Routine invasive strategies versus selective invasive strategies for unstable angina and non-ST elevation myocardial infarction in the stent era

BACKGROUND

People with unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI) are managed with a combination of medical therapy, invasive angiography and revascularisation. Specifically, two approaches have evolved: either a 'routine invasive' strategy whereby all patients undergo coronary angiography shortly after admission and, if indicated, coronary revascularisation; or a 'selective invasive' (also referred to as 'conservative') strategy in which medical therapy alone is used initially, with a selection of patients for angiography based upon evidence of persistent myocardial ischaemia. Uncertainty exists as to which strategy provides the best outcomes for these patients. This Cochrane review is an update of a Cochrane review originally published in 2006, to provide a robust comparison of these two strategies in the early management of patients with UA/NSTEMI.

OBJECTIVES

To determine the benefits and harms associated with the following.1. A routine invasive versus a conservative or 'selective invasive' strategy for the management of UA/NSTEMI in the stent era.2. A routine invasive strategy with and without glycoprotein IIb/IIIa receptor antagonists versus a conservative strategy for the management of UA/NSTEMI in the stent era.

SEARCH METHODS

We searched the following databases and additional resources up to 25 August 2015: the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library, MEDLINE and EMBASE, with no language restrictions.

SELECTION CRITERIA

We included prospective randomised controlled trials (RCTs) that compared invasive with conservative or 'selective invasive' strategies in participants with acute UA/NSTEMI.

DATA COLLECTION AND ANALYSIS

Two review authors screened the records and extracted data in duplicate. Using intention-to-treat analysis with random-effects models, we calculated summary estimates of the risk ratio (RR) with 95% confidence intervals (CIs) for the primary endpoints of all-cause death, fatal and non-fatal myocardial infarction (MI), combined all-cause death or non-fatal MI, refractory angina and re-hospitalisation. We performed further analysis of included studies based on whether glycoprotein IIb/IIIa receptor antagonists were used routinely. We assessed the heterogeneity of included trials using Pearson χ² (Chi² test) and variance (I² statistic) analysis. Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, we assessed the quality of the evidence and the GRADE profiler (GRADEPRO) was used to import data from Review Manager 5.3 (Review Manager) to create Summary of findings (SoF) tables.

MAIN RESULTS

Eight RCTs with a total of 8915 participants (4545 invasive strategies, 4370 conservative strategies) were eligible for inclusion. We included three new studies and 1099 additional participants in this review update. In the all-study analysis, evidence did not show appreciable risk reductions in all-cause mortality (RR 0.87, 95% CI 0.64 to 1.18; eight studies, 8915 participants; low quality evidence) and death or non-fatal MI (RR 0.93, 95% CI 0.71 to 1.2; seven studies, 7715 participants; low quality evidence) with invasive strategies compared to conservative (selective invasive) strategies at six to 12 months follow-up. There was appreciable risk reduction in MI (RR 0.79, 95% CI 0.63 to 1.00; eight studies, 8915 participants; moderate quality evidence), refractory angina (RR 0.64, 95% CI 0.52 to 0.79; five studies, 8287 participants; moderate quality evidence) and re-hospitalisation (RR 0.77, 95% CI 0.63 to 0.94; six studies, 6921 participants; moderate quality evidence) with routine invasive strategies compared to conservative (selective invasive) strategies also at six to 12 months follow-up.Evidence also showed increased risks in bleeding (RR 1.73, 95% CI 1.30 to 2.31; six studies, 7584 participants; moderate quality evidence) and procedure-related MI (RR 1.87, 95% CI 1.47 to 2.37; five studies, 6380 participants; moderate quality evidence) with routine invasive strategies compared to conservative (selective invasive) strategies.The low quality evidence were as a result of serious risk of bias and imprecision in the estimate of effect while moderate quality evidence was only due to serious risk of bias.

AUTHORS' CONCLUSIONS

In the all-study analysis, the evidence failed to show appreciable benefit with routine invasive strategies for unstable angina and non-ST elevation MI compared to conservative strategies in all-cause mortality and death or non-fatal MI at six to 12 months. There was evidence of risk reduction in MI, refractory angina and re-hospitalisation with routine invasive strategies compared to conservative (selective invasive) strategies at six to 12 months follow-up. However, routine invasive strategies were associated with a relatively high risk (almost double the risk) of procedure-related MI, and increased risk of bleeding complications. This systematic analysis of published RCTs supports the conclusion that, in patients with UA/NSTEMI, a selectively invasive (conservative) strategy based on clinical risk for recurrent events is the preferred management strategy.

WITHDRAWN: Puerarin injection for unstable angina pectoris

The Editor/CRG withdrew this review as the current author team is unable to progress to the final stage of the review update. The editors consider this title as low priority for the current portfolio of the Heart Group and therefore this title is not open to a new author team.

The editorial group responsible for this previously published document have withdrawn it from publication.

Puerarin injection for unstable angina pectoris

BACKGROUND

Puerarin is extracted from the Chinese herb puerariae lobata. Many users of Chinese herbal medicine believe that puerarin has positive effects in the treatment of coronary heart disease (CHD). In recent years puerarin injection has been widely used to treat CHD and angina pectoris.

OBJECTIVES

To assess the benefits and harms of puerarin injection for unstable angina.

SEARCH STRATEGY

The following electronic databases were searched: The Cochrane Controlled Trials Register on The Cochrane Library (Issue 3, 2004), MEDLINE (1995 to 2004), EMBASE (1995 to 2004), CBM (1995 to 2004), Chinese Cochrane Centre Controlled Trials Register (to 2004), Current Controlled Trials (www.controlled-trials.com) and The National Research Register. We also hand searched 60 Chinese traditional medicine journals.

SELECTION CRITERIA

Randomised controlled trials undertaken on adults with unstable angina evaluating the following types of interventions: Puerarin injection compared to western drugs or placebo, or puerarin injection used with western drugs compared to western drugs alone.

DATA COLLECTION AND ANALYSIS

Data were extracted and analysed independently by two reviewers. Differences in data extraction and analysis were resolved by consensus, referring back to the original article. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

20 trials involving 1240 people were included. All trials identified were classified as having a high risk of bias because of poor reported methodology. The duration of treatment was 7-20 days and no information supplied suggested longer follow-ups were conducted for any trials. This limited the observation to participants who were not undertaking normal activities of daily living. The primary outcome (death) was not report in any trial. For all the secondary outcome measures, frequency of acute angina attacks, improvements in ECG, doses and incidence of nitroglycerine needed and levels of plasma endothelin, there was no evidence that puerarin had better or worse effects to other conventional treatments. There was strong evidence to suggest that puerarin injection plus western drugs was a better treatment option than western drugs alone.

AUTHORS' CONCLUSIONS

Puerarin injection may be effective in unstable angina when used in addition to conventional treatments. However, these finding should be interpreted with care because of the very low methodological quality of studies and potential publication bias. In the light of the findings, a more rigorously designed, randomised double-blind placebo-controlled trial is needed.