Mechanical properties and performances of contemporary drug-eluting stent: focus on the metallic backbone

Manufacturing, Processing, and Characterization of Self-Expanding Metallic Stents: A Comprehensive Review

This paper aims to review the State of the Art in metal self-expanding stents made from nitinol (NiTi), showing shape memory and superelastic behaviors, to identify the challenges and the opportunities for improving patient outcomes. A significant contribution of this paper is its extensive coverage of multidisciplinary aspects, including design, simulation, materials development, manufacturing, bio/hemocompatibility, biomechanics, biomimicry, patency, and testing methodologies. Additionally, the paper offers in-depth insights into the latest practices and emerging trends, with a special emphasis on the transformative potential of additive manufacturing techniques in the development of metal stents. By consolidating existing knowledge and highlighting areas for future innovation, this review provides a valuable roadmap for advancing nitinol stents.

Ultra-thin everolimus-eluting stents in atherosclerotic lesions: Three years follow-up with subgroup analysis of ultra-long stents

OBJECTIVES

To assess the long-term (3 years) safety and efficacy of Tetrilimus everolimus-eluting stent (EES) and subgroup analysis of outcomes of ultra-long (44/48 mm) Tetrilimus EES implantation in patients with long coronary lesions.

MATERIAL AND METHODS

In this observational, single-centre, single-arm, investigator-initiated registry, 558 patients who underwent implantation of Tetrilimus EES for the treatment of coronary artery disease were retrospectively included. The primary endpoint was occurrence of any major adverse cardiac event (MACE) at 12 months follow-up (composite of cardiac death, myocardial infarction [MI], and target lesion revascularization [TLR]) and we hereby report 3 years follow-up data. Stent thrombosis was assessed as a safety endpoint. A subgroup analysis of patients with long coronary lesions is also reported.

RESULTS

A total of 558 patients (57.0 ± 10.2 years) received 766 Tetrilimus EES (1.3 ± 0.5 stents/patient) to treat 695 coronary lesions. In subgroup analysis of 143 patients implanted with ultra-long EES, 155 lesions were intervened successfully with only one Tetrilimus EES (44/48 mm) implanted per lesion. At 3 years, event rates of 9.1% MACE with predominance of MI (4.4%), followed by 2.9% TLR and 1.7% cardiac death, and only 1.0% stent thrombosis were reported in overall population, while in a subgroup of patients implanted with ultra-long EES, 10.4% MACE and 1.5% stent thrombosis were reported.

CONCLUSIONS

Three years clinical outcomes showed favourable long-term safety and excellent performance of Tetrilimus EES in high-risk patients and complex coronary lesions in routine clinical practice, including a subgroup of patients with long coronary lesions, with acceptable primary and safety endpoints.

Long-Term Outcome of Drug-Coated Balloon vs Drug-Eluting Stent for Small Coronary Vessels: PICCOLETO-II 3-Year Follow-Up

BACKGROUND

Native vessel coronary artery disease represents 1 of the most attractive fields of application for drug-coated balloons (DCBs). To date, several devices have been compared with drug-eluting stents (DESs) in this setting with different outcomes.

OBJECTIVES

The authors sought to compare the short- and long-term performance of the paclitaxel DCB with the everolimus-eluting stent in patients with de novo lesions in small coronary vessel disease.

METHODS

PICCOLETO II (Drug Eluting Balloon Efficacy for Small Coronary Vessel Disease Treatment) was an academic, international, investigator-driven, multicenter, open-label randomized clinical trial in which patients were allocated to a DCB (n = 118) or DES (n = 114). We previously reported the superiority of DCBs regarding in-lesion late lumen loss at 6 months. Herein we report the final 3-year clinical follow-up with the occurrence of major adverse cardiac events (MACEs), a composite of cardiac death, nonfatal myocardial infarction, target lesion revascularization, and its individual components.

RESULTS

The 3-year clinical follow-up (median 1,101 days; IQR: 1,055-1,146 days) was available for 102 patients allocated to DCB and 101 to DES treatment. The cumulative rate of all-cause death (4% vs 3.9%; P = 0.98), cardiac death (1% vs 1.9%; P = 0.56), myocardial infarction (6.9% vs 2%; P = 0.14), and target lesion revascularization (14.8% vs 8.8%; P = 0.18) did not significantly differ between DCBs and DESs. MACEs and acute vessel occlusion occurred more frequently in the DES group (20.8% vs 10.8% [P = 0.046] and 4% vs 0% [P = 0.042], respectively).

CONCLUSIONS

The long-term clinical follow-up of the PICCOLETO II randomized clinical trial shows a higher risk of MACEs in patients with de novo lesions in small vessel disease when they are treated with the current-generation DES compared with the new-generation paclitaxel DCB. (Drug Eluting Balloon Efficacy for Small Coronary Vessel Disease Treatment [PICCOLETO II]; NCT03899818).

Is There an Advantage of Ultrathin-Strut Drug-Eluting Stents over Second- and Third-Generation Drug-Eluting Stents?

In patients undergoing percutaneous coronary intervention, the second-generation drug-eluting stents (DES) are considered the gold standard of care for revascularization. By reducing neointimal hyperplasia, drug-eluting coronary stents decrease the need for repeat revascularizations compared with conventional coronary stents without an antiproliferative drug coating. It is important to note that early-generation DESs were associated with an increased risk of very late stent thrombosis, most likely due to delayed endothelialization or a delayed hypersensitivity reaction to the polymer. Studies have shown a lower risk of very late stent thrombosis with developing second-generation DESs with biocompatible and biodegradable polymers or without polymers altogether. In addition, research has indicated that thinner struts are associated with a reduced risk of intrastent restenosis and angiographic and clinical results. A DES with ultrathin struts (strut thickness of 70 µm) is more flexible, facilitates better tracking, and is more crossable than a conventional second-generation DES. The question is whether ultrathin eluting drug stents suit all kinds of lesions. Several authors have reported that improved coverage with less thrombus protrusion reduced the risk of distal embolization in patients with ST-elevation myocardial infarction (STEMI). Others have described that an ultrathin stent might recoil due to low radial strength. This could lead to residual stenosis and repeated revascularization of the artery. In CTO patients, the ultrathin stent failed to prove non-inferiority regarding in-segment late lumen loss and showed statistically higher rates of restenosis. Ultrathin-strut DESs with biodegradable polymers have limitations when treating calcified (or ostial) lesions and CTOs. However, they also possess certain advantages regarding deliverability (tight stenosis, tortuous lesions, high angulation, etc.), ease of use in bifurcation lesions, better endothelialization and vascular healing, and reducing stent thrombosis risk. In light of this, ultrathin-strut stents present a promising alternative to existing DESs of the second and third generation. The aims of the study are to compare ultrathin eluting stents with second- and third-generation conventional stents regarding procedural performance and outcomes based on different lesion types and specific populations.

Performance evaluation of biodegradable polymer sirolimus and ascorbic acid eluting stent systems

The purpose of this study was to evaluate the performance of biodegradable polymer sirolimus and ascorbic acid eluting stent systems with four commercially available drug-eluting stents (DES). We investigated the characterization of mechanical properties by dimension, foreshortening, recoil, radial force, crossing profile, folding shape, trackability, and dislodgement force. Additionally, we identify the safety and efficacy evaluation through registry experiments. Each foreshortening and recoil of D + Storm® DES is 1.3 and 3.70%, which has better performance than other products. A post-marketing clinical study to evaluate the performance and safety of D + Storm® DES is ongoing in real-world clinical settings. Two hundred one patients were enrolled in this study and have now completed follow-up for up to 1 month. No major adverse cardiovascular event (MACE) occurred in any subjects, confirming the safety of D + Storm® DES in the clinical setting. An additional approximately 100 subjects will be enrolled in the study and the final safety profile will be assessed in 300 patients. In conclusion, this study reported the objective evaluation of DES performance and compared the mechanical responses of four types of DES available in the market. There is little difference between the four cardiovascular stents in terms of mechanical features, and it can help choose the most suitable stent in a specific clinical situation if those features are understood. Graphical abstract.

The comparative short-term efficacy and safety of drug-coated balloon vs. drug-eluting stent for treating small-vessel coronary artery lesions in diabetic patients

Purpose

This meta-analysis aimed to explore the comparative short-term efficacy and safety of drug-coated balloon (DCB) vs. drug-eluting stent (DES) for treating small-vessel coronary artery lesions in diabetic patients.

Methods

We searched PubMed, EMBASE, the Cochrane Library, and China National Knowledgement Infrastructure (CNKI) for retrieving relevant studies regarding the comparison of DCB with DES in treating small-vessel coronary artery lesions in diabetic patients until May 31, 2022. Two independent authors screened study, extracted data, and assessed methodological quality. Then, the meta-analysis was conducted using RevMan software, version 5.4.

Results

We included 6 studies with 847 patients in this meta-analysis. Pooled results showed that DCB was associated with fewer major adverse cardiac events (MACE) [RR, 0.60; 95% confidence interval (CI), 0.39-0.93; p = 0.02], myocardial infarction (MI) (RR, 0.42; 95% CI, 0.19-0.94; p = 0.03), target lesion revascularization (TLR) (RR, 0.24; 95% CI, 0.08-0.69; p < 0.001), target vessel revascularization (TVR) (RR, 0.33; 95% CI, 0.18-0.63; p < 0.001), binary restenosis (RR, 0.27; 95% CI, 0.11-0.68; p = 0.005), and late lumen loss (LLL) [mean difference (MD), -0.31; 95% CI, -0.36 to -0.27; p < 0.001], but was comparable technique success rate, death, minimal lumen diameter (MLD), and net lumen gain (NLG) to DES. There was no difference in long-term outcomes between these two techniques.

Conclusions

This meta-analysis shows that DCB is better than DES in the short-term therapeutic efficacy and safety of small-vessel coronary artery lesions in diabetic patients. However, more studies are required to validate our findings and investigate the long-term effects and safety of DCB.

Additive Manufacturing of Drug-Eluting Multilayer Biodegradable Films

Drug-eluting films made of bioresorbable polymers are a widely used tool of modern personalized medicine. However, most currently existing methods of producing coatings do not go beyond the laboratory, as they have low encapsulation efficiency and/or difficulties in scaling up. The PLACE (Printed Layered Adjustable Cargo Encapsulation) technology proposed in this article uses an additive approach for film manufacturing. PLACE technology is accessible, scalable, and reproducible in any laboratory. As a demonstration of the technology capabilities, we fabricated layered drug-eluting polyglycolic acid films containing different concentrations of Cefazolin antibiotic. The influence of the amount of loaded drug component on the film production process and the release kinetics was studied. The specific loading of drugs was significantly increased to 200-400 µg/cm² while maintaining the uniform release of Cefazolin antibiotic in a dosage sufficient for local antimicrobial therapy for 14 days. The fact that the further increase in the drug amount results in the crystallization of a substance, which can lead to specific defects in the cover film formation and accelerated one-week cargo release, was also shown, and options for further technology development were proposed.

Coronary Stenting: Reflections on a 35-Year Journey

Stenting was introduced as a therapy for coronary artery disease 35 years ago, and is currently the most commonly performed minimally invasive procedure globally. Percutaneous coronary revascularization, initially with plain old balloon angioplasty and later with stenting, has dramatically affected the outcomes of acute myocardial infarction and acute coronary syndromes. Coronary stenting is probably the most intensively studied therapy in medicine on the basis of the number of randomized clinical trials for a broad range of indications. Continuous improvements in stent materials, design, and coatings concurrent with procedural innovations have truly been awe-inspiring. The story of stenting is replete with high points and some low points, such as the initial experience with stent thrombosis and restenosis, and the more recent disappointment with bioabsorbable scaffolds. History has shown rapid growth of stent use with expansion of indications followed by contraction of some uses in response to clinical trial evidence in support of bypass surgery or medical therapy. In this review we trace the constantly evolving story of the coronary stent from the earliest experience until the present time. Undoubtedly, future iterations of stent design and materials will continue to move the stent story forward.

A Narrative Review of Ultrathin-strut Drug-eluting Stents: The Thinner the Better?

Second-generation drug-eluting stents (DES) are considered standard of care for revascularization of patients undergoing percutaneous coronary intervention. Besides the polymer and antiproliferative drug used, the metallic backbone of DES is an attractive target for further development. Ultrathin-strut DES (≤70 μm strut thickness) are more flexible, have an improved trackability and crossability compared to conventional second-generation DES. Importantly, ultrathin-strut DES reduce the risk of in-stent restenosis, thereby decreasing the risk of angiographic and clinical restenosis. In this narrative review, we will discuss the clinical outcomes of the commercially available ultrathin-strut DES.

Cardiovascular Stents: A Review of Past, Current, and Emerging Devices

One of the leading causes of morbidity and mortality worldwide is coronary artery disease, a condition characterized by the narrowing of the artery due to plaque deposits. The standard of care for treating this disease is the introduction of a stent at the lesion site. This life-saving tubular device ensures vessel support, keeping the blood-flow path open so that the cardiac muscle receives its vital nutrients and oxygen supply. Several generations of stents have been iteratively developed towards improving patient outcomes and diminishing adverse side effects following the implanting procedure. Moving from bare-metal stents to drug-eluting stents, and recently reaching bioresorbable stents, this research field is under continuous development. To keep up with how stent technology has advanced in the past few decades, this paper reviews the evolution of these devices, focusing on how they can be further optimized towards creating an ideal vascular scaffold.

Elastic stent recoil in coronary total occlusions: Comparison of durable-polymer zotarolimus eluting stent and ultrathin strut bioabsorbable-polymer sirolimus eluting stent

Objectives

To compare stent recoil (SR) of the thin‐strut durable‐polymer Zotarolimus‐eluting stent (dp‐ZES) and the ultrathin‐strut bioabsorbable‐polymer Sirolimus‐eluting stent (bp‐SES) in chronic total occlusions (CTOs) and to investigate the predictors of high SR in CTOs.

Background

Newer ultrathin drug eluting stent might be associated with lower radial force and higher elastic recoil due to the thinner strut design, possibly impacting on the rate of in‐stent restenosis and thrombosis.

Methods

Between January 2017 and November 2019, consecutive patients with CTOs undergoing percutaneous coronary intervention were evaluated. Only patients treated with dp‐ZES or bp‐SES were included and stratified accordingly. Quantitative coronary angiography analysis was used to assess absolute SR, relative SR, absolute focal SR, relative focal SR, high absolute, and high relative focal SR.

Results

A total of 128 lesions (67 treated with dp‐ZES and 61 with bp‐SES) in 123 patients were analyzed. Between bp‐SES and dp‐ZES no differences were found in absolute SR (p = .188), relative SR (p = .138), absolute focal SR (p = .069), and relative focal SR (p = .064). High absolute and high relative focal SR occurred more frequently in bp‐SES than in dp‐ZES (p = .004 and p = .015). Bp‐SES was a predictor of high absolute focal SR (Odds ratio [OR] 3.29, 95% confidence interval [CI] 1.50–7.22, p = .003]. High‐pressure postdilation and bp‐SES were predictors of high relative focal SR (OR 2.22, 95% CI 1.01–4.86, p = .047; OR 2.74, 95% CI 1.24–6.02, p = .012, respectively).

Conclusions

Both stents showed an overall low SR. However, ultra‐thin strut bp‐SES was a predictor of high absolute and high relative focal SR.

Analytical methods for braided stents design and comparison with FEA

Braiding technology is nowadays commonly adopted to build stent-like devices. Indeed, these endoprostheses, thanks to their typical great flexibility and kinking resistance, find several applications in mini-invasive treatments, involving but not limiting to the cardiovascular field. The design process usually involves many efforts and long trial and error processes before identifying the best combination of manufacturing parameters. This paper aims to provide analytical tools to support the design and optimization phases: the developed equations, based on few geometrical parameters commonly used for describing braided stents and material stiffness, are easily implementable in a worksheet and allow predicting the radial rigidity of braided stents, also involving complex features such as multiple twists and looped ends, and the diameter variation range. Finite element simulations, previously validated with respect to experimental tests, were used as a comparator to prove the reliability of the analytical results. The illustrated tools can assess the impact of each selected parameter modification and are intended to guide the optimal selection of geometrical and mechanical stent proprieties to obtain the desired radial rigidity, deliverability (minimum diameter), and, if forming processes are planned to modify the shape of the stent, the required diameter variations (maximum and minimum diameters).

Current perspectives on bioresorbable scaffolds in coronary intervention and other fields

Introduction: The first-generation bioresorbable scaffolds (BRSs) had a large strut profile to compensate for the insufficient radial strength of bioresorbable polymer materials, resulting in higher scaffold thrombosis rates than conventional drug-eluting stents. To improve the clinical safety and efficacy, the new generation BRSs have been improved by optimal structure design, post-processing of bioresorbable polymer materials, or altering bioresorbable metallic alloys.Areas covered: This review summarizes the lessons learned from the first-generation BRS, updates the clinical outcomes of trials evaluating ABSORB bioresorbable vascular scaffold at long-term and bioresorbable metallic alloy-based devices, and examines recent outcomes of BRS treated in STEMI patients. This review also provides an overview of the current clinical data of seven BRSs manufactured in Asia, and of the BRSs extended application in other clinical arenas.Expert opinion: Drawbacks of the first-generation BRSs need to be addressed by the next generation of these stents with novel materials and technologies. Clinical research, including randomized controlled trials, are required to further evaluate BRSs application in coronary artery disease. The encouraging results of BRSs innovation applied in the peripheral arteries and gastrointestinal tracts support other potential clinical applications of BRS technology.

Twelve-month clinical outcomes of sirolimus-eluting stent in coronary artery disease: An experience in real-world Indian patients

Objective:

Supraflex (Sahajanand Medical Technologies Pvt. Ltd, Surat, India) is the latest generation of biodegradable polymer-coated sirolimus-eluting coronary stent designed on ultra-thin (60 µm) cobalt–chromium platform with flexible “S-link.” The present study was designed to establish the safety and clinical performance of Supraflex in real-world Indian patients with coronary artery disease.

Methods:

The study included 839 consecutive patients with coronary artery disease who were implanted with Supraflex from January 2014 to August 2017 at six different tertiary care centers in India. Follow-up was performed at 30 days, 6 months, and 12 months after the index procedure. The primary end-point of the study was the incidence of major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction (MI), and target lesion revascularization (TLR) at the 12-month follow-up. The occurrence of stent thrombosis was analyzed as safety end-point.

Results:

A total of 1025 lesions were treated by implantation of 1098 Supraflex stents. At the 12-month follow-up, MACE was 4.92%, including 7 (0.86%) cardiac deaths, 16 (1.97%) MI, and 17 (2.09%) TLR. Only three incidences of stent thrombosis were found at the 12-month follow-up.

Conclusion:

The study results showed excellent safety and clinical effectiveness of Supraflex in a high proportion of high-risk real-world Indian patients with coronary artery disease. (Anatol J Cardiol 2020; 24: 364-9)

The ultra-thin strut sirolimus-eluting coronary stent: SUPRAFLEX

Percutaneous coronary interventions with drug-eluting stents is currently the preferred revascularization treatment strategy for coronary artery disease. Following the first generation, the second-generation drug-eluting stents was designed with a thinner strut, better biocompatible polymer with/without bioresorbable coating or even polymer-free struts. The SUPRAFLEX stent system has ultra-thin struts (60 μm) across all stent diameters and a biodegradable polymer coating, enabling 70% of the sirolimus elution within 7 days. SUPRAFLEX has been assessed in large scale randomized controlled trials. This review summarizes the design of the SUPRAFLEX stent, the results of the pivotal clinical trials and outlines the ongoing research programs.

The effect of intrinsic characteristics on mechanical properties of poly(l-lactic acid) bioresorbable vascular stents

Poly(L-lactic acid) (PLLA) is currently the bioresorbable polymer of choice for vascular stents with its superior biocompatibility and mechanical properties. However, it is still difficult to enhance the radial supporting capacity of PLLA stents without increasing the strut thickness. In this study, the performance of laser-cut thin-strut stents from two groups of PLLA tubes are investigated. We considered two groups of PLLA tubes. Group 1 indicates the longitudinally stretched from original 150-μm-thick tubes, and Group 2 indicates the directly thinned from original 150-μm-thick tubes. Three stages of mechanical tests were conducted in this study, which are defined as tensile tests of dog-bone specimens, radial loading tests of tubes and radial loading tests of stents. The results suggest that Group 2 has higher radial supporting capacity than Group 1 with the same wall thickness. This work serves as a basis for manufacturing thin-strut stents with sufficient radial supporting capacity.

Risk of Dislodgement of Ultrathin Drug Eluting Stents Versus Thick Drug Eluting Stents

Modern ultrathin struts drug eluting stents (DES), due to their constructive characteristics, might be more prone to stent dislodgment than the old thick DES. Our study is aimed to retrospectively analyze and compare the incidence and outcomes of stents dislodgment in thick (TSS) and ultrathin strut stents (USS).We retrospectively analyzed the procedural and medical data of 8,564 consecutive patients (mean age 64.3 ± 11.2 years old, 4442 males) who underwent percutaneous coronary intervention with DES implantation in our Institution between 1st January 2005 to 1st January 2020. Overall, 25,692 (mean of 3.2 stent for patients) have been implanted over the study period (10648 TSS and 15044 and USS, respectively). Stent dislodgment globally occurred in 0.56% of the implanted stents (0.28% vs 0.78%, p <0.001 for TTS and USS, respectively). Coronary artery calcifications, ostial lesion, coronary artery tortuosity, and a lesion length >25 mm were independent predictors of type I and II USS dislodgments. At 12 months follow up, the rate of target lesion failure was higher in the TTS group (30.7 vs 12.7 %, p <0.001). Stent dislodgement is unusual in the modern era but is more frequent using USS than TTS DES.

Evaluation of Mechanical Performances of Stents with 38 mm Length in Long Lesion

Objective

Single stent with 38 mm length has emerged as a potential solution for long lesion treatment using PCI. However, long stents need to come over a longer lesion length combined with a higher incidence of tortuous calcification, requiring a stent to provide superior transport and compliance and reduce elastic retraction. Here, we evaluated the mechanical performances of the existing four types of drug eluting stents with 38 mm length, which could provide guidance for clinicians to choose the proper stents for the patients.

Methods

The stents with 38 mm length from XIENCE Xpedition (Abbott, US), SYNERGY (Boston Scientific, US), FIREHAWK (Microport, China), and HELIOS (HELIOS, China) were collected. Mechanical parameters of stents including crossing ability, compliance, elastic recoil, and longitudinal strength were performed.

Results

The resistance force of stents from XIENCE Xpedition was smaller than FIREHAWK (p < 0.05), which indicates that the stent from XIENCE Xpedition has better crossing ability. The ratio of stent diameter reduction from both XIENCE Xpedition and SYNERGY was less than 3% with no statistical difference. In addition, the elastic recoil percentage of stents from SYNERGY, XIENCE Xpedition, FIREHAWK, and HELIOS was 1.16%, 2.62%, 3.66%, and 4.19%, respectively, indicating that SYNERGY had better elastic recoil compared to FIREHAWK and HELIOS (p < 0.05), which indicates that the stent from XIENCE Xpedition has better crossing ability. The ratio of stent diameter reduction from both XIENCE Xpedition and SYNERGY was less than 3% with no statistical difference. In addition, the elastic recoil percentage of stents from SYNERGY, XIENCE Xpedition, FIREHAWK, and HELIOS was 1.16%, 2.62%, 3.66%, and 4.19%, respectively, indicating that SYNERGY had better elastic recoil compared to FIREHAWK and HELIOS (p < 0.05), which indicates that the stent from XIENCE Xpedition has better crossing ability. The ratio of stent diameter reduction from both XIENCE Xpedition and SYNERGY was less than 3% with no statistical difference. In addition, the elastic recoil percentage of stents from SYNERGY, XIENCE Xpedition, FIREHAWK, and HELIOS was 1.16%, 2.62%, 3.66%, and 4.19%, respectively, indicating that SYNERGY had better elastic recoil compared to FIREHAWK and HELIOS (

Conclusion

The evaluation of mechanical properties for the stent with 38 mm length including crossing ability, compliance, elastic recoil, and longitudinal strength could provide reference index for more accurately clinical application for long lesion treatment.

Serial invasive imaging follow-up of the first clinical experience with the Magmaris magnesium bioresorbable scaffold

Objectives

To assess the performance of the commercially available Magmaris sirolimus‐eluting bioresorbable scaffold (BRS) with invasive imaging at different time points.

Background

Coronary BRS with a magnesium backbone have been recently studied as an alternative to polymeric scaffolds, providing enhanced vessel support and a faster resorption rate. We aimed to assess the performance of the commercially available Magmaris sirolimus‐eluting BRS at different time points.

Methods

A prospective, single‐center, nonrandomized study was performed at the Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands. Six patients with stable de novo coronary artery lesions underwent single‐vessel revascularization with the Magmaris sirolimus‐eluting BRS. Invasive follow‐up including intravascular imaging using optical coherence tomography (OCT) was performed at different time points.

Results

At a median of 8 months (range 4–12 months) target lesion failure occurred in one patient. Angiography revealed a late lumen loss of 0.59 ± 0.39 mm, a percentage diameter stenosis of 39.65 ± 15.81%, and a binary restenosis rate of 33.3%. OCT showed a significant reduction in both minimal lumen area (MLA) and scaffold area at the site of the MLA by 43.44 ± 28.62 and 38.20 ± 25.74%, respectively. A fast and heterogeneous scaffold degradation process was found with a significant reduction of patent struts at 4–5 months.

Conclusions

Our findings show that the latest iteration of magnesium BRS suffers from premature dismantling, resulting in a higher than expected decrease in MLA.

Plasma nitriding under low temperature improves the endothelial cell biocompatibility of 316L stainless steel

OBJECTIVES

To evaluate the effects of the surface modification of 316L stainless steel (SS) by low-temperature plasma nitriding on endothelial cells for stent applications.

RESULTS

X-ray diffraction (XRD) confirmed the incorporation of nitrogen into the treated steel. The surface treatment significantly increased SS roughness and hydrophilic characteristics. After 4 h the cells adhered to the nitride surfaces and formed clusters. During the 24 h incubation period, cell viability on the nitrided surface was higher compared to the polished surface. Nitriding reduced late apoptosis of rabbit aorta endothelial cell (RAEC) on the SS surface.

CONCLUSION

Low temperature plasma nitriding improved the biocompatible of stainless steel for use in stents.