Off-pump CABG reduces complement activation but does not significantly affect peripheral endothelial function: a prospective randomized study

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.

Blood loss after coronary artery bypass by aspirin responsiveness assessed with preoperative VerifyNow aspirin testing

BACKGROUND

Aspirin is important for preventing thrombotic events but also increases bleeding complications. Minimizing bleeding while preventing thrombotic events remains challenging in patients undergoing coronary artery bypass grafting (CABG). Establishing the patient's preoperative aspirin response could distinguish patients at risk for perioperative blood loss.

OBJECTIVE

Aim was to compare 12-h blood loss after CABG between aspirin-sensitive and aspirin-resistant patients.

PATIENTS/METHODS

The primary analysis of this substudy of the POPular CABG trial (NCT02352402) included patients that used aspirin monotherapy preoperatively. A preoperative platelet function test by the VerifyNow aspirin assay was performed before CABG and patients were classified as aspirin-sensitive or aspirin-resistant based on an aspirin reaction units cutoff value of 550. The primary end point was 12-hour blood loss after CABG. The secondary end point was, among others, clinical bleeding events after CABG.

RESULTS

A total of 128 patients were included in the primary analysis. Of these, 116 patients were aspirin sensitive and 12 were aspirin resistant. Mean blood loss 12 hours after CABG was 555 ± 278 mL in aspirin-sensitive patients and 406±110 mL in aspirin-resistant patients (P = .04). All bleeding events (n = 15; 11.7%) occurred in aspirin-sensitive patients.

CONCLUSIONS

In patients who are on aspirin preoperatively, aspirin sensitivity was associated with 12-hour blood loss after CABG, suggesting that preoperative VerifyNow aspirin testing could identify patients undergoing CABG at high risk for perioperative bleeding.

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].

Meta-analysis of interleukin 6, 8, and 10 between off-pump and on-pump coronary artery bypass groups

This study aimed to evaluate the role of off-pump coronary artery bypass (CAB) surgery on the decrease of postoperative inflammatory responses in patients. We systematically searched databases of PubMed and Embase to select the related studies. Interleukin (IL) 6, 8, and 10 were used as outcomes and pooled analysis was performed using R 3.12 software. Standardized mean differences (SMDs) and their 95% confidence intervals (95% CIs) were considered as effect estimates. A total of 27 studies, including 1340 participants, were recruited in this meta-analysis. The pooled analyses showed that postoperative concentration of IL-10 at 12 hours was significantly lower in off-pump CAB group compared to on-pump CAB group (SMD = -1.3640, 95% CI = -2.0086--0.7193). However, no significant differences were found in pre and postoperative concentrations of IL-6 and 8 between off-pump and on-pump CAB groups. These results suggest that there is no advantage of off-pump CAB surgery in the reduction of inflammation compared to on-pump CAB surgery.

The inflammatory response to extracorporeal membrane oxygenation (ECMO): a review of the pathophysiology

Extracorporeal membrane oxygenation (ECMO) is a technology capable of providing short-term mechanical support to the heart, lungs or both. Over the last decade, the number of centres offering ECMO has grown rapidly. At the same time, the indications for its use have also been broadened. In part, this trend has been supported by advances in circuit design and in cannulation techniques. Despite the widespread adoption of extracorporeal life support techniques, the use of ECMO remains associated with significant morbidity and mortality. A complication witnessed during ECMO is the inflammatory response to extracorporeal circulation. This reaction shares similarities with the systemic inflammatory response syndrome (SIRS) and has been well-documented in relation to cardiopulmonary bypass. The exposure of a patient’s blood to the non-endothelialised surface of the ECMO circuit results in the widespread activation of the innate immune system; if unchecked this may result in inflammation and organ injury. Here, we review the pathophysiology of the inflammatory response to ECMO, highlighting the complex interactions between arms of the innate immune response, the endothelium and coagulation. An understanding of the processes involved may guide the design of therapies and strategies aimed at ameliorating inflammation during ECMO. Likewise, an appreciation of the potentially deleterious inflammatory effects of ECMO may assist those weighing the risks and benefits of therapy.

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.

On-pump versus off-pump coronary artery bypass surgery: what is the status after ROOBY, DOORS, CORONARY and GOPCABE?

Off-pump coronary artery bypass surgery has been purported to be safer than conventional coronary artery bypass surgery performed using cardiopulmonary bypass. This theory was supported by a number of early series, but failed to be confirmed by a number of small, randomized, controlled trials. Conversely, it has been suggested that revascularization after off-pump surgery is associated with fewer grafts and lower graft patency, potentially leading to a higher risk of cardiovascular morbidity and need for repeated coronary interventions. Since 2009, four major randomized controlled trials have been published, increasing the level of evidence significantly.

Risk of stroke with percutaneous coronary intervention compared with on-pump and off-pump coronary artery bypass graft surgery: Evidence from a comprehensive network meta-analysis

BACKGROUND

Although some trials have reported that on-pump coronary artery bypass graft (CABG) surgery may be associated with higher rates of stroke than percutaneous coronary intervention (PCI), whether stroke is more common after off-pump CABG compared with PCI is unknown. We therefore sought to determine whether off-pump CABG is associated with an increased risk of stroke compared with PCI by means of network meta-analysis.

METHODS

Randomized controlled trials (RCTs) comparing CABG vs PCI were searched through MEDLINE, EMBASE, Cochrane databases, and proceedings of international meetings.

RESULTS

Eighty-three RCTs with 22,729 patients randomized to on-pump CABG (n = 10,957), off-pump CABG (n = 7,119), or PCI (n = 4,653) were analyzed. Thirty-day rates of stroke were significantly lower in patients treated with PCI compared with either off-pump CABG (odds ratio [OR]; 0.39, 95% CI, 0.19-0.83) or on-pump CABG (OR, 0.26; 95% CI, 0.12-0.47). Compared with on-pump CABG, off-pump CABG was associated with significantly lower 30-day risk of stroke (OR, 0.67; 95% CI, 0.41-0.95). However, in sensitivity analyses restricted to high-quality studies, studies with more than either 100 or 1,000 patients, or studies with protocol definition or adjudication of stroke by a clinical events committee, the precision of the point estimate for the 30-day risk of stroke between off-pump vs on-pump CABG was markedly reduced.

CONCLUSIONS

Percutaneous coronary intervention is associated with lower 30-day rates of stroke than both off-pump and on-pump CABG. Further studies are required to determine whether the risk of stroke is reduced with off-pump CABG compared with on-pump CABG.

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.

Comparable biocompatibility of Phisio- and Bioline-coated cardiopulmonary bypass circuits indicated by the inflammatory response

Background: The biocompatibility of cardiopulmonary bypass surfaces has been improved by heparin and polymer surface modifications. The present study compared the effect of two such coatings on the inflammatory reactions after open heart surgery.

Methods:Thirty patients undergoing elective heart surgery were randomly assigned to receive one of two types of coated circuits: Bioline (n=15) or phosphorylcholine (Phisio, n=15). The platelet and leukocyte counts, neutrophil activation (myeloperoxidase), complement activation (C3a and TCC), concentrations of lactate dehydrogenase, 27 cytokines (including interleukins, chemokines and growth factors), thrombin-antithrombin complexes, and the endothelial cell marker syndecan-1 were analyzed at five predetermined time points until 24 hrs post operatively.

Results: Most measurements were comparable in both groups. However, myeloperoxidase was significantly higher in the Bioline group (p < 0.001). Postoperative lactate dehydrogenase concentrations were significantly higher in the Phisio group (p<0.01) and the maximal concentration of thrombin-antithrombin complexes 2 hours postoperatively tended to be higher in the Phisio group (p=0.08), consistent with a longer aortic cross-clamp and cardiopulmonary bypass time. Conclusions: The two circuits exhibited a comparable degree of in vivo biocompatibility.

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.

Syndecan-1 plasma levels during coronary artery bypass surgery with and without cardiopulmonary bypass

The glycocalyx covering the endothelium is shed during ischemia and reperfusion. The shedding is accompanied by increased levels of the glycocalyx component syndecan-1 in the circulation. Our aim was to compare plasma levels of syndecan-1 in patients undergoing coronary artery bypass grafting (CABG), with or without the use of cardiopulmonary bypass (CPB). Syndecan-1 plasma concentrations were measured in patients undergoing CABG on-pump (n = 22) or off-pump (n = 22). The syndecan-1 concentration increased significantly from 29.5 ± 4.6 ng/mL at baseline to 98.7 ± 9.8 ng/mL (p < 0.01) after the start of CPB or 30 minutes after the induction of anesthesia in the off-pump group. There were no significant differences in peak syndecan-1 plasma concentrations between on-pump and off-pump patients. Plasma levels of syndecan-1 increased significantly during CABG, with or without the use of CPB. There were no significant differences in syndecan-1 concentrations in the two groups.

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.

Effects of preoperative aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in patients undergoing off-pump coronary artery bypass graft surgery

OBJECTIVE

Preoperative exposure to clopidogrel and aspirin significantly increases postoperative bleeding in patients undergoing on-pump coronary artery bypass graft surgery. Off-pump coronary bypass grafting has been proposed as an alternative technique to attenuate postoperative bleeding associated with clopidogrel. This study aimed to determine the effects of aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in off-pump coronary artery bypass grafting.

METHODS

One hundred six patients scheduled for off-pump coronary artery bypass grafting were divided into three groups: aspirin and clopidogrel discontinued more than 6 days before surgery (group 1, n = 35), aspirin and clopidogrel continued until 3 to 5 days before surgery (group 2, n = 51), and both medications continued within 2 days of surgery (group 3, n = 20). Thromboelastographic tracings were analyzed before induction of anesthesia. Routine coagulation profiles were measured before and after surgery. A cell salvage device was used during surgery and salvaged blood was reinfused. Chest tube drainage and blood transfusion requirement were recorded postoperatively.

RESULTS

Patient characteristics, operative data, and thromboelastographic tracings were similar among the groups. There were significant decreases in hematocrit level and platelet count and prolongation in prothrombin time postoperatively in all groups without any intergroup differences. The amounts of perioperative blood loss and blood transfusion required were all similar among the groups.

CONCLUSION

Preoperative clopidogrel and aspirin exposure even within 2 days of surgery does not increase perioperative blood loss and blood transfusion requirements in patients undergoing elective off-pump coronary artery bypass grafting.

Comparison of inflammatory responses after off-pump and on-pump coronary surgery using surface modifying additives circuit

BACKGROUND

Cardiac surgery is followed by various degrees of inflammation, which have harmful consequences. Because of the central role of extracorporeal circulation (EC), off-pump coronary bypass surgery is deemed preferable. Do different modalities of EC challenge this view?

METHODS

Four groups of similar patients underwent coronary surgery: (group 1) on-pump, EC with closed surface modifying additives (SMA) circuit and no pump suckers (n = 20); (group 2) on-pump, EC with open SMA circuit and pump suckers (n = 20); (group 3) off-pump (beating heart) and heparin 3 mg/kg (n = 20); (group 4) off-pump (beating heart) and heparin 1 mg/kg (n = 20). Interleukins (IL)-6, IL-8, IL-10, myeloperoxidase, elastase, and terminal complex of the complement (TCC) were analyzed at various times: at induction (time I); after heparin (time II); after complete revascularization (time III); after protamine (time IV); and 24 hours later (time V).

RESULTS

The TCC was significantly higher in groups 1 and 2 at time III. The pattern of IL-6 was the same for the four groups. No significant difference in myeloperoxydase content was noted; however, elastase was significantly higher in the two EC (on-pump) groups.

CONCLUSIONS

Except for the complement system and elastase, on-pump surgery with SMA-coated circuits did not elicit any greater inflammatory response than off-pump surgery.

Cellular inflammatory response and clinical outcome in cardiac surgery

PURPOSE

This review briefly summarizes recent advances in the understanding of the pathophysiology of the inflammatory response to cardiac surgery and its ties to clinical outcomes. Links between specific inflammatory mediators and vulnerable organs will be emphasized, along with genetic risk factors that render specific patients susceptible to these complications.

RECENT FINDINGS

Circulation of blood on the cardiopulmonary bypass circuit and the operative procedure itself provoke activation of circulating hematopoietic cells and vascular endothelial cells. These activated cells subsequently secrete mediators that amplify this inflammatory response and activated phagocytes undergo changes that facilitate their exit from the circulation into tissue, where they exacerbate organ complications of the procedure. Cardiac, renal and pulmonary dysfunction are among the most common complications of cardiac surgery and progress has been made in recent years demonstrating how the cellular inflammatory response is related to adverse outcomes in these organs. Accordingly, this review will focus on these three systems and the pathophysiology of their cardiac surgical complications.

SUMMARY

Advances in our understanding of the pathways by which inflammatory mediators contribute to host injury offers the promise of interventions that are tailored to specific risks and the possibility of preoperatively identifying those patients most likely to benefit.

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.

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.