Note from the National Guideline Clearinghouse (NGC): The National Institute for Health and Clinical Excellence (NICE) commissioned an independent academic centre to perform a systematic literature review on the technology considered in this appraisal and prepare an assessment report. The assessment report for this technology appraisal was prepared by the Liverpool Reviews and Implementation Group, University of Liverpool (see the "Availability of Companion Documents" field).
Identification of Evidence: Clinical Effectiveness and Cost-effectiveness
Search Strategy
The search incorporated a number of strategies. Search terms for electronic databases included a combination of index terms (e.g., STENTS and CORONARY DISEASE) and free text words (e.g., 'stent' and 'coronary').
No limitation was included on study type and therefore identification of clinical effectiveness and cost-effectiveness data were combined within the electronic searches.
The following electronic databases were searched for relevant published literature for the period from December 2002 to June 2005. Searching dated from the limit of the searches in the Assessment Group's previous assessment.
- CDSR (Cochrane Database of Systematic Reviews)
- CENTRAL (Cochrane Central Register of Controlled Trials)
- DARE (Database of Abstracts of Reviews of Effectiveness)
- EMBASE
- HTA database
- ISI Web of Science- Proceedings (Index to Scientific & Technical Proceedings)
- ISI Web of Science- Science Citation Index Expanded
- MEDLINE
- NHS EED (National Health Service Economic Evaluation Database)
In addition, MEDLINE (using the PubMed interface) was searched again later in the assessment (spanning 1 March to 3 Aug 2005) in order to identify publications that might not have been indexed at the time of the main electronic searching. Details of the search strategies and the number of references retrieved for each search are provided in Appendix 1 of the Assessment Report (see the "Availability of Companion Documents" field).
Reference lists of included studies and device manufacturer submissions were searched to identify other relevant studies of clinical effectiveness, costs or cost-effectiveness.
Handsearching of cardiology conference abstracts was conducted. Latest conference proceedings for the following meetings were obtained for the purposes of handsearching:
- American College of Cardiology
- American Heart Association
- British Cardiac Society
- European Society of Cardiology
- Transcatheter Cardiovascular Therapeutics
Internet resources were examined for information on clinical studies and cost data. These included the following:
All the references were exported to an EndNote bibliographic database, Thomson ISI ResearchSoft, Cal., USA.
Selection of Clinical Effectiveness and Cost-Effectiveness Evidence
The records identified in the electronic searches were assessed for inclusion in two stages. Firstly pairs of reviewers independently scanned all the titles and abstracts and identified the potentially relevant articles to be retrieved. Any differences in selection choice were discussed between the pairs and consensus reached in all cases. Full text reports of these selected papers were then obtained and assessed independently by at least two reviewers for inclusion. The inclusion/exclusion assessment of each reviewer was recorded on a pre-tested, standardised form. Data on levels of agreement between reviewers is available from the Assessment Group upon request.
A table summarising the selection and inclusion of studies is provided in the Appendix 1 of the Assessment Report (see the "Availability of Companion Documents" field).
Methods for Reviewing Clinical Effectiveness
Inclusion Criteria
Studies were considered eligible for inclusion if they met the following criteria:
Study Design
- Randomised controlled trials (RCTs); non-randomised controlled trials (such as prospective registries); non-controlled studies (except case reports of single patient experience).
Population
- Adults with coronary artery disease (CAD), undergoing treatment of native and intervention naïve vessel(s) by percutaneous coronary intervention (PCI) with the use of stent(s).
Intervention
- Drug-eluting coronary artery stents which were expected to be available for use by the NHS close to the time of the assessment.
Comparators
- Drug-eluting stent (DES) versus non drug-eluting bare-metal stent (BMS)
- DES of different design (i.e., DES versus DES).
Outcomes
Studies were included in the clinical review if they reported primary data on one or more of the following outcomes:
- Combined event rate (major adverse cardiac events [MACE], target vessel failure [TVF]) or event free survival
- Mortality (all cause, cardiac)
- Acute myocardial infarction (AMI)
- Target lesion revascularisation (TLR)
- Target vessel revascularisation (TVR)
- Repeat revascularisation (PCI/stent, other PCI or coronary artery bypass grafting [CABG])
- Adverse effects (thrombosis, mal-absorption; incomplete stent apposition; device failures/defects)
- Angiographic binary restenosis
- Late loss
- Health-related quality of life
Exclusion Criteria
Studies were excluded based on the following criteria:
- Single case reports
- Randomised controlled trials (RCTs) that:
- Provided only unplanned, interim findings
- Provided data on only a sub-group of the enrolled patients
- Were continuing to recruit patients
- Where patients numbers treated with specific intervention (i.e., a particular type of stent) could not be determined
- Studies of:
- Treatment of in-stent restenosis
- Treatment of saphenous vein grafts
- Comparison of:
- DES with other PCI interventions (e.g., atherectomy, rotabaltors, brachytherapy)
- DES with surgery
- Variations of drug-loading among single DES types ('brands')
Methods for Reviewing Cost-Effectiveness
Inclusion and Exclusion Criteria
Using explicit, predetermined criteria, two reviewers independently identified reports for inclusion in the review of published economic evaluations and as a source of cost or related data to inform development of the Assessment Group's own economic evaluation and budget impact assessment.
Any disagreements in inclusion for the cost-effectiveness assessment were resolved through discussion.
Inclusion Criteria
Study Design
Full economic evaluations that compared two or more options and considered both costs and consequences including:
- Cost-effectiveness analysis
- Cost-utility analysis
- Cost-benefit analysis
Population
Adults with CAD, undergoing treatment of native and intervention naïve vessel(s) by PCI with the use of stent(s).
Intervention
Drug-eluting coronary artery stents which were expected to be available for use by NHS close to the time of the assessment. As for the review of clinical effects.
Comparators
- Drug-eluting stent versus non drug-eluting BMS
- DES of different design
Health Outcomes in an Economic Framework
- Quality adjusted life years (QALY)
- Disease specific measures, such as: MACE, repeat revascularisations avoided, MACE free survival, TLR and TVR
Exclusion Criteria
Reports were excluded from the review of economic evaluations if:
- The main source of clinical efficacy data was not explicitly stated
- No attempt to synthesise costs and benefits was conducted
- The source was a letter, editorial, review, commentary or methodological paper.