To evaluate the evidence of:

1. The use of Percutaneous Transluminary Coronary Angioplasty (PTCA) with elective stenting for patients with coronary artery disease (CAD).

2. The use of PTCA with stenting for sub-optimal PTCA results for patients with CAD.

MEDLINE (1993 to April 1988) and Healthstar (1995 to March 1998) were searched. The Cochrane Library, Gears, Best Evidence, and the National Research Register were also searched, but the search dates were not given.

Study designs of evaluations included in the review

No inclusion criteria were placed on studies to be included in the review.

Specific interventions included in the review

Percutaneous Transluminary Coronary Angioplasty (PTCA) plus elective stenting, PTCA plus stenting for sub-optimal results, and PTCA alone. Studies evaluating the use of bail-out stenting were not included. Elective stenting occurs when the decision to insert a stent is taken before the procedure is performed. Sub-optimal stenting occurs when patients who are assessed as having an unsatisfactory PTCA are administered a stent, i.e. the decision to insert a stent is taken on completion of PTCA.

Three out of five trials evaluated the Palmaz-Schatz stent. One trial evaluated the Wiktor stent and the remaining trial did not mention the type of stent used.

Participants included in the review

Patients with coronary artery disease. Studies assessed slightly different coronary artery disease patient groups in terms of number of diseased vessels, presence of stable/unstable angina and types and sizes of lesions.

Outcomes assessed in the review

The primary long-term outcome measures evaluated in most of the trials were:

1. Angiographic evidence of restenosis, presented as the proportion of patients with at least 50% stenosis at follow up.

2. Requirement for revascularisation of the previously treated lesion (i.e. PTCA and/or CABG).

3. Number of clinically significant events suffered by the patients.

How were decisions on the relevance of primary studies made?

The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.

The validity of the included studies was not formally assessed. However, the authors did note the number of studies that used intention to treat analysis and blinding of outcome assessors to treatment allocation.

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

How were the studies combined?

Studies were summarised narratively.

How were differences between studies investigated?

Tests for heterogeneity were not performed.

Five randomised controlled studies, comprising 1247 participants were included in the evidence for the use of PTCA plus elective stenting versus PTCA alone. One large randomised trial evaluated the use of antiplatelet therapy versus anticoagulant therapy. Two cost analyses were also included.

The use of PTCA plus elective stenting versus PTCA alone: Four out of five randomised controlled studies (RCTs) found that stenting leads to significantly reduced angiographic restenosis rate. In four studies that reported the number of clinically significant events, two studies reported no events in either group, and the two remaining studies found that stenting leads to a reduction in events. One study found a significantly reduced requirement for revascularisation with stenting, and one study found no difference. Of four studies that reported mortality rates, two found no deaths in either group, and two reported no difference in survival rates between the two groups. The precision of the estimates was low for some of the comparisons. In all of the studies, a small number of patients receiving stenting suffered from stent thrombosis (2-7%) and bleeding complications associated with the prophylactic anticoagulant regimen. The largest and longest case series reported evaluated 175 patients who were followed for five years. The restenosis rate was 26%, with late restenosis (occurring more than 6 months after implantation) in 2% of patients.

Use of antipletelet therapy (ticlopidine and aspirin therapy): Anticoagulant therapy and antiplatelet therapy have been used to reduce the risk of stent thrombosis. A large randomised controlled trial evaluated the use of antiplatelet therapy (ticlopidine plus aspirin) versus anticoagulant therapy (intravenous heparin, phenprocoumon and aspirin) after stent placement with PTCA. The incidence of severe haemorrhagic events, peripheral vascular events, and cardiac events (acute MI, reinterventions, repeat PTCA, bypass surgery) was significantly lower with antiplatelet therapy and there were no thrombotic occlusions in the antiplatelet group.

PTCA plus stenting for sub-optimal results versus PTCA alone: No RCTs on stenting for sub-optimal PTCA or comparative studies of sub-optimal stenting, elective stenting, and PTCA alone were found. Some case series studies were found which involved patients who received stents electively, for sub-optimal PTCA results, or as a bailout procedure. However, it was not possible to evaluate the effectiveness of stenting after a sub-optimal PTCA result because outcomes of stenting in the included groups were combined.

The report also presents results on the benefits of elective stenting, quality of life and a sensitivity analysis based on these.

The authors report that the cost of an intracoronary stent is around £400 to £600. Another cost is that of ticlopidine, the anticoagulant therapy used to prevent sub-acute thrombosis. This costs around £30 for 20 tablets, i.e. £84 per 28 days treatment. Therefore the cost of a stent and ticlopidine is approximately between £500 and £700.

The cost of PTCA with stent was £2,664 at Southampton General hospital and £1,233 for PTCA alone (cost-difference £1,431). At Bristol hospital, the cost of PTCA with stent was £4,232 and the cost of PTCA alone was £3,000 (cost-difference £1,232). These costs take into account the fact that approximately 7% of PTCA alone patients require bail-out stenting.

The additional cost per additional QALY with stents is approximately £250,000. A sensitivity analysis showed that the additional cost per additional QALY ranged from £20,000 to £772,000. The additional cost per additional QALY is highly sensitive to small changes in the assumptions made in the calculation. These estimates are based on the evidence to date and may not reflect current practice.

The authors also report a published cost-analyses and savings from receiving PTCA with stents (through reduced need for repeat PTCA on the same lesion).

A cost-utility study of a decision analytic model developed by Cohen et al. (see Other Publications of Related Interest) to evaluate the potential cost-effectiveness of stenting for symptomatic single-vessel coronary disease was also reported.

There was inadequate information on which to base a recommendation on the use of stents for sub-optimal PTCA. The evidence for elective stents from RCTs is good in so far as the elective addition of stents to PTCA reduces symptomatic restenosis over the following 12 months. The authors noted that the trials were of good quality although the inclusion criteria were narrow and follow up was short. In one study, 10 patients had to receive a stent in order to prevent any restenosis a year later. However, the quality of life associated with this benefit appears to be small, the long term effects of coronary artery stenting are unknown, and the costs of the intervention are relatively high. Careful selection of patients is needed, with a high degree of operator skill in order to receive the greatest benefits.

The review focuses on two clear review questions. The primary studies were summarised appropriately.

The search could have been extended to include handsearching of relevant journals and an attempt to identify unpublished material by searching the grey literature, and contacting experts in the field. Publication bias cannot be ruled out. Inclusion and exclusion criteria were not reported. The authors did not perform a formal validity assessment involving scoring, although they did report some validity information relating to the randomised controlled studies. It would have been useful to assess whether the assignment to the treatment groups was really random, and whether the groups were treated identically, other than for the named interventions. Sufficient details of the five randomised controlled trials were presented. Details of case-series studies evaluating the use of PTCA plus stenting for sub-optimal results versus PTCA alone were not presented, neither were the cost analyses studied.

The conclusions follow from the results.

The authors note that Northern General Hospital, Sheffield has just obtained funding to coordinate a multicentre European trial evaluating stenting for a sub-optimal result. Economic data will also be collected in this trial.

Practice: The authors note that the reduction in restenosis and reduced need for revascularisation makes PTCA with stents a more attractive option for patients who would otherwise have received a CABG.

Research: The authors state that there is a need for further research to evaluate the cost-effectiveness of PTCA with currently used stents for patients with coronary artery disease who are presently deemed suitable for this procedure. This research should include the collection of economic data. If this is not possible, they suggest a meta-analysis of trials published to date with modelling may be of use.

1. Cohen DJ, Breall JA, Ho KK, Kuntz RE, Goldman L, Baim DS, et al. Evaluating the potential cost-effectiveness of stenting as a treatment for symptomatic single-vessel coronary disease. Use of a decision-analytic model. Circulation 1994;89:1859-1874.

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.