Off Pump Coronary Artery Bypass Graft Surgery Versus Conventional Coronary Artery Bypass Graft Surgery: A Systematic Review of the Literature

Hospital-Based HTA and Know4Go at MEDICI in London, Ontario, Canada

The majority of healthcare in Canada is universally provided and publicly funded through the provincial government.

Neurological complications of cardiac surgery

As increasing numbers of elderly people undergo cardiac surgery, neurologists are frequently called upon to assess patients with neurological complications from the procedure. Some complications mandate acute intervention, whereas others need longer term observation and management. A large amount of published literature exists about these complications and guidance on best practice is constantly changing. Similarly, despite technological advances in surgical intervention and modifications in surgical technique to make cardiac procedures safer, these advances often create new avenues for neurological injury. Accordingly, rapid and precise neurological assessment and therapeutic intervention rests on a solid understanding of the evidence base and procedural variables.

Off-pump coronary artery bypass grafting in a low-volume center

BACKGROUND

The advantages of off-pump coronary artery bypass grafting (OPCAB) are well documented; however, the conversion of OPCAB to cardiopulmonary bypass (CPB) is associated with higher morbidity and mortality. This issue is of particular concern in low-volume centers or centers that are beginning to use OPCAB. We present an OPCAB methodology that uses a maximum number of arterial grafts.

METHODS

We routinely use OPCAB in every patient unless there is another associated condition. We used the following methods to improve the safety of OPCAB: (1) maintaining normothermia, (2) routine use of a pulmonary artery catheter, (3) routine use of a femoral arterial line, (4) routine use of a cell saver, and (5) complete revascularization.

RESULTS

We included 173 consecutive patients in the study. All patients underwent OPCAB without any conversion to CPB. Hemodynamic compromise in 5 patients (2.89%) required insertion of an intra-aortic balloon pump (IABP). OPCAB was completed in all 5 patients after IABP insertion. Blood transfusions (BTs) were avoided in 55 patients (31.8%), and 68 patients (39.3%) required ≤2 units of blood.

CONCLUSION

The OPCAB technique is still evolving. Low-volume centers have higher rates of conversion to CPB. Hypotension due to an impaired left ventricular function can be successfully treated by using an IABP. Although blood loss can be managed with BTs, use of a cell saver helps to reduce the number of BTs. We conclude that our technique of total arterial OPCAB using a cell saver can be safely performed in a low-volume center.

Cardioprotection during cardiac surgery

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide. For a large number of patients with CHD, coronary artery bypass graft (CABG) surgery remains the preferred strategy for coronary revascularization. Over the last 10 years, the number of high-risk patients undergoing CABG surgery has increased significantly, resulting in worse clinical outcomes in this patient group. This appears to be related to the ageing population, increased co-morbidities (such as diabetes, obesity, hypertension, stroke), concomitant valve disease, and advances in percutaneous coronary intervention which have resulted in patients with more complex coronary artery disease undergoing surgery. These high-risk patients are more susceptible to peri-operative myocardial injury and infarction (PMI), a major cause of which is acute global ischaemia/reperfusion injury arising from inadequate myocardial protection during CABG surgery. Therefore, novel therapeutic strategies are required to protect the heart in this high-risk patient group. In this article, we review the aetiology of PMI during CABG surgery, its diagnosis and clinical significance, and the endogenous and pharmacological therapeutic strategies available for preventing it. By improving cardioprotection during CABG surgery, we may be able to reduce PMI, preserve left ventricular systolic function, and reduce morbidity and mortality in these high-risk patients with CHD.

2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines

BACKGROUND

Practice guidelines reflect published literature. Because of the ever changing literature base, it is necessary to update and revise guideline recommendations from time to time. The Society of Thoracic Surgeons recommends review and possible update of previously published guidelines at least every three years. This summary is an update of the blood conservation guideline published in 2007.

METHODS

The search methods used in the current version differ compared to the previously published guideline. Literature searches were conducted using standardized MeSH terms from the National Library of Medicine PUBMED database list of search terms. The following terms comprised the standard baseline search terms for all topics and were connected with the logical 'OR' connector--Extracorporeal circulation (MeSH number E04.292), cardiovascular surgical procedures (MeSH number E04.100), and vascular diseases (MeSH number C14.907). Use of these broad search terms allowed specific topics to be added to the search with the logical 'AND' connector.

RESULTS

In this 2011 guideline update, areas of major revision include: 1) management of dual anti-platelet therapy before operation, 2) use of drugs that augment red blood cell volume or limit blood loss, 3) use of blood derivatives including fresh frozen plasma, Factor XIII, leukoreduced red blood cells, platelet plasmapheresis, recombinant Factor VII, antithrombin III, and Factor IX concentrates, 4) changes in management of blood salvage, 5) use of minimally invasive procedures to limit perioperative bleeding and blood transfusion, 6) recommendations for blood conservation related to extracorporeal membrane oxygenation and cardiopulmonary perfusion, 7) use of topical hemostatic agents, and 8) new insights into the value of team interventions in blood management.

CONCLUSIONS

Much has changed since the previously published 2007 STS blood management guidelines and this document contains new and revised recommendations.

The influence of a low ejection fraction on long-term survival in systematic off-pump coronary artery bypass surgery

OBJECTIVE

Poor left-ventricular ejection fraction (EF) is a recognized operative and long-term risk factor in coronary artery bypass surgery. Over the past decade, off-pump coronary artery bypass surgery has emerged as a new strategy to address myocardial revascularization in poor left-ventricular EF patients, but few reports have documented long-term results. The aim of this study was to investigate long-term clinical results in off-pump coronary artery bypass patients with ≤ 35% left-ventricular EF.

METHODS

From September 1996 to May 2006, 1250 patients underwent off-pump coronary artery bypass revascularization, and were prospectively followed-up at the Montreal Heart Institute. Among them, 137 patients (pts) had a preoperative left-ventricular EF ≤ 35%. Follow-up was completed in 97% of patients.

RESULTS

Mean follow-up was 66 ± 34 months. Rate of grafts per pts was comparable in both groups. Overall 30-day mortality was 1.7% (1.5% EF >35% pts vs 2.9% in EF ≤ 35% pts; p = 0.19). Ten-year survival was lower in poor EF patients (44 ± 7% vs 76 ± 2%), and remained significant even after adjusting for risk factors (p = 0.04). Freedom from cardiac death for both groups was also significantly reduced in poor EF patients (p = 0.008). After adjustment, freedom from the combined end point of cardiac or sudden death, myocardial infarction, repeat coronary revascularization, unstable angina, and cardiac failure was comparable in both groups (p = 0.5).

CONCLUSIONS

Off-pump coronary artery bypass surgery can be performed adequately and safely in poor EF patients. However, overall and cardiac survival was decreased in this subset of patients with a comparable freedom from major cardiac adverse related events.

[Early extubation in cardiac surgery]

INTRODUCTION

An early extubation in cardiac surgery (fast track cardiac anaesthesia) refers to mechanical ventilation during 1-6 hours after the intervention, the extubation criteria being the same as for any other surgery. Different protocols have been established for managing patients undergoing fast track anaesthesia, with high-thoracic epidural anaesthesia being increasingly used in the last few years.

MATERIAL AND METHODS

Thirty-five consecutive patients scheduled for OPCAB surgery, who were planned for very fast track cardiac anaesthesia (planned extubation within one hour after the end of the operation), were included in the study. Combined high-thoracic epidural and general anaesthesia was performed in all patients, with bupivacain as a local anaesthetic and inhalational or intravenous anesthetic used for general anaesthesia.

RESULTS

Thirty three of 35 patients (94.3%) were extubated early, with the mean duration of the mechanical ventilation of 56 +/- 92 minutes. Very fast track cardiac anaesthesia was performed successfully in 24/35 (68.8%) patients; these patients had higher ejection fraction, lower Euroscore, shorter duration of the surgery, and fewer numbers of grafts, as compared to the patients extubated early. Euroscore was the only independent predictor of the early extubation (higher score--longer mechanical ventilation time).

DISCUSSION AND CONCLUSION

Our results suggest that high-toracic epidural anaesthesia enables successful early tracheal extubation in the population of patients scheduled for OPCAB cardiac surgery. We had no complications related to this type of anaesthesia and very good perioperative results.

In-hospital outcomes of off-pump multivessel total arterial and conventional coronary artery bypass grafting: single surgeon, single center experience

BACKGROUND

Despite increasing recognition that off-pump coronary artery bypass surgery and total arterial revascularization individually are associated with improved outcomes, concerns persist regarding the safety of combining these two techniques. We compared in-hospital outcomes for off-pump multivessel total arterial and conventional coronary artery bypass grafting.

METHODS

From September 1998 to September 2008, 580 consecutive patients receiving off-pump multivessel arterial grafts only were compared with a control group of patients (n = 806) undergoing off-pump coronary artery bypass grafting with internal thoracic artery and saphenous veins operated on by the same surgeon. Two different statistical approaches were used to compare groups in this retrospective analysis. First, propensity score analysis was used to match patients from each group. Second, a multivariate analysis was performed looking at a combined patient outcome of death, intraaortic balloon counterpulsation utilization, myocardial infarction, stroke, prolonged ventilation, and reoperation for any cause on all patients in both groups.

RESULTS

After matching by propensity score, the major clinical outcomes in total arterial (n = 346) and control (n = 346) groups were found to be similar. The in-hospital mortality in the total arterial group was 1.2% as compared with 2.0% in matched patients (p = 0.8). However, patients in the total arterial group were found to have a significantly increased incidence of reexploration for bleeding (p < 0.0001) and blood product usage (p < 0.0001). There was a higher incidence of combined morbidity outcome (18.8% versus 12.1%; p = 0.001) for the control group compared with the total arterial group. Multivariate analysis failed to show that total arterial grafting was an independent predictor of the combined morbidity outcome.

CONCLUSIONS

Off-pump multivessel total arterial grafting can be performed safely with superior in-hospital outcomes compared with off-pump conventional coronary artery bypass grafting.

[Not Available]

Aim:

We aimed to report our postoperative results in elderly patients that had off-pump coronary bypass grafting.

Method:

Data of 173 patients with isolated coronary bypass 70 years of age or older were retrospectively evaluated. One month follow-up data were evaluated in all patients. After getting verbal informed consent a total of 91 patients were included in the quality of life assessment via EuroQoL form. The data of patients with age of 70-74 and 75 or older were compared.

Results:

The mean ages of patients at age of 70-74 and ≥75 were 71.69±0.16 and 76.81±0.23 years; respectively. Eleven cases had in-hospital mortality (%6 of 173 patients). The mean follow-up period for the group that were reached for EuroQoL assessment was 46,3 ± 20,8 months. The percent of cases among the whole study group that had participated in the quality of life questionnaire were in good condition in terms of mobility, self-care, usual activities, pain/discomfort, anxiety/depression were %75, %87, %81, %92 and %89; respectively.

Discussion:

Off-pump coronary bypass operation may be safely used in elderly patients with high quality of life and low morbidity and mortality.

Minimally invasive direct coronary artery bypass and off-pump coronary artery bypass surgery: anesthetic considerations

Many new surgical technologies are being developed, with the overall aim of improving outcomes. One common feature of many new technologies is that they offer a safer approach than previous techniques; one of the greatest forces for change over the last 30 years is risk reduction. Cardiac surgery risk has been effectively undercut by percutaneous-based procedures, which have offered dramatic reductions in risk--at least in the short term. Beating heart techniques, whether minimally invasive direct coronary artery bypass (MIDCAB), off-pump coronary artery bypass surgery (OPCAB), or in other forms, such as percutaneous valve replacement, are likely to dramatically increase over the next decade. What role OPCAB and MIDCAB techniques will play in this new era is anyone's guess.

Current Status of Off-Pump Coronary Artery Bypass Surgery

The expanding indications for angioplasty coupled with the successful short and mid-term results of randomized controlled trials of drug-eluting stents have already had an unquestionable impact on the practice of coronary revascularization operations. However, coronary artery bypass grafting remains a major mode of therapy for coronary artery disease. It is likely that surgery will continue to be preferred for more complex subsets and that surgeons will have to continue to maintain good results in patients with more complex problems. Concerns regarding morbidity associated with conventional surgical myocardial revascularization on cardiopulmonary bypass have led to a resurgence of interest in off-pump bypass surgery during the last decade, with the expectation that it would be safer if cardiopulmonary bypass could be avoided. This review summarizes the impact of off-pump bypass surgery in reducing the morbidity and mortality associated with conventional coronary artery bypass on cardiopulmonary bypass by evaluating the current best-available evidence from randomized controlled trials and meta-analyses comparing off-pump surgery with conventional bypass grafting.

Pexelizumab reduces death and myocardial infarction in higher risk cardiac surgical patients

BACKGROUND

Morbidity and mortality after coronary artery bypass graft surgery are directly related to specific preoperative risk factors. We assessed the influence of preoperative risk factors on the effect of pexelizumab, a C5 complement inhibitor, to reduce postoperative morbidity and mortality in this post hoc analysis of the Pexelizumab for Reduction in Myocardial Infarction and MOrtality in Coronary Artery Bypass Graft surgery (PRIMO-CABG) trial, a phase III double-blind, placebo-controlled study of 3,099 patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass.

METHODS

The composite endpoint of death or myocardial infarction or both through postoperative day 30 was examined in subpopulations of patients with pre-specified risk factors, which included diabetes mellitus, prior coronary artery bypass graft, urgent intervention, female sex, history of neurologic event, history of congestive heart failure, and two or more previous myocardial infarctions or a recent myocardial infarction. Stratified post hoc analyses were also performed on patients presenting with two or more and three or more of those risk factors.

RESULTS

Pexelizumab significantly reduced the incidence of the composite endpoint of death or myocardial infarction through postoperative day 30 by 28% in patients with two or more risk factors (p = 0.004) and 44% in patients with three or more risk factors (p < 0.001).

CONCLUSIONS

The C5 complement inhibitor, pexelizumab, reduced morbidity and mortality among high-risk patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Cognitive Outcomes in Elderly High-Risk Patients After Off-Pump Versus Conventional Coronary Artery Bypass Grafting

Background— It has been suggested that the risk of cerebral dysfunction is less with off-pump coronary artery bypass grafting (OPCAB) than with conventional coronary artery bypass grafting (CCAB). However, evidence for this statement is preliminary, and additional insight is needed.

Methods and Results— The study was a substudy of the randomized Best Bypass Surgery trial that compared OPCAB with CCAB treatment with respect to intraoperative and postoperative mortality and morbidity in patients with a moderate to high level of predicted preoperative risk. The outcome was cognitive function. A total of 120 elderly patients (mean age 76 years, SD 4.5 years) underwent psychometric testing before surgery and at a mean of 103 (SD 15) days postoperatively with a neuropsychological test battery that included 7 parameters from 4 tests. Cognitive dysfunction was defined as the occurrence of at least 2 of the 7 possible deficits. Secondary analysis was performed on the basis of the definition of a 20% decline in cognitive scores compared with baseline, and with z score analysis. Cognitive dysfunction was identified in 4 of the 54 patients (7.4%, 95% confidence interval [CI] 2.1% to 17.9%) in the OPCAB group and 5 of the 51 patients (9.8%, 95% CI 3.3% to 21.4%) in the CCAB group. We found no difference in incidence of cognitive dysfunction between the groups regardless of the definition applied.

Conclusions— In elderly high-risk patients, no significant difference was found in the incidence of cognitive dysfunction 3 months after either OPCAB or CCAB.

Cognitive and neurobehavioral dysfunction after cardiac bypass procedures

From a cognitive standpoint, CABG as currently practiced appears to be safe for the great majority of patients, but transient changes involving memory, executive functions, and motor speed may still occur in a subset of patients during the first few days to weeks after CABG. The etiology most likely is multifactorial and includes a synergistic effect of microemboli, hypo-perfusion, and other variables associated with major surgery. Older age and degree of pre-existing cerebrovascular disease have been identified as important risk factors. The short-term cognitive changes appear to be reversible by 3 months after surgery for most patients. Late cognitive decline after CABG,occurring between 1 and 5 years after the surgery, has been well documented,but controlled studies demonstrating that this decline is specifically attributable to the use of cardiopulmonary bypass itself rather than to progression of underlying cerebrovascular disease or other age-related changes are pending.