By Giuseppe De Luca
Pharmacological and/or mechanical reperfusion therapies have greatly contributed to the reduction in mortality achieved over the last two decades in patients with STEMI. Bare metal stents have been shown to reduce target vessel revascularisation in STEMI, with comparable rates of death and/or re-infarction compared to plain balloon angioplasty. As shown by several randomised trials and meta-analysis, drug-eluting stents have further reduced restenosis and target vessel revascularisation in patients without acute coronary syndromes, as compared to bare metal stents. Initial meta-analyses showed the efficacy and safety of drug-eluting stents at short-term follow-up in the setting of STEMI, with no safety issues. However, concerns have emerged regarding a potentially higher risk of stent thrombosis with drug-eluting stents that might be even more pronounced among patients with STEMI, as suggested by a prospective registry. In fact, several factors may account for the potential higher risk of stent thrombosis in the setting of STEMI, such as: 1) coronary vasospasm that may lead to stent undersizing; 2) residual intracoronary thrombus trapped between vessel wall and stent struts that may lead to late stent malapposition after thrombus dissolution; 3) Delayed re-endothelisation.
Therefore, the aim of the DESERT (Drug-eluting stents in primary angioplasty) cooperation was to perform a pooled patient-level meta-analysis of randomised trials to evaluate the risks and benefits of drug-eluting stents in comparison to bare metal stents in patients undergoing primary percutaneous coronary intervention for STEMI. We examined all completed randomised trials of drug-eluting stents for STEMI. Individual patient data were obtained from 11 out of 13 trials identified, including a total of 6,298 patients – 3,980 (63.2%) randomised to drug-eluting stents (99% sirolimus-eluting or paclitaxel-eluting) and 2,318 (36.8%) randomised to bare metal stents.
At long-term follow-up (1,201±440 days), drug-eluting stents significantly reduced the occurrence of target vessel revascularisation (12.7% vs. 20.1%; p<0.0001, pheterogenity=0.20), without any significant difference in terms of mortality, re-infarction and stent thrombosis. By landmark analysis, however, we observed a significant increase in the risk of very late (>1 year) re-infarction (6.6% vs. 3%, p=0.02, pheterogenity=0.62), and stent thrombosis (3.1% vs. 1.4%, p=0.01, pheterogenity=0.99) as compared to bare metal stents with drug-eluting stents.
The results of this pooled patient-level meta-analysis shows that among STEMI patients undergoing primary percutaneous coronary intervention, sirolimus- and paclitaxel-eluting stents compared to bare metal stents are associated with a significant reduction in target vessel revascularisation at long-term follow-up. Although there were no differences in cumulative mortality, re-infarction or stent thrombosis, the incidence of very late re-infarction and stent thrombosis was increased with these drug-eluting stents. These data certainly support the need for further large investigations with new generation drug-eluting stents, including devices with reabsorbable polymers (Nobori, Biomatrix), polymer-free (Create) and self-expandable (Stentys) drug-eluting stents, which will certainly help to overcome some technical issues that are related to the difficult field of thrombus-containing lesions, where they are expected to maximise the benefits in terms of restenosis while keeping low the risk of in-stent thrombosis.
Giuseppe De Luca is aggregate professor of Cardiology and chief, Interventional Cardiology, Eastern Piedmont University, Novara, Italy.