Evidence for use of coronary stents. A hierarchical bayesian meta-analysis.

BACKGROUND

Coronary stents are widely used in interventional cardiology, but a current quantitative systematic overview comparing routine coronary stenting with standard percutaneous transluminal coronary angioplasty (PTCA) and restricted stenting (provisional stenting) has not been published.

PURPOSE

To summarize results from all randomized clinical trials comparing routine coronary stenting with standard PTCA.

DATA SOURCES

Electronic databases were searched by using the key words angioplasty and stent. References from identified articles were also reviewed. In addition, several prominent general medical and cardiology journals were searched and agencies known to perform systematic reviews were consulted.

STUDY SELECTION

All comparative randomized clinical trials were included, except those involving primary angioplasty for the treatment of acute myocardial infarction.

DATA EXTRACTION

A specified protocol was followed, and two of the authors independently extracted the data. Outcomes assessed were total mortality, myocardial infarction, angiographic restenosis, coronary artery bypass surgery, repeated PTCA, and freedom from angina.

DATA SYNTHESIS

The results were synthesized by using a Bayesian hierarchical random-effects model. A total of 29 trials involving 9918 patients were identified. There was no evidence for a difference between routine coronary stenting and standard PTCA in terms of deaths or myocardial infarctions (odds ratio, 0.90 [95% credible interval [CrI], 0.72 to 1.11]) or the need for coronary artery bypass surgery (odds ratio, 1.01 [CrI, 0.79 to 1.31]). Coronary stenting reduced the rate of restenosis (odds ratio, 0.52 [CrI, 0.37 to 0.69]) and the need for repeated PTCA (odds ratio, 0.59 [CrI, 0.50 to 0.68]). The trials showed a wide range of crossover rates from PTCA to stenting. By use of a multiplicative model, each 10% increase in crossover rate decreased the need for repeated angioplasty by approximately 8% (odds ratio multiplying factor, 1.08 [CrI, 0.98 to 1.18]). Routine stenting probably reduces the need for repeated angioplasty by fewer than 4 to 5 per 100 treated persons compared with PTCA with provisional stenting. Studies were not blinded and suggest a bias with a possible overestimation of this benefit.

CONCLUSIONS

In the controlled environment of randomized clinical trials, routine coronary stenting is safe but probably not associated with important reductions in rates of mortality, acute myocardial infarction, or coronary artery bypass surgery compared with standard PTCA with provisional stenting. Coronary stenting is associated with substantial reductions in angiographic restenosis rates and the subsequent need for repeated PTCA, although this benefit may be overestimated because of trial designs. The incremental benefit of routine stenting for reducing repeated angioplasty diminishes as the crossover rate of stenting with conventional PTCA increases.