Authors' objectives

A meta-analysis to compare the relative merits of initial policies of percutaneous coronary angioplasty (PCA) and coronary artery bypass grafts (CABG) for patients with severe angina.

Searching

No search strategy was given but the authors state: 'Given the interest in the topic, the effectiveness of large annual cardiological meetings in enhancing communication and the extent of our collective awareness of research in this area, it is unlikely that any sizable randomised trials have been missed.'

Study selection

Assessment of study quality

The authors do not report the method used to assess validity, or how the validity assessment was performed.

Data extraction

A standard proforma was sent to every principal investigator requesting the following information for each treatment group: number of randomised patients, median length of follow-up, number receiving randomised procedure, and the distribution of angina grade at 1 and 3 years after randomisation. All data and results on events are recorded in accordance with analysis by intention to treat, except for event rates during hospital admission.

Methods of synthesis

Results of the review

Although 9 trials were identified, only 8 were included in the meta-analysis: 1 trial was unable to supply data because of a predefined commitment to achieve 5 years of follow-up before publication or release of information. The meta-analysis included 3,371 patients (1,661 CABG and 1,710 PCA).

The total deaths for CABG and PCA were 73 and 79 respectively, with a relative risk (RR) of 1.08 (95% confidence interval, CI: 0.79, 1.50).

17.8% of patients randomised to PCA, required further CABG within the first year, while in subsequent years the need for additional CABG was around 2% per annum. The rate of additional non-randomised interventions in the first year of follow-up was 33.7% for patients randomised to PCA and 3.3% for CABG. Significant heterogeneity was found between the PCA trials in the re-intervention rates.

The prevalence of angina after 1 year was higher in the PCA group (RR 1.56, 95% CI: 1.30, 1.88) but at 3 years this difference had attenuated (RR 1.23, 95% CI: 0.99, 1.54).

Separate analyses of the 732 single- and 2,639 multi-vessel patients revealed significantly lower first-year mortality and angina prevalence rates in single-vessel patients, and also lower rates of additional intervention.

Authors' conclusions

Initial myocardial revascularisation strategies of PCA and CABG, in patients who are suitable for either treatment, are associated with similar medium-term risk of death and myocardial infarction. However, clear differences exist between the two treatment policies in terms of requirement for additional revascularisation procedures and relief of symptoms over 3 years. Further follow-up of all randomised patients is required to assess the longer-term effects of PCA and CABG on clinical outcome.

CRD commentary

The authors of the meta-analysis are the principal investigators of the component studies.

Since no search strategy is reported, it is possible that some relevant studies have been excluded. No details were provided on how decisions relating to the relevance of primary studies were taken, or how validity was judged. Data extraction was undertaken by the principal investigators of the included studies.

It is questionable whether these studies should have been combined since the trials differ in their objectives, inclusion criteria and length of follow-up, as discussed at length by the authors. The calculated pooled estimate of effect is of questionable value, owing to significant differences in mortality and angina rates of the single- and multi-vessel disease patients.

Bibliographic details

Pocock S J, Henderson R A, Rickards A F, Hampton J R, King S B, Hamm C W, Puel J, Heub W, Goy J J, Rodriguez A. Meta-analysis of randomised trials comparing coronary angioplasty with bypass surgery. Lancet 1995; 346: 1184-1189. [PubMed: 7475657]

Other publications of related interest

This additional published commentary may also be of interest. White HD. Angioplasty versus bypass surgery. Lancet 1995;346:1174-5.

Indexing Status

Subject indexing assigned by NLM

MeSH

Angina Pectoris /epidemiology /mortality /therapy; Angioplasty, Balloon, Coronary; Cause of Death; Coronary Artery Bypass; Follow-Up Studies; Humans; Myocardial Infarction /etiology; Prevalence; Prognosis; Randomized Controlled Trials as Topic; Reoperation

AccessionNumber

11995003064

Database entry date

31/01/1997

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.