A Nuclear Magnetic Resonance Spectroscopy as a Method for Evaluation of In Vivo Poly-l-Lactide Biodegradation Kinetics From Stent-Polymer Matrices: An Experimental Study Utilizing Porcine Model of In-Stent Restenosis

Polymer Coating Integrity, Thrombogenicity and Computational Fluid Dynamics Analysis of Provisional Stenting Technique in the Left Main Bifurcation Setting: Insights from an In-Vitro Model

Currently, the provisional stenting technique is the gold standard in revascularization of lesions located in the left main (LM) bifurcation. The benefit of the routine kissing balloon technique (KBI) in bifurcation lesions is still debated, particularly following the single stent treatment. We compared the latest-generation drug-eluting stent (DES) with no side branch (SB) dilatation “keep it open” technique (KIO) vs. KBI technique vs. bifurcation dedicated drug-eluting stent (BD-DES) implantation. In vitro testing was performed under a static condition in bifurcation silicone vessel models. All the devices were implanted in accordance with the manufacturers’ recommendations. As a result, computational fluid dynamics (CFD) analysis demonstrated a statistically higher area of high shear rate in the KIO group when compared to KBI. Likewise, the maximal shear rate was higher in number in the KIO group. Floating strut count based on the OCT imaging was significantly higher in KIO than in KBI and BD-DES. Furthermore, according to OTC analysis, the thrombus area was numerically higher in both KIO and KBI than in the BD-DES. Scanning electron microscopy (SEM) analysis shows the highest degree of strut coating damage in the KBI group. This model demonstrated significant differences in CFD analysis at SB ostia with and without KBI optimization in the LM setting. The adoption of KBI was related to a meaningful reduction of flow disturbances in conventional DES and achieved results similar to BD-DES.

Two-Step Geometry Design Method, Numerical Simulations and Experimental Studies of Bioresorbable Stents

The stent-implantation process during angioplasty procedures usually involves clamping the stent onto a catheter to a size that allows delivery to the place inside the artery. Finding the right geometrical form of the stent to ensure good functionality in the open form and to enable the clamping process is one of the key elements in the stent-design process. In the first part of the work, an original two-step procedure for stent-geometry design was proposed. This was due to the necessary selection of a geometry that would provide adequate support to the blood-vessel wall without causing damage to the vessel. Numerical simulations of the crimping and deployment processes were performed to verify the method. At the end of this stage, the optimal stent was selected for further testing. In addition, numerical simulations of selected experimental tests (catheter-crimping process, compression process) were used to verify the obtained geometrical forms. The results of experimental tests on stents produced by the microinjection method are presented. The digital image correlation (DIC) method was used to compare the results of numerical simulation and experimental tests. The two-step modeling approach was found to help select the appropriate geometry of the expanded stent, which is an extremely important step in the design of the crimping process. In the part of the paper where the results obtained by numerical simulation were compared with those gained by experiment and using the DIC method, a good compatibility of the displacement results can be observed. For both longitudinal and transverse (pinch) stent compression, the results practically coincide. The paper presents also the application of the DIC method which significantly expands the research possibilities, allowing for a detailed inspection of the deformation state and, above all, verification of local dangerous areas. This approach significantly increases the possibility of assessing the quality of the stents.

Safety and efficacy of biodegradable polymer-coated thin strut sirolimus-eluting stent vs. durable polymer-coated everolimus-eluting stent in patients with acute myocardial infarction

Introduction

The biodegradable polymer drug-eluting stents were developed to improve vascular healing. However, further data are needed to confirm the safety and efficacy of these stents in patients with acute myocardial infarction (AMI).

Aim

We sought to determine the 1-year clinical follow-up in patients with AMI treated with a thin strut biodegradable polymer-coated sirolimus-eluting stent (BP-SES) versus a durable coating everolimus-eluting stent (DP-EES).

Material and methods

We analyzed patients with AMI (STEMI and NSTEMI) treated with either a BP-SES (ALEX, Balton, Poland, n = 886) or DP-EES (XIENCE, Abbott, USA, n = 1054) with available 1-year clinical follow-up using propensity score matching. Outcomes included target vessel revascularization (TVR) as the efficacy outcome and all-cause death, myocardial infarction, and definite/probable stent thrombosis as safety outcomes.

Results

After propensity score matching 672 patients treated with BP-SES and 672 patients treated with DP-EES were selected. Procedural and clinical characteristics were similar between the groups. In-hospital mortality was similar in both tested groups. One-year follow-up demonstrated comparable efficacy outcome TVR (BP-SES 7.1% vs. DP-EES 5.2%, p = 0.14), as well as similar safety outcomes of all-cause death, myocardial infarction, and definite/probable stent thrombosis.

Conclusions

The thin-strut biodegradable polymer coated sirolimus-eluting stent demonstrated comparable clinical outcomes at 1 year after implantation to the DP-EES. These data support the relative safety and efficacy of BP-SES in AMI patients undergoing percutaneous coronary intervention.

Bioresorbable polymer-coated thin strut sirolimus-eluting stent vs durable polymer-coated everolimus-eluting stent in daily clinical practice: Propensity matched one-year results from interventional cardiology network registry

OBJECTIVES

We sought to determine the 1-year clinical follow-up in patients treated with the thin strut (71 μm) bioabsorbable polymer-coated sirolimus-eluting stent (BP-SES) vs durable coating everolimus eluting stent (DP-EES) in daily clinical routine.

BACKGROUND

Presence of durable polymers may be associated with late/very late stent thrombosis occurrence and the need for prolonged dual antiplatelet therapy. Bioabsorbable polymers may facilitate stent healing, thus enhancing clinical safety.

METHODS

Interventional Cardiology Network Registry is a prospective, multicenter, observational registry of 21,400 consecutive patients treated with PCI since 2010. We analyzed 4,670 patients treated with either a BP-SES (ALEX, Balton, Poland) or DP-EES (XIENCE, Abbott, USA) with available 1-year clinical follow-up using propensity-score matching. Outcomes included target vessel revascularization (TVR) as efficacy outcome and all cause death, myocardial infarction (MI), and definite/probable stent thrombosis as safety outcomes.

RESULTS

After propensity score matching, 1,649 patients treated with BP-SES and 1,649 patients treated with DP-EES were selected. Procedural and clinical characteristics were similar between both groups. There was no significant difference between tested groups in in-hospital mortality. One-year follow-up demonstrated comparable efficacy outcome, TVR (BP-SES 5.9% vs DP-EES 4.6% P = 0.45), as well as comparable safety outcomes, all cause death, MI and definite/probable stent thrombosis.

CONCLUSIONS

In this multicenter registry, the BP-SES thin strut biodegradable polymer-coated sirolimus-eluting stent demonstrated comparable clinical outcomes at 1-year after implantation to the DP-EES. These data support the relative safety and efficacy of DP-SES in a broad range of patients undergoing percutaneous coronary intervention.

Research on a Nonwoven Fabric Made from Multi-Block Biodegradable Copolymer Based on l-Lactide, Glycolide, and Trimethylene Carbonate with Shape Memory

The presented paper concerns scientific research on processing a poly(lactide-co-glycolide-co-trimethylene carbonate) copolymer (PLLAGLTMC) with thermally induced shape memory and a transition temperature around human body temperature. The material in the literature called terpolymer was used to produce smart, nonwoven fabric with the melt blowing technique. Bioresorbable and biocompatible terpolymers with shape memory have been investigated for its medical applications, such as cardiovascular stents. There are several research studies on shape memory in polymers, but this phenomenon has not been widely studied in textile products made from shape memory polymers (SMPs). The current research aims to explore the characteristics of the PLLAGLTMC nonwoven fabric in detail and the mechanism of its shape memory behavior. In this study, the nonwoven fabric was subjected to thermo-mechanical, morphological, and shape memory analysis. The thermo-mechanical and structural properties were investigated by means of differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopic examination, and mercury porosimetry measurements. Eventually, the gathered results confirmed that the nonwoven fabric possessed characteristics that classified it as a smart material with potential applications in medicine.