A pooled analysis of 11 previously published trials provides evidence that drug-eluting stents (DES)—increasingly used in coronary angioplasty—have benefits over bare-metal stents (BMS) by reducing the need for later revascularisation and reducing the risk of cardiac events.
However the study did not find that the use of DES reduced the risk of death or heart attack compared with BMS. Stents are small wire-mesh tubes positioned in the coronary artery after balloon angioplasty to help widen the artery, thereby increasing bloodflow to the heart. A potential complication of stenting is the reaction from cells in the wall of the coronary artery to the presence of a stent; cell proliferation in response to stenting can cause the coronary artery to become occluded.
The development of DES over the past decade offers potential benefits over BMS as the pharmacological agent on a DES can counteract this response.
Mark J Eisenberg (Jewish General Hospital/McGill University, Montreal, Canada) and colleagues did a meta-analysis (pooled analysis) of 11 randomised trials comparing BMS and stents eluting the drugs sirolimus or paclitaxel. Over 5000 patients took part in the 11 studies combined. The rate of severe cardiac events was half that of patients given BMS (8% compared with 16%). The proportion of patients who had restenosis (recurrence of coronary artery narrowing 6–12 months after stenting) was far greater—almost 30%—than in patients given DES (around 9%).
Dr Eisenberg comments: “Drug-eluting stents have a substantial effect on angiographic restenosis and the need for repeat revascularisation procedures when implanted in patients who are at low risk of subsequent restenosis. However, as with bare-metal stents, there is no evidence that drug-eluting stents have any effect on medium-term death rates or rates of heart attack. Drug-eluting stents appear to be safe over the short and medium term, although the data are currently too sparse for firm conclusions to be drawn. Long-term follow-up and results from larger studies investigating drug-eluting stents are needed”.
An accompanying commentary (p 558) by Joachim Schofer (Centre for Cardiology and Vascular Intervention, Hamburg, Germany) is cautiously optimistic about these results while stressing that longer-term follow-up results of high-risk patients are needed ‘before drug-eluting stents deserve the term panacea’.