Ultrathin bioresorbable polymer sirolimus-eluting stents in US patients undergoing coronary revascularization: 1-Year outcomes from the BIOFLOW VII trial.

BACKGROUND: Ultrathin strut coronary drug-eluting stents (DES) have demonstrated improved safety and efficacy in large contemporary trials. The evaluation of an ultrathin strut DES in a post-market United States (US) patient population was undertaken. OBJECTIVE: The purpose of this post-approval study is to confirm that the clinical performance of an ultrathin strut bioresorbable polymer sirolimus-eluting stent (BP SES) in clinical practice is similar to that observed with BP SES in the BIOFLOW V pivotal trial. METHODS: BIOFLOW VII is a prospective, multicenter, single-arm US post-market approval study to confirm the clinical performance of BP SES in a real-world setting. The primary endpoint of 1-year target lesion failure (TLF) was compared with a performance goal of 6.9% based on an adapted BIOFLOW V trial BP SES TLF rate and TLF rates from other US market-released DES utilizing the Society for Cardiovascular Angiography and Interventions definition for peri-procedural myocardial infarction (MI). Subjects undergoing percutaneous coronary intervention with BP SES were consented within 24 h post-index procedure with planned follow-up through 5 years. RESULTS: Among 556 enrolled patients, clinical demographics included: 34.7% female, 35.6% with diabetes mellitus, and 56.8% with acute coronary syndromes. The average stent length (mean ± standard deviation) was 20.2 ± 11.8 mm, and the mean number of stents per patient was 1.3 ± 0.6. Procedure success was 99.1% (551/556), and device success was 99.9% (689/690). Among 531 subjects included in the primary endpoint analysis, the 1-year rate of TLF rate was 1.7% (9/531), and the primary endpoint was met compared with the performance goal (p < 0.0001, 95% confidence interval: 0.69%, 3.43%). Rates of target vessel MI and clinically driven target lesion revascularization were 1.3% (7/531) and 0.9% (5/531), with no occurrence of cardiac death. Definite stent thrombosis was observed for two cases (0.4%; 2/556) with one acute (≤24 h) and one late (>30 days and ≤1 year) event. CONCLUSION: In a post-approval study, 1-year clinical outcomes with BP SES were consistent with prior trials supporting the safety and effectiveness of ultrathin BP SES.

Recent Advances in Stent Technology: Do They Reduce Cardiovascular Events?

PURPOSE OF REVIEW: Drug-eluting stents are used in nearly all cases of percutaneous coronary revascularization and have been shown to be superior to balloon angioplasty or bare metal stents. The designs of these stents are continually evolving to maximize efficacy and safety. RECENT FINDINGS: This review outlines the important components of a drug-eluting stent and highlights the changes in stent design that have led to the optimization of clinical outcomes. Most stents used in contemporary times are thin strut, durable polymer drug-eluting stents (DES) that elute either everolimus or zotarolimus. Newer DES designs incorporating bioresorbable polymers or ultrathin struts have shown encouraging safety and efficacy profiles. DES are essential for the management of patients with obstructive coronary artery disease and are used in most coronary interventions. Changes in stent designs over the past 30 years reflect the ongoing need to address the limitations of earlier stents aimed to improve patient outcomes.

NIR-Based Intelligent Sensing of Product Yield Stress for High-Value Bioresorbable Polymer Processing.

PLA (polylactide) is a bioresorbable polymer used in implantable medical and drug delivery devices. Like other bioresorbable polymers, PLA needs to be processed carefully to avoid degradation. In this work we combine in-process temperature, pressure, and NIR spectroscopy measurements with multivariate regression methods for prediction of the mechanical strength of an extruded PLA product. The potential to use such a method as an intelligent sensor for real-time quality analysis is evaluated based on regulatory guidelines for the medical device industry. It is shown that for the predictions to be robust to processing at different times and to slight changes in the processing conditions, the fusion of both NIR and conventional process sensor data is required. Partial least squares (PLS), which is the established 'soft sensing' method in the industry, performs the best of the linear methods but demonstrates poor reliability over the full range of processing conditions. Conversely, both random forest (RF) and support vector regression (SVR) show excellent performance for all criteria when used with a prior principal component (PC) dimension reduction step. While linear methods currently dominate for soft sensing of mixture concentrations in highly conservative, regulated industries such as the medical device industry, this work indicates that nonlinear methods may outperform them in the prediction of mechanical properties from complex physicochemical sensor data. The nonlinear methods show the potential to meet industrial standards for robustness, despite the relatively small amount of training data typically available in high-value material processing.

One-year outcomes of patients undergoing complex percutaneous coronary intervention with three contemporary drug-eluting stents.

OBJECTIVES: We aimed to evaluate the 1-year outcomes of three everolimus-eluting stents (EES) for complex percutaneous coronary intervention (PCI). BACKGROUND: It is controversial whether contemporary bioresorbable-polymer drug-eluting stents (BP-DES) are associated with better outcomes compared with durable-polymer DES (DP-DES). METHODS: Patients undergoing PCI with cobalt-chromium (CoCr)-DP-EES (Xience), platinum-chromium (PtCr)-DP-EES (Promus), or PtCr-BP-EES (Synergy) at one high-volume institution between 2015 and 2017 were included. The primary endpoint was 1-year major adverse cardiac events (MACE), a composite of death, myocardial infarction, and target-vessel revascularization. Associations were also examined in patients undergoing complex PCI. Multivariable analysis was conducted to adjust for baseline differences across groups. RESULTS: We included n = 5,446 patients (CoCr-DP-EES, n = 3,177; PtCr-DP-EES, n = 1,555; PtCr-BP-EES, n = 714). Patients treated with PtCr-BP-EES had higher comorbidity burden and procedural complexity. At 1 year, MACE rates were 8.9% for CoCr-DP-EES versus 8.9% for PtCr-DP-EES versus 8.6% for PtCr-BP-EES (p = .97). The incidence of definite/probable stent thrombosis (ST) was also similar (0.6 vs. 0.4 vs. 0.3%, p = .69). Complex PCI was performed in n = 2,894/5,446 (53.1%). At 1 year, MACE rates were 11.5 versus 10.7 versus 10.3%, respectively (p = .83). The incidence of definite/probable ST was also similar (0.9 vs. 0.3 vs. 0.3%, p = .22). On multivariable analysis, stent type was not an independent predictor of MACE either in the overall or in the complex PCI population. CONCLUSIONS: We observed comparable 1-year rates of MACE and definite/probable ST in patients undergoing PCI with CoCr-DP-EES, PtCr-DP-EES, and PtCr-BP-EES. Results were unchanged among patients undergoing complex PCI. Future multicenter randomized studies should confirm and extend our findings.

Comparison of 6-month vascular healing response after bioresorbable polymer versus durable polymer drug-eluting stent implantation in patients with acute coronary syndromes: A randomized serial optical coherence tomography study.

OBJECTIVES: This study was conducted to use optical coherence tomography (OCT) to compare vascular healing between bioresorbable polymer (BP) and durable polymer (DP) everolimus-eluting stents (EES) in patients with acute coronary syndromes (ACS). BACKGROUND: Whether BP-EES induce better vascular healing compared to contemporary DP-EES remains controversial, especially for ACS. METHODS: In this prospective, randomized, non-inferiority trial, we used OCT to compare 6-month vascular healing in patients with ACS randomized to BP versus DP-EES: percent strut coverage (primary endpoint, non-inferiority margin of 2.0%) and neointimal thickness and percent neointimal hyperplasia (NIH) volume. As an exploratory analysis, morphological factors related to the endpoints and the effect of underlying lipidic plaque on stent healing were evaluated. RESULTS: A total of 104 patients with ACS were randomly assigned to BP-EES (n = 52) versus DP-EES (n = 52). Of these, 86 patients (40 BP-EES and 46 DP-EES) were included in the final OCT analyses. Six-month percent strut coverage of BP-EES (83.6 ± 11.4%) was not non-inferior compared to those of DP-EES (81.6 ± 13.9%), difference 2.0% (lower 95% confidence interval-2.6%), pnon-inferiority  = 0.07. There were no differences in neointimal thickness 70.0 ± 33.9 µm versus 67.2 ± 33.9 µm, p = 0.71; and percent NIH volume 7.5 ± 4.7% versus 7.3 ± 5.3%, p = 0.85. By multivariable linear regression analysis, stent type was not associated with percent strut coverage or percent NIH volume; however, percent baseline embedded struts or stent expansion was positively associated with percent NIH volume. Greater NIH volume was observed in lipidic compared with non-lipidic segments (8.7 ± 5.6% vs. 6.1 ± 5.2%, p = 0.005). CONCLUSIONS: Six-month strut coverage of BP-EES was not non-inferior compared to those of DP-EES in ACS patients. Good stent apposition and expansion were independently associated with better vascular healing.

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.

Early endothelialization associated with a biolimus A9 bioresorbable polymer stent in a porcine coronary model.

Although Nobori®, with a bioresorbable polymer and biolimus A9 abluminal coating, has unique characteristics, few data exist regarding endothelialization early after implantation. Fifteen Nobori® and 14 control bare-metal stents (S-stent™) were implanted in 12 pigs. Histopathology of stented segments, inflammation, and intimal fibrin content was evaluated on the 2nd and 14th day after implantation. On the 2nd day, endothelial cells were morphologically and immunohistologically confirmed on the surface of both stents, although some inflammatory cells might be involved. Stent surface endothelialization evaluated with a scanning electron microscope showed partial cellular coverage in both stents. On the 14th day, neointimal thickness and percentage of the neointimal area were significantly lower in Nobori® than in S-stent™ (51.4 ± 4.5 vs. 76.4 ± 23.6 µm, p < 0.05 and 10.8 ± 2.6 vs. 14.1 ± 4.2%, p < 0.01). No significant differences were found in these parameters on the 2nd day (17.3 ± 14.9 vs. 26.7 ± 13.6 µm and 3.7 ± 3.0 vs. 6.7 ± 3.7%), in inflammatory and intimal fibrin content scores. These results demonstrate that endothelialization could occur early after Nobori® implantation with similar inflammatory reaction to bare-metal stents, probably contributing to low frequency of in-stent thrombosis and restenosis.

Safety and efficacy profile of bioresorbable-polylactide-polymer-biolimus-A9-eluting stents versus durable-polymer-everolimus- and zotarolimus-eluting stents in patients with acute coronary syndrome.

BACKGROUND: Comparative data on long-term safety and efficacy of bioresorbable-polymer-BES versus durable-polymer-EES/ZES in ACS setting have hitherto been lacking. We sought to assess the safety and efficacy of bioresorbable-polymer-biolimus-A9-eluting stents (BES) compared with thin-strut-durable-polymer-everolimus- and zotarolimus-eluting stents (EES/ZES) in patients with acute coronary syndrome (ACS) undergoing PCI. METHODS AND RESULTS: Between 2007 and 2012, 1,547 patients were implanted with new-generation drug-eluting stents (DES). Out of these, 369 received BES and 1,178 EES/ZES. The primary endpoint was probable/definite stent thrombosis (ST) while the secondary endpoint was a composite of all-cause death, myocardial infarction (MI), target vessel revascularization (TVR) and definite ST up to 5 years. As stent assignment was not random, we performed a propensity score matching (PSM), with 1:3 ratio, to account for potential confounders. Primary analysis demonstrated no significant differences between both groups for the primary endpoint of ST (BES vs. EES/ZES: 1.6% vs. 1.9%; mean-event-time = 1,797 days vs. 1,795 days, respectively; P = 0.75) and composite safety endpoint (BES vs. EES/ZES: 12.5% vs. 12.9%; mean-event-time = 1,631 days vs. 1,620 days, respectively; P = 0.88). Results regarding the 5-year-ST- and safety endpoint remained non-significant after PSM (P = 0.85, P = 0.56; respectively). After stratification based on cardiovascular risk, no difference regarding ST and composite outcome measure has been documented between both stent groups in high-risk- and low-risk patients. The type of stent did neither predict ST (HR 1.11, 95%CI 0.45-2.74, P = 0.82) nor composite safety endpoint (HR 0.93, 95%CI 0.67-1.30, P = 0.69). CONCLUSIONS: Long-term safety and efficacy of bioresorbable-polymer-BES and durable-polymer-EES/ZES appear comparable in patients with ACS. © 2016 Wiley Periodicals, Inc.

A randomized, prospective, intercontinental evaluation of a bioresorbable polymer sirolimus-eluting coronary stent system: the CENTURY II (Clinical Evaluation of New Terumo Drug-Eluting Coronary Stent System in the Treatment of Patients with Coronary Artery Disease) trial.

AIM: The aim of this study was to establish safety and efficacy of a new sirolimus-eluting stent with bioresorbable polymer, Ultimaster (BP-SES). Sirolimus-eluting stent with bioresorbable polymer was compared with everolimus-eluting, permanent polymer, Xience stent (PP-EES) in the frame of a CENTURY II clinical trial designed to make global clinical data compliant with regulatory requirements in Europe and Japan. METHODS AND RESULTS: The CENTURY II is a prospective, multicentre, randomized (1 : 1), single blind, controlled, non-inferiority clinical trial conducted at 58 study sites in Japan, Europe, and Korea. A total of 1123 patients requiring a percutaneous coronary intervention (PCI) procedure, with implantation of drug-eluting stent (DES), were enrolled [total population (TP)]. Randomization of patients was stratified for the subset of patients matching requirements for DES in Japan (Cohort JR, n = 722). Baseline patient demographic and angiographic characteristics were similar in both study arms, with minimal differences between the TP and Cohort JR. The primary endpoint, freedom from target lesion failure (TLF) at 9 months-TLF [composite of cardiac death, target-vessel-related myocardial infarction (MI) and target lesion revascularization]-was 95.6% with BP-SES and 95.1% with PP-EES (Pnon-inferiority<0.0001). Composite of cardiac death and MI rate was 2.9 and 3.8% (P = 0.40) and target vessel revascularization was 4.5% with BP-SES and 4.2% with PP-EES (P = 0.77). The stent thrombosis rate was 0.9% in both arms. In Cohort JR, freedom from TLF was 95.9 and 94.6% (Pnon-inferiority < 0.0005) with BP-SES and PP-EES, respectively. CONCLUSION: The new bioresorbable polymer sirolimus-eluting stent showed safety and efficacy profiles similar to durable polymer everolimus-eluting stent at 9-month follow-up. STUDY REGISTRATION NUMBER: UMIN000006940.

Mechanical fabrication and evaluation of bioresorbable barbed sutures with different barb geometries.

Bioresorbable polymeric sutures are gaining interest from surgeons and patients as they reduce surgical stress and trauma. This study involves two bioresorbable polymers, namely, catgut and poly(4-hyrdorxybutyrate) (P4HB) that are used widely in cosmetic procedures. P4HB barbed sutures are favorably used in rhytidectomy (micro-facelifts) procedures while catgut sutures are widely used for external wound closure after surgical interventions. This study involves the mechanical fabrication of catgut and P4HB barbed sutures and compares their mechanical and anchoring properties. Barbed sutures were fabricated with two different barb geometries namely, straight and curved barbs. The mechanical properties were evaluated via tensile testing, and the anchoring performance was studied by means of a suture-tissue pull-out protocol using porcine dermis tissue which was harvested from the medial dorsal site. The fabricated barbed sutures of both materials showed a similar trend compared to non-barbed sutures of decreases in failure stress, strain at failure, and work to rupture or toughness which was reduced by about 70%. At the same time there was a 15% increase in the initial modulus or stiffness of the barbed sutures. The pull-out force for the barbed sutures with straight barbs was similar for both P4HB (5.04±0.8N) and catgut (4.47±3.8N), and as expected, were higher than that of non-barbed sutures of the same size. It was also observed that barbed sutures with curved barbs also required a higher pull-out force than those sutures with straight barbs. It was concluded that by barbing sutures with different barb shapes and geometries, a range of barbed suture products could be fabricated, each meeting the closure requirements for different types of tissue and therefore being suitable for different surgical procedures.

Comparison of endothelial shear stress between ultrathin strut bioresorbable polymer drug-eluting stent vs durable-polymer drug-eluting stent post-stent implantation: An optical coherence tomography substudy from BIOFLOW II.

BACKGROUND: Recent clinical data indicate a different performance of biodegradable polymer (BP)-drug eluting stent (DES) compared to durable polymer (DP)-DES. Whether this can be explained by a beneficial impact of BP-DES stent design on the local hemodynamic forces distribution remains unclear. OBJECTIVES: To compare endothelial shear stress (ESS) distribution after implantation of ultrathin (us) BP-DES and DP-DES and examine the association between ESS and neointimal thickness (NIT) distribution in the two devices at 9 months follow up. METHODS AND RESULTS: We retrospectively identified patients from the BIOFLOW II trial that had undergone OCT imaging. OCT data were utilized to reconstruct the surface of the stented segment at baseline and 9 months follow-up, simulate blood flow, and measure ESS and NIT in the stented segment. The patients were divided into 3 groups depending on whether DP-DES (N = 8, n = 56,160 sectors), BP-DES with a stent diameter of >3 mm (strut thickness of 80 µm, N = 6, n = 36,504 sectors), or BP-DES with a stent diameter of ≤3 mm (strut thickness of 60 µm, N = 8, n = 50,040 sectors) were used for treatment. The ESS, and NIT distribution and the association of these two variables were estimated and compared among the 3 groups. RESULTS: In the DP-DES group mean NIT was 0.18 ± 0.17 mm and ESS 1.68 ± 1.66 Pa; for the BP-DES ≤3 mm group the NIT was 0.17 ± 0.11 mm and ESS 1.49 ± 1.24 Pa and for the BP-DES >3 mm group 0.20 ± 0.23 mm and 1.42 ± 1.24 Pa respectively (p < 0.001 for both NIT and ESS comparisons across groups). A negative correlation between NIT and baseline ESS was found, the correlation coefficient for all the stented segments was -0.33, p < 0.001. CONCLUSION: In this OCT sub-study of the BIOFLOW II trial, the NIT was statistically different between groups of patients treated with BP-DES and DP-DES. In addition, regions of low ESS were associated with increased NIT in all studied devices.

Five-year clinical outcomes of a 2.25 mm sirolimus-eluting stent in Japanese patients with very small coronary artery disease: final results of the CENTURY JSV study.

The aim of this study is to evaluate the long-term safety and efficacy of the 2.25 mm bioresorbable-polymer sirolimus-eluting Ultimaster stent in a Japanese patient population. Treatment of coronary artery disease in very small vessels is associated with an increased risk for cardiac events. The CENTURY JSV study is a prospective, multicenter, single-arm study. Seventy patients with stable and unstable coronary artery disease with a coronary lesion eligible for implantation with a 2.25 mm stent were enrolled in this study. Patients underwent clinical follow-up through 5-year after the PCI procedure. The mean age was 70.4 ± 9.2 years. The prevalence of diabetes mellitus was 37.1%, all not insulin dependent. The incidence of major adverse cardiac events, defined as cardiac death, target vessel myocardial infarction (MI), and clinically driven target lesion revascularization (CD-TLR) at 5 years was 5.7%. A non-Q wave MI was noted in 1.4% and 4.3% underwent a CD-TLR. There was no stent thrombosis during the entire follow-up period. No cardiac events were reported between 2 and 5 years. This is the first study to demonstrate safety and effectiveness for 5 years after treatment of very small coronary disease with 2.25 mm-diameter DES.Clinical trial registration: UMIN000012928.

Multi-objective design optimization of bioresorbable braided stents.

BACKGROUND AND OBJECTIVES: Bioresorbable braided stents, typically made of bioresorbable polymers such as poly-l-lactide (PLLA), have great potential in the treatment of critical limb ischemia, particularly in cases of long-segment occlusions and lesions with high angulation. However, the successful adoption of these devices is limited by their low radial stiffness and reduced elastic modulus of bioresorbable polymers. This study proposes a computational optimization procedure to enhance the mechanical performance of bioresorbable braided stents and consequently improve the treatment of critical limb ischemia. METHODS: Finite element analyses were performed to replicate the radial crimping test and investigate the implantation procedure of PLLA braided stents. The stent geometry was characterized by four design parameters: number of wires, wire diameter, initial stent diameter, and braiding angle. Manufacturing constraints were considered to establish the design space. The mechanical performance of the stent was evaluated by defining the radial force, foreshortening, and peak maximum principal stress of the stent as objectives and constraint functions in the optimization problem. An approximate relationship between the objectives, constraint, and the design parameters was defined using design of experiment coupled with surrogate modelling. Surrogate models were then interrogated within the design space, and a multi-objective design optimization was conducted. RESULTS: The simulation of radial crimping was successfully validated against experimental data. The radial force was found to be primarily influenced by the number of wires, wire diameter, and braiding angle, with the wire diameter having the most significant impact. Foreshortening was predominantly affected by the braiding angle. The peak maximum principal stress exhibited contrasting behaviour compared to the radial force for all parameters, with the exception of the number of wires. Among the Pareto-optimal design candidates, feasible peak maximum principal stress values were observed, with the braiding angle identified as the differentiating factor among these candidates. CONCLUSIONS: The exploration of the design space enabled both the understanding of the impact of design parameters on the mechanical performance of bioresorbable braided stents and the successful identification of optimal design candidates. The optimization framework contributes to the advancement of innovative bioresorbable braided stents for the effective treatment of critical limb ischemia.

Lactide and Ethylene Brassylate-Based Thermoplastic Elastomers and Their Nanocomposites with Carbon Nanotubes: Synthesis, Mechanical Properties and Interaction with Astrocytes.

Polylactide (PLA) is among the most commonly used polymers for biomedical applications thanks to its biodegradability and cytocompatibility. However, its inherent stiffness and brittleness are clearly inappropriate for the regeneration of soft tissues (e.g., neural tissue), which demands biomaterials with soft and elastomeric behavior capable of resembling the mechanical properties of the native tissue. In this work, both L- and D,L-lactide were copolymerized with ethylene brassylate, a macrolactone that represents a promising alternative to previously studied comonomers (e.g., caprolactone) due to its natural origin. The resulting copolymers showed an elastomeric behavior characterized by relatively low Young's modulus, high elongation at break and high strain recovery capacity. The thermoplastic nature of the resulting copolymers allows the incorporation of nanofillers (i.e., carbon nanotubes) that further enable the modulation of their mechanical properties. Additionally, nanostructured scaffolds were easily fabricated through a thermo-pressing process with the aid of a commercially available silicon stamp, providing geometrical cues for the adhesion and elongation of cells representative of the nervous system (i.e., astrocytes). Accordingly, the lactide and ethylene brassylate-based copolymers synthesized herein represent an interesting formulation for the development of polymeric scaffolds intended to be used in the regeneration of soft tissues, thanks to their adjustable mechanical properties, thermoplastic nature and observed cytocompatibility.

Ultrathin Bioresorbable Polymer Sirolimus-Eluting Stents Versus Durable Polymer Everolimus-Eluting Stents: BIOFLOW V Final 5-Year Outcomes.

BACKGROUND: Randomized trials have demonstrated the superiority of ultrathin strut drug-eluting stents compared with alternative stent designs. Whether these differences persist over late-term follow-up is uncertain. OBJECTIVES: This study sought to compare late-term (5-year) clinical outcomes among patients treated with ultrathin strut (60 µm) bioresorbable polymer sirolimus-eluting stents (BP SES) and thin strut (81 µm) durable polymer everolimus-eluting stents (DP EES). METHODS: BIOFLOW V (Biotronik Prospective Randomized Multicenter Study to Assess the Safety and Effectiveness of the Orsiro Sirolimus Eluting Coronary Stent System in the Treatment of Subjects with Up to Three De Novo or Restenotic Coronary Artery Lesions V) was an international, 2:1 randomized trial comparing percutaneous coronary intervention with ultrathin strut BP SES versus thin strut DP EES regarding the primary endpoint of 12-month target lesion failure (TLF). Prespecified outcomes through 5 years were assessed. RESULTS: Among 1,334 patients randomized to treatment with BP SES (n = 884) or DP EES (n = 450), the 5-year rates of TLF were 12.3% for BP SES and 15.3% for DP EES (P = 0.108). Revascularization with BP SES was associated with a significantly lower target vessel-related myocardial infarction (6.6% vs 10.3%, P = 0.015) and late/very late definite/probable stent thrombosis (0.3% vs 1.6%, P = 0.021). Ischemia-driven target lesion revascularization was numerically but not significantly lower with BP SES (5.9% vs 7.7%, P = 0.202). Cardiac death rates were 2.6% versus 1.9% (P = 0.495) for BP SES and DP EES, respectively. CONCLUSIONS: In a large, randomized trial, TLF and the individual outcomes of cardiac death and target lesion revascularization at 5 years were similar among patients treated with BP SES versus DP EES. Both target vessel-related myocardial infarction and late/very late definite/probable stent thrombosis were significantly lower with BP SES. These results confirm the durability of safety and the effectiveness of percutaneous coronary intervention with ultrathin BP SES.

Can an ultrathin strut stent design and a polymer free, proendothelializing probucol matrix coating improve early strut healing? The FRIENDLY-OCT trial. An intra-patient randomized study with OCT, evaluating early strut coverage of a novel probucol coated polymer-free and ultra-thin strut sirolimus-eluting stent compared to a biodegradable polymer sirolimus-eluting stent.

BACKGROUND: incomplete strut coverage determines the risk of stent thrombosis in the first months after stent implantation. AIMS: To evaluate the potential better early healing of a novel probucol coated polymer free ultra-thin strut sirolimus eluting stent (PF-SES). [Clinical trial unique identifier: NCT02785237]. METHODS: Patients with two (angiographically similar) lesions with clinical indication for PCI were enrolled. The investigated stent was compared to a thin strut, bioresorbable polymer, sirolimus eluting stent (BP-SES). Every patient received both stents, one in each lesion, assigned in a randomized sequence. OCT was systematically performed at 3 months. Primary end point was the difference in the proportion of covered struts at 3 months (defined as ≥20 µm of tissue coverage). Secondary end points included differences in percentage of uncovered struts (0 µm coverage), mean strut coverage thickness, and malapposed struts' coverage proportion. Major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization, and definite or probable stent thrombosis) at 12 months were also evaluated. RESULTS: 70 patients were included. At 3 months, a consistent and significantly higher strut coverage rate (≥20 µm) was observed in PF-SES as compared to BP-SES, both for well apposed (87.3% versus 79.1%, p < 0.001) and malapposed struts (50.4% vs 37.8%, p 0.00). Uncoverage rate (0 µm) was also significantly lower for the PF-SES (3.1% vs 5.3%, p < 0.001). There were no differences in clinical endpoints. CONCLUSION: The probucol coated non-polymeric ultra-thin strut sirolimus eluting stent showed a significantly better early strut coverage at 3 months.

One-Month Dual Antiplatelet Therapy After Bioresorbable Polymer Everolimus-Eluting Stents in High Bleeding Risk Patients.

Background It is unknown whether contemporary drug-eluting stents have a similar safety profile in high bleeding risk patients treated with 1-month dual antiplatelet therapy following percutaneous coronary interventions. Methods and Results We performed an interventional, prospective, multicenter, single-arm trial, powered for noninferiority with respect to an objective performance criterion to evaluate the safety of percutaneous coronary interventions with Synergy bioresorbable-polymer everolimus-eluting stent followed by 1-month dual antiplatelet therapy in patients with high bleeding risk. In case of need for an oral anticoagulant, patients received an oral anticoagulant in addition to a P2Y12 inhibitor for 1 month, followed by an oral anticoagulant only. The primary end point was the composite of cardiac death, myocardial infarction, or definite or probable stent thrombosis at 1-year follow-up. The study was prematurely interrupted because of slow recruitment. From April 2017 to October 2019, 443 patients (age, 74.8±9.2 years; women, 29.1%) at 10 Italian centers were included. The 1-year primary outcome occurred in 4.82% (95% CI, 3.17%-7.31%) of patients, meeting the noninferiority compared with the predefined objective performance criterion of 9.4% and the noninferiority margin of 3.85% (Pnoninferiority<0.001) notwithstanding the lower-than-expected sample size. The rates of cardiac death, myocardial infarction, and definite or probable stent thrombosis were 1.88% (95% CI, 0.36%-2.50%), 3.42% (95% CI, 2.08%-5.62%), and 0.94% (95% CI, 0.35%-2.49%), respectively. Conclusions Among high bleeding risk patients undergoing percutaneous coronary interventions with the Synergy bioresorbable-polymer everolimus-eluting stent, a 1-month dual antiplatelet therapy regimen is safe, with low rates of ischemic and bleeding events. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03112707.

One-year performance of biorestorative polymeric coronary bypass grafts in an ovine model: correlation between early biomechanics and late serial Quantitative Flow Ratio.

OBJECTIVES: This study aimed to investigate the impact of mechanical factors at baseline on the patency of a restorative conduit for coronary bypass grafts in an ovine model at serial follow-up up to 1 year. METHODS: The analyses of 4 mechanical factors [i.e. bending angle, superficial wall strain and minimum and maximum endothelial shear stress (ESS)] were performed in 3D graft models reconstructed on baseline (1-month) angiograms frame by frame by a core laboratory blinded for the late follow-up. The late patency was documented by Quantitative Flow Ratio (QFR®) that reflects the physiological status of the graft. The correlation between 4 mechanical factors and segmental QFR (△QFR) were analysed on 10 equal-length segments of each graft. RESULTS: A total of 69 graft geometries of 7 animals were performed in the study. The highest △QFR at 12 months was colocalized in segments of the grafts with the largest bending angles at baseline. Higher △QFR at 3 months were both at the anastomotic ends and were colocalized with the highest superficial wall strain at baseline. High baseline ESS was topographically associated with higher △QFR at the latest follow-up. Correlations of minimum and maximum ESS with △QFR at 3 months were the strongest among these parameters (ρ = 0.30, 95% CI [-0.05 to 0.56] and ρ = 0.27, 95% CI [-0.05 to 0.54], respectively). CONCLUSIONS: Despite the limited number of grafts, this study suggests an association between early abnormal mechanical factors and late flow metrics of the grafts. The understanding of the mechanical characteristics could help to improve this novel conduit.

A serial optical frequency-domain imaging study of early and late vascular responses to bioresorbable-polymer sirolimus-eluting stents for the treatment of acute myocardial infarction and stable coronary artery disease patients: results of the MECHANISM-ULTIMASTER study.

The purpose of this study was to assess early and late vascular healing in response to bioresorbable-polymer sirolimus-eluting stents (BP-SESs) for the treatment of patients with ST-elevation myocardial infarction (STEMI) and stable coronary artery disease (CAD). A total of 106 patients with STEMI and 101 patients with stable-CAD were enrolled. Optical frequency-domain images were acquired at baseline, at 1- or 3-month follow-up, and at 12-month follow-up. In the STEMI and CAD cohorts, the percentage of uncovered struts (%US) was significantly and remarkably decreased during early two points and at 12-month (the STEMI cohort: 1-month: 18.75 ± 0.78%, 3-month: 10.19 ± 0.77%, 12-month: 1.80 ± 0.72%; p < 0.001, the CAD cohort: 1-month: 9.44 ± 0.78%, 3-month: 7.78 ± 0.78%, 12-month: 1.07 ± 0.73%; p < 0.001 respectively). The average peri-strut low-intensity area (PLIA) score in the STEMI cohort was significantly decreased during follow-up period (1.90 ± 1.14, 1.18 ± 1.25, and 1.01 ± 0.72; p ≤ 0.001), whereas the one in the CAD cohort was not significantly changed (0.89 ± 1.24, 0.67 ± 1.07, and 0.64 ± 0.72; p = 0.59). In comparison with both groups, differences of %US and PLIA score at early two points were almost disappeared or close at 12 months. The strut-coverage and healing processes in the early phase after BP-SES implantation were significantly improved in both cohorts, especially markedly in STEMI patients. At 1 year, qualitatively and quantitatively consistent neointimal coverage was achieved in both pathogenetic groups.

Computational Analysis of Mechanical Performance for Composite Polymer Biodegradable Stents.

Bioresorbable stents (BRS) represent the latest generation of vascular scaffolds used for minimally invasive interventions. They aim to overcome the shortcomings of established bare-metal stents (BMS) and drug-eluting stents (DES). Recent advances in the field of bioprinting offer the possibility of combining biodegradable polymers to produce a composite BRS. Evaluation of the mechanical performance of the novel composite BRS is the focus of this study, based on the idea that they are a promising solution to improve the strength and flexibility performance of single material BRS. Finite element analysis of stent crimping and expansion was performed. Polylactic acid (PLA) and polycaprolactone (PCL) formed a composite stent divided into four layers, resulting in sixteen unique combinations. A comparison of the mechanical performance of the different composite configurations was performed. The resulting stresses, strains, elastic recoil, and foreshortening were evaluated and compared to existing experimental results. Similar behaviour was observed for material configurations that included at least one PLA layer. A pure PCL stent showed significant elastic recoil and less shortening compared to PLA and composite structures. The volumetric ratio of the materials was found to have a more significant effect on recoil and foreshortening than the arrangement of the material layers. Composite BRS offer the possibility of customising the mechanical behaviour of scaffolds. They also have the potential to support the fabrication of personalised or plaque-specific stents.