk pacemaker lead extraction case is described, wherein a chronically implanted lead that had perforated the right atrium was successfully removed without the need for cardiopulmonary bypass. In this report we share our approach to this challenging extraction case and describe an infrequently utilized off-pump hybrid technique that we term the "lead-inverting stitch".

CASE PRESENTATION

A 74 year-old Caucasian woman with complete heart block and remote pacemaker implantation presents with a swollen and erythematous infected pacemaker pocket necessitating device extraction. Chest computerized tomographic imaging revealed a chronically perforating right atrial lead tip approximately 2 cm within the pericardial space. A successful hybrid transvenous and open surgical extraction approach was undertaken without the need for cardiopulmonary bypass; this was made possible due to a successfully positioned "lead-inverting stitch".

CONCLUSION

Implantable cardiac electrical device infections are amongst the most dreaded post implant complications. Risks of device extraction are further complicated in cases of chronic lead perforations. Extraction strategies that avoid cardiopulmonary bypass initiation are preferred.

Comparison of the effects of on-pump and off-pump coronary artery bypass surgery on cerebral oxygen saturation using near-infrared spectroscopy

BACKGROUND

Central nervous system complications are the most clinically important of those affecting mortality in patients undergoing coronary artery surgery. Newly developed sophisticated techniques and surgical interventions obviating the need for cardiopulmonary pumps have facilitated avoidance of these complications. In this study, we compared the impact of on-pump and off-pump coronary artery bypass surgery on cerebral oxygenation using near-infrared spectroscopy.

METHODS

This study included 40 patients with no comorbidities who were scheduled for on-pump (n = 20) and off-pump (n = 20) cardiac surgery. Preoperative and postoperative Standardized Mini-Mental State Examination (SMMSE) scores, perioperative mean arterial blood pressure (MAP), hematocrit (Hct), peripheral oxygen saturation (SpO2), regional cerebral oximetry values (rSO2), body temperature, and partial pressure of carbon dioxide (PCO2) were recorded, for all patients. Intergroup and intragroup comparisons were then performed.

RESULTS

The mean operative time was longer in the on-pump group. SMMSE scores were similar and relevant postoperative values were lower in both groups. Perioperative MAP, PCO2, and SpO2 were similar in both groups. SpO2 and PCO2 did not differ from baseline levels in either group, while the postextubation MAP at 2 h postoperatively remained low. Hct levels decreased during the perioperative and postoperative periods, while the body temperature declined perioperatively and to a greater degree in the on-pump group. The intraoperative and postoperative rSO2 decreased in both groups. In the on-pump group, the decrease in rSO2 was more prominent during the interval between the start and closure of the sternotomy.

CONCLUSIONS

Physiological alterations that occur during coronary artery surgery affect cerebral oxygenation during and after the operation irrespective of the application of a cardiopulmonary pump. Cerebral oxygenation decreases to a greater extent during on-pump surgery; however, probably because of the neuroprotective effects of hypothermia, the postoperative changes resemble those of off-pump surgery.

Perioperative management of combined carotid and coronary artery bypass grafting procedures

The objective of this review is to provide a high level overview on current thinking for treatment of patients with combined carotid and coronary artery disease given that these patients are at higher risk of adverse cardiac events, stroke, and death. This review discusses (1) the current literature addressing perioperative stroke risk in the setting of coronary artery bypass graft, (2) the literature regarding different surgical approaches when both carotid and coronary revascularization are being considered, and (3) the data available to guide optimal management of this complex patient population to minimize complications regardless of the surgical approach taken.

Influence of intraoperative cerebral oximetry monitoring on neurocognitive function after coronary artery bypass surgery: a randomized, prospective study

OBJECTIVES

Postoperative cognitive decline is common after cardiac surgery, but it is often unrecognized at the time of hospital discharge. However, it has a great impact on patient's quality of life. Cerebral oximetry with the INVOS (IN Vivo Optical Spectroscopy) system provides the possibility of non-invasive, continuous measurement of regional cerebral oxygen saturation (rSO2), which can improve patients' outcome. The aim of this study was to examine whether cerebral oximetry can decrease the incidence of cognitive decline after coronary artery bypass grafting.

METHODS

We have performed a prospective, randomized study with 200 patients enrolled. Patients were divided into INVOS interventional group and CONTROL group without monitoring of cerebral oximetry. A standardized interventional protocol was performed in the INVOS group to maintain rSO2 above 80% of the patient's baseline value or above 50% of the absolute value. Cognitive evaluation was performed in all patients before and 7 days after surgery. Logistic regression was used to reveal predictors of cognitive decline.

RESULTS

The incidence of cognitive decline 7 days after surgery was significantly lower (P = 0.002) in the INVOS interventional group (28%) than in the CONTROL group (52%). Intraoperative use of INVOS monitoring was associated with lower incidence of cognitive decline (odds ratio 0.21). In addition, predictors of cognitive decline revealed by multivariate logistic regression were older age, higher EuroSCORE and SAPS II (Simplified Acute Physiology Score) values, lower educational level and persistence of preoperative atrial fibrillation. Patients with prolonged rSO2 desaturation, defined as rSO2 area under the curve (AUC) of more than 150 min% for desaturation below 20% of baseline or AUC of more than 50 min% for desaturation below 50% absolute value, had an increased risk of cognitive decline.

CONCLUSION

Postoperative cognitive outcome was significantly better in patients with intraoperative cerebral oximetry monitoring. Prolonged rSO2 desaturation is a predictor of cognitive decline and has to be avoided.

Innominate artery as an alternative site for proximal anastomoses in patients with a severely calcified aorta

BACKGROUND

Atheromatous plaques of the ascending aorta are one of the most important risk factors for postoperative mortality and morbidity in coronary artery bypass grafting (CABG). We have retrospectively analyzed the results of proximal anastomoses constructed on the innominate artery in patients with calcific atheromatous plaques (CAP) in their ascending aorta detected intraoperatively.

PATIENTS AND METHODS

This study is a retrospective review of 16 consecutive patients who underwent CABG operations and had CAP on their ascending aorta between November 2006 and June 2009. The atheromatous lesions were detected intraoperatively and the operation plan was changed to off-pump surgery. All the proximal anastomoses were made on the innominate artery, left internal thoracic artery (LITA) or the other saphenous vein grafts (SVG). Thirteen patients were male and three were female with a mean age of 63.7 ± 5.3 (ranged, 53-71) years.

RESULTS

A total of 56 distal anastomoses (3.5 per patient) and 25 proximal anastomoses on the innominate artery were performed. Of the 16 patients, seven (43.7%) had received a sequential SVG; two (12.5%) patients, sequential LITA graft; and one (6.25%) patient sequential SVG and LITA graft. One of the proximal anastomoses was performed on the SVG in four patients (25%) and on the LITA graft in one patient (6.2%). One patient (6.2%) died due to cerebrovascular morbidity. No other complications were observed.

CONCLUSIONS

The innominate artery is an alternative site for proximal anastomoses in patients with calcific atheromatous aorta.

Neurocognitive outcomes after cardiac surgery

PURPOSE OF REVIEW

To summarize recent studies of neurocognitive dysfunction after cardiac surgery, as well as to outline efforts and approaches toward advancing the field.

RECENT FINDINGS

Observational studies have improved our understanding of the incidence and the trajectory of cognitive decline after cardiac surgery; however, the magnitude of this neurocognitive change remains controversial because of the inconsistent definitions and the lack of a gold-standard diagnostic modality. Nonetheless, physicians commonly see patients with functional and cognitive impairments after cardiac surgery, which utilize healthcare resources and impact quality of life. Novel approaches have utilized advanced neuroimaging techniques as well as innovative monitoring modalities to improve the efficiency of neuroprotective strategies during cardiac surgery.

SUMMARY

Adverse cognitive and neurologic outcomes following cardiac surgery range from discrete neurocognitive deficits to severe neurologic injury such as stroke and even death. The elderly are at higher risk of suffering these outcomes and the public health dimension of this problem is expected to accelerate. Future studies should combine advanced neuroimaging with genomic, transcriptional, proteomic, and metabolomic profiling to improve our understanding of the pathophysiologic mechanisms and optimize the diagnosis, prevention, and treatment of neurocognitive injury.

The role of head computed tomography imaging in the evaluation of postoperative neurologic deficits in cardiac surgery patients

BACKGROUND

Computed tomography (CT) scans of the head without contrast are routinely obtained to evaluate neurologic deficits after cardiac surgery, but their utility is unknown. We evaluated our experience with this imaging modality to determine its value.

METHODS

We retrospectively identified cardiac surgery patients with postoperative neurologic deficits occurring during the first week after surgery between January 2000 and December 2012. Stroke was defined by neurologist's determination, whereas a nonfocal deficit (NFD) was defined by the presence of seizure, delirium, or cognitive impairment. We defined early noncontrast head CT as occurring within 7 days of surgery. Outcomes included positive findings on CT, in-hospital mortality, and length of stay. Multivariate logistic regression identified predictors of positive findings on head CT.

RESULTS

Within the population of 11,070 postoperative patients, 451 had early noncontrast head CT scans (4%). Two hundred two (44.7%) were associated with stroke, and 249 (55.2%) were associated with NFD. Among stroke patients, 40 of 202 (20%) showed acute infarction, 17 of 202 (8%) showed subacute infarction, and 5 of 202 (2%) showed hemorrhage. Among NFD patients, 1 of 248 (0.4%) showed acute infarction, 4 of 248 (1.6%) showed subacute infarction, and 1 of 248 (0.4%) showed hemorrhage. There was no difference in in-hospital mortality (stroke, 42 of 201 [21%] versus NFD, 41 of 248 [16%]; p = 0.2) or length of stay (stroke, 24 d versus NFD, 22 d; p = 0.5). On multivariable logistic regression, only focal deficits and aortic procedures predicted a positive finding on CT scan.

CONCLUSIONS

This study reviewed the utility of early postoperative noncontrast head CT in cardiac surgery patients. With focal neurologic deficits, this imaging modality was positive for approximately one third of patients, but rarely positive for NFD. Its use in this setting has limited utility.

Correlation between cerebral tissue and central venous oxygen saturation during off-pump coronary bypass graft surgery

We compared simultaneous regional cerebral oxygen saturation and central venous oxygen saturation at different time periods in 20 adult patients (median age, 57.9; range, 35 to 76 years) undergoing off-pump coronary artery bypass (OPCAB) graft surgery (n= 20). Mean arterial pressure (MAP), partial pressure of carbon dioxide (PcvCO(2)), heart rate, haematocrit (Hct), lactate and patient oxygen saturation (SpO(2)) were also recorded as a secondary analysis to determine independent predictors of cerebral desaturation and interactions between predictors. The cross-sectional analysis performed at each time point showed several significant moderate to strong positive correlations between central venous oxygen saturation and both right and left cerebral oxygen saturations; however, right cerebral saturations correlated better with central venous saturations than left cerebral saturation. Partial pressure of carbon dioxide (PcvCO(2)) was identified as a major predictor of cerebral saturation 0.59 (p < 0.001). Central venous saturation can be used as a surrogate measure of cerebral oxygen saturation during OPCAB surgery.

Carotid artery disease and stroke during coronary artery bypass surgery

Stroke is a devastating complication during coronary artery bypass grafting. Screening may identify patients at highest risk. Surgical timing, sequence strategies and carotid stenting remain unresolved. Selective use of techniques could prevent adverse neurological sequelae while achieving complete myocardial revascularization.

No major differences in 30-day outcomes in high-risk patients randomized to off-pump versus on-pump coronary bypass surgery: the best bypass surgery trial

BACKGROUND

Off-pump coronary artery bypass grafting compared with coronary revascularization with cardiopulmonary bypass seems safe and results in about the same outcome in low-risk patients. Observational studies indicate that off-pump surgery may provide more benefit in high-risk patients. Our objective was to compare 30-day outcomes in high-risk patients randomized to coronary artery bypass grafting without or with cardiopulmonary bypass.

METHODS AND RESULTS

We randomly assigned 341 patients with a EuroSCORE > or = 5 and 3-vessel coronary disease to undergo coronary artery bypass grafting without or with cardiopulmonary bypass. Patients were followed through the Danish National Patient Registry. The primary outcome was a composite of adverse cardiac and cerebrovascular events (ie, all-cause mortality, acute myocardial infarction, cardiac arrest with successful resuscitation, low cardiac output syndrome/cardiogenic shock, stroke, and coronary reintervention). An independent adjudication committee blinded to treatment allocation assessed the outcomes. Baseline characteristics were well balanced between groups. The mean number of grafts per patient did not differ significantly between groups (3.22 in off-pump group and 3.34 in on-pump group; P=0.11). Fewer grafts were performed to the lateral part of the left ventricle territory during off-pump surgery (0.97 versus 1.14 after on-pump surgery; P=0.01). No significant differences in the composite primary outcome (15% versus 17%; P=0.48) or the individual components were found at 30-day follow-up.

CONCLUSIONS

Both off- and on-pump coronary artery bypass grafting can be performed in high-risk patients with low short-term complications. CLINICAL TRIAL REGISTRATION- clinicaltrials.gov. Identifier: NCT00120991.

Postoperative Care of the Cardiac Surgical Patient

The subspecialty of interventional cardiology began in 1977. Since then, the discipline of interventional cardiology has matured rapidly, particularly with regards to ischemic heart disease. As a result, more patients are undergoing percutaneous catheter interventional therapy for ischemic heart disease and fewer patients are undergoing surgical myocardial revascularization. Those patients referred for surgical revascularization are generally older and have more complex problems. Furthermore, as the population ages more patients are referred to surgery for valvular heart disease. The result of these changes is a population of surgical patients older and sicker than previously treated.

Effect of isoflurane on the beta-adrenergic and endothelium-dependent relaxation of pig cerebral microvessels after cardiopulmonary bypass

We examined the direct vasomotor effect of isoflurane as well as its effect on endothelium-dependent and beta-adrenergic vasodilation of cerebral microcirculation following either normothermic cardiopulmonary bypass (CPB) or profoundly hypothermic CPB with circulatory arrest. Pigs were placed on CPB; the systemic temperature was either maintained at 37 degrees C or lowered to 15 degrees C with 60 minutes of circulatory arrest. After 2 hours of CPB, the animals were separated from CPB; 15 minutes later the brain was quickly harvested in cold Krebs solution. Control animals were not instrumented and their brains were similarly harvested. Arteries of approximately 100 microm were dissected and changes in diameter monitored by in vitro videomicroscopy. Following preconstriction with the thromboxane analogue U46619 1 micromol/L, percent relaxation to the endothelium-dependent dilator adenosine diphosphate (ADP) 10(-9) to 10(-4) mol/L, the endothelium-independent dilator sodium nitroprusside (SNP) 10(-9) to 10(-4) mol/L, or the beta-adrenergic agonist isoproterenol 10(-12) to 10(-4) mol/L was measured either in the presence or absence of isoflurane 2%. Additionally, with or without preconstriction with U46619 1 micromol/L, vessel diameter changes were monitored with increasing concentrations of isoflurane 0-3%. Dose-response curves were compared by two-way analysis of variance. Vasodilation to ADP or isoproterenol, but not SNP, was attenuated after normothermic CPB (N-CPB) or profoundly hypothermic CPB (PH-CPB). Although isoflurane attenuated vasodilation of control vessels to ADP or isoproterenol, isoflurane did not further attenuate vasodilation to ADP or isoproterenol after N-CPB or PH-CPB. The direct vasomotor effect of isoflurane depended on the preexisting tone of the vessels, constricting vessels without preconstriction and dilating them after preconstriction. These findings may have implications on the incidence of neuropsychological dysfunction after CPB and use of isoflurane.

Screening for carotid artery disease before cardiac surgery: is current clinical practice evidence based?

BACKGROUND

There is no clear consensus as to the correct screening procedure to identify patients undergoing cardiac surgery and who are at greatest risk of stroke because of the presence of significant carotid artery stenosis. Such screening is important because some patients benefit from combined carotid and cardiac surgery and, regardless of this, the information gained puts the cardiac surgeon in a position to provide an accurate assessment of surgical risk. Our objective was to examine current clinical practice of carotid artery investigation prior to urgent cardiac surgery and to review this illustrative practice in the context of the world literature.

HYPOTHESIS

The study aimed to establish that current typical practice for screening cardiac surgical patients for carotid artery disease is illogical according to the evidence in the world literature.

METHODS

The study consisted of a retrospective assessment of all patients undergoing urgent cardiac surgery and a Medline-derived literature review, and included all patients undergoing urgent cardiac surgery at a tertiary cardiothoracic center between January 1 and December 31, 1997.

RESULTS

Of 529 patients undergoing urgent cardiac surgery, 44 (8%) were screened preoperatively by duplex Doppler ultrasonography for carotid disease. The indications for screening were asymptomatic carotid bruit in 24 patients, history of stroke or transient ischemic attack (TIA) in 12 patients, and neither stroke, TIA, or bruit in 7 patients. The tests were requested either by the attending cardiologists or by the cardiac surgeon to whom they were referred. One patient had already been diagnosed as having carotid artery disease in the past. Thirteen patients underwent additional carotid investigations. Eleven patients were demonstrated to have internal carotid artery stenosis > or = 60% and 3 patients underwent combined cardiac and carotid surgery. Review of the literature revealed the following groups to be at increased risk of future stroke unrelated to surgery, and of postoperative stroke: those with a history of stroke or TIA, those with carotid bruits, and, of importance, all patients with significant carotid stenosis. Recent data suggest that symptomatic patients and the elderly are at greatest risk.

CONCLUSIONS

Only 8% of patients undergoing urgent cardiac surgery in a 1-year period were screened for carotid artery disease. We suggest that screening should definitely be performed in all patients with a history of stroke or TIA, all patients with a bruit, and all patients aged > 65 years. The literature suggests, however, that significant reductions in stroke rate could be achieved by screening the whole cardiac surgical population, although there is a paucity of data that are specifically pertinent to this patient subgroup. Further data are therefore required for the construction of a scientifically valid and medicolegally sound policy.

Reducing emboli in cardiac surgery: does it make a difference?

Particulate embolization remains a serious complication of cardiac surgery. Adverse events associated with particulate embolization affect patient morbidity and long-term survival, and increase the length of hospital stay and the cost of health care. Today, atherosclerosis plays a role in at least two-thirds of all adverse events after coronary artery revascularization, and postoperative stroke is the second most common cause of operative mortality. Because many lower-risk patients now undergo interventional revascularization, higher-risk patients are now typically referred for surgical revascularization. These patients are older and sicker, and have multiple comorbidities, making them more susceptible to adverse events. For these high-risk patients, surgeons should be proactive in attempting to reduce the possibility of emboli. Patients must be carefully assessed before surgery to determine their risk, and if the risk is high, surgeons should consider using newer, innovative devices, and techniques in their operative strategy that have proven to be effective in mitigating some of the potential embolic adverse events. A multifaceted, preventive strategy can make a difference, not only in reducing particulate emboli, but also in reducing morbidity and in lowering the economic burden on the health-care system. This brief review will address three areas of focus that are important for the prevention of particulate embolization: (i) prevalence and morbidity of atherosclerotic disease; (ii) risk factors for adverse neurologic events; and (iii) prevention/mitigation of adverse events for patients undergoing cardiac surgery.

Off-pump coronary artery bypass graft surgery in California, 2003 to 2005

BACKGROUND

The impact of off-pump coronary artery bypass graft surgery (OPCAB) on operative mortality compared to conventional coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CCB) has not been clarified.

METHOD

Patient clinical characteristics were compared between OPCAB and CCB for isolated CABG surgeries in 2003 to 2005 using data from the California CABG outcomes reporting program. A propensity score method and logistic regression models were used to compute propensity-adjusted operative mortality for patients undergoing OPCAB or CCB.

RESULTS

Of 57,284 isolated CABGs, 13,515 (22.9%) were OPCAB. Compared to CCB, OPCAB patients were older, more females/nonwhite, and had a higher prevalence of certain noncardiac risk factors but were fewer with diabetes, acute myocardial infarction, New York Heart Association class IV heart failure or angina, cardiogenic shock, prior cardiac surgery, left main coronary disease, or > or =3-vessel coronary disease (all P < .01). Overall, the propensity-adjusted operative mortalities (PAOMRs) were significantly lower in OPCAB patients compared to CCB patients (OPCAB 2.59% [95% CI 2.52%-2.67%] vs CCB 3.22% [95% CI 3.17%-3.27%]). Off-pump CABG had a protective advantage for all quintile subgroups (all P < .05). However, within the OPCAB cohort, those who converted to CCB intraoperately had higher PAOMR (converters 3.47% [95% CI 3.16%-3.77%] vs nonconverters 2.53% [95% CI 2.46%-2.61%]). Age, female sex, nonwhite race, diabetes, congestive heart failure, prior cadiac surgery, left main disease, and with > or =3 diseased coronary arteries were associated with a higher risk of intraoperative conversion from OPCAB to CCB (all <0.05).

CONCLUSION

OPCAB and CCB patients had significantly different preoperative risk profiles, and OPCAB was associated with lower operative mortality compared to CCB.

The use of the retinal nerve fiber layer thickness measurement in determining the effects of cardiopulmonary bypass procedures on the optic nerve

BACKGROUND

Our aim was to determine the effects of cardiopulmonary bypass procedures on the optic nerve by retinal nerve fiber layer thickness measurements.

METHODS

Retinal nerve fiber layer thickness was measured using the GDx Nerve Fiber Analyser, 1 day before the surgery and on postoperative days 1, 5 and 30 in 20 patients undergoing coronary artery bypass grafting surgery.

RESULTS

Postoperative mean values for retinal nerve fiber layer thickness, except symmetry on the first day and except symmetry and superior nasal ratio on the fifth day, were statsitically decreased. Only the value for the inferior ratio was significantly lower at the end of the first month.

CONCLUSIONS

Cardiopulmonary bypass procedures cause a temporary decrease in retinal nerve fiber layer thickness.

Brain oxymetry in the operating room: current status and future directions with particular regard to cytochrome oxidase

Near-infrared spectroscopy (NIRS) is a cerebral monitoring method that noninvasively and continuously measures cerebral hemoglobin oxygenation and the redox state of cytochrome oxidase using highly tissue-permeable near-infrared light. This technique now has wide clinical application, and its usefulness in the measurement of cerebral hemoglobin oxygenation has been confirmed under global cerebral injury and/or hypoxemic hypoxia; however, regional cerebral infarction located far from the monitoring site may not be detected by NIRS. Furthermore, the specificity and accuracy of the measurement of the redox state of cytochrome oxidase remain controversial. We apply NIRS to both animal and clinical investigations. Based on these results, we discuss the significance of the measurement of cerebral hemoglobin oxygenation and cytochrome oxidase in vivo and in clinical medicine. Using our algorithm, cytochrome oxidase signals are unaffected by hemoglobin signals, even when hematocrit values change from 35 to 5% under cardiopulmonary bypass in a dog model. In the clinical study, cytochrome oxidase during surgery is likely to be a good (though not perfect) predictor of postoperative cerebral outcome. NIRS appears to be a promising technology, but additional investigations are required to establish its clinical efficacy and justify its routine use during operative and perioperative periods.