Efficacy and Safety of a Polytetrafluoroethylene Membrane Wrapped a Single Layer of Sirolimus-Eluting Stent in a Porcine Coronary Perforation Model

Abstract

Background: Covered stents are effective in treating coronary artery perforation (CAP), however, the high rate of immediate device deployment failure and in-stent restenosis have limited the application of the currently covered stents.

Methods: We designed a covered stent system consisting of a single layer of drug-eluting stent and a layer of polytetrafluoroethylene (PTFE) membrane wrapped at the outer layer of the stent. The immediate sealing effect of our novel covered stent was observed by using an Ellis type III CAP model. The device's success was defined as its ability to seal the perforation, assessed by visual estimation and final thrombolysis in myocardial infarction (TIMI) 3 flow. The antiproliferative effect was evaluated in 12 swine, which were randomly assigned to treatment (sirolimus-eluting covered stents) and control (bare metal covered stents) groups. Coronary angiography and optical coherence tomography (OCT) were performed at index procedure, 1- and 6-month after stent implantation. All swine were sacrificed for histopathological analyses at 6-month.

Results: The device success rate was 100%. All swine were alive at 6-month follow-up. At 1-month, the treatment group had a larger minimal luminal diameter (MLD) (1.89 $\pm$ 0.29 mm vs. 0.63 $\pm$ 0.65 mm, p = 0.004) and lower late luminal loss (LLL) (0.47 $\pm$ 0.15 mm vs. 1.80 $\pm$ 0.34 mm, p $<$ 0.001) compared with control group. At 6-month, the treatment group had a numerically higher MLD (0.94 $\pm$ 0.75 mm vs. 0.26 $\pm$ 0.46 mm; p = 0.230) and lower LLL (1.43 $\pm$ 0.85 mm vs. 2.17 $\pm$ 0.28 mm; p = 0.215) compared with control group. Histological analyses revealed the mean plaque area was lower in the treatment group (2.99 $\pm$ 0.81 ${\mathrm{mm}}^2$ vs. 4.29 $\pm$ 0.77 ${\mathrm{mm}}^2$ , p = 0.035) than in the control group. No in-stent thrombosis was observed in either group.

Conclusions: In the porcine model of coronary perforation, the PTFE membrane wrapped sirolimus-eluting stent showed a high device success rate in sealing the perforation. The drug-eluting covered stent demonstrated a relatively sustained antiproliferative effect up to 6 months post-implantation.

Keywords: coronary artery perforation; covered stent; percutaneous coronary intervention.

Fig. 1.

The flow chart of the study. CAG, Coronary angiography; CAP, coronary perforation; ISR, in-stent restenosis; OCT, optical coherence tomography; PCI, percutaneous coronary interventions.

Fig. 2.

The representative example of CAP model and covered stent implantation. (A) Baseline CAG. (B) Construction of CAP model (B1, micro-catheter, B2, soft guidewire, B3, stiff guidewire). (C) Streaming of contrast through an exit hole (white arrow). (D) Stent positioning. (E) Stent dilation. (F) Complete closure of the perforation. CAP, coronary perforation; CAG, Coronary angiography.

Fig. 3.

Representative examples of CAG follow-up at all time points. Two swine died of anesthetic accident in the control group. The CAG data was not available in 1 swine from the control group and 2 swine from the treatment group, respectively. CAG, Coronary angiography.

Fig. 4.

Representative examples of OCT follow-up at all time points. OCT, Optical Coherence Tomography.

Fig. 5.

Representative examples of histological follow-up. *p 0.05 Treatment group (n = 6) vs. Control group (n = 4).