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

A meta-analysis of the prospective randomised trials of coronary revascularisation before noncardiac vascular surgery with attention to the type of coronary revascularisation performed

BM Biccard and RN Rodseth.

Review published: 2009.

CRD summary

The review found that preoperative percutaneous coronary intervention before non-cardiac vascular surgery had significantly worse 30-day outcomes than medical therapy, but preoperative coronary artery bypass graft led to significantly lower long-term rates of death or myocardial infarction. Due to methodological problems, including a lack of randomised comparisons, these conclusions may not be reliable.

Authors' objectives

To assess the effects of preoperative coronary revascularisation in patients undergoing non-cardiac vascular surgery and compare different types of coronary revascularisation in this context.

Searching

PubMed was searched to February 2009. Search terms were reported. Reference lists of reviews and eligible studies were checked.

Study selection

Randomised controlled trials (RCTs) of preoperative coronary revascularisation in patients who underwent non-cardiac vascular surgery were eligible for inclusion. Studies were required to report all-cause and/or cardiac mortality and nonfatal myocardial infarction.

Participants in the review were scheduled for elective vascular surgery (aortic aneurysm repair or infra-inguinal surgery). Mean or median age ranged from 66 to 71 years. Included studies applied different eligibility criteria for coronary revascularisation and as a result their participant risk profiles differed; one of the two studies had a higher rate of three-vessel coronary artery disease and significant left main stem disease. Rates of prior myocardial infarction and congestive cardiac failure were approximately 42% and 10% in one study and 98% and 46% in the other. Rates of diabetes mellitus ranged from 29% to 40% across study groups. Interventions in the review included coronary artery bypass graft (CABG) and percutaneous coronary intervention (PCI) using bare-metal or drug-eluting stents with or without antiplatelet therapy (aspirin or clopidogrel). Controls received medical management only. Median delay from randomisation to non-cardiac surgery was 54 days in the intervention group and 18 days in controls for one study. The review reported mortality, non-fatal myocardial infarction and mortality or non-fatal myocardial infarction combined (death/myocardial infarction) at 30 days and/or at late follow-up (one year and 2.7 years).

Two reviewers independently selected the studies. Disagreements were resolved by consensus or by contact with the original authors.

Assessment of study quality

Two reviewers independently assessed study validity. Disagreements were resolved by consensus. Criteria used to assess validity were not reported.

Data extraction

Odds ratios (ORs) and 95% confidence intervals (CIs) were extracted or calculated from the numbers of events in the two groups of each study.

Two reviewers independently extracted data. Disagreements were resolved by consensus. Primary study authors were contacted for more information if required.

Methods of synthesis

Studies were combined to calculate pooled odds ratios and 95% CIs. Heterogeneity was assessed using Χ2 and I2 tests. Fixed-effect models were used for all analyses unless there was significant heterogeneity, in which case random-effects models were used. Subgroup analyses were conducted that compared PCI and CABG individually against controls and against each other.

Results of the review

Two RCTs (n=611 total, range 101 and 510) were included in the review.

Preoperative coronary revascularisation was associated with significantly higher rates of 30-day all-cause mortality (OR 2.01, 95% CI 1.04 to 3.89), 30-day death/myocardial infarction (OR 1.84, 95% CI 1.21 to 2.80) and late death/myocardial infarction (OR 1.60, 95% CI 1.16 to 2.21) than optimal medical therapy. There was no statistically significant difference between the groups for 30-day non-fatal myocardial infarction.

Compared to medical therapy, PCI was associated with a significantly higher rate at 30 days of non-fatal myocardial infarction (OR 2.14, 95% CI 1.05 to 4.36, I2=42.8%, random-effects model) and death/myocardial infarction (OR 2.44, 95% CI 1.54 to 3.82). There were non-significant trends to inferior results for other outcomes.

Compared to medical therapy, CABG was associated with non-significant trends to worse results for 30-day outcomes and a trend to superior results for late death/myocardial infarction.

When CABG and PCI were compared, CABG was significantly superior for late death/myocardial infarction (OR 0.60, 95% CI 0.37 to 0.98). There was a non-significant trend that favoured CABG for 30-day death/myocardial infarction.

Heterogeneity was low (I2=0% to 9.7%) for all subgroup analyses except those mentioned above.

Authors' conclusions

Preoperative PCI before non-cardiac vascular surgery had significantly worse 30-day outcomes than medical therapy, but preoperative CABG led to significantly lower long-term rates of death or non-fatal myocardial infarction than PCI.

CRD commentary

The objectives and inclusion criteria of the review were clear. The search was limited to a single database, so some studies may have been missed. It was unclear whether the search was limited by publication status and language. Publication bias was not formally assessed. Steps were taken to minimise risks of reviewer bias and error by having more than one reviewer independently select studies, undertake validity assessment and extract data. The authors did not report criteria used to assess study validity and no details were provided about the quality of individual studies (such as allocation concealment, follow-up rates). These factors made it difficult to evaluate the reliability of the data presented. The statistical methods used to combine data and assess heterogeneity were appropriate in most respects, although possible reasons for substantial heterogeneity (where it occurred in a subgroup analysis) were not explored.

The authors' conclusions about the relative effects of PCI and CABG may not be reliable, as they were based on non-randomised comparisons. The choice of intervention (PCI or CABG) depended on clinical judgement and it was possible that patients at higher risk received PCI; prevalence of risk factors in the two groups was not compared. The authors noted potential for deaths early in the study to bias the results for long-term outcomes.

Due to methodological problems, including a lack of randomised comparisons of CABG and PCI, the authors' conclusions may not be reliable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that further research was needed to determine the indications and optimum timing for CABG in vascular surgical patients. Guideline recommendations at the time of teh review may not adequately reflect the value of prophylactic coronary revascularisation.

Funding

Not stated.

Bibliographic details

Biccard BM, Rodseth RN. A meta-analysis of the prospective randomised trials of coronary revascularisation before noncardiac vascular surgery with attention to the type of coronary revascularisation performed. Anaesthesia 2009; 64(10): 1105-1113. [PubMed: 19735402]

Indexing Status

Subject indexing assigned by NLM

MeSH

Aged; Coronary Artery Bypass; Humans; Middle Aged; Myocardial Infarction /etiology; Myocardial Revascularization /adverse effects /methods; Randomized Controlled Trials as Topic; Treatment Outcome; Vascular Surgical Procedures /adverse effects /mortality

AccessionNumber

12009109103

Database entry date

03/11/2010

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: 19735402

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