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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Meta-analysis of on-pump and off-pump coronary arterial revascularization

ZZ Feng, J Shi, XW Zhao, and ZF Xu.

Review published: 2009.

Link to full article: [Journal publisher]

CRD summary

This review concluded that there was no difference in mortality, stroke, myocardial infarction or revascularisation at one year following off-pump coronary artery bypass compared to conventional (using cardiopulmonary bypass) coronary artery bypass. Although there were some reporting errors in the text, the review appeared generally well conducted and the authors conclusions appear reasonable.

Authors' objectives

To assess the effects of off-pump coronary artery bypass (OPCAB) compared to conventional coronary artery bypass (CCAB).


MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Current Contents, DARE, NHS EED and INAHTA databases were searched from inception to April 2008. Search terms were given. No language restrictions were applied. Bibliographies of identified studies, scientific meeting abstracts and related journals were checked. Authors of studies were contacted.

Study selection

Randomised controlled trials (RCTs) that compared OPCAB to CCAB (with cardiopulmonary bypass) in adults who underwent single or multiple vessel coronary bypass and that reported at least one relevant clinical outcome were eligible for inclusion. Hybrid (OPCAB plus balloon angioplasty) and robotically assisted surgery studies were excluded. Primary outcomes of interest were all cause mortality, stroke, myocardial infarction and revascularisation (repeat coronary artery bypass or balloon angioplasty). Outcomes were assessed at one year.

Most of the included studies were on either first time CABG or excluded emergency surgery. People in higher risk groups (aged over 70, renal dysfunction, pulmonary disease, aortic disease, ongoing ischaemia) were under represented.

Two authors independently assessed studies for inclusion.

Assessment of study quality

Quality was assessed using the Jadad scale. Points were awarded for items related to randomisation, blinding and completeness of follow-up to a maximum score of 5.

Two reviewers independently assessed the quality of included studies. Disagreements were resolved by consensus.

Data extraction

Odds ratios (OR) with 95% confidence intervals (CI) were calculated. Where necessary, authors of studies were contacted to clarify data and ensure that data from individual studies were not inadvertently included more than once.

Two authors independently extracted data

Methods of synthesis

Where possible data were analysed on an intention-to-treat basis.

Pooled odds ratios and 95% CI were calculated using a fixed-effect and a random-effects model. The fixed-effect results were reported.

Heterogeneity was assessed using the Q statistic and I2. Subgroup analyses investigated differences based on number of diseased vessels (two or more), length of follow-up (two or more years) and number of participants (100 or more). Sensitivity analyses investigated study quality (Jadad score 3 or more) and publication status,

Publication bias was assessed using a funnel plot.

Results of the review

Ten RCTs (2,018 participants) were included. Five studies scored 2 for quality, four scored 3 and one scored 5. Length of follow-up ranged from one to 3.8 years.

There were no differences between OPCAB and CCAB for mortality (OR 1.00, 95% CI 0.56 to 1.77), stroke (OR 0.56, 95% CI 0.21 to 1.47), revascularisation (OR 1.38, 95% CI 0.72 to 2.67) and myocardial infarction (OR 0.61, 95% CI 0.31 to 1.17).

Subgroup analyses showed similar results. Sensitivity analyses showed no association between trial quality and outcomes. There were no unpublished studies.

Authors' conclusions

There was no difference in mortality, stroke, myocardial infarction or revascularisation at one year following off-pump coronary artery bypass (OPCAB) compared with conventional (using cardiopulmonary bypass) coronary artery bypass.

CRD commentary

The aims of the review were clearly stated in terms of intervention, participants, study design and outcomes. The search covered a number of appropriate sources. Attempts were made to eliminate the effects of language and publication biases. The methods of study selection, data extraction and quality assessment were likely to have reduced the possibility of reviewer error or bias. Quality was assessed. However, a scoring method was used and this is not considered to be the best method for accurately assessing the quality of studies. The methods of analyses appeared appropriate. Heterogeneity was assessed. The authors stated that participants of the included studies were not those of higher risk, so the results may not be generalisable to all populations. There were some discrepancies in the numbers reported in the results (corrected in a following publication, see Other Publications of Related Interest).

The review appeared to generally well conducted and the authors' conclusions appear reasonable.

Implications of the review for practice and research

The authors did not state any implications for research or for practice.


None stated

Bibliographic details

Feng ZZ, Shi J, Zhao XW, Xu ZF. Meta-analysis of on-pump and off-pump coronary arterial revascularization. Annals of Thoracic Surgery 2009; 87(3): 757-765. [PubMed: 19231385]

Other publications of related interest

Correction: Annals of Thoracic Surgery 2009; 87:2008

Indexing Status

Subject indexing assigned by NLM


Coronary Artery Bypass; Coronary Artery Bypass, Off-Pump; Humans; Randomized Controlled Trials as Topic



Database entry date


Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 19231385


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