In this study we compared the efficacy of SES and PES in real-world patients with acute STEMI undergoing primary PCI. There were no significant differences between the two stents regarding the incidence of 2-year MACE (8.3% in SES vs. 16.4% in PES; p
0.28) and ST rates (6.25% in SES, 7.59% in PES; p
1.0). Recent prospective trials which compared bare-metal stents with DESs in primary PCI showed superiority of DESs in terms of target vessel revascularization with similar rates of death, reinfarction, and ST.7,9,10
TYPHOON and PASSION trials were large randomized clinical trials which investigate the safety and effectiveness of DESs in primary PCI.7,8
The SES arm of TYPHOON and PES arm of PASSION study showed that 1-year MACE rates were 7.3 and 8.8% respectively.7,8
There were also several published studies that compared SES with PES in elective patients. In SIRTAX trial 1012 stable and unstable patients are treated with SES and PES.11
At the end of the study, investigators found fewer MACE after SES implantation, primarily by decreasing rates of clinical and angiographic restenosis.
Galløe et al compared SES with PES in broad range of patients including STEMI, NSTEMI, unstable angina pectoris, and stable angina.12
In this randomized trial, there were no significant differences in clinical outcomes between patients receiving SES and PES. However, data from the comparison of the different DES type in primary PCI are very limited. The PROSIT trial randomized 308 patients with STEMI to SES and PES.13
There were no differences regarding primary end points (death, reinfarction, ST, and target lesion revascularization) between two stents in 12-month follow-up (5.8% in SES vs. 11.7% in PES; p
0.05). The results of that study were also consistent with our findings. T-SEARCH and RESEARCH registries compared SES and PES in different clinical situations including STEMI.14
In the relatively small subgroup analysis the incidence of MACE was similar between SES and PES groups. ZEST-AMI trial compared the effectiveness of zotarilimus-eluting stent, SES, and PES in primary PCI patients.15
This multicenter, prospective, and randomized trial included 328 STEMI patients. At 12 months, cumulative incidence rates of MACE between zotarilimus-eluting stent, SES, and PES groups were not different from each other.15
The rate of ST in our study (definite and probable according to Academic Research Consortium criteria) was 6.25% in the SES group and 7.59% in the PES group at 2 years. This rate was much higher than the previously reported rates of ST in large meta-analyses, which showed rates of cumulative ST to be 1.5% for SES and 1.8% for PES at 4 years.16
It was also higher than 1.3% reported ST rate for the PES group in PROSIT trial.13
In SES arm of TYPHOON trial ST rate at 1 year was 3.4% and in PES group in HORIZON-AMI trial ST rate at 1 year was 3.2%.7,17
The difference between ST rates may be due to several reasons. First, the STEMI itself is an independent predictor of ST. In the report by Romano et al, ST rate at 2 years was 3.2% in real-world STEMI patients treated with DES which was higher than previous trial of DES that included only elective cases18
(ST rate ranged from 0 to 1.1%). Second, the high rate of ST in our study may be related with patient characteristics, as 10% of our patients were in shock; in-hospital thrombotic rates and mortality was higher than previous randomized trials. Similarly, recent report of real-world patients showed 5.1% ST (definite and probable) at 6 months which was very high.19
Third, the definition of ST may differ between trials. Some studies defined ST as angiographic documentation of thrombus in stented vessel. But this definition did not include Academic Research Consortium defined probable ST. Angiographic documentation of thrombus in the present study was 2.08% in the SES group and 5.06% in the PES group. Fourth, almost all currently available trials have provided relatively short-term data (<12 months) which did not reflect the incidence of very late ST (>1 year). In our trial very late ST rates were 2.08% in the SES group and 2.53% in the PES group, so high ST rates may be related with the 2-year follow-up period of our study. But at the end it is hard to draw clear conclusion regarding ST from such a small number of patients and bigger trials are needed to clarify this issue.
The most important limitations of our study were retrospective design, small sample size, and the lack of multivariable statistical analysis.