This review assessed the use of drug-eluting stents (DES) in Australia. The authors found that DES are effective in reducing the need for revascularisation. However, there are still uncertainties associated with their cost-effectiveness. Only stents available in Australia were reviewed, and there were some limitations to the review. This should be born in mind when interpreting the results.

To assess the costs and benefits of drug-eluting stents (DES) in an Australian setting.

MEDLINE, EMBASE, Current Contents, CINAHL and the Cochrane Library were searched from 1966 to June 2004. Websites of health technology assessment agencies and bibliographies of relevant articles were checked. Only studies published in English were eligible for inclusion. Studies reported as abstracts only were excluded.

Study designs of evaluations included in the review

Systematic reviews or randomised controlled trials (RCTs) were eligible for inclusion.

Specific interventions included in the review

Studies on DES currently in use in Australia (polymer-based paclitaxel or sirolimus-eluting stents) were eligible for inclusion. The comparator was bare metal stents (BMS). Both direct stenting and pre-dilation were used in the included studies. Co-therapies included intraprocedural heparin and aspirin. In addition, some participants received glycoprotein IIb/IIIa inhibitors, or clopidogrel or ticlopidine for 2 to 6 months.

Participants included in the review

Studies of people with de-novo atherosclerotic coronary artery lesions, with or without diabetes, stent restenosis, long lesions (greater than 18 mm) or small-diameter vessels (equal or less than 2.5 mm), were eligible for inclusion. The included studies contained 69 to 89% men, and the mean ages of the participants ranged from 60.1 to 64.9 years. Some participants had diabetes, hypertension, hyperlipidaemia, unstable angina or prior myocardial infarction (MI). Mean lesion lengths ranged from 10 to 15 mm and mean reference vessel diameters from 2.6 to 3.0 mm. People with acute MI were excluded. Details of the exclusion criteria for lesion types were reported.

Outcomes assessed in the review

The outcomes of interest were mortality, MI, coronary artery bypass grafting (CABG), revascularisation of the stented lesion (target lesion revascularisation) or in-stent thrombosis at 12 months' follow-up.

How were decisions on the relevance of primary studies made?

Two reviewers independently assessed studies for inclusion.

The National Health and Medical Research Council's quality checklist was used to assess the quality of the included studies. No further details were given.

Two reviewers independently assessed the quality of the studies.

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

Relative risks (RRs) and 95% confidence intervals (CIs) were calculated for each study. When event rates were reported as percentages only, the numbers of events were calculated by reference to related publications or conference proceedings.

How were the studies combined?

A fixed-effect model was used to pool the RRs. Data from paclitaxel- and sirolimus-eluting stents were pooled separately.

How were differences between studies investigated?

Cochran's Q test was used to assess heterogeneity between the studies. Subgroup analyses included those based on groups of people at high risk of restenosis (with diabetes, small-vessel lesions and long lesions requiring more than one stent).

Seven RCTs (3,390 participants) were included: four assessed sirolimus-eluting stents (1,748 participants) and three assessed paclitaxel-eluting stents (1,642 participants).

All trials were reported to be of a high quality.

Stent thrombosis was reported in 0.6% of participants and there was no difference between the DES and BMS groups.

Paclitaxel-eluting stents (3 RCTs).

There was no significant difference between paclitaxel-eluting stents and BMS in relation to in-stent thrombosis (P=0.77), death (P=0.81), MI (P=0.12) or CABG (P=0.09). There was a statistically significant decrease in the need for target lesion revascularisation with paclitaxel-eluting stents compared with BMS (RR 0.29, 95% CI: 0.20, 0.43, P<0.001).

Sirolimus-eluting stent (4 RCTs).

There was no significant difference between sirolimus-eluting stents and BMS in relation to in-stent thrombosis (P=0.99), death (P=0.46; 2 RCTs), MI (P=0.61; 2 RCTs) or CABG (P=0.31; 2 RCTs). There was a statistically significant decrease in the need for target lesion revascularisation with sirolimus-eluting stents compared with BMS (RR 0.20, 95% CI: 0.13, 0.29, P<0.001; 2 RCTs).

The results of the subgroup analyses were reported.

The difference in costs at 12 months was AU$620 between sirolimus-eluting stents and BMS, and AU$632 between paclitaxel-eluting stents and BMS. Estimates of the incremental cost per target lesion revascularisation avoided at 12 months ranged from AU$3,746 (sirolimus trials) to AU$6,117 (paclitaxel trials). Full details of the cost-effectiveness analysis are available in the report (see Other Publications of Related Interest).

DES are effective in reducing the need for revascularisation. However, there are still uncertainties concerning their cost-effectiveness.

The inclusion criteria for this review were clearly stated. A range of sources was searched, but the search was limited to studies published in English and abstracts were excluded. It is therefore possible that studies were missed. Methods were used to reduce the potential for error and bias during the selection of studies and quality assessment. However, it was unclear whether similar methods were used during the data extraction process. The quality of the included studies was assessed and a checklist cited, but no further details were provided and the definition of high quality was not reported. Pooling was appropriately stratified according to the drug used in the stents.

This review was limited to DES available in Australia. The authors discussed further limitations of their review and, given some of these, some caution may be required when interpreting the their conclusions. However, the conclusions drawn are conservative.

Practice: The authors did not state any implications for practice.

Research: Further research is needed to directly evaluate clinical outcomes and the economic implications of DES in an Australian setting. This should include quality of life outcomes.

Medical Services Advisory Committee. Drug-eluting stents. Canberra: Australian Department of Health and Aging; 2005 (accessed Aug 2005). Available at: URL: http://www7.health.gov.au/msac/pdfs/reports/msacref30.pdf

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.