NORSTENT shows bare metal stents have improved

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pascal-meier
Pascal Meier

The NORSTENT (Norwegian coronary stent trial) study, which was presented at the 2016 European Society of Cardiology congress (27–31 August, Rome, Italy) found no difference in survival between patients who received a drug-eluting and those who received a bare metal stent. Pascal Meier explains why he believes drug-eluting stents remain the first-line choice for percutaneous coronary intervention (PCI) but NORSTENT shows contemporary bare metal stent to be a safe alternative.

Having nearly become extinct in many cath labs, bare metal stents have come back into focus with NORSTENT. As reported by Cardiovascular News, this trial showed that

—after a median follow-up of six years—the rate of a composite primary outcome of all-cause death or myocardial infarction was similar between patients who underwent PCI with a contemporary bare metal stent and those who underwent PCI with a drug-eluting stent: 17.1% vs. 16%, respectively (p=0.66). Further, there were no relevant differences in physical limitations, angina frequency, and reported quality of life.

However, drug-eluting stents were designed to reduce the risk of restenosis (compared with bare metal stents) and NORSTENT indicates that they are associated with an about 50% reduced rate of  need for target lesion revascularisation (5.3% vs 10.3%; p<0.001). Interestingly, they were also associated with a trend towards a lower rate of definite stent thrombosis (0.8% vs. 1.2% for bare metal stents; p=0.0498).

These results are in line with another recent trial comparing drug-eluting stents with bare metal stents. For example, the LEADERS FREE trial randomised 2,466 patients to undergo PCI with a polymer-free, biolimus-eluting stent (BioFreedom, Biosensors) or with a bare metal stent.  This study used a very short duration of dual antiplatelet therapy (DAPT) and showed that the BioFreedom stent was associated with a 50% reduction in target lesion revascularisaiton. Also, the safety profile of the drug-eluting stent was similar or even better than that of the bare metal stent: the composite of cardiac death, myocardial infarction, or stent thrombosis was 9.4% in the drug-eluting stent group and 12.9% in the bare metal stent group (p<0.001 for noninferiority).  Event rates in this trial were higher than anticipated, which is rarely the case in modern trials and the bare metal stent used—Gazelle (Biosensors)—is based on a stainless steel platform. Therefore, a comparison with other newer generation bare metal stents may show different outcomes.

The BASKET-SAVAGE trial indicates that the reduction in restenosis with drug-eluting stents may be even greater in certain subsets. This was the largest study, to date, to evaluate drug-eluting stents in saphenous vein grafts, and it showed that drug-elutng stents were associated with target vessel revascularisation rate of 4.5% at three years compared with 19.1% for bare metal stents. This trial stopped early due to slow enrollment (only 173 patients had been recruited) and used older generation stent platform (Taxus, Boston Scientific).

Overall, NORSTENT reminds us that bare metal stents have—like drug-eluting stents—evolved over time and are now associated with impressively low risks for restenosis (about 10% over six years) and stent thrombosis (around 1% over six years). Also in the trial, both groups of patients (drug-eluting stent and bare metal stent) received DAPT for nine months but DAPT need only be given for month after bare metal stent implantation—a clear advantage for patients at high bleeding risk, in those with planned urgent surgery or under oral anticoagulation.

However, according to LEADERS FREE, drug-eluting stents may be as least as safe (or even safer) than bare metal stents even when patients are prescribed a short duration of DAPT. Also, in all the studies discussed, drug-eluting stents reduced the risk of restenosis; In BASKET-SAVAGE, the reduction was even greater than it was in NORSTENT (about 75%). Additionally while drug-eluting stents used to be much more expensive than bare metal stents, their price has dropped dramatically over recent years—and by avoiding re-interventions, they are increasingly cost-effective.

Newer generation drug-eluting stents seem to be both very effective and very safe, and they should stay the first choice for most patients. However, the performance of bare metal stents have also improved over time and may be an effective and safe option for certain subsets of patients—such as those at higher bleeding risk, with planned major surgery and those with anticipated poor compliance to DAPT, especially if their restenosis risk is limited (larger diameter arteries, non-diabetics, short lesions).

Pascal Meier is at the University of Geneva, Geneva, Switzerland and at University College London (UCL), London, UK.