Comparison of the polymer-free biolimus-coated BioFreedom stent with the thin-strut biodegradable polymer sirolimus-eluting Orsiro stent in an all-comers population treated with percutaneous coronary intervention: Rationale and design of the randomized SORT OUT IX trial

Revolutionizing Cardiovascular Frontiers: A Dive Into Cutting-Edge Innovations in Coronary Stent Technology

Plain balloon angioplasty was the initial method used to enlarge the intracoronary lumen size. However, it was linked to acute coronary closure due to early vessel recoil. This led to the invention of coronary stents, which offer mechanical support to open and maintain the vascular lumen. Nevertheless, the metallic scaffold introduced other issues, such as thrombosis and restenosis caused by neointimal proliferation. To address these concerns, polymers were employed to cover the scaffold, acting as drug reservoirs and regulators for controlled drug release. The use of polymers prevents direct contact between blood and metallic scaffolds. Drugs within the stent were incorporated to inhibit proliferation and expedite endothelialization in the healing process. Despite these advancements, adverse effects still arise due to the inflammatory reaction caused by the polymer material. Consequently, resorbable polymers and scaffolds were later discovered, but they have limitations and are not universally applicable. Various scaffold designs, thicknesses, materials, polymer components, and drugs have their own advantages and complications. Each stent generation has been designed to address the shortcomings of the preceding generation, yet new challenges continue to emerge. Conflicting data regarding the long-term safety and efficacy of coronary stents, especially in the extended follow-up, further complicates the assessment.

Individualizing Medicinal Therapy Post Heart Stent Implantation: Tailoring for Patient Factors

The field of cardiovascular medicine is undergoing a transformative shift towards personalized medicinal therapy, particularly in the context of post stent implantation. This narrative review explores the significance, challenges, and future directions of individualized treatment strategies for patients with coronary stents. The review highlights the pivotal role of personalized approaches in optimizing treatment efficacy and minimizing adverse events. Real-world clinical studies and trials underscore the importance of tailoring antiplatelet therapy based on platelet function testing, genetic testing, and risk scoring. These studies reveal that personalized medicinal treatment improves clinical outcomes by balancing preventing thrombotic events and mitigating bleeding risks. Challenges, including cost, test availability, patient adherence, and ethical considerations, are discussed in depth, shedding light on the complexities of implementing personalized approaches. Technological advancements, including omics data integration, artificial intelligence, and big data analytics, shape the future of personalized medicinal therapy. These tools enable precise pharmacogenomic selection of medications and the development of integrated risk-scoring systems. Patient engagement and education are also central, with empowered patients and remote monitoring contributing to collaborative decision-making. In conclusion, the narrative review underscores that personalized medicinal therapy post stent implantation holds immense promise for revolutionizing cardiovascular care. By embracing a comprehensive approach that considers genetics, clinical factors, and patient preferences, healthcare providers can optimize treatment outcomes and improve patient quality of life. The evolving landscape of personalized medicine offers a glimpse into a future where tailored treatment strategies become the cornerstone of precision cardiovascular care.

Clinical Outcomes of Polymer-Free Versus Polymer-Coated Drug-Eluting Stents in Patients With Coronary Artery Disease: A Systematic Review and Meta-Analysis

Drug-eluting stents have transformed the treatment of coronary artery disease (CAD), and there are two types: polymer-free and polymer-coated stents. Polymer-free stents have a coating that is quickly absorbed by the body, whereas polymer-coated stents have a coating that remains on the stent surface. This meta-analysis and systematic review aimed to compare the clinical outcomes of these two stent types in patients with coronary artery disease. The literature and abstracts from significant databases were reviewed to compare polymer-free drug-eluting stents (PF-DES) and polymer-coated drug-eluting stents (PC-DES) for the treatment of coronary artery disease (CAD). The primary efficacy endpoints of the study were all-cause mortality and deaths from cardiovascular and non-cardiovascular causes. Among the secondary outcomes were incidences of myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), stent thrombosis, stroke, and major adverse cardiovascular events (MACEs). In terms of the primary outcomes, the combined analysis revealed a marginally lower risk of all-cause mortality (relative risk, RR (95% CI) = 0.92 (0.85, 1.00), p = 0.05, I² = 0%) with the use of PF-DES versus PC-DES. Nonetheless, there was no significant difference in cardiovascular mortality (RR (95% CI) = 0.97 (0.87, 1.08)) or non-cardiovascular mortality (RR (95% CI) = 0.87 (0.69, 1.10), p = 0.25, I² = 9%) between the groups. Furthermore, univariate meta-regression revealed that male gender and prior myocardial infarction were independently associated with an increased risk of all-cause mortality and cardiovascular disease. According to the current meta-analysis, no statistically significant differences existed in PF-DES and PC-DES outcomes. More extensive research is needed to investigate these findings further and establish their validity.

Drug-Eluting, Bioresorbable Cardiovascular Stents─Challenges and Perspectives

Globally, the leading causes of natural death are attributed to coronary heart disease and type 1 and type 2 diabetes. High blood pressure levels, high cholesterol levels, smoking, and poor eating habits lead to the agglomeration of plaque in the arteries, reducing the blood flow. The implantation of devices used to unclog vessels, known as stents, sometimes results in a lack of irrigation due to the excessive proliferation of endothelial tissue within the blood vessels and is known as restenosis. The use of drug-eluting stents (DESs) to deliver antiproliferative drugs has led to the development of different encapsulation techniques. However, due to the potency of the drugs used in the initial stent designs, a chronic inflammatory reaction of the arterial wall known as thrombosis can cause a myocardial infarction (MI). One of the most promising drugs to reduce this risk is everolimus, which can be encapsulated in lipid systems for controlled release directly into the artery. This review aims to discuss the current status of stent design, fabrication, and functionalization. Variables such as the mechanical properties, metals and their alloys, drug encapsulation and controlled elution, and stent degradation are also addressed. Additionally, this review covers the use of polymeric surface coatings on stents and the recent advances in layer-by-layer coating and drug delivery. The advances in nanoencapsulation techniques such as liposomes and micro- and nanoemulsions and their functionalization in bioresorbable, drug-eluting stents are also highlighted.

Ultrathin Struts Drug-Eluting Stents: A State-of-the-Art Review

New-generation drug-eluting stents (DESs) represent the standard of care for patients undergoing percutaneous coronary intervention (PCI). Recent iterations in DES technology have led to the development of newer stent platforms with a further reduction in strut thickness. This new DES class, known as ultrathin struts DESs, has struts thinner than 70 µm. The evidence base for these devices consists of observational data, large-scale meta-analyses, and randomized trials with long-term follow-up, which have been conducted to investigate the difference between ultrathin struts DESs and conventional new-generation DESs in a variety of clinical settings and lesion subsets. Ultrathin struts DESs may further improve the efficacy and safety profile of PCI by reducing the risk of target-lesion and target-vessel failures in comparison to new-generation DESs. In this article, we reviewed device characteristics and clinical data of the Orsiro (Biotronik, Bülach, Switzerland), Coroflex ISAR (B. Braun Melsungen, Germany), BioMime (Meril Life Sciences Pvt. Ltd., Gujarat, India), MiStent (MiCell Technologies, USA), and Supraflex (Sahajanand Medical Technologies, Surat, India) sirolimus-eluting stents.

Ten-year clinical outcomes of polymer-free versus durable polymer new-generation drug-eluting stent in patients with coronary artery disease with and without diabetes mellitus : Results of the Intracoronary Stenting and Angiographic Results: Test Efficacy of Sirolimus- and Probucol- and Zotarolimus-Eluting Stents (ISAR-TEST 5) trial

BACKGROUND

Very long-term outcomes according to diabetic status of patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) with new-generation drug-eluting stents (DES) are scant. Both, the durable polymer zotarolimus-eluting stent (DP-ZES), the first DES to gain FDA-approval for specific use in patients with diabetes mellitus, and the polymer-free sirolimus- and probucol-eluting stent (PF-SES), with a unique design that enables effective drug release without the need of a polymer offer the potential to enhance clinical long-term outcomes especially in patients with diabetes mellitus.

METHODS

We investigate 10-year clinical outcomes of the prespecified subgroups of patients with and without diabetes mellitus, randomly assigned to treatment with PF-SES versus DP-ZES in the ISAR-TEST 5 trial. The primary endpoint of interest was major adverse cardiac events (MACE), defined as the composite of all-cause death, any myocardial infarction or any revascularization. Further endpoints of interest were cardiac death, myocardial infarction related to the target vessel and target lesion revascularization as well as the individual components of the primary composite endpoint and the incidence of definite or probable stent thrombosis at 10 years.

RESULTS

This analysis includes a total of 3002 patients randomly assigned to PF-SES (n = 2002) or DP-ZES (n = 1000). Prevalence of diabetes mellitus was high and comparable, 575 Patients (28.7%) in PF-SES group and 295 patients (29.5%) in DP-ZES group (P = 0.66). At 10 years 53.5% of patients with diabetes mellitus and 68.5% of patients without diabetes mellitus were alive. Regarding major adverse cardiac events, PF-SES as compared to DP-ZES showed comparable event rates in patients with diabetes mellitus (74.8% vs. 79.6%; hazard ratio 0.86; 95% CI 0.73-1.02; P = 0.08) and in patients without diabetes (PF-SES 62.5% vs. DP-ZES 62.2%; hazard ratio 0.99; 95% CI 0.88-1.11; P = 0.88).

CONCLUSION

At 10 years, both new-generation DES show comparable clinical outcome irrespective of diabetic status or polymer strategy. Event rates after PCI in patients with diabetes mellitus are considerable higher than in patients without diabetes mellitus and continue to accrue over time.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00598533, Registered 10 January 2008, https://clinicaltrials.gov/ct2/show/NCT00598533?term=NCT00598533 Kaplan-Meier estimates of endpoints of interest for patients with vs. without diabetes mellitus treated with PF-SES vs. DP-ZES. Bar graphs: Kaplan-Meier estimates as percentages. PF-SES: polymer-free sirolimus-eluting stent; DP-ZES: durable polymer zotarolimus-eluting stent; DM: diabetes mellitus. Comparison of event rates of individual endpoints in patients with and without diabetes mellitus treated with PF-SES vs. DP-ZES all without statistically significant differences. Comparison of event rates of individual endpoints in overall patients with vs. without diabetes mellitus significantly different (P ≤ 0.01 for all comparisons).

Development of a Model Based on Physical Mechanisms for the Explanation of Drug Release: Application to Diclofenac Release from Polyurethane Films

In this study, we present a method for prediction of the drug-release profile based on the physical mechanisms that can intervene in drug release from a drug-carrier. The application presented here incorporates the effects of drug concentration and Reynolds number defining the circulating flow in the testing vein. The experimental data used relate to the release of diclofenac from samples of non-degradable polyurethane subjected to static and continuous flow. This case includes simultaneously three mechanisms: burst-release, diffusion and osmotic pressure, identified beforehand here as being able to contribute to the drug liberation. For this purpose, authors coded the Sequential Quadratic Programming Algorithm to solve the problem of non-linear optimization. The experimental data used to develop the mathematical model obtained from release studies carried out in water solution at 37 °C, for three concentrations of diclofenac and two water flow rates. We discuss the contribution of mechanisms and kinetics by considering two aforementioned parameters and, following that, we obtain the specific-model and compare the calculated results with the experimental results for the reserved cases. The results showed that drug percentage mostly affect the burst release, however flow rate has affected the osmotic release. In addition, release kinetics of all the mechanisms have increased by increasing the values of two considered parameters.

Endpoint selection for noninferiority percutaneous coronary intervention trials: a methodological description

Background:

The objective of this review is to provide a practical update on endpoint selection for noninferiority (NI) studies in percutaneous coronary intervention studies.

Methods:

A PubMed search was conducted for predefined terms to explore the use of NI designs and intrapatient comparisons to determine their current importance. Sample size calculations for the most frequently used endpoints with NI hypotheses were done to increase statistical awareness.

Results:

Reported NI trials, with the most frequently chosen clinical endpoint of major adverse cardiac events (MACE), had NI margins ranging from 1.66% to 5.00%, resulting in patient populations of 400–1500 per treatment group. Clinical study endpoints comprising of MACE complemented with rates of bleeding complications and stent thrombosis (ST) are suggested to conduct a statistically and clinically meaningful NI trial. Study designs with surrogate endpoints amenable to intrapatient randomizations, are a very attractive option to reduce the number of necessary patients by about half. Comparative clinical endpoint studies with MACE and ST/bleeding rates to study a shortened dual antiplatelet therapy (DAPT) in coronary stent trials are feasible, whereas ST as the sole primary endpoint is not useful.

Conclusions:

Expanded composite clinical endpoints (MACE complemented by ST and bleeding rates and intrapatient randomization for selected surrogate endpoints) may be suitable tools to meet future needs in device approval, recertification and reimbursement.

The Orsiro Ultrathin, Bioresorbable-Polymer Sirolimus-Eluting Stent: A Review of Current Evidence

Advances in stent design and the development of bioresorbable polymers have allowed the development of novel stent technologies such as the Orsiro bioresorbable-polymer sirolimus eluting stent (BP-SES). Over several noninferiority trials, the BP-SES has demonstrated itself to be a safe and effective therapy for obstructive coronary artery disease. This article reviews the current evidence of the efficacy of the BP-SES and examines its performance in high-risk populations, such as patients presenting with ST-segment myocardial infarction, chronic total occlusions, diabetes, and small vessel disease.

Orsiro: ultrathin bioabsorbable polymer sirolimus-eluting stent

Recent stent developments aimed to reduce and eliminate the long-term inflammatory response include thinner struts, modifications to stent design and the development of bioresorbable polymers (BP). We aimed to summarize the main findings and to discuss the established and the potential benefits of the Orsiro BP sirolimus-eluting stents in everyday clinical use. We have reviewed the available evidence on the clinical performance of the Orsiro BP drug-eluting stents. Orsiro BP sirolimus-eluting stents is clinically proven and showed noninferiority against major drug-eluting stents and provides high safety and efficacy profile at long-term follow-up. Furthermore, it may be the preferred treatment option in specific subgroups as acute coronary syndrome, as shown in the BIOFLOW V trial.