Off-pump coronary artery bypass surgery technique for total arterial myocardial revascularization: a prospective randomized study

Clinical outcomes of on-pump versus off-pump coronary-artery bypass surgery: a meta-analysis

BACKGROUND

The ongoing debate regarding off-pump coronary artery bypass grafting (CABG) and on-pump CABG has endured for over three decades. Although numerous randomized controlled trials (RCTs) and meta-analyses have been reported, new evidence has emerged. Therefore, an updated and comprehensive meta-analysis to guide clinical practice is essential.

MATERIALS AND METHODS

A comprehensive search for eligible articles published after 2000, reporting RCTs involving at least 100 patients and comparing off-pump CABG with on-pump CABG, was performed throughout the databases including Embase, Ovid Medline, and Web of Science. The primary interested outcomes included the short-term incidence of stroke and long-term mortality. The primary analysis utilized fixed-effect model with the inverse variance method. The Grade of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of evidence.

RESULTS

After thorough screening, 39 articles were included, consisting of 28 RCTs and involving a total of 16 090 patients. Off-pump CABG significantly reduced the incidence of short-term stroke (1.27 vs. 1.78%, OR: 0.74, P =0.03, high certainty). However, it was observed to be associated with increased mid-term coronary reintervention (2.77 vs. 1.85%, RR: 1.49, P <0.01, high certainty) and long-term mortality (21.8 vs. 21.0%, RR: 1.09, P =0.02, moderate certainty).

CONCLUSIONS

Off-pump CABG significantly reduces the short-term incidence of stroke, but it also increases the incidence of mid-term coronary reintervention. Moreover, it may increase long-term mortality.

Randomized evidence on graft patency after off-pump versus on-pump coronary artery bypass grafting: An updated meta-analysis

BACKGROUND

The debate between off-pump CABG (OPCAB) and on-pump CABG (ONCAB) has been ongoing for decades. We aimed to provide a comprehensive update of the current randomized controlled trials (RCTs) in evaluating the graft patency of OPCAB versus ONCAB.

MATERIALS AND METHODS

A literature search was conducted in PubMed, EMBASE, and the Cochrane Library databases until April 30, 2021. All RCTs from 2003 to 2020 comparing the results of graft patency between OPCAB and ONCAB were included. We compared the overall graft occlusion between the two groups, and subgroup analyses were conducted based on different types of conduits and target territories, crossover from off-pump to on-pump rate, and the length of follow-up.

RESULTS

Sixteen RCTs were identified, with 5743 grafts in the OPCAB group and 5898 in the ONCAB group. OPCAB was associated with a higher risk of occlusion in the overall graft (RR: 1.31; 95% CI, 1.17-1.46), saphenous vein graft (SVG) (RR: 1.40; 95% CI, 1.23-1.59), grafts to left anterior descending (LAD) territory (RR: 1.52; 95% CI, 1.11-2.08) and left circumflex artery (LCX) territory (RR: 1.45; 95% CI, 1.19-1.76), while no significant difference was observed between the two groups in respect of arterial conduits and grafts to right coronary artery (RCA) territory. Furthermore, the lower crossover rate and longer length of follow-up appeared to reduce the association between OPCAB and lower graft patency.

CONCLUSIONS

The current meta-analysis indicates that, compared with ONCAB, graft patency is poorer with OPCAB for overall grafts, SVG grafts, grafts to LAD and LCX territories, whereas the results remain comparable for arterial conduits and grafts to RCA territory.

Representation of Women in Randomized Trials in Cardiac Surgery: A Meta-Analysis

Background

Women have traditionally been underrepresented in randomized clinical trials (RCTs). We performed a systematic evaluation of the inclusion of women in cardiac surgery RCTs published in the past 2 decades.

Methods and Results

MEDLINE, EMBASE, and the Cochrane Library were searched (2000 to July 2020) for RCTs written in English, comparing ≥2 adult cardiac surgical procedures. The percentage of women enrolled and its association with year of publication, sample size, mean age, funding source, geographic location, number of sites involved, and interventions tested were analyzed using a meta‐analytic approach. Fifty‐one trials were included. Of 25 425 total patients, 5029 were women (20.8%; 95% CI, 17.6–24.4; range, 0.5%–57.9%). The proportion of women dropped significantly during the study period (29.6% in 2000 versus 13.1% in 2019, P<0.001). Women were significantly more represented in European trials (26.2%; 95% CI, 21.2–31.9), and less represented in trials of coronary bypass surgery versus other interventions (16.8%; 95% CI, 12.3–22.7 versus 33.6%; 95% CI, 27.4–40.5; P=0.0002) and in trials enrolling younger patients (P=0.009); the percentage of women was higher in industry‐sponsored versus non‐industry sponsored trials (31.7%; 95% CI, 27.2–36.6 versus 15.5%; 95% CI, 10.0–23.2; P=0.0004) and was not associated with trial sample size (P=0.52) or study design (multicenter versus monocenter: P=0.22). After exclusion of trials conducted at Veteran Affairs centers, women representation was 24.4% (95% CI, 21.1–28.0; range, 10.4%–57.9%), with no significant changes during the study period.

Conclusions

The proportion of women in cardiac surgery trials is low and likely inadequate to provide meaningful estimates of the treatment effect.

Effect of Age on Clinical Outcomes Following On-/Off-Pump Coronary Artery Bypass: Meta-Analysis and Meta-Regression

Objective

There is currently much debate about which patients would benefit more after on- or off-pump coronary artery bypass grafting (CABG). The aim of this meta-analysis and meta-regression is to investigate the effect of age on short-term clinical outcomes after these approaches.

Methods

To identify potential studies, systematic searches were carried out in the Excerpta Medica dataBASE (EMBASE), PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL). The search strategy included the key concepts of “cardiopulmonary bypass” AND “coronary artery bypass grafting” AND “off pump” OR “on pump”. This was followed by a meta-analysis and meta-regression investigating the effect of age on the incidences of stroke, myocardial infarction (MI), and mortality.

Results

Thirty-seven studies including 15,324 participants were analysed. Overall, there was a significant odds reduction for patients receiving off-pump CABG suffering a stroke (odds ratio [OR] 0.770, 95% confidence intervals [CI] 0.594, 0.998, P=0.048); however, when patients were subdivided according to different age bands, this difference disappeared. There were also no significant differences in the odds of mortality (OR 0.876, 95% CI 0.703, 1.093, P=0.241) or MI (OR 0.937, 95% CI 0.795, 1.105, P=0.439). Meta-regression analysis revealed no significant relationship between age and stroke (P=0.652), age and mortality (P=548), and age and MI (P=0.464).

Conclusion

Patients undergoing CABG are becoming older and may suffer from multiple comorbidities increasing their risk profile. However, with respect to short-term clinical outcomes, the patient’s age does not help in determining whether off- or on-pump is superior.

Prevalence and Impact of Treatment Crossover in Cardiac Surgery Randomized Trials: A Meta-Epidemiologic Study

Background Crossover dilutes treatment effect and reduces statistical power of intention-to-treat analysis. We examined incidence and impact on cardiac surgery randomized controlled trial (RCT) outcomes of crossover from experimental to control interventions, or vice versa. Methods and Results MEDLINE, EMBASE, and Cochrane Library were searched, and RCTs (≥100 patients) comparing ≥2 adult cardiac surgical interventions were included. Crossover from the initial treatment assignment and relative risks (RRs) for each trial's primary end point and mortality at longest available follow-up were extracted. All RRs were calculated as >1 favored control group and <1 favored experimental arm. Primary outcome was the effect estimate for primary end point of each RCT, and secondary outcome was all-cause mortality; both were appraised as RR at the longest follow-up available. Sixty articles reporting on 47 RCTs (25 440 patients) were identified. Median crossover rate from experimental to control group was 7.0% (first quartile, 2.0%; third quartile, 9.7%), whereas from control to experimental group, the rate was 1.3% (first quartile, 0%; third quartile, 3.6%). RRs for primary end point and mortality were higher in RCTs with higher crossover rate from experimental to control group (RR, 1.01 [95% CI, 0.94-1.07] versus RR, 0.80 [95% CI, 0.66-0.97] and RR, 1.02 [95% CI, 0.95-1.11] versus RR, 0.94 [95% CI, 0.82-1.07], respectively). Crossover from control to experimental group did not alter effect estimates for primary end point or mortality (RR, 0.82 [95% CI, 0.63-1.05] versus RR, 0.95 [95% CI, 0.86-1.04] and RR, 0.88 [95% CI, 0.73-1.07] versus RR, 1.02 [95% CI, 0.95-1.09], respectively). Conclusions Crossover from experimental to control group is associated with outcomes of cardiac surgery RCTs. Crossover should be minimized at designing stage and carefully appraised after study completion.

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].

Off- Versus On-Pump Coronary Surgery and the Effect of Follow-Up Length and Surgeons' Experience: A Meta-Analysis

Background The debate on the relative benefits of off-pump and on-pump coronary artery bypass surgery ( OPCABG and ONCABG ) is still open. We aimed to provide an updated and complete summary of the evidence on the differences between OPCABG and ONCABG and to explore whether the length of the follow-up and the surgeons' experience in OPCABG modify the comparative results. Methods and Results All randomized clinical trials comparing OPCABG and ONCABG were included. Primary outcome was follow-up mortality. Secondary outcomes were operative mortality, perioperative stroke, perioperative myocardial infarction, and late repeated revascularization. Subgroup analyses were performed based on the length of the follow-up and the percentage of crossover from the OPCABG group (used as a surrogate of surgeon experience with OPCABG ). One hundred four trials were included (20 627 patients, OPCABG : 10 288; ONCABG : 10 339). Weighted mean follow-up time was 3.7 years (range 1-7.5 years). OPCABG was associated with a higher risk of follow-up mortality (incidence rate ratio 1.11, 95% confidence interval 1.00-1.23, P=0.05). The difference was significant only for trials with mean follow-up of ≥3 years and for studies with a crossover rate of ≥10%. There was a trend toward lower risk of perioperative stroke and higher need for late repeated revascularization in the OPCABG arm. Conclusions OPCABG is associated with a higher incidence of incomplete revascularization, an increased need for repeated revascularization, and decreased midterm survival compared with ONCABG . Surgeon inexperience in OPCABG is associated with late mortality.

Neurological complications are avoidable during CABG

Objective:

To review the incidence of stroke in patients undergoing CABG and the impact of a preventive strategy adopted at tertiary care unit of cardiac surgery.

Methods:

The data of all patients who underwent isolated CABG (N= 722) from July 2016 to August 2017 at Faisalabad Institute of Cardiology was retrieved for this retrospective study. All operations were done on cardiopulmonary bypass and cold blood cardioplegia. Numeric data was summarized as Mean ± Standard Deviation while categoric variables were summarized into frequency and percentage.

Results:

Mean age of patients was 53.83±8.8 years. Mean Parsonnet and Logistic EuroScore were 4.3±3.2 and 3.3±0.9 respectively. Forty nine patients (6.78%) had significant carotid artery disease. Mean number of grafts was 2.8±0.82. Diabetes was present in 27.8% patients. Neurological complications were noticed in 14 patients (1.94%) who included 12 permanent paralyses. Further subgroup analysis revealed that 67 patients who were operated by single clamp technique remained free of neurological complications. This is clinically remarkable finding but due to small population size it is statistically non- significant.

Conclusion:

The incidence of neurological complications can be reduced significantly by adopting the appropriate preventing measures. Use of Single Clamp technique may be the reasons of such a low incidence of stroke in this study.

Efficacy and effectiveness of on- versus off-pump coronary artery bypass grafting: A meta-analysis of mortality and survival

BACKGROUND

Despite many studies comparing on- versus off-pump coronary artery bypass graft (CABG), there is no consensus as to whether one of these techniques offers patients better outcomes.

METHODS

We searched PubMed from inception to June 30, 2015, and identified additional studies from bibliographies of meta-analyses and reviews. We identified 42 randomized controlled trials (RCTs) and 31 rigorously adjusted observational studies (controlling for the Society of Thoracic Surgeons-recognized risk factors for mortality) reporting mortality for off-pump versus on-pump CABG at specified time points. Trial data were extracted independently by 2 researchers using a standardized form. Differences in probability of mortality (DPM) were estimated for the RCTs and observational studies separately and combined, for time points ranging from 30 days to 10 years.

RESULTS

RCT-only data showed no significant differences at any time point, whereas observational-only data and the combined analysis showed short-term mortality favored off-pump CABG (n = 1.2 million patients; 36 RCTs, 26 observational studies; DPM [95% confidence interval (CI)], -44.8% [-45.4%, -43.8%]) but that at 5 years it was associated with significantly greater mortality (n = 60,405 patients; 3 RCTs, 5 observational studies; DPM [95% CI], 10.0% [5.0%, 15.0%]). At 10 years, only observational data were available, and off-pump CABG showed significantly greater mortality (DPM [95% CI], 14.0% [11.0%, 17.0%]).

CONCLUSIONS

Evidence from RCTs showed no differences between the techniques, whereas rigorously adjusted observational studies (with >1.1 million patients) and the combined analysis indicated that off-pump CABG offers lower short-term mortality but poorer long-term survival. These results suggest that, in real-world settings, greater operative safety with off-pump CABG comes at the expense of lasting survival gains.

Mortality risk factors from converting off-pump coronary artery bypass to on-pump coronary artery bypass

Introduction:

A number of large-scale retrospective studies revealed that off-pump coronary artery bypass (OPCAB) was superior to on-pump coronary artery bypass (ONCAB). The aim of the study was to investigate risk factors for mortality when OPCAB is converted to ONCAB.

Methods:

Patients who underwent OPCAB conversion to ONCAB at the Beijing Anzhen Hospital between January 2003 and January 2013 were assigned to the non-survivor and survivor groups. Background demographics, illness history and preoperative, intraoperative and postoperative variables were compared.

Results:

Of the 247 cases, 15.4% of the patients died. Patients in the non-survivor group were older and more frequently had diabetes mellitus (DM), arrhythmia, myocardial infarction (MI) in the past 30 days (all p<0.05) and MI combined with mitral regurgitation (p<0.0001); they more frequently had bigger left ventricular end-diastolic dimension (p=0.0019), greater fall in blood pressure, ventricular fibrillation for longer periods, longer conversion time and bypass graft occlusion. All patients in the non-survivor group received intra-aortic balloon pump compared to 89.5% in the survivor group and extracorporeal membrane oxygenation was more common. Left main coronary artery disease (OR=4.431, 95%CI: 2.440-8.048, p<0.0001), blood pressure decline ⩽40 mmHg (OR=0.509, 95%CI: 0.447-0.580, p<0.0001) and time for conversion to ONCAB ⩾20 min were independently associated with mortality. Rates of postoperative complications, such as renal failure, cerebral infarction or hemorrhage, MI and redo sternotomy, were higher in the non-survivor group.

Conclusions:

Conversion from OPCAB to ONCAB is associated with high mortality. Risk factors include left main artery disease and duration of blood pressure decline >40 min.

Aortic Arch Atheroma: Stroke Reduction in Cardiac Surgical Patients

Cardiac surgery is increasingly performed on elderly patients with extensive coronary artery abnormalities who have impaired left ventricular function, decreased physiologic reserve, and multiple comorbid conditions. Considerable numbers of these patients develop perioperative neurologic complications ranging from subtle cognitive dysfunction to more evident postoperative confusion, delirium, and, less commonly, clinically apparent stroke. Magnetic resonance imaging studies have elucidated that a considerable number of patients have new ischemic brain infarcts, particularly after conventional coronary artery bypass graft surgery. Mechanisms of cerebral injury during and after cardiac surgery are discussed. Intraoperative transesophageal echocardiography and epiaortic scanning for detection of atheromatous disease of the proximal thoracic aorta is paramount in identifying patients at high risk from neurologic injury. It is important to recognize that our efforts to minimize neurologic injury should not be limited to the intraoperative period. Particular efforts should be directed to temperature management, glycemia control, and pharmacologic neuroprotection extending into the postoperative period. Preoperative magnetic resonance angiography may be of value for screening patients with significant atheroma of the proximal thoracic aorta. It is likely that for patients with no significant atheromatous disease, conventional coronary artery revascularization is the most effective long-term strategy, whereas patients with atheromatous thoracic aorta may be better managed with beating heart surgery, hybrid techniques, or medical therapy alone. Patient stratification based on the aortic atheromatic burden should be addressed in future trials designed to tailor treatment strategies to improve long-term outcomes of coronary heart disease and reduce the risks of perioperative neurologic injury.

On-Pump versus Off-Pump Complete Arterial Revascularization Using Bilateral Internal Mammary Arteries and the T-Graft Technique: Clinical and Angiographic Results for 3,445 Patients in 13 Years of Follow-Up

BACKGROUND

This is an investigation of complete arterial coronary artery bypass grafting (CACABG) using bilateral internal mammary arteries (IMA) and the T-graft technique either on- or off-pump as a routine approach to treat coronary artery disease.

METHODS

Between January 2000 and December 2012, 3,445 patients underwent on-pump (n = 2,216) or off-pump (n = 1,229) CACABG. A 30-day follow-up was performed prospectively, a long-term follow-up by a questionnaire, and coronary angiography in selected patients.

RESULTS

End points at 30 days were death, myocardial infarction, stroke, repeat revascularization, renal replacement, reoperation, sternal wound infection and atrial fibrillation. FitzGibbon A patency rates were 89.8 vs. 91.4% (p = 0.464) with consecutive percutaneous coronary intervention in the grafted area of 1.8 vs. 1.1% (p = 0.693) on- vs. off-pump, and no reoperation in the grafted area in both groups.

CONCLUSION

CACABG by use of skeletonized bilateral IMA with the T-graft technique performed either on- or off-pump is a safe and effective approach.

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.

Agreement of treatment effects for mortality from routinely collected data and subsequent randomized trials: meta-epidemiological survey

OBJECTIVE

To assess differences in estimated treatment effects for mortality between observational studies with routinely collected health data (RCD; that are published before trials are available) and subsequent evidence from randomized controlled trials on the same clinical question.

DESIGN

Meta-epidemiological survey.

DATA SOURCES

PubMed searched up to November 2014.

METHODS

Eligible RCD studies were published up to 2010 that used propensity scores to address confounding bias and reported comparative effects of interventions for mortality. The analysis included only RCD studies conducted before any trial was published on the same topic. The direction of treatment effects, confidence intervals, and effect sizes (odds ratios) were compared between RCD studies and randomized controlled trials. The relative odds ratio (that is, the summary odds ratio of trial(s) divided by the RCD study estimate) and the summary relative odds ratio were calculated across all pairs of RCD studies and trials. A summary relative odds ratio greater than one indicates that RCD studies gave more favorable mortality results.

RESULTS

The evaluation included 16 eligible RCD studies, and 36 subsequent published randomized controlled trials investigating the same clinical questions (with 17,275 patients and 835 deaths). Trials were published a median of three years after the corresponding RCD study. For five (31%) of the 16 clinical questions, the direction of treatment effects differed between RCD studies and trials. Confidence intervals in nine (56%) RCD studies did not include the RCT effect estimate. Overall, RCD studies showed significantly more favorable mortality estimates by 31% than subsequent trials (summary relative odds ratio 1.31 (95% confidence interval 1.03 to 1.65; I(2)=0%)).

CONCLUSIONS

Studies of routinely collected health data could give different answers from subsequent randomized controlled trials on the same clinical questions, and may substantially overestimate treatment effects. Caution is needed to prevent misguided clinical decision making.

The impact of off-pump surgery in end-organ function: practical end-points

Most surgeons perform coronary bypass surgery with the aid of cardiopulmonary bypass, which inflicts a massive systemic inflammatory response to the body leading to adverse clinical outcome. In an attempt to make CABG less invasive, interest have been diverted to the off pump technique.

The current review attempts to bring an insight onto the last ten years knowledge on the off-pump impact in end organ function, with an aim to draw some clear conclusions in order to allow practitioners to reflect on the subject.

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.

Off-pump coronary surgery: current justifications

Although the literature has failed to project an overall superiority of off-pump vs. on-pump surgery, nevertheless, small randomized control trials and large meta-analysis studies have concluded that the incidence of a stroke is less than 1 % when anaortic off-pump techniques are advocated in patients with diseased ascending aorta. Furthermore, off-pump techniques or their combination with hybrid procedures may lead to a reduction of adverse outcome in the aged high-risk population with concomitant poor left ventricular function and co-morbidities. However, despite this, controversy still exists among the cardiac surgery community in terms of the benefit of this technique and its safety; hence, off-pump is becoming out of fashion. In this review paper, by looking at a "marginal group of patients" (elderly, high risks, atherosclerotic aortas) we attempt to re-establish and justify this technique and re-invent its usage.

On-pump with beating heart or cardioplegic arrest for emergency conversion to cardiopulmonary bypass during off-pump coronary artery bypass

BACKGROUND AND OBJECTIVES

Intraoperative conversion, especially under emergent circumstances during off-pump coronary artery bypass (OPCAB), is associated with a significantly higher rate of hospital mortality. This study compared the clinical early outcomes of patients emergently converting to cardiopulmonary bypass (CPB) with or without cardioplegic arrest and evaluated the efficacy of an on-pump beating heart technique for these critically ill patients.

DESIGN AND SETTING

A retrospective study of patients treated at The First Affiliated Hospital of China Medical University over an 8-year period (2005 to 2013).

PATIENTS AND METHODS

Between January 2005 and September 2013, 104 patients were emergently converted to CPB during OPCAB. In the first 55 patients (53%), the cardioplegic arrest was performed. In the most recent 49 patients (47%), the on-pump beating heart procedure was used without cardioplegic arrest.

RESULTS

There were no significant differences in their baseline clinical characteristics, number of anastomoses performed per patient, and reasons for conversions (P > .05). A significant reduction occurred in the observed mortality between the cardioplegic arrest group and the on-pump beating heart group (25.6% vs 6.1%, P=.008). A statistical difference was found between the cardioplegic arrest group and the on-pump beating heart group in the time of CPB, peak cardiac troponin I, duration of inotropic support, time to extubation, intensive care unit stay, postoperative hospital stay, incidence of new intra-aortic balloon pump support, and pulmonary complications (P < .05). The incidence of blood requirements, postoperative myocardial infarction, new-onset atrial fibrillation, hemodialysis, stroke, infective complications, and resurgery for bleeding were lower in on-pump beating heart group, but the difference did not reach statistical significance (P > .05).

CONCLUSION

The on-pump beating heart technique is the preferred method of emergency conversion to CPB during OPCAB. It has lower postoperative mortality and morbidity than the cardioplegic arrest.

Composite arterial grafting

The success of coronary artery bypass grafting, the gold standard for the treatment of multivessel coronary artery disease, is limited by poor long-term vein-graft patency. By contrast, the left internal mammary artery has been demonstrated to have a superior graft patency rate and has provided excellent clinical results. This suggests that the use of arterial conduits for coronary artery bypass grafting may be beneficial for long-term results. Recently, there has been an upsurge in the use of arterial grafts for myocardial revascularization based on the clinical advantage of the use of the left internal mammary artery as a bypass conduit. Many retrospective studies have supported the safety and the effectiveness of arterial grafting, and it has become apparent that the free arterial graft can be used as a branched or a lengthened conduit to the in situ arterial graft by adopting one or more of the several composite grafting techniques. Arterial composite grafts with or without sequential grafting techniques appear an attractive strategy as increased number of distal coronary anastomoses can be performed, with a limited number of grafts, avoiding proximal aortic anastomoses. However, concerns regarding the total dependence of the coronary bypass flow on the flow of one in situ arterial graft and technical error, resulting in compromised flow in one or both limbs of the composite graft have prevented composite arterial grafting from being universally adopted. It is expected that in the near future a prospective, multi-institutional, randomized controlled trial, to compare the short- and long-term outcomes of exclusive arterial grafting using composite and conventional aortocoronary revascularization strategies, will be undertaken to validate the safety and efficacy of composite arterial grafting.

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.

Preoperative hematocrit concentration and the risk of stroke in patients undergoing isolated coronary-artery bypass grafting

Background. Identification and management of risk factors for stroke following isolated coronary artery bypass grafting (CABG) could potentially lower the risk of such serious morbidity. Methods. We retrieved data for 30-day stroke incidence and perioperative variables for patients undergoing isolated CABG and used multivariate logistic regression to assess the adjusted effect of preoperative hematocrit concentration on stroke incidence. Results. In 2,313 patients (mean age 65.9 years, 73.6% men), 43 (1.9%, 95% CI: 1.4–2.5) developed stroke within 30 days following CABG (74.4% within 6 days). After adjustment for a priori defined potential confounders, each 1% drop in preoperative hematocrit concentration was associated with 1.07 (95% CI: 1.01–1.13) increased odds for stroke (men, OR: 1.08, 95% CI: 1.01–1.16; women, OR: 1.02, 95% CI: 0.91–1.16). The predicted probability of stroke for descending preoperative hematocrit concentration exceeded 2% for values <37% (<37% for men (adjusted OR: 2.39, 95% CI: 1.08–5.26) and <38% for women (adjusted OR: 2.52, 95% CI: 0.53–11.98), with a steeper probability increase noted in men). The association between lower preoperative hematocrit concentration and stroke was evident irrespective of intraoperative transfusion use. Conclusion. Screening and management of patients with low preoperative hematocrit concentration may alter postoperative stroke risk in patients undergoing isolated CABG.

Off-pump coronary artery bypass grafting--the current state

The optimal strategy for coronary revascularization remains controversial. Currently, most surgical revascularizations are performed with the use of cardiopulmonary bypass (ONCAB), yet over the past 20 years off-pump coronary artery bypass grafting (OPCAB) has been increasingly used because of the increased awareness of the deleterious effects of cardiopulmonary bypass (CPB) and aortic manipulation. Small, prospective, randomized controlled trials have lacked sufficient sample size to demonstrate differences in early and long-term outcomes. Larger observational studies that are better powered to statistically compare outcomes have shown more favorable in-hospital outcomes and equivalent long-term outcomes with OPCAB and ONCAB. The benefits of OPCAB techniques may be more apparent for patients at high risk for complications associated with CPB and aortic manipulation. Recent studies have demonstrated improved outcomes in higher-risk patients undergoing OPCAB, as well as improved neurological outcomes. The purpose of this review is to outline the recent literature comparing OPCAB with ONCAB, and to demonstrate efficacy of OPCAB as a useful technique for coronary revascularization.

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.

A comparison of long-term mortality for off-pump and on-pump coronary artery bypass graft surgery

BACKGROUND

The survival difference between off-pump and on-pump coronary artery bypass graft surgery for follow-up longer than 5 years is not well-understood. The objective of this study is to examine the difference in 7-year mortality after these 2 procedures.

METHODS AND RESULTS

The state of New York's Cardiac Surgery Reporting System was used to identify the 2640 off-pump and 5940 on-pump patients discharged from July through December 2000. The National Death Index was used to ascertain patients' vital statuses through 2007. A logistic regression model was fit to predict the probability of receiving an off-pump procedure using baseline patient characteristics. Off-pump and on-pump patients were matched with a 1:1 ratio based on the probability of receiving an off-pump procedure. Kaplan-Meier survival curves for the 2 procedures were compared using the propensity-matched data, and the hazard ratio for death for off-pump in comparison with on-pump procedures was obtained. In subgroup analyses, the significance of interactions between type of surgery and baseline risk factors was tested. In this study, 2631 pairs of off-pump and on-pump patients were propensity matched. The 7-year Kaplan-Meier survival rates were 71.2% and 73.4% (P=0.07) for off-pump and on-pump surgery, respectively. The hazard ratio for death (off-pump versus on-pump) was 1.10 (95% confidence interval: 0.99 to 1.21, P=0.07). No statistical significance was detected for the interaction terms between the type of surgery and a number of different baseline risk factors.

CONCLUSIONS

The difference in long-term mortality between on-pump and off-pump coronary artery bypass graft surgery is not statistically significant.

Impact of off-pump to on-pump conversion rate on post-operative results in patients undergoing off-pump coronary artery bypass

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: In patients undergoing off-pump coronary artery bypass (OPCAB) surgery, does the off-pump to on-pump conversion rate have an impact on post-operative results? Altogether more than 420 papers were found using the reported search, of which 14 randomized controlled trials (RCTs) represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated and ordered according to the sample size. In the 14 RCTs reviewed, the off-pump to on-pump conversion rate incidence ranged from 0 to 13.3%. The most frequent causes of conversion were haemodynamic instability and intramyocardial-coronary target. A low conversion rate (<2%) was reported by five studies. Three of them did not show any difference in terms of mortality between the OPCAB and on-pump groups, one showed better survival of the OPCAB group at 5 years, and one reported better early survival of the OPCAB group. Three of these trials describe a high OPCAB experience and reported that patients undergoing OPCAB had a shorter post-operative stay and lower morbidity compared with patients undergoing on-pump coronary artery bypass grafting. Five RCTs showed a high conversion rate (>9%), and among them, one reported lower morbidity of the OPCAB patients, three were not able to show any benefit in terms of morbidity of the OPCAB, and one reported worse survival and patency graft rate of the OPCAB group. Four RCTs reported conversion rates ranging from 3.7 to 7.0%, describing a wide spectrum of results. We conclude that RCTs with a high off-pump to on-pump conversion rate were often associated with a lower experience in OPCAB of the surgeons participating in the trials. These studies were also mostly unable to show any benefit in terms of mortality or morbidity of OPCAB over the on-pump strategy. On the contrary, a low conversion rate is mostly reported by RCTs with a high structured experience in OPCAB. These trials were mostly able to show a benefit, in terms of morbidity and survival, of the OPCAB over the on-pump strategy.

Teaching off-pump coronary artery bypass surgery

Off-pump coronary artery revascularization requires a unique skill set and a different conduct of operation compared with on-pump coronary artery bypass. Not only must the surgeon perform anastomoses on the beating heart, but he/she must understand the hemodynamic consequences of cardiac positioning and stabilization, the effects of regional ischemia on hemodynamic function, contractility, and arrhythmias, and the importance of anesthesia and grafting sequence given variants of anatomy and clinical conditions. Given these differences, the ability to teach off-pump coronary artery bypass to residents and surgeons places unique demands on the teaching surgeon. In this article, we review the available literature about the safety and efficacy of teaching off-pump coronary artery bypass to residents, discuss the fundamentals for training residents, and review the future of simulation and new training paradigms and the impact this will have on current training methods.

Off-pump coronary artery bypass may increase late mortality: a meta-analysis of randomized trials

BACKGROUND

Although a lot of randomized trials of off-pump coronary artery bypass grafting (CABG) versus on-pump CABG were conducted, the majority of them reported only early outcomes. Previous meta-analyses of a few randomized trials found no differences for 1-year to 2-year mortality.

METHODS

We focused late (> or = 1 year) all-cause mortality and performed a meta-analysis of randomized controlled trials of off-pump versus on-pump CABG. The MEDLINE, the EMBASE, and the Cochrane Central Register of Controlled Trials were searched using PubMed and OVID. For each study, data regarding all-cause mortality in both the off-pump and on-pump groups were used to generate risk ratios (RRs) and 95% confidence intervals. Study-specific estimates were combined using inverse variance-weighted averages of logarithmic RRs in both fixed-effects and random-effects models.

RESULTS

Our search identified 11 results of 12 randomized trials (4,326 patients) of off-pump versus on-pump CABG. Pooled analysis demonstrated a statistically significant increase in midterm all-cause mortality by a factor of 1.37 with off-pump relative to on-pump CABG (RR, 1.373; 95% confidence interval, 1.043 to 1.808). Exclusion of any single result, except for the largest (>2,000 patients) trial, from the analysis did not substantively alter the overall result of our analysis. Eliminating the largest trial demonstrated a statistically nonsignificant benefit of on-pump over off-pump CABG for midterm all-cause mortality (RR, 1.344; 95% confidence interval, 0.952 to 1.896).

CONCLUSIONS

The results of our analysis suggest that off-pump CABG may increase late all-cause mortality by a factor of 1.37 over on-pump CABG. Longer term mortality from randomized trials of off-pump versus on-pump CABG is needed.

Reoperative off-pump coronary artery bypass grafting: current outcomes, concerns and controversies

Increasing numbers of patients have undergone coronary artery bypass grafting in the last four decades. As a result, the incidence of reoperative coronary artery bypass grafting is rising. Reoperative procedures pose several technical difficulties and are associated with increased operative risks, which exceed those of the initial revascularization. As the incidence of reoperative procedures is increasing so is the experience of reoperative coronary artery bypass grafting, with the resultant evolution of several alternative strategies to lower the operative risks. These strategies include alternative techniques for re-entry, strict avoidance of graft manipulation to minimize the risk of graft atheroembolism, and modification of the method of myocardial protection, depending on the status of the native coronary circulation and the patency of venous or arterial grafts. Off-pump coronary artery bypass grafting is one such technique that, through the avoidance of inherent risks of cardiopulmonary bypass, has the potential to reduce the morbidity associated with reoperative coronary artery bypass grafting. This article evaluates the current outcomes of reoperative off-pump coronary artery bypass grafting, and highlights the concerns and controversies associated with this strategy.

Off-pump coronary artery bypass: techniques, pitfalls, and results

In an attempt to advance the surgical treatment of coronary artery disease, surgeons sought a way to offer the proven benefits of coronary revascularization and avoid the side effects of cardiopulmonary bypass by performing revascularization in the beating heart (off-pump coronary artery bypass). This review will describe the development and refinement of the technique, pitfalls to its widespread adoption, and an up-to-date assessment of current results.

Y grafting for coronary artery bypass: is it as good as single grafting?

PURPOSE OF REVIEW

The use of multiple arterial grafting has gained popularity in recent years due to its clinical advantages when compared with conventional CABG surgery. The purpose of the present review is to focus in particular on the safety and efficacy of composite Y grafting in coronary surgery.

RECENT FINDINGS

Several studies demonstrated mid-term and long-term benefits of total arterial myocardial revascularization when compared with conventional CABG, that is utilizing the left internal mammary artery and multiple veins. Nevertheless, there have been concerns whether it is safe to have a single inflow rather than multiple aorto-coronary grafts. There is evidence in literature that composite arterial grafting is nowadays a well established technique, and several configurations can be performed according to the specific patients' needs. Moreover, the use of Y grafting completely avoids aortic manipulation, especially when used in association with the off-pump technique.

SUMMARY

Composite Y grafting with the exclusive use of arterial conduits is a well tolerated and effective technique. The choice of the second arterial conduit should be tailored according to the specific patients' characteristics. The association of composite arterial grafting and off-pump technique allows a no-touch technique of the ascending aorta, thereby also minimizing the risk of neurological events.