New-generation drug-eluting coronary stents in octogenarians: Patient-level pooled analysis from the TWENTE I-IV trials

BACKGROUND

Patients aged ≥80 years are often treated with new-generation drug-eluting stents (DES), but data from randomized studies are scarce owing to underrepresentation in most trials. We assessed 1-year clinical outcome of octogenarians treated with new-generation DES versus younger patients.

METHODS

We pooled patient-level data of 9,204 participants in the TWENTE, DUTCH PEERS, BIO-RESORT, and BIONYX (TWENTE I-IV) randomized trials. The main clinical end point was target vessel failure (TVF), a composite of cardiac death, target vessel-related myocardial infarction (MI), or clinically indicated target vessel revascularization.

RESULTS

The 671 octogenarian trial participants had significantly more comorbidities. TVF was higher in octogenarians than in 8,533 patients <80 years (7.3% vs 5.3%, hazard ratio [HR]: 1.36, 95% CI: 1.0-1.83, P = .04). The cardiac death rate was higher in octogenarians (3.9% vs 0.8%, P < .001). There was no significant between-group difference in target vessel MI (2.3% vs 2.3%, P = .88) and repeat target vessel revascularization (1.9% vs 2.8%, P = .16). In multivariate analyses, age ≥ 80 years showed no independent association with TVF (adjusted HR: 1.04, 95% CI: 0.76-1.42), whereas the risk of cardiac death remained higher in octogenarians (adjusted HR: 3.38, 95% CI: 2.07-5.52, P < .001). In 6,002 trial participants, in whom data on major bleeding were recorded, octogenarians (n = 459) showed a higher major bleeding risk (5.9% vs 1.9%; HR: 3.08, 95% CI: 2.01-4.74, P < .001).

CONCLUSIONS

Octogenarian participants in 4 large-scale randomized DES trials had more comorbidities and a higher incidence of the main end point TVF. Cardiac mortality was higher in octogenarians, whereas there was no increase in MI or target vessel revascularization rates. Treatment of octogenarian patients with new-generation DES appears to be safe and effective.

Comparative preclinical evaluation of a polymer-free sirolimus-eluting stent in porcine coronary arteries

Background:

Polymer-free drug-eluting stents (DES) without permanent-polymer coating may be associated with rapid vessel healing, providing a rationale to reduce dual-antiplatelet therapy (DAPT). The aim of the current study was to compare vessel healing of a polymer-free sirolimus-eluting stent (PF-SES), its bare metal stent (BMS) analogue to a permanent polymer-based sirolimus-eluting stent (SES) with proven effectiveness in porcine coronary arteries.

Material and methods:

An ultrathin-strut cobalt–chromium PF-SES, its BMS analogue and an SES with a permanent polymer were used to study vessel healing and their antistenotic potential. Stents were implanted in porcine coronary arteries for histopathologic analysis at 7, 28 and 180 days.

In an additional in vitro study, the thrombogenicity of PF-SES was compared with a fluoropolymer-coated everolimus-eluting stent (EES) which demonstrated low stent thrombosis rates in numerous studies.

Results:

In the animal study, neointimal growth and injury scores were minimal and inflammation scores were low in the neointima and adventitia in all study groups. After 28 days, neointimal area was lowest in PF-SES when compared with SES and BMS (1.48 ± 0.55 mm² versus 2.43 ± 0.69 mm² versus 1.90 ± 0.85 mm², respectively, p < 0.05) and endothelialization of luminal surfaces was nearly complete in all groups, though SES show the least coverage with occasional adherent luminal inflammatory cells (p > 0.05). At 180 days, neointimal area and thickness were most pronounced in SES (p < 0.05) and comparable with BMS implantations, which were characterized by nearly completed vessel healing. PF-SES and BMS had complete endothelialization, absence of fibrin and sustained low inflammatory reaction when compared with the permanent polymer-based SES (inflammation score: PF-SES 0.41 ± 0.74 versus SES 2.52 ± 1.72 versus BMS 0.30 ± 0.65, respectively, p < 0.05 BMS versus SES). Granuloma formation and fibrin accumulation were most pronounced in SES but did not reach statistical significance, p > 0.05). In the in vitro thrombogenicity study, the PF-SES confirmed comparable antithrombogenic properties with regard to the parameters fibrin and platelet binding, and platelet aggregation when compared with the EES.

Conclusions:

As compared with BMS, the ultrathin-strut cobalt–chromium PF-SES showed similar endothelialization at 28 days and comparable healing characteristics at 180 days efficacious inhibition of neointimal proliferation in porcine coronary arteries with low inflammation responses and a BMS-like endothelialization at 180 days. In addition, in an in vitro model, the PF-SES also confirmed low thrombogenicity as compared with the EES.