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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

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

Impact of enhanced external counterpulsation on Canadian Cardiovascular Society angina class in patients with chronic stable angina: a meta-analysis

SA Shah, RJ Shapiro, R Mehta, and JA Snyder.

Review published: 2010.

CRD summary

The review concluded that approximately 86% of chronic stable angina patients who underwent enhanced external counterpulsation treatment improved by at least one Canadian Cardiovascular Society class at the end of therapy. Potential for biases within the review and uncertain quality of the evidence base limits the reliability of the pooled results. The call for further research appears warranted.

Authors' objectives

To evaluate the true magnitude of benefit from enhanced external counterpulsation (EECP) by determining the effect of EECP on Canadian Cardiovascular Society (CCS) angina class in patients with chronic stable angina.

Searching

MEDLINE, EMBASE and CINAHL were searched from 1950 to February 2009 for articles in English. Search terms were reported. Reference lists of relevant reviews were searched.

Study selection

Prospective studies of EECP in patients with predominantly stable angina were eligible for inclusion. Studies had to report usable data on CCS angina class in the form of classes reported before and after 35 one-hour EECP sessions. Studies that reported data as mean baseline angina class before and after treatment were excluded. Studies from International EECP Patient Registry (IEPR) and EECP Consortium register were excluded to prevent double counting. Case series, case reports and abstracts were excluded.

The included trials studied 34 to 35 sessions of EECP over four to seven weeks in patients with chronic stable angina. Baseline CCS class varied from 1-4 to 3-4. Patient age, where reported, ranged from 61 to 68 years. The proportion of patients who had undergone previous percutaneous coronary intervention (PCI) ranged from 20% to 88%, undergone previous coronary artery bypass surgery (CABG) ranged from 41% to 91% and those with a previous myocardial infarction ranged from 30% to 79%.

The authors did not state how many reviewers performed study selection.

Assessment of study quality

The authors did not state whether they assessed validity.

Data extraction

Data on CCS class were extracted and used to calculate the proportion of patients who improved by at least one CCS angina class, together with 95% confidence intervals (CIs). Data were extracted only for EECP arms of studies.

Three reviewers independently extracted data. Disagreements were resolved by discussion.

Methods of synthesis

A random-effects meta-analysis was used to calculate pooled effect sizes and their 95% CIs. Statistical heterogeneity was assessed using the Q statistic. Subgroup analysis was conducted on the basis of patients who underwent PCI, CABG and previous myocardial infarction. Sensitivity analyses were conducted using fixed-effect meta-analysis and by excluding larger studies. Publication bias was assessed using funnel plots and Egger weighted regression.

Results of the review

Thirteen studies (949 participants) were included in the review.

A reduction of at least one CCS class was seen in 86% of the population (95% CI 82% to 90%). Sensitivity analyses using a fixed effects meta-analysis and excluding two studies did not alter the results. Subgroup analysis produced effect sizes that ranged from 79% to 90%.

The funnel plots showed some asymmetry, but Egger’s test indicated no evidence of publication bias.

Authors' conclusions

Approximately 86% of chronic stable angina patients who underwent EECP treatment improved by at least one CCS class at the end of therapy.

CRD commentary

Inclusion criteria for the review were clearly defined. Several relevant data sources were searched. There was potential for language bias as only studies in English were included. Publication bias was assessed and not detected. Attempts were made to reduce reviewer error and bias during data extraction; the authors did not report whether they used the same methods for study selection. The authors did not report a formal quality assessment.

There were baseline differences across the trials, notably in the proportions of patients with previous PCI, CABG and myocardial infarction. Trials were combined using appropriate statistical methods. Statistical heterogeneity was assessed, but the results were not fully reported.

Potential for biases within the review and uncertain quality of the evidence base limits the reliability of the pooled results. The authors’ call for further research appears warranted.

Implications of the review for practice and research

Practice: The authors stated that currently EECP therapy should be considered as an option for patients who were refractory to or not suitable for medical management and/or invasive therapy.

Research: The authors stated a need for further controlled long-term studies to determine the place of EECP therapy in the management of patients with chronic stable angina.

Funding

Not stated.

Bibliographic details

Shah SA, Shapiro RJ, Mehta R, Snyder JA. Impact of enhanced external counterpulsation on Canadian Cardiovascular Society angina class in patients with chronic stable angina: a meta-analysis. Pharmacotherapy 2010; 30(7): 639-645. [PubMed: 20575628]

Indexing Status

Subject indexing assigned by NLM

MeSH

Adult; Angina Pectoris /etiology /surgery /therapy; Canada; Cardiovascular System; Counterpulsation /adverse effects /methods; Humans; Prospective Studies; Treatment Outcome

AccessionNumber

12010005297

Database entry date

03/04/2012

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: 20575628

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