Low Thrombosis Risks in Durable Polymer and Biodegradable Polymer Drug-Eluting Stents

Thrombosis Risks in Stents Scaffolds
Thrombosis Risks in Stents Scaffolds
Target vessel and lesion revascularization risks were low in both drug-eluting stents and bioresorabable vascular scaffolds, but only drug-eluting stents were associated with reduced risk of repeat revascularization compared to bare metal stents.

In a meta-analysis of nearly 150 clinical trials, contemporary drug-eluting stents (DES), including durable polymer (DP), biodegradable polymer (BP), and polymer-free devices, demonstrated low risks of definite or probable stent thrombosis (ST) at 1 year.

In addition, bioresorbable vascular scaffold (BVS) had an increased risk of device thrombosis compared with cobalt-chromium EES (CoCr-EES), platinum-chromium EES (PtCr-EES), and Orsiro hybrid sriolimus-eluting stents (O-SES). Findings were published in JACC: Cardiovascular Interventions.

“The main advantage of DES is the reduction of repeat revascularization compared with bare metal stents (BMS),” researchers wrote. “However, concerns about the long-term safety of earlier-generation DES have provoked recent advances in DES.”

Data from 126 526 patients were analyzed for definite or probable ST at 1 year, as defined by the Academic Research Consortium (ARC). Safety end points included early ST, late ST, definite ST, all-cause death, cardiac death, and myocardial infarction (MI). Target vessel revascularization (TVR) and target lesion revascularization (TLR) were included as efficacy end points.

Trials were included in the analysis if 2 or more coronary stents or scaffolds were compared in patients undergoing percutaneous coronary intervention (PCI). Trials were not included if they compared 2 stents with different designs within the same category (eg, BMS vs any DES).

Researchers were focused on the following stents: BMS, paclitaxel-eluting stents (PES), SES, Endeavor zotarolimus-eluting stents (E-ZES), PtCr-EES, BP-EES, Resolute zotarolimus-eluting stents (R-ZES), BP biolimus A9-eluting stents, O-SES, polymer-free sirolimus- and probucol-eluting stents (dual DES), and BVS.

The primary end point was available in 110 studies, which encompassed 111 088 patients. All DES with the exception of PES and BVS were superior in BMS in terms of definite or probable ST. In contrast, all other stents, except BVS and E-ZES were superior to PES, and CoCr-EES, O-SES, and PtCr-EES were associated with significantly lower risks of ST compared to BVS and E-ZES. Researchers also found that CoCr-EES and O-SES were significantly better than SES and BP-BES.

With regard to definite ST, 107 studies had available data with 106 543 patients. BP-BES, SES, R-ZES, O-SES, CoCr-EES, and PtCr-EES were found to be superior to BMS while SES, CoCr-EES, and PtCr-EES were superior to PES. CoCr-EES was also associated with a lower risk of ST compared to E-ZES, BP-BES, and SES.

In terms of other safety and efficacy end points, there were no statistical differences in all-cause death or cardiac death in the comparisons between stents. In addition, the outcomes of MI within 1 year were similar to those of the primary end point, though SES, R-ZES, BP-BES, E-ZES, PtCr-EES, CoCr-EES, and O-SES had significantly lower risks of MI vs BMS, while SES, BP-BES, E-ZES, PtCr-EES, CoCr-EES, and O-SES had significantly lower risks of MI than PES. There were low risks of TVR and TLR in both DES and BVS, but all DES were associated with reduced risk of repeat revascularization compared to BMS, and PES, and E-ZES demonstrated inferiority compared to other devices.

“Preclinical and autopsy data showed that delayed vascular healing after DES implantation is an important determinant of ST,” researchers wrote. “Recent advances in DES designs were largely driven by the efforts to reduce the risk of thrombotic events. This study confirms the safety of contemporary DP-DES and BP-DES in terms of ST at 1 year.”

However, they also noted that a limitation of the study was restricting the primary end point to 1 year since certain devices may only demonstrate benefit after longer follow-up periods.

“The benefit of BVS may emerge after 1 year, as complete degradation of the BVS is achieved in 1 to 4 years post-implantation. Extended follow-up of ongoing clinical trials would shed more light on the safety of the device,” the authors concluded.


Kang S-H, Chae I-H, Park J-J, et al. Stent thrombosis with drug-eluting stents and bioresorbable scaffolds: evidence from a network meta-analysis of 147 trials. JACC Cardiovasc Interv. 2016. doi:10.1016/j.jcin.2016.03.038.