Reduction of the inflammatory response in patients undergoing minimally invasive coronary artery bypass grafting

Platelet transfusion enhances pro-aggregatory status shortly after coronary artery bypass grafting (CABG while modulating platelet pro-inflammatory state 1-week post-surgery

During coronary artery bypass grafting (CABG), the surgical procedure, particularly the manipulation of the major arteries of the heart, induces a significant inflammatory state that may compromise platelet function to the extent that platelet transfusion is required. Given stored platelets as a major source of biological mediators, this study investigates the effects of platelet transfusion on the major pro-aggregatory, pro-inflammatory and immunomodulatory markers of platelets. Platelets from 20 patients, 10 who received platelet transfusion and 10 without, were subjected to flow cytometery where P-selectin and CD40 ligand (CD40L) expressions and PAC-1 binding (activation-specific anti GPIIb/GPIIIa antibody) analysed at five-time points of 24 h before surgery, immediately, 2 h, 24 h and 1 week after surgery. Analysis of intra-platelet transforming growth factor-beta-1 (TGF-β1) was also conducted using western blotting. Patients with platelet transfusion showed increased levels of P-selectin, CD40L and intra-platelet TGF-β1 2-h after surgery compared to those without transfusion (p < 0.05). PAC-1 binding was increased 24 h after surgery in transfused patients (p < 0.05). Given the significant post-transfusion elevation of platelet TGF-β1, P-sel/CD40L reduction in transfused patients a week after was of much interest. This study showed for the first time the significant effects of platelet transfusion on the pro-inflammatory, pro-aggeregatory and immunomodulatory state of platelets in CABG patients, which manifested with immediate, midterm and delayed consequences. While the increased pro-inflammatory conditions manifested as an immediate effect of platelet transfusion, the pro-aggregatory circumstances emerged 24 h post-transfusion. A week after surgery, attenuations of pro-inflammatory markers of platelets in transfused patients were shown, which might be due to the immunomodulatory effects of TGF-β1.

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Off-pump versus on-pump coronary artery bypass graft surgery outcomes in patients with severe left ventricle dysfunction: inverse probability weighted study

Objective

In this study we aimed to compare on-pump and off-pump coronary artery bypass grafting (CABG) outcomes in patients presented with low left ventricular ejection fraction (EF) as a high-risk group of patients.

Methods

In this registry-based study from 2014 and 2016, all patients with severe left ventricular dysfunction (EF less than 35%) were included and followed until 2020. The median follow-up period was 47.83 [38.41, 55.19] months. Off pump CABG (OPCABG) was compared with on-pump CABG (ONCABG) in terms of mid-term non-fatal cardiovascular events (CVEs) and all-cause mortality. Propensity score method (with inverse probability weighting technique) was used to compare these two groups.

Results

From 14,237 patients who underwent isolated CABG, 2055 patients with EF ≤ 35% were included; 1705 in ONCABG and 350 patients in OPCABG groups. Although OPCABG was associated with lower risk of 30-days mortality (Odds Ratio [OR]: 0.021; Confidence Interval [CI] 95% [0.01, 0.05], P < 0.001); there was no significant difference between OPCABG and ONCABG in term of mid-term mortality and non-fatal CVEs ((Hazard ratio [HR]: 0.822; 95%CI [0.605, 1.112], p = 0.208) and (HR: 1.246; 95%CI [0.805, 1.929], p = 0.324), respectively). Patients with more than three traditional coronary artery disease risk factors, had more favorable outcomes (in terms of mid-term mortality) if underwent OPCABG (HR: 0.420; 95%CI [0.178, 0.992], p = 0.048).

Conclusion

OPCABG was associated with lower risk of 30-days mortality; however, mid-term outcomes were comparable in both OPCABG and ONCABG techniques.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02895-0.

Serum Proteomics of Older Patients Undergoing Major Cardiac Surgery: Identification of Biomarkers Associated With Postoperative Delirium

Background

Postoperative delirium (POD) is an acute altered mental state commonly encountered after cardiac surgery. The pathophysiological mechanisms underlying POD remain unclear. We aimed to identify circulating proteins significantly altered after major cardiac surgery with cardiopulmonary bypass (CPB). We also aimed to enable inferences on associations with POD.

Methods

Serum and whole blood samples were collected before CPB (n = 16 patients; n = 8 with POD) and again from the same patients on postoperative day 1. All patients were clinically evaluated for POD on postoperative days 1–3. An aptamer-based proteomics platform (SOMAscan) was used to quantify serum protein abundance in patients with POD compared with non-POD controls. We also performed a lipopolysaccharide (LPS)-based in vitro functional analysis (TruCulture) on whole blood samples from patients with POD and non-POD controls to approximate surgical stress. Cytokine levels were determined using a Luminex immunoassay.

Results

Cardiac surgery with CPB resulted in a significant (p_adj < 0.01) change in 48.8% (637 out of 1,305) of proteins detected by SOMAscan. Gene set enrichment showed that the most impacted biological processes involved myeloid cell activation. Specifically, activation and degranulation of neutrophils were the top five highest-scoring processes. Pathway analyses with the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that metabolic enzymes, particularly those of glycolysis, were elevated in serum concentration after surgery. Several proteins were significantly increased postoperatively in patients diagnosed with POD relative to the non-POD controls, with interleukin-6 (IL-6) showing the greatest fold-change. LPS stimulation of whole blood samples confirmed these findings. Linear regression analysis showed a highly significant correlation between Confusion Assessment Method (CAM) scores and CPB-mediated changes in cGMP-inhibited 3′,5′-cyclic phosphodiesterase A (PDE3A).

Conclusions

Cardiac surgery with CPB resulted in inflammasome changes accompanied by unexpected increases in metabolic pathways. In exploratory analyses, we found that POD was associated with changes in the expression level of various proteins, most notably IL-6 and PDE3A. This study and ongoing protein biomarker studies will likely help quantify risk or confirm the diagnosis for POD and increase understanding of its pathophysiological mechanisms.

Serum Proteomics of Older Patients Undergoing Major Cardiac Surgery: Identification of Biomarkers Associated With Postoperative Delirium

BACKGROUND

Postoperative delirium (POD) is an acute altered mental state commonly encountered after cardiac surgery. The pathophysiological mechanisms underlying POD remain unclear. We aimed to identify circulating proteins significantly altered after major cardiac surgery with cardiopulmonary bypass (CPB). We also aimed to enable inferences on associations with POD.

METHODS

Serum and whole blood samples were collected before CPB (n = 16 patients; n = 8 with POD) and again from the same patients on postoperative day 1. All patients were clinically evaluated for POD on postoperative days 1-3. An aptamer-based proteomics platform (SOMAscan) was used to quantify serum protein abundance in patients with POD compared with non-POD controls. We also performed a lipopolysaccharide (LPS)-based in vitro functional analysis (TruCulture) on whole blood samples from patients with POD and non-POD controls to approximate surgical stress. Cytokine levels were determined using a Luminex immunoassay.

RESULTS

Cardiac surgery with CPB resulted in a significant (p_adj < 0.01) change in 48.8% (637 out of 1,305) of proteins detected by SOMAscan. Gene set enrichment showed that the most impacted biological processes involved myeloid cell activation. Specifically, activation and degranulation of neutrophils were the top five highest-scoring processes. Pathway analyses with the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that metabolic enzymes, particularly those of glycolysis, were elevated in serum concentration after surgery. Several proteins were significantly increased postoperatively in patients diagnosed with POD relative to the non-POD controls, with interleukin-6 (IL-6) showing the greatest fold-change. LPS stimulation of whole blood samples confirmed these findings. Linear regression analysis showed a highly significant correlation between Confusion Assessment Method (CAM) scores and CPB-mediated changes in cGMP-inhibited 3',5'-cyclic phosphodiesterase A (PDE3A).

CONCLUSIONS

Cardiac surgery with CPB resulted in inflammasome changes accompanied by unexpected increases in metabolic pathways. In exploratory analyses, we found that POD was associated with changes in the expression level of various proteins, most notably IL-6 and PDE3A. This study and ongoing protein biomarker studies will likely help quantify risk or confirm the diagnosis for POD and increase understanding of its pathophysiological mechanisms.

Repeat Coronary Artery Bypass Grafting: A Meta-Analysis of Off-Pump versus On-Pump Techniques in a Large Cohort of Patients

BACKGROUND

Redo coronary artery bypass grafting (CABG) can be performed with either the off-pump (OPCAB) or the on-pump (ONCAB) technique.

METHOD

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this meta-analysis compared the safety and efficacy of OPCAB versus ONCAB redo CABG.

RESULTS

Twenty-three (23) eligible studies were included (OPCAB, n=2,085; ONCAB, n=3,245). Off-pump CABG significantly reduced the risk of perioperative death (defined as in-hospital or 30-day death rate), myocardial infarction, atrial fibrillation, and acute kidney injury. The two treatment approaches were comparable regarding 30-day stroke and late all-cause mortality.

CONCLUSIONS

Off-pump redo CABG resulted in lower perioperative death and periprocedural complication rates. No difference was observed in perioperative stroke rates and long-term survival between the two techniques.

Minimally Invasive vs Open Coronary Surgery: A Multi-Institutional Analysis of Cost and Outcomes

BACKGROUND

Limited multi-institutional data evaluating minimally invasive cardiac surgery (MICS) coronary artery bypass surgery (CABG) outcomes have raised concern for increased resource utilization compared with standard sternotomy. The purpose of this study was to assess short-term outcomes and resource utilization with MICS CABG in a propensity-matched regional cohort.

METHODS

Isolated CABG patients (2012-2019) were extracted from a regional Society of Thoracic Surgeons database. Patients were stratified by MICS CABG vs open CABG via sternotomy, propensity-score matched 1:2 to balance baseline differences, and compared by univariate analysis.

RESULTS

Of 26,255 isolated coronary artery bypass graft patients, 139 MICS CABG and 278 open CABG patients were well balanced after matching. There was no difference in the operative mortality rate (2.2% open vs 0.7% MICS CABG, P = .383) or major morbidity (7.9% open vs 7.2% MICS CABG, P = .795). However, open CABG patients received more blood products (22.2% vs 12.2%, P = .013), and had longer intensive care unit (45 vs 30 hours, P = .049) as well as hospital lengths of stay (7 vs 6 days, P = .005). Finally, median hospital cost was significantly higher in the open CABG group ($35,011 vs $27,906, P < .001) compared with MICS CABG.

CONCLUSIONS

Open CABG via sternotomy and MICS CABG approaches are associated with similar, excellent perioperative outcomes. However, MICS CABG was associated with fewer transfusions, shorter length of stay, and ∼$7000 lower hospital cost, a superior resource utilization profile that improves patient care and lowers cost.

Off-Pump versus Conventional Coronary Artery Bypass Grafting: A Meta-Analysis and Consensus Statement from the 2004 ISMICS Consensus Conference

Background

The purpose of this evidence-based consensus statement is to systematically review and meta-analyze the randomized and nonrandomized evidence comparing off-pump (OPCAB) to conventional coronary artery bypass (CCAB) surgery and to provide consensus on the role of OPCAB in low- and high-risk surgical patients.

Methods and Results

This consensus conference was conducted according to the American College of Cardiology (ACC)/American Heart Association (AHA) standards for development of clinical practice guidelines. The Steering Committee collated all published studies of OPCAB versus CCAB through May 2004 and developed six questions central to controversies surrounding OPCAB surgery in mortality, morbidity, and resource utilization. For mixed-risk patient populations, meta-analysis of 37 randomized clinical trials (3,369 patients, Level A) reported across a total of 53 papers, and two meta-analyses of nonrandomized trials (Level B) comparing OPCAB versus CCAB were identified. For high-risk patient populations, we performed a meta-analysis of 3 randomized and 42 nonrandomized trials (26,349 patients, Level B).

Conclusion

Meta-analysis of Level A and B evidence provided the basis for the following consensus statements in patients undergoing surgical myocardial revascularization: (1) OPCAB should be considered a safe alternative to CCAB with respect to risk of mortality [Class I, Level A]; (2) With appropriate use of modern stabilizers, heart positioning devices, and adequate surgeon experience, similar completeness of revascularization and graft patency can be achieved [Class IIa, Level A]; (3) OPCAB is recommended to reduce perioperative morbidity [Class I, Level A]; (4) OPCAB may be recommended to minimize midterm cognitive dysfunction [Class IIa, Level A]; (5) OPCAB should be considered as an equivalent alternative to CCAB in regard to quality of life [Class I, Level A]; (6) OPCAB is recommended to reduce the duration of ventilation, ICU and hospital stay, and resource utilization [Class I, Level A]; (7) OPCAB should be considered in high-risk patients to reduce perioperative mortality, morbidity, and resource utilization [Class IIa, Level B].

Impact of cardiopulmonary bypass surgery on cytokines in epicardial adipose tissue: comparison with subcutaneous fat

BACKGROUND

Cardiac surgery and cardiopulmonary bypass (CPB) have been shown to stimulate a systemic inflammatory response which has been associated with adverse postoperative outcomes. Adipose tissue, both epicardial (EAT) and subcutaneous (SAT), is a known source of inflammatory cytokines, but its role in the pathophysiology of surgery- and CPB-induced systemic inflammatory response has not been fully elucidated. Therefore, we conducted a study to establish levels of selected cytokines in EAT and SAT prior to and after surgery with CPB.

METHODS

Adipose tissue samples were obtained from patients undergoing planned cardiac surgery on CPB. Samples from EAT and SAT were collected before and immediately after CPB. Levels of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), adipocyte fatty acid-binding protein (AFABP), leptin and adiponectin were determined by ELISA, which were adjusted for a total concentration of proteins in the individual samples.

RESULTS

Samples from 77 patients (mean age 67.68 ± 11.5 years) were obtained and analysed. Leptin, adiponectin, TNF-α and AFABP were shown to decrease their concentrations statistically significantly in the EAT after CPB while no statistically significant drop was observed in the SAT. On the contrary, IL-6 showed only a slight and statistically insignificant decrease in the EAT after CPB and it was in the SAT where a statistically significant drop was observed.

DISCUSSION

One of the most relevant findings of this study was the marked decrease in EAT levels of TNF-α, AFABP, leptin and adiponectin after the CPB termination. Our results suggest that EAT might serve as a pool of cytokines which are released into the circulation in reaction to surgery with CPB. Should these novel findings be confirmed, new strategies to assess and possibly reduce EAT contribution on adverse outcomes of cardiac surgery may be developed.

Costs, Clinical Outcomes, and Health-Related Quality of Life of Off-Pump vs. On-Pump Coronary Bypass Surgery

BACKGROUND

Off-pump coronary bypass surgery avoids the potential complications of cardiopulmonary bypass. However, its acceptance depends on medical and economic outcome. The aim of this prospective non-randomised study was to compare functional and economic outcome of off-pump and on-pump surgery at 1-year follow-up.

METHODS

102 patients (pts) treated with either off-pump (60pts) or on-pump surgery (42pts) were studied. Pts with left ventricular dysfunction, recent myocardial infarction (<1 month), renal impairment, valve surgery, previous stroke or coagulopathy were excluded. Variable and fixed costs were obtained for each treatment group during operative and postoperative care. In-hospital endpoints included all-cause mortality and complications (defined as excessive bleeding [>6 units blood transfusion], peri-operative myocardial infarction, atrial fibrillation, stroke, and infection). All cause mortality; cost-effectiveness and quality of life were assessed 1 year after surgery.

RESULTS

The in-hospital mortality was similar in the two treatment groups. Off-pump group had significantly fewer postoperative complication rate (off-pump 41% vs. on-pump 72%, p=0.001). The mean in-hospital cost was lower for off-pump surgery (off-pump 6.515+/-926 euro vs. on-pump 9.872+/-1.299 euro, p<0.0001) as well as the mean length of hospital stay (off-pump 4.93+/-0.93 days vs. on-pump 6.58+/-1.04 days, p<0.0001). At 1 year, all cause mortality, quality of life indices, return to work rate and treatment satisfaction was similar in both groups.

CONCLUSION

Off-pump myocardial revascularization maintains the advantages of conventional surgery in terms of survival and freedom from cardiac events while reducing the in-hospital cost.

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

The recent development of off-pump coronary artery bypass (OPCAB) graft surgical techniques has led to numerous observational and several randomized trials that have investigated outcomes compared with the current gold standard of conventional on-pump coronary bypass (CCAB) graft surgery. This systematic review assesses the current randomized trials that compare OPCAB and CCAB. Numerous end points were investigated, including mortality, stroke, myocardial infarction, atrial fibrillation, blood transfusions, wound infections, and renal failure. In addition to these important outcomes, resource utilization markers were also examined such as hospital length of stay, intensive care unit length of stay, and duration of intubation/ventilation. Finally, when level I evidence from randomized trials was unavailable, level II evidence was examined. This was done for subgroup analysis, where currently no randomized trials exist, looking at OPCAB in high-risk patients. Recommendations were made as to who should receive OPCAB and the potential benefits in this patient population.

Off-pump cardiac surgery abolishes complement activation

Background. This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting. Patients and methods. Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, β -thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively. Results. Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in β-thromboglobulin and F1 + 2, respectively. Notably, there were no inter-group differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01). Conclusions. Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group. Perfusion (2007) 22, 251—256.

Off-pump coronary artery bypass grafting improves short-term outcomes in high-risk patients compared with on-pump coronary artery bypass grafting: Meta-analysis

OBJECTIVES

To assess the benefits and risks of off-pump coronary artery bypass (OPCAB) versus coronary artery bypass grafting (CABG) through a meta-analysis of randomized controlled trials (RCTs), and to investigate the relationship between outcomes and patient risk profile.

METHODS

PubMed, Embase, the Cumulative Index of Nursing and Allied Health Literature, Scopus, Web of Science, Cochrane Library, and major conference proceedings databases were searched for RCTs comparing OPCAB and CABG and reporting short-term (≤ 30 days) outcomes. Endpoints assessed were all-cause mortality, myocardial infarction (MI), and cerebral stroke.

RESULTS

The meta-analysis included 100 studies, with a total of 19,192 subjects. There was no difference between the 2 techniques with respect to all-cause mortality and MI (odds ratio [OR], 0.88; 95% confidence interval [CI], 0.71-1.09; P = .25; I(2) = 0% and OR, 0.90; 95% CI, 0.77-1.05; P = .19; I(2) = 0%, respectively). OPCAB was associated with a significant 28% reduction in the odds of cerebral stroke (OR, 0.72; 95% CI, 0.56-0.92; P = .009; I(2) = 0%). A significant relationship between patient risk profile and benefits from OPCAB was found in terms of all-cause mortality (P < .01), MI (P < .01), and cerebral stroke (P < .01).

CONCLUSIONS

OPCAB is associated with a significant reduction in the odds of cerebral stroke compared with conventional CABG. In addition, benefits of OPCAB in terms of death, MI, and cerebral stroke are significantly related to patient risk profile, suggesting that OPCAB should be strongly considered in high-risk patients.

ISMICS Consensus Conference and Statements of Randomized Controlled Trials of Off-Pump versus Conventional Coronary Artery Bypass Surgery

Objective

At this consensus conference, we developed evidence-informed consensus statements and recommendations on the practice of off-pump coronary artery bypass graft (OPCAB) by systematically reviewing and performing meta-analysis of the randomized controlled trials (RCTs) comparing OPCAB and conventional coronary artery bypass (CCAB).

Methods

All RCTs of OPCAB versus CCAB through April 2013 were screened, and 102 relevant RCTs (19,101 patients) were included in a systematic review and meta-analysis (15 RCTs of 9551 high-risk patients; and 87 RCTs of 9550 low-risk patients) in accordance with the Cochrane Collaboration and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. Consensus statements for the risks and benefits of OPCAB surgery in mortality, morbidity, and resource use were developed based on best available evidence.

Results

Compared to CCAB, it is reasonable to perform OPCAB to reduce risks of stroke [class IIa, level of evidence (LOE) A], renal dysfunction/failure (class IIa, LOE A), blood transfusion (class I, LOE A), respiratory failure (class I, LOE A), atrial fibrillation (class I, LOE A), wound infection (class I, LOE A), ventilation time, and ICU and hospital length of stay (class I, LOE A). However, OPCAB may be associated with a reduced number of grafts performed (class I, LOE A) and with diminished graft patency (class IIa, LOE A, with increased coronary reintervention at 1 year and beyond (class IIa, LOE A), as well as increased mortality at a median follow-up of 5 years (class IIb, LOE A).

Conclusions

OPCAB compared with CCAB may improve outcomes in the short-term (stroke, renal dysfunction, blood transfusion, respiratory failure, atrial fibrillation, wound infection, ventilation time, and length of stay). However, over the longer-term, OPCAB may be associated with reduced graft patency, and increased risk of cardiac re-intervention and death.

Elevated preoperative neutrophil/lymphocyte ratio as a predictor of increased long-term survival in minimal invasive coronary artery bypass surgery compared to sternotomy

Background

Neutrophil lymphocyte ratio (NLR) is a predictor of major adverse cardiovascular outcomes. Our study explores the value of NLR in predicting long-term mortality after minimally invasive coronary artery bypass surgery (MICS) via lateral left-thoracotomy versus conventional sternotomy coronary artery bypass grafting (CABG) surgery.

Methods

A total of 1126 consecutive patients (729 sternotomy CABG and 397 MICS) from a single tertiary center between 2005 and 2008 were followed until 2011. We stratified the patients into equal tertiles according to preoperative NLR. The primary outcome, all-cause mortality, was compared among the NLR tertiles.

Results

Out of the 1126 patients included in the study, 1030 (91%) patients underwent off-pump CABG . The first (NLR <2.3) tertile had a significantly lower 5-year mortality (30/371 =8%) in comparison to the second (NLR =2.3-3.4) and third (NLR ≥3.5) tertiles (49/375 =13% and 75/380 =20%), respectively with p < 0.0001. After multivariate adjustment, NLR was a significant independent predictor of mortality (hazard ratio [HR] per each unit increase of NLR was 1.05, 95% confidence interval [CI] 1.01-1.10, p = 0.008). MICS and sternotomy CABG groups with NLR <3 had similar mortality (21/221 =9.5% and 40/403 =9.9%), p = 1. However among patients with NLR ≥3, MICS had a significantly lower mortality (23/176 = 13.1%) compared to the sternotomy CABG (70/326 =21.5%), p = 0.02. According to the multivariate analysis of patients with NLR ≥3, MICS had a significantly lower mortality compared to sternotomy CABG (HR = 0.44, 95% CI 0.24-0.78, p = 0.005).

Conclusion

Elevated preoperative NLR is an independent predictor of long-term mortality after CABG. Among the patients with NLR ≥ 3, MICS was associated with a significantly improved survival compared with sternotomy CABG.

Does Off-pump Coronary Artery Bypass Reduce the Prevalence ofAtrial Fibrillation?

INTRODUCTION

To examine whether or not off-pump CABG (Coronary Artery Bypass Reduce) reduces the incidence of AF after cardiac surgery.

METHODS

The study was carried out in 939 consecutive coronary artery disease patients with sinus rhythm from which 383 patients underwent off-pump CABG, and 556 patients were operated through on-pump CABG. All patients were monitored postoperatively during intensive care unit (ICU) stay. Then, the incidence and predictive risk factors of post operative AF (POAF) in two groups were determined and compared with each other.

RESULTS

Overall, the mean age of the patients was 56.0±12.8 years with 234 patients (24.9%) being older than 65 years. POAF developed in 38 patients (9.9%) of the off-pump and in 93 patients (16.7%) of the on-pump CABG. There was significant difference between two groups when considering the incidence of POAF (P=0.002). Among preoperative risk factors, age>65 years had a significant association with the incidence of AF in both groups. This study also showed that most of the POAF cases converted to sinus rhythm after treatment. Moreover, these finding demonstrated that conversion to sinus rhythm is significantly more probable in off-pump group (P=0.006).

CONCLUSION

A reduced prevalence of POAF could be observed in patients with off-pump as compared with on-pump techniques. Furthermore, conversion to sinus rhythm in off-pump group was significantly more probable than on-pump group.

Clinical outcome and quality of life after reoperative CABG: off-pump versus on-pump - observational pilot study

Background

Coronary artery bypass grafting (CABG) on cardiopulmonary bypass (CBP) is associated with significant morbidity and mortality. In high-risk patients, doomed for reoperation the adverse effects of CBP may be more striking. We evaluated the results of reoperative CABG (redo-CABG) by either off-pump (OPCAB) or on-pump (ONCAB). Clinical endpoints were perioperative myocardial infarction, mortality, survival and as the most striking difference between prior studies the quality of life (QoL).

Methods

We performed a prospective, non-randomized assessment for patients who underwent redo-CABG by redo-OPCAB (n = 40) or redo-ONCAB (n = 40) at our institution between January 2007 and December 2010. For evaluation of QoL the SF-36 health survey was used with self-administered assessment.

Results

During follow-up 37 of 40 patients were alive in the redo-OPCAB group versus 32 of 40 patients in the redo-ONCAB group (p < 0.05). The shorter operation time, less blood loss, fewer perioperative myocardial infarctions, the higher rate of totally arterial revascularisation and shorter intensive care stay were the significantly beneficial differences for patients in the redo-OPCAB group (p < 0.05). The 3-year survival rate was higher in the redo-OPCAB group with 81 ± 12% versus 63 ± 9%in the redo-ONCAB group. The quality of life survey did not reveal any significant differences between both groups.

Conclusion

In conclusion, with our present retrospective study, we could demonstrate the safety and efficacy of the redo-OPCAB technique with even higher 3-year survival rate. Both techniques seem to have similar impact on the outcome of patients.

CD62L (L-selectin) shedding for assessment of perioperative immune sensitivity in patients undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

To investigate the suitability of blood granulocyte and monocyte sensitivity, as measured by the quantity of different agonists required to induce CD62L shedding, for assessment of perioperative immune changes in patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

Patients scheduled for aortocoronary bypass grafting or for valve surgery were included in this prospective observational study. Blood samples were drawn before anesthesia induction, directly after surgery and 48 hours after anesthesia induction. We determined the concentration of two different inflammatory stimuli--lipoteichoic acid (LTA) and tumor necrosis factor alpha (TNF)--required to induce shedding of 50% of surface CD62L from blood granulocytes and monocytes. In parallel monocyte surface human leukocyte antigen (HLA)-DR, and plasma interleukin (IL)-8, soluble (s)CD62L, soluble (s)Toll-like receptor (TLR)-2 and ADAM17 quantification were used to illustrate perioperative immunomodulation.

RESULTS

25 patients were enrolled. Blood granulocytes and monocytes showed decreased sensitivity to the TLR 2/6 agonist Staphylococcus aureus LTA immediately after surgery (p = 0.001 and p = 0.004 respectively). In contrast, granulocytes (p = 0.01), but not monocytes (p = 0.057) displayed a decreased postoperative sensitivity to TNF. We confirmed the presence of a systemic inflammatory response and a decreased immune sensitivity in the post-surgical period by measuring significant increases in the perioperative plasma concentration of IL-8 (p ≤ 0.001) and sTLR (p = 0.004), and decreases in monocyte HLA-DR (p<0.001), plasma sCD62L (p ≤ 0.001). In contrast, ADAM17 plasma levels did not show significant differences over the observation period (p = 0.401).

CONCLUSIONS

Monitoring granulocyte and monocyte sensitivity using the "CD62L shedding assay" in the perioperative period in cardiac surgical patients treated with the use of cardiopulmonary bypass reveals common changes in sensitivity to TLR2/6 ligands and to TNF stimulus. Further long-term follow-up studies will address the predictive value of these observations for clinical purposes.

Off-pump versus on-pump coronary artery bypass grafting for ischaemic heart disease

BACKGROUND

Coronary artery bypass grafting (CABG) is performed both without and with cardiopulmonary bypass, referred to as off-pump and on-pump CABG respectively. However, the preferable technique is unclear.

OBJECTIVES

To assess the benefits and harms of off-pump versus on-pump CABG in patients with ischaemic heart disease.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 1, 2011), MEDLINE (OVID, 1950 to February 2011), EMBASE (OVID, 1980 to February 2011), Science Citation Index Expanded on ISI Web of Science (1970 to February 2011) and CINAHL (EBSCOhost, 1981 to February 2011) on 2 February 2011. No language restrictions were applied.

SELECTION CRITERIA

Randomised clinical trials of off-pump versus on-pump CABG irrespective of language, publication status and blinding were selected for inclusion.

DATA COLLECTION AND ANALYSIS

For statistical analysis of dichotomous data risk ratio (RR) and for continuous data mean difference (MD) with 95% confidence intervals (CI) were used. Trial sequential analysis (TSA) was used for analysis to assess the risk of random error due to sparse data and to multiple updating of accumulating data.

MAIN RESULTS

Eighty-six trials (10,716 participants) were included. Ten trials (4,950 participants) were considered to be low risk of bias. Pooled analysis of all trials showed that off-pump CABG increased all-cause mortality compared with on-pump CABG (189/5,180 (3.7%) versus 160/5144 (3.1%); RR 1.24, 95% CI 1.01 to 1.53; P =.04). In the trials at low risk of bias the effect was more pronounced (154/2,485 (6.2%) versus 113/2,465 (4.6%), RR 1.35,95% CI 1.07 to 1.70; P =.01). TSA showed that the risk of random error on the result was unlikely. Off-pump CABG resulted in fewer distal anastomoses (MD -0.28; 95% CI -0.40 to -0.16, P <.00001). No significant differences in myocardial infarction, stroke, renal insufficiency, or coronary re-intervention were observed. Off-pump CABG reduced post-operative atrial fibrillation compared with on-pump CABG, however, in trials at low risk of bias, the estimated effect was not significantly different.

AUTHORS' CONCLUSIONS

Our systematic review did not demonstrate any significant benefit of off-pump compared with on-pump CABG regarding mortality, stroke, or myocardial infarction. In contrast, we observed better long-term survival in the group of patients undergoing on-pump CABG with the use of cardiopulmonary bypass and cardioplegic arrest. Based on the current evidence, on-pump CABG should continue to be the standard surgical treatment. However, off-pump CABG may be acceptable when there are contraindications for cannulation of the aorta and cardiopulmonary bypass. Further randomised clinical trials should address the optimal treatment in such patients.

Coronary artery bypass grafting with and without manipulation of the ascending aorta--a meta-analysis

BACKGROUND

The main criticism of surgery in the SYNTAX trial was increased rate of stroke when compared to percutaneous coronary intervention. We aimed to determine whether avoiding aortic manipulation would decrease the rate of stroke.

METHOD

We performed a meta-analysis of seven studies comparing coronary artery bypass grafting (CABG) with and without manipulation of the ascending aorta.

RESULTS

When anaortic off-pump coronary artery bypass grafting (OPCAB) was compared with conventional CABG, the rate of stroke was 0.38% vs. 1.87% (p<0.0001). When anaortic OPCAB was compared with OPCAB using a side-clamp or proximal graft anastomosis device the rate of stroke was 0.31% vs. 1.35% (p=0.003).

CONCLUSION

Avoiding aortic manipulation during CABG may decrease the rate of peri-operative stroke.

Study on the risk factors of postoperative hypoxemia in patients undergoing coronary artery bypass grafting

BACKGROUND

To investigate 576 patients undergoing coronary artery bypass grafting (CABG) and to evaluate independent high risk factors of postoperative hypoxemia following CABG.

METHODS AND RESULTS

The pre-, intra-, and post-operative materials in patients who had CABG performed on them from March 2004 to March 2008 in our hospital were analyzed retrospectively. The relative factors of postoperative hypoxemia were tested through descriptive analysis and logistic regression, and the independent risk factors were obtained. Among the 576 patients investigated, 156 cases suffered from postoperative hypoxemia, and the incidence rate of postoperative hypoxemia was 27.08%. Through descriptive analysis and logistic regression, the independent risk factors of postoperative hypoxemia were as follows: preoperative chronic pulmonary diseases (odds ratio (OR)=8.531, 95% confidence interval (CI) 3.136-23.210), preoperative acute myocardial infarction (OR=3.351, 95% CI 1.539-7.296), and preoperative diabetes (OR=3.108, 95% CI 1.439-6.713). Preoperative acute myocardial infarction (OR=2.091, 95% CI 1.520-4.416) is the independent risk factor during assisted ventilation after surgery, and preoperative chronic pulmonary diseases (OR=7.19, 95% CI 2.807-18.413), pre-operative diabetes (OR=3.605, 95% CI 1.631-7.967), and preoperative acute myocardial infarction (OR=3.604, 95% CI 1.518-8.543) are the 3 independent risk factors after decannulation following CABG.

CONCLUSIONS

Preoperative chronic pulmonary diseases, preoperative acute myocardial infarction, and preoperative diabetes are 3 independent risk factors of postoperative hypoxemia following CABG.

The effects of atorvastatin on the occurrence of postoperative atrial fibrillation after off-pump coronary artery bypass grafting surgery

BACKGROUND

Atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery is still the most common arrhythmic complication. This study evaluated whether pretreatment with atorvastatin protects against AF after off-pump CABG.

METHODS

One hundred twenty-four patients without a history of AF or previous statin use, who were scheduled to undergo elective off-pump CABG, were enrolled. Patients were randomized to control group (n = 62) or to atorvastatin group (n = 62) who were administered atorvastatin 20 mg/d for 3 days before the surgery. Primary outcome was the incidence of postoperative AF. Secondary outcomes were major adverse cardiac and cerebrovascular events, persistent AF at 1 month, and identification of the markers to predict inhospital postoperative AF.

RESULTS

The incidence of AF was significantly lower in the atorvastatin group than in the control group (13% vs 27%, P = .04). The incidence of major adverse cardiac and cerebrovascular events and persistent AF at 1 month was similar in comparisons between the groups. Postoperative peak N-terminal pro-brain natriuretic peptide levels were significantly higher in the patients with AF (P = .03). Multivariate analysis identified pretreatment with atorvastatin as an independent factor associated with a significant reduction in postoperative AF (odds ratio 0.34, P = .04). Higher postoperative peak N-terminus pro-B-type natriuretic peptide levels were associated with the development of postoperative AF (odds ratio 1.02 per 100 pg/mL, P = .03).

CONCLUSIONS

Pretreatment with atorvastatin significantly reduced the occurrence of postoperative AF after off-pump CABG.

Clinical outcomes in randomized trials of off- vs. on-pump coronary artery bypass surgery: systematic review with meta-analyses and trial sequential analyses

AIMS

To assess the clinical outcomes of off- vs. on-pump coronary artery bypass surgery in randomized trials.

METHODS AND RESULTS

We searched electronic databases and bibliographies until June 2007. Trials were assessed for risk of bias. Outcome measures were all-cause mortality, myocardial infarction, stroke, atrial fibrillation, and renewed coronary revascularization at maximum follow-up. We applied trial sequential analysis to estimate the strength of evidence. We found 66 randomized trials. There was no statistically significant differences regarding mortality [relative risk (RR) 0.98; 95% confidence interval (CI) 0.66-1.44], myocardial infarction (RR 0.95; 95% CI 0.65-1.37), or renewed coronary revascularization (RR 1.34; 95% CI 0.83-2.18). We found a significant reduced risk of atrial fibrillation (RR 0.69; 95% CI 0.57-0.83) and stroke (RR 0.53; 95% CI 0.31-0.91) in off-pump patients. However, when continuity correction for zero-event trials was included, the reduction in stroke became insignificant (RR 0.62; 95% CI 0.32-1.19). Trial sequential analysis demonstrated overwhelming evidence supporting that off-pump bypass surgery reduces atrial fibrillation.

CONCLUSION

Off-pump surgery reduces the risks of postoperative atrial fibrillation compared with on-pump surgery. For death, myocardial infarction, stroke, and renewed coronary revascularization, the evidence is still weak and more low-bias risk trials are needed.

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.

[Myocardial revascularization without extracorporeal circulation]

Contemporary treatment of coronary disease includes: drug treatment, percutaneous coronary angioplasty (PCI), with or without stent implantation and surgical myocardial revascularization. For more than 30 years, conventional coronary bypass (on-pump CABG), using cardiopulmonary bypass (CPB), represented the standard regarding myocardial revascularization, particularly in patients suffering from three vessel disease or left main coronary artery stenosis. Recent development of invasive cardiology and increased interest in coronary surgery on the beating heart (OPCAB), challenging traditional on-pump CABG procedure, as optimal strategy for the treatment of coronary artery disease. In order to improve clinical outcome, OPCAB seems to be a good choice in patients with co-morbidities critical for use of CPB. Results of OPCAB revascularization in general patient population are considerably different and require further evaluation. This review article shows the development of OPCAB and elaborates potential advantages and weaknesses of this method of revascularization, from both, theoretical and clinical point of view, compared to standard surgical myocardial revascularization.

Impact of off-pump coronary artery bypass surgery on systemic inflammation: current best available evidence

The systemic inflammatory response after coronary artery bypass grafting using cardiopulmonary bypass (CPB) contributes substantially to postoperative organ dysfunction and coagulation disorders. Important features of this inflammatory reaction include the activation of complement and leukocytes, the release of proinflammatory cytokines, alterations in the metabolism of nitric oxide, and an increase in the production of oxygen-free radicals, which in some cases may lead to oxidant stress injury. Several strategies including the use of steroids, use of aprotinin, heparin-coated CPB circuits, and hemofiltration have been reported to reduce the inflammatory reaction induced by CPB and its consequences. A more radical and effective way of counteracting the effects of the inflammatory reaction and oxidative stress may be the omission of CPB itself. The development and application of off-pump coronary artery bypass (OPCAB) technology has largely been driven by this theme of avoiding systemic inflammatory reaction to decrease the incidence and/or severity of adverse outcomes. This review article discusses the influence of cardiopulmonary bypass on systemic inflammation and attempts to evaluate the current best available evidence on the impact of OPCAB on systemic inflammation.

Predictive Significance of Plasma Levels of Interleukin-6 and High-Sensitivity C-Reactive Protein in Atrial Fibrillation after Coronary Artery Bypass Surgery

BACKGROUND

Postoperative atrial fibrillation (AF) plays a major role in the determination of hemodynamic deterioration and can be associated with cardiovascular events after coronary artery surgery. Elevated interleukin (IL)-6 and C-reactive protein (CRP) levels in patients with AF suggest a role of inflammation in the pathogenesis of AF. We conducted a study to investigate the correlation between postoperative AF and IL-6 and high-sensitivity CRP (hsCRP).

MATERIALS AND METHODS

Forty-nine patients with a mean age of 60.3 +/- 10.7 years were enrolled in this study. Preoperative and postoperative first day blood samples were collected to assess the IL-6 and hsCRP levels. IL-6 levels were measured by enzyme-linked immunosorbent assay, and hsCRP was measured by rate turbidimetry method.

RESULTS

Fourteen patients (28.5%) developed AF postoperatively. Patients who developed AF showed elevated serum concentrations of postoperative first day IL-6 (P < .001), preoperative hsCRP (P < .005), and postoperative first day hsCRP (P < 0.001). Preoperative hsCRP levels (P < .002) and postoperative first day IL-6 (P < .001) and hsCRP (P < 0.001) levels were associated with prolonged endotracheal intubation time. Prolonged intensive care unit stay showed significant correlations with elevated levels of preoperative hsCRP (P < 0.002) and postoperative first day IL-6 (P < 0.001) and hsCRP (P < 0.001). There was also statistical significance between the AF+ and AF- groups regarding intensive care unit stay and endotracheal intubation times (P < .001 and P < .001, respectively). Cut-off points for postoperative first day IL-6, preoperative hsCRP, and postoperative first day hsCRP were 46.4 pg/mL (sensitivity = 92.9% and specificity = 80%), 0.46 mg/L (sensitivity = 71% and specificity = 75%), and 17.9 mg/L (sensitivity = 92.9% and specificity = 78%), respectively.

CONCLUSIONS

Elevated IL-6 and hsCRP levels in patients with postoperative AF suggest inflammatory components have a role of in the pathogenesis of AF.

Deleterious effects of cardiopulmonary bypass in coronary artery surgery and scientific interpretation of off-pump's logic

Cardiopulmonary bypass (CPB) has been suggested to be a cause of complex systemic inflammatory response that significantly contributes to several adverse postoperative complications. In the last few years, off-pump coronary artery bypass grafting (OPCAB) has gained widespread attention as an alternative technique to conventional on-pump coronary artery bypass grafting (ONCAB). However, a degree of uncertainty regarding the relative merits of ONCAB and OPCAB continues to be a significant issue. Surgeons supporting off-pump surgery, state that the avoidance of the CPB leads to significantly reduced myocardial ischemia-reperfusion injury, postoperative systemic inflammatory response and other biological derangements, a feature that may improve the clinical outcomes. However, perfection in perioperative care, surgical technique and methods of attenuating the untoward effects of CPB has resulted in better clinical outcome of ONCAB as well. Possible reasons of these controversial opinions are that high-quality studies have not comprehensively examined relevant patient outcomes and have enrolled a limited range of patients. Some studies may have been too small to detect clinically important differences in patient outcomes between these two modalities. We present a review of the available scientific interpretation of the literature on OPCAB with regard to safety, hemodynamic changes, inflammation, myocardial preservation and oxidative stress. We also sought to determine from different reported retrospective and randomized control studies, the initial and the long-term benefits of this approach, despite the substantial learning curve associated with OPCAB.

Cell Salvage Alters the Systemic Inflammatory Response After Off-Pump Coronary Artery Bypass Grafting Surgery

BACKGROUND

Retransfused cardiotomy suction blood contains elevated inflammatory markers and is a bypass independent source of inflammatory mediators. We hypothesized that, during off-pump coronary artery bypass (OPCAB) grafting surgery, avoiding retransfusion of unwashed cardiotomy suction blood would beneficially alter both urinary and plasma cytokine concentrations and be renoprotective.

METHODS

Thirty-seven OPCAB surgery patients were randomly allocated to control (retransfusion of unwashed shed blood) and treatment (retransfusion of washed shed blood or discarding of unwashed blood) groups. Over 72 hours we measured plasma (tumor necrosis factor-alpha [TNF-alpha], interleukin-8, interleukin-6, interleukin-10, TNF soluble receptor-2, and interleukin-1 receptor antagonist) and urinary TNF soluble receptor-2 and interleukin-1 receptor antagonist and markers of renal injury and dysfunction (N-acetyl beta D glucosaminidase and alpha1-microglobulin).

RESULTS

We demonstrated elevated proinflammatory cytokines in cardiotomy suction blood, which were effectively eliminated by cell salvage. After retransfusion, in comparison with controls, the treatment group had reduced plasma TNF soluble receptor-2. As compared with controls, treatment group patients also demonstrated significantly reduced levels of the urinary anti-inflammatory cytokine TNF soluble receptor-2. There were no between group differences in markers of renal injury or dysfunction.

CONCLUSIONS

We have demonstrated that the management of shed mediastinal blood alters perioperative, systemic, plasma and urinary cytokine homeostasis at OPCAB surgery but does not impact on subclinical renal injury or dysfunction in this low risk group of patients.

Systemic Stress Hormone Response in Patients Undergoing Open Heart Surgery With or Without Cardiopulmonary Bypass

BACKGROUND

Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamics and organ perfusion. Leptin, an adipocyte-derived factor, has been proposed to play a role in systemic inflammation. We examined perioperative release of leptin and cortisol in patients undergoing open heart surgery with or without cardiopulmonary bypass.

METHODS

Forty-nine patients were enrolled in this prospective study. Conventional coronary artery bypass grafting was performed in 19 patients (ONCABG; group I), and heart valve surgery in 15 patients (group II). Fifteen patients (group III) received off-pump coronary artery bypass grafting (OPCABG). Blood samples were collected preoperatively and for as long as 72 hours postoperatively. Plasma levels of leptin and cortisol were measured by enzyme-linked immunosorbent assay.

RESULTS

Leptin serum levels decreased during the operation, reaching 73.2% of the baseline in group I, 85.3% in group II, and 38.9% in group III (p < 0.05), 2 hours postoperatively. Thereafter, leptin levels increased gradually to 218.6% of the baseline in group I and 313.7% in group II 24 hours after the operation (p < 0.01). However, patients in the OPCABG group showed only a moderate increase in serum leptin levels. Plasma cortisol levels rose to a maximum of 532.9% of baseline in group I, 526.4% in group II, and 280% in group III 12 hours postoperatively (p < 0.01).

CONCLUSIONS

Open heart surgery is associated with acute perioperative changes in plasma levels of neurohormonal stress factors leptin and cortisol. A different pattern of leptin and cortisol release was observed in patients operated on without cardiopulmonary bypass.

Off-Pump Surgery Is Associated With Reduced Occurrence of Stroke and Other Morbidity as Compared With Traditional Coronary Artery Bypass Grafting

Background and Purpose— There is growing enthusiasm for coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB). Although deleterious effects of CPB are known, it remains to be proven that avoiding CPB will result in reduction in morbidity. We sought to determine whether off-pump surgery is associated with reduced occurrence of adverse outcomes as compared with CABG with CPB.

Methods— Studies were identified by searching the MEDLINE, EMBASE and the Cochrane Register 1980 to 2006 (February). We also searched the reference lists of randomized clinical trials (RCT) and reviews to look for additional studies. Study selection: RCTs comparing off-pump surgery to CABG with CPB. No restriction applied on the size of the trial or end point reports. Data extraction: 2 reviewers independently searched for studies, read abstracts and abstracted all data. Data synthesis: combined estimates were obtained using fixed or random effect meta-analyses. Relative risks and risk differences were calculated. Heterogeneity was assessed using χ 2 and I 2 values.

Results— There were 3996 patients enrolled in 41 RCTs (mean age 62, 22% female). No study reported information on race. Off-pump CABG was associated with a 50% reduction in the relative risk of stroke (95% CI, 7% to 73%), 30% reduction in atrial fibrillation (AF; 95% CI, 16% to 43%) and 48% reduction in wound infection (95% CI, 26% to 63%) with no heterogeneity among RCTs. This translated into avoidance of 10 strokes, 80 cases of AF and 40 infections per 1000 CABG. Fewer distal grafts were performed and there was evidence for >10 reinterventions per 1000 with off-pump CABG. Long-term follow-up is not yet reported in the trials.

Conclusions— Off-pump CABG is associated with reduced risk of stroke, AF and infections as compared with CABG with CPB. Evidence should be generalized taking into account RCT enrollment limitations, drawbacks related to training requirements, propensity to perform fewer grafts and likely reinterventions after off-pump surgery.

Modulation of systemic inflammatory response after cardiac surgery

Cardiac surgery and cardiopulmonary bypass initiate a systemic inflammatory response largely determined by blood contact with foreign surfaces and the activation of complement. It is generally accepted that cardiopulmonary bypass initiates a whole-body inflammatory reaction. The magnitude of this inflammatory reaction varies, but the persistence of any degree of inflammation may be considered potentially harmful to the cardiac patient. The development of strategies to control the inflammatory response following cardiac surgery is currently the focus of considerable research efforts. Diverse techniques including maintenance of hemodynamic stability, minimization of exposure to cardiopulmonary bypass circuitry, and pharmacologic and immunomodulatory agents have been examined in clinical studies. This article briefly reviews the current concepts of the systemic inflammatory response following cardiac surgery, and the various therapeutic strategies being used to modulate this response.

Impact of Off-Pump Coronary Artery Bypass Surgery on Postoperative Bleeding: Current Best Available Evidence

Cardiopulmonary bypass (CPB) is a prerequisite for open-heart surgery, and is a procedure routinely used. CPB exposes blood to artificial surfaces, to mechanical trauma from the pump, to alterations in temperature, and to dilution with fluids, whole blood, plasma products, and drugs, and leads to the activation of platelets, coagulation, and fibrinolysis. Coagulopathy during cardiac surgery with CPB results in impairment in hemostasis and subsequently higher morbidity and mortality. Recent advances in surgical techniques and postoperative management have aimed at reducing postoperative morbidity and mortality. Off-pump coronary artery bypass (OPCAB) surgery is one such advance that attempts to avoid the deleterious effects of extracorporeal circulation by performing myocardial revascularization without CPB. Emerging evidence from several randomized controlled trials (RCTs) as well as large registries such as the Society of Thoracic Surgeons (STS) database suggests that OPCAB reduces the postoperative morbidity and mortality. This review article attempts to evaluate the current best available evidence from RCTs on the impact of OPCAB on postoperative bleeding and transfusion requirements.

Postoperative chest radiographic changes after on- and off-pump coronary surgery

AIM

A variety of chest radiograph abnormalities are recognized after coronary artery bypass grafting (CABG). This study analyzes the appearance of preoperative and postoperative chest radiographs in two groups of patients undergoing myocardial revascularization with or without the use of cardiopulmonary bypass (CPB).

METHODS

Chest radiographs (preoperative and at 1 day, 6 days and 6 to 8 weeks post operatively) were analyzed according to a detailed protocol in cases of conventional CABG on CPB (n=60) or off-pump coronary artery bypass (OPCAB) (n=60) surgery. On each film 17 different major potential postoperative abnormalities were analyzed.

RESULTS

Clinical findings were similar in the two groups. Patients undergoing OPCAB surgery had decreased blood loss, decreased red cell and platelet transfusion, significantly lower intubation time and required less postoperative inotropic support compared with patients undergoing CPB. The CPB group had a significantly higher incidence of left band atelectasis than the OPCAB group (37.6% vs 17.5%, p=0.01) at 6 days postoperatively. There was no other statistically significant difference in any of the 16 remaining major chest radiograph findings between the two groups.

CONCLUSION

Although OPCAB surgery is associated with improved clinical outcome compared with conventional CABG surgery, the analysis of postoperative chest radiographs demonstrated only a minor benefit as shown by a reduced degree of left band atelectasis in the OPCAB group.

Off-Pump Coronary Artery Surgery for Reducing Mortality and Morbidity

OBJECTIVES

The purpose of this study was to assess the effects of off-pump coronary bypass surgery (OPCAB) on mortality and morbidity.

BACKGROUND

Despite its potential for reducing morbidity and mortality, OPCAB's role in clinical practice remains controversial.

METHODS

A meta-analysis of 37 randomized controlled trials (RCTs) (n = 3,449) and 22 risk-adjusted (logistic regression or propensity-score) observational studies (n = 293,617) was performed. Two reviewers performed literature searches (MEDLINE, EMBASE, PubMed, reference lists), quality assessment, and data extraction. Treatment effects were calculated as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

In RCTs, OPCAB was associated with reduced atrial fibrillation (OR 0.59; 95% CI 0.46 to 0.77) and trends toward reduced 30-day mortality (OR 0.91 95% CI 0.45 to 1.83), stroke (OR 0.52; 95% CI 0.25 to 1.05), and myocardial infarction (OR 0.79; 95% CI 0.50 to 1.25). Observational studies showed OPCAB to be associated with reduced 30-day mortality (OR 0.72; 95% CI 0.66 to 0.78), stroke (OR 0.62; 95% CI 0.55 to 0.69), infarction (OR 0.66; 95% CI 0.50 to 0.88), and atrial fibrillation (OR 0.78; 95% CI 0.74 to 0.82). At one to two years, OPCAB was associated with trends toward reduced mortality, but also increased repeat revascularization (RCT: OR 1.75, 95% CI 0.78 to 3.94; Observational: OR 1.35, 95% CI 0.76 to 2.39).

CONCLUSIONS

Randomized controlled trials did not find, aside from atrial fibrillation, the statistically significant reductions in short-term mortality and morbidity demonstrated by observational studies. These discrepancies might be due to differing patient-selection and study methodology. Future studies must focus on improving research methodology, recruiting high-risk patients, and collecting long-term data.