This review concluded that stent implantation for stable coronary artery disease showed no evidence of benefit compared with initial medical therapy for the prevention of death, nonfatal myocardial infarction, unplanned revascularization, or angina. There were a number of limitations of the review, and very few patients had drug-eluting stents, so the reliability and applicability of the conclusions is uncertain.

To compare the effect of initial coronary stent implantation versus medical therapy on death, nonfatal myocardial infarction, unplanned revascularization, and persistent angina in patients with stable coronary artery disease.

MEDLINE was searched with no language restrictions from 1970 to September 2011; search terms were reported. Bibliographies of retrieved articles and prior reviews were also searched.

Randomised controlled trials (RCTs) with at least one year follow-up that compared percutaneous coronary intervention plus medical therapy versus medical therapy alone in patients with stable coronary artery disease were eligible for inclusion. Eligible trials had to report individual outcomes of mortality and nonfatal myocardial infarction. To be included, at least 50% of percutaneous coronary intervention procedures had to be stent implantation.

Some of the included trials restricted recruitment to patients who had stabilised after an myocardial infarction; the proportion with previous myocardial infarction in other trials ranged from 15 to 46%. The mean age of participants ranged from 57 to 64 years. The proportion of men ranged from 68 to 100%. The proportion of participants with diabetes ranged from 14 to 100% (most trials had less than 35%). The mean ejection fraction ranged from 36 to 67%. One to two vessels were treated. Stents were implanted in 72 to 100% of patients (most were bare-metal stents). Medical therapy included aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, and/or statins.

The number of reviewers selecting studies for the review was not reported.

Trial quality was assessed using the Jadad scale.

The number of reviewers performing the quality assessment was not stated.

The incidence of all-cause mortality, nonfatal myocardial infarction/reinfarction, unplanned revascularization (percutaneous coronary intervention or coronary artery bypass graft) during follow-up, and persistent angina were extracted for the longest follow-up available (maximum of five years) by two independent reviewers; disagreements were resolved by discussion. Odds ratios (OR) and 95% confidence intervals (CI) were calculated on an intention-to-treat basis. Where medical therapy was compared against percutaneous coronary intervention and coronary artery bypass graft, only medical therapy versus stent implantation was extracted.

Pooled odds ratios and 95% confidence intervals were calculated using a random-effects model. Heterogeneity was assessed using the Cochran Q and Ι².

Trials recruiting asymptomatic patients following myocardial infarction were analysed separately in subgroup analyses. Sensitivity analyses were conducted to investigate the impact of each individual trial and the inclusion of trials with no mortality events in either treatment group.

Publication bias was assessed using a funnel plot and the Egger weighted linear regression test.

Eight trials met the inclusion criteria (n=7,229 patients, range 66 to 2,287). Mean follow-up was 4.3 years (range one to five years). None of the trials concealed allocation or reported using any blinding. Seven trials reported reasons for withdrawals.

Overall there were 649 deaths (OR 0.98, 95% CI 0.83 to 1.15; Ι²=0), 322 out of 3,617 patients in the stent arms (8.9%), and 327 out of 3,612 patients in the medical therapy arms (9.1%). There was no statistically significant difference between the stent and medical therapy groups for nonfatal myocardial infarction, unplanned revascularization, or persistent angina, either overall or in the subgroup analyses conducted.

There was no evidence of publication bias.

Initial stent implantation for stable coronary artery disease showed no evidence of benefit compared with initial medical therapy for prevention of death, nonfatal myocardial infarction, unplanned revascularization, or angina.

The authors addressed a clear review question, supported by well-defined inclusion criteria. The search was limited to a single electronic database and, although no language restrictions were applied and publication bias was investigated, missed studies could not be ruled out. Data extraction was conducted in duplicate, but it was unclear whether similar methods to reduce error and bias were employed during study selection and quality assessment. Trial quality was assessed using established criteria for RCTs, but the usefulness of the few criteria used was limited (given the nature of the interventions) and review specific criteria were not evaluated.

Very few of the patients included in the trials had drug-eluting stents, so the generalisability of the results to the wider percutaneous coronary intervention population was uncertain. Given the limited generalisability and the limitations of the review, the conclusions and implications for practice should be treated with some caution.

Practice: The authors stated that: up to 76% of patients with stable coronary artery disease could avoid percutaneous coronary intervention altogether if treated with optimal medical therapy; upstream testing to demonstrate ischaemic patients with stable angina symptoms may not be necessary; and current recommendations for instituting optimal medical therapy in patients with stable coronary artery disease rather than proceeding directly to stent implantation were supported.

Research: The authors did not state any implications research.

California Health Care Foundation, USA; Parsemus Foundation, California, USA.

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.