Drug-eluting stents are equally safe and more efficacious than bare-metal stents for patients with a coronary artery disease

The present article draws a comparison between various subtypes of drug-eluting stents (DES) and bare metal stents (BMS), evaluating their safety and efficacy.

Coronary artery disease (CAD) is a heart condition caused by the narrowing of the coronary arteries which nourish the heart. This in turn causes a restriction of blood supply that cannot meet the needs of the heart muscle. Treatment relies on the restoration of blood supply to the heart. This can be done using stents. Stents are mesh tubes that support the narrowed blood vessel and keep it open. It is inserted into coronary arteries during a procedure called angioplasy, or percutaneous coronary intervention (PCI). There are two main types of stents: bare metal stents, BMS (metal mesh tubes) and drug-eluting stents, DES (a stent coated with a drug that prevents cells from re-blocking it). The most common complication of stents is the process of restenosis, i.e. re-narrowing or blocking of the stent. DES are designed to inhibit restenosis. There are many subtypes of DES, which release different drugs. These include sirolimus-, paclitaxel-, everolimus-, zotarolimus-eluting, and zotarolimus–resolute stents (SES, PES, EES, ZES, and ZES-R, respectively). With so many varieties, it is important to compare each DES against BMS as well as against other DES in order to establish the superior one in terms of safety and efficacy.

This analysis included 76 trials that compared BMS to one or more DES, or different DES to one another. Trials had to follow-up with patients for at least 6 months and include at least 100 patients. Furthermore, trials had to assess measures of efficacy and/or safety. Efficacy was evaluated by the time to failure of the initial stent, indicated by either recurrence of symptoms (called target vessel revascularization or TVR) or the need for another intervention at the same vessel (referred to as target lesion revascularization or TLR). Measures of safety were: death, heart attack, and stent thrombosis (the formation of a blood clot within the stent).

DES were found to be generally superior to BMS for both efficacy and safety, both short- and long-term. However, not every variety of DES was superior to BMS, or equally effective as one another. DES reduced TVR and TLR relative to BMS, but sirolimus (SES), zotarolimus–resolute (ZES-R), and everolimus (EES) performed best for these measures. DES did not affect the likelihood of death relative to BMS, but did reduce the risk of heart attack (with the exception of PES, which was not different than BMS). Overall, DES did not affect the risk of stent thrombosis, but EES significantly reduced this risk relative to BMS and other DES.

DES were generally equally safe and more effective compared to BMS at preventing TVR, TLR, and heart attacks. Among the DES subtypes, EES, SEZ and ZES-R were the most efficacious and EES (everolimus-eluting stent) was the safest stent, reducing the risk of stent thrombosis.

The present analysis did not take into account medications taken after the procedure (angioplasty). Patients undergoing angioplasty must take drugs (such as plavix and/or aspirin) for a certain period of time in order to prevent stent thrombosis. This data is crusial for safety analysis. In addition, the definition of heart attacks differed between the trials included in the analysis. Altogether, the results DO provide the relative safety and efficacy of the different stents, but should to be interpreted with caution.

If you are considering an intervention such as angioplasty (PCI), discuss with your cardiologist the different types and subtypes of stents and their relative benefits.