For the past decade, clinicians have watched the drug- eluting stent market evolve. But what are the real short-term and long-term safety and efficacy benefits of the technology when compared with bare-metal stents? Researchers found that DES may be better at reducing the risk of target vessel revascularization without increasing other factors like stent thrombosis, and everolimus eluting stents may take the cake when compared to other DES.
The study published online May 14 in Circulation, was designed to analyze the short- and long-term safety and efficacy of DES when compared to BMS. Sripal Bangalore, MD, MHA, of the New York University Medical School in New York City, and colleagues mined randomized clinical trials ( RCTs) that compared any currently FDA-approved durable stents and polymer DES including sirolimus eluting stents (SES), paclitaxel eluting stents (PES), everolimus eluting stents (EES) and zotarolimus eluting stents (ZES) and ZES-Resolute. The trials also compared the aforementioned DES to BMS, included at least 100 patients and had a follow-up of at least six months.
The authors evaluated short-term and long-term efficacy (target vessel revascularization [TVR], target lesion revascularization [TLR]) and safety (death, MI, stent thrombosis). Data were evaluated from 77 randomized trials with 117,762 patient-years of follow-up.
The researchers reported that DES reduced long-term TVR rates of 39 percent to 61 percent when compared with BMS . However, these rates varied by type of DES. The authors noted EES had the lowest TVR rate (a less than 42 percent probability). No incidence of stent thrombosis was reported with any DES when compared with BMS.
When compared with SES, EES and ZES-Resolute had similar efficacy but PES and ZES were less efficacious at reducing TVR. Additionally, it was recognized that there was a more than 58 percent probability that SES had the lowest TVR rates when compared to all other stents, according to the authors. This was followed by ZES-Resolute (probability 24 percent) and EES (probability 17 percent). Lastly, the researchers noted the median TVR rate with BMS was 15.8 percent and there was an 11 percent decrease in the rate with the most efficacious DES (SES).
In terms of safety, there was no increase in death with any of the DES when compared with BMS. The short-term death rate was 0.3 percent for all stents. Significant reductions of 33 percent to 45 percent were seen in the odds of MI with all DES except PES, when compared with BMS.
“The introduction of DES has resulted in a dramatic reduction in both angiographic restenosis and in the need for repeat revascularization when compared with BMS,” the authors wrote. “This benefit is explained by the inhibition of fibromuscular hyperplasia through targeted delivery of cytostatic/cytotoxic drugs. However, the drug eluted, the kinetics of elution and duration of elution varies with DES type.”
While the authors noted that the findings were “not surprising” in terms of the reduction of TVR/TLR seen with DES, what was unforeseen was the magnitude of the reduction, which varied by DES type.
“Our probability analysis allowed for a relative scaling of the stents such that for efficacy, EES, SES, and ZES-R were the most efficacious stents,” the authors wrote.
Stent thrombosis has been a previous issue with DES. “BMS has therefore been the benchmark for safety standards for stent evaluation. The results of our analysis showed no increase in the risk of stent thrombosis with DES with appropriate concomitant antiplatelet therapy,” the authors wrote. In fact, the researchers found a reduction in stent thrombosis risk with EES when compared with BMS.
“Moreover, newer generation stents such as the EES and ZES-R have changes in stent design, including thinner struts, use of cobalt-chromium rather than stainless steel stents, thinner and more biocompatible polymers that may elicit less inflammatory response with consequent decrease in stent thrombosis,” the authors summed.