Platelet glycoprotein IIb/IIIa blockers for percutaneous coronary revascularization, and unstable angina and non-ST-segment elevation myocardial infarction

WITHDRAWN: Puerarin injection for unstable angina pectoris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The editorial group responsible for this previously published document have withdrawn it from publication.

Surveillance search techniques identified the need to update systematic reviews

OBJECTIVE

This article reports on literature surveillance methods to identify new evidence eligible for updating systematic reviews.

STUDY DESIGN AND SETTING

Five surveillance search approaches are tested in the context of identifying studies that would signal major or invalidating new evidence for existing systematic reviews of health care interventions. Recall for each search approach was assessed as proportion of a composite yield of relevant studies across all search approaches that were identified by that approach. Screening burden was the number of studies that would need to be reviewed to identify the evidence that would necessitate updating.

RESULTS

Searches were tested in a cohort of 77 systematic reviews. No one method yielded consistently high recall of relevant new evidence, so combinations of the strategies were examined. A search algorithm based on PubMed's related article search in combination with a subject searching using clinical queries was the most effective combination, retrieving all relevant new records in 68 cases. Screening burden was a median of 71 new records per review (inter-quartile range: 42-161).

CONCLUSION

Surveillance for emerging evidence that signals the need to update systematic reviews is feasible using a combination of subject searching and searching based on the PubMed's related article function.

[Effectiveness and safety of triple antiaggregation in patients undergoing coronary intervention]

OBJECTIVE

To evaluate glycoprotein IIb/IIIa inhibitors (GPIIb/IIIa inhibitors) effectiveness and safety in patients with non-ST segment elevation acute coronary syndrome (NSTEACS) or stable coronary disease referred for percutaneous coronary revascularization pre-treated with aspirin and thienopyridines by means of a systematic review.

SOURCE OF DATA

Electronic search using Medline, Embase, Pascal, Cochrane Library and ISI Proceedings and manual review of the articles found.

STUDY SELECTION

We included randomized controlled trials that assessed the clinical efficacy (risk of death or infarction) and safety (bleeding and thrombocytopenia) of GPIIb/IIIa inhibitors in patients pretreated with thienopyridines.

DATA EXTRACTION

Data were obtained by duplicate.

RESULTS

Nine randomized controlled trials (8,604 patients) were included. Addition of GPIIb/ IIIa inhibitors reduced the risk of death or myo-cardial infarction at 30 days in those trials that included patients with NSTEACS (RR 0.67; 95%CI 0.56-0.80) but not in studies that excluded NSTEACS patients (RR 1.07; 95%CI 0.75-1.53) (p test of interaction 0.0175), As a counterpart, GPIIb/ IIIa inhibitors increased the risk of bleeding and thrombocytopenia.

CONCLUSIONS

Use of GPIIb/IIIa inhibitors reduces the risk of adverse cardiac events in NSTEACS patients pre-treated with aspirin and thienopyridines but increases the risk of severe bleeding and thrombocytopenia. Its utilization in stable coronary patients does not seem justified.

Glycoprotein IIb-IIIa inhibitors for acute ischaemic stroke

BACKGROUND

Glycoprotein (GP) IIb-IIIa inhibitors block the final common pathway to platelet aggregation antagonising with receptors that bind fibrinogen molecules forming bridges between adjacent platelets. Thus, GP IIb-IIIa inhibitors could favour endogenous thrombolysis by reducing thrombus growth and prevent thrombus re-formation by competitive inhibition with fibrinogen. Currently used in clinical practice for acute coronary syndromes and percutaneous coronary interventions, they could also be useful for patients with acute ischaemic stroke.

OBJECTIVES

To assess efficacy and safety of GP IIb-IIIa inhibitors in acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (last searched 31 May 2005). In addition, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to June 2005) and EMBASE (1980 to June 2005). In an effort to identify further published, unpublished and ongoing trials we searched reference lists and contacted trial authors and pharmaceutical companies.

SELECTION CRITERIA

We aimed to analyse unconfounded randomised controlled trials comparing GP IIb-IIIa inhibitors with placebo in patients with acute ischaemic stroke. Only patients who started the treatment within six hours of stroke onset were included.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Two trials involving 474 patients were included. Only data for 414 patients treated within six hours were considered. Patients were treated with intravenous abciximab or placebo. Treatment with abciximab was associated with a non-significant reduction of death and dependency combined (odds ratio (OR) 0.79; 95% confidence interval (CI) 0.54 to 1.17) and of death alone (OR 0.67; 95% CI 0.36 to 1.25). Treatment with abciximab was associated with a non-significant increase of symptomatic intracranial haemorrhages (OR 4.13; 95% CI 0.86 to 19.67) and of major extracranial haemorrhages (OR 1.51; 95% CI 0.25 to 9.12).

AUTHORS' CONCLUSIONS

There is currently not enough evidence from randomised controlled trials regarding the efficacy or safety of GP IIb-IIIa inhibitors therapy in acute ischaemic stroke. Results from ongoing trials will help to understand the risk to benefit ratio of these agents.

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.

Treating individuals 4: can meta-analysis help target interventions at individuals most likely to benefit?

Meta-analyses of randomised trials aim to summarise the effects of interventions across many patients, and can seem remote from the clinical issue of how individual patients should be treated and which patient groups will benefit the most from treatment. One method that attempts to address this point entails relating the overall effect in every trial to summaries of patient characteristics. This is called meta-regression. The interpretation of such analyses is not straightforward, however, because of a combination of confounding and other biases. Much more useful is to compare the outcomes for patient subgroups within trials and combine these results across trials. Unfortunately this method is rarely possible using published information, so analyses of individual patient data from trials are necessary. Also, although meta-analyses generally summarise an intervention's effect as a relative risk reduction, the groups of patients with the greatest absolute risk reduction have the most to gain.