Polymer-free versus durable polymer drug-eluting stents in patients with coronary artery disease: A meta-analysis

Nanotechnology in development of next generation of stent and related medical devices: Current and future aspects

Coronary stents have saved millions of lives in the last three decades by treating atherosclerosis especially, by preventing plaque protrusion and subsequent aneurysms. They attenuate the vascular SMC proliferation and promote reconstruction of the endothelial bed to ensure superior revascularization. With the evolution of modern stent types, nanotechnology has become an integral part of stent technology. Nanocoating and nanosurface fabrication on metallic and polymeric stents have improved their drug loading capacity as well as other mechanical, physico-chemical, and biological properties. Nanofeatures can mimic the natural nanofeatures of vascular tissue and control drug-delivery. This review will highlight the role of nanotechnology in addressing the challenges of coronary stents and the recent advancements in the field of related medical devices. Different generations of stents carrying nanoparticle-based formulations like liposomes, lipid-polymer hybrid NPs, polymeric micelles, and dendrimers are discussed highlighting their roles in local drug delivery and anti-restenotic properties. Drug nanoparticles like Paclitaxel embedded in metal stents are discussed as a feature of first-generation drug-eluting stents. Customized precision stents ensure safe delivery of nanoparticle-mediated genes or concerted transfer of gene, drug, and/or bioactive molecules like antibodies, gene mimics via nanofabricated stents. Nanotechnology can aid such therapies for drug delivery successfully due to its easy scale-up possibilities. However, limitations of this technology such as their potential cytotoxic effects associated with nanoparticle delivery that can trigger hypersensitivity reactions have also been discussed in this review. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

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 Stents: Technical and Clinical Progress

Drug-eluting stents (DES) demonstrated superior efficacy when compared to bare metal stents and plain-old balloon angioplasty and are nowadays used in almost all percutaneous revascularization procedures. The design of the stent platforms is constantly improving to maximize its efficacy and safety. Constant development of DES includes adoption of new materials used for scaffold production, new design types, improved overexpansion abilities, new polymers coating and, finally, improved antiproliferative agents. Especially nowadays, with the immense number of available DES platforms, it is crucial to understand how different aspects of stents impact the effect of their implantation, as subtle differences between various stent platforms could impact the most important issue-clinical outcomes. This review discusses the current status of coronary stents and the impact of stent material, strut design and coating techniques on cardiovascular outcomes.

A prospective, multicentre first-in-man study of the polymer-free ultrathin-strut BIOrapid stent (BIOVITESSE)

BACKGROUND

Polymer-free drug-coated stents aim to avoid the inflammatory potential of durable polymers, thereby improving the long-term safety profile, and allowing a shorter duration of dual antiplatelet therapy.

AIMS

The BIOVITESSE study was conducted to assess the safety and clinical performance of the BIOrapid polymer-free coronary stent system coated with a novel highly lipophilic sirolimus derivate.

METHODS

BIOVITESSE was a prospective, multicentre, first-in-man study that enrolled subjects with de novo coronary lesions in two cohorts of 33 patients each. The primary endpoint of the first cohort was strut coverage at one month as assessed by optical coherence tomography. The primary endpoint of the second cohort was late lumen loss at nine-month follow-up.

RESULTS

Patients were on average 63 years old (range: 42-87) and 12% had diabetes. The 66 patients had 70 lesions with an average lesion length of 12.5±5.4 mm. Predilatation was performed in 91.4% and post-dilatation in 87.1% lesions; device success was obtained in 97.4%. At one month, 95.2±5.6% (95% CI: 93.2-97.2) of struts were covered and at nine months, in-stent late lumen loss was 0.31±0.30 mm (95% CI: 0.20-0.42) and in-segment late lumen loss was 0.20±0.29 mm. Two target lesion failures occurred (3.1%): one at day 1 (to cover an asymptomatic stent edge dissection), and one at day 288 post-procedure for restenosis. No stent thrombosis was reported during the 12-month study duration.

CONCLUSIONS

The BIOrapid stent system exhibited an excellent safety profile, high strut coverage at one-month, and moderate angiographic efficacy according to the late lumen loss at nine-month angiographic follow-up.

Evolutionary perspective of drug eluting stents: from thick polymer to polymer free approach

Background

Introduction of Bare Metal Stents (BMS) was itself a revolutionary step in the history of the medical industry; however, Drug Eluting Stents (DES) maintained its superiority over BMS in every aspect from restenosis rate to late lumen loss. The reason behind the magnanimous position of the DES in the stent market is the degree of improvement with which it evolves. New and better stents come into the market every year, surpassing their predecessors by many folds.

Literature review

This review paper discusses the journey of DES with supporting clinical trials in detail. In the first generation, there were stainless-steel stents with thicker coatings. Although they had superior results compared to BMS, there was still room for improvement. Afterward came the second-generation stents, which had superior metal platforms with thinner struts and thin coatings. The drugs were also changed from Paclitaxel and Sirolimus to Zotrolimus and Everolimus. These stents performed best; however, there was an issue of permanent coating, which remained intact over the stent surface after complete drug elution and started to cause issues in longer-term studies. Hence, an improved version of DES was introduced to these permanent coatings called the third generation of drug eluting stents, which initially utilized biodegradable polymer and ultimately moved towards polymer free drug coatings. This generation has introduced a unique amalgam of technologies to achieve its polymer free coatings; however, researchers have numerous prospects of growth in this field. This review paper highlights the major coups of stent technology evolution from BMS to DES, from thick polymeric coatings to thin coatings and from durable polymers to polymer free DES.

Conclusion

In conclusion, though the medical industry promptly accepted BMS as the best treatment option for cardiovascular diseases; however, DES has provided even better results than BMS. In DES, the first and second generation has ruled the technology for many years and are still on the shelves. Still, the issues aroused due to durable polymer shifted the attention towards biodegradable drug eluting stents, the third generation growing rapidly. But the scientific community has not restricted themselves and is investigating bioresorbable stents that completely eliminate the polymer intervention in drug eluting stent technology.

Safety and efficacy of the polymer-free and polymer-coated drug-eluting stents in patients undergoing percutaneous coronary intervention

INTRODUCTION

The relative safety and efficacy of polymer-free (PF) versus polymer-coated (PC) drug-eluting stents (DES) in patients with angina or acute coronary syndrome (ACS) undergoing percutaneous coronary intervention has received limited study.

METHOD

Digital databases were queried to identify relevant studies. Major adverse cardiovascular events (MACE) and secondary outcomes were compared using a random effect model to calculate unadjusted odds ratios (OR).

RESULTS

A total of 28 studies consisting of 23,198 patients were included in the final analysis. On pooled analysis, there was no significant difference in the odds of MACE (OR 0.98, 95% CI 0.91-1.08) and major bleeding (OR 0.87, 95% CI 0.61-1.24) between patients undergoing PF-DES versus PC-DES. Similarly, the odds of myocardial infarction, stroke, stent thrombosis, cardiovascular mortality and need for target vessel revascularization was similar between the two groups. PF-DES was favored due to significantly lower odds of non-cardiac death (OR 0.78, 95% CI 0.68-89) and all-cause mortality (OR 0.87, 95% CI 0.80-0.95), but had a higher need for target lesion revascularization (OR 1.2, 95% CI 1.02-1.42). A subgroup analysis based on follow up duration, clinical presentation, presence of diabetes and class of eluting drugs mirrored the net estimates for all outcomes with a few exceptions. A sensitivity and meta-regression analysis showed no influence of single-study and duration of antiplatelet therapy on pooled outcomes.

CONCLUSION

In patients presenting with angina or ACS, PF-DES might be favored due to lower all-cause mortality and equal risk of ischemic adverse cardiovascular and major bleeding events compared with PC-DES.

Influence of Drug Incorporation on the Physico-Chemical Properties of Poly(l-Lactide) Implant Coating Matrices-A Systematic Study

Local drug delivery has become indispensable in biomedical engineering with stents being ideal carrier platforms. While local drug release is superior to systemic administration in many fields, the incorporation of drugs into polymers may influence the physico-chemical properties of said matrix. This is of particular relevance as minimally invasive implantation is frequently accompanied by mechanical stresses on the implant and coating. Thus, drug incorporation into polymers may result in a susceptibility to potentially life-threatening implant failure. We investigated spray-coated poly-l-lactide (PLLA)/drug blends using thermal measurements (DSC) and tensile tests to determine the influence of selected drugs, namely sirolimus, paclitaxel, dexamethasone, and cyclosporine A, on the physico-chemical properties of the polymer. For all drugs and PLLA/drug ratios, an increase in tensile strength was observed. As for sirolimus and dexamethasone, PLLA/drug mixed phase systems were identified by shifted drug melting peaks at 200 °C and 240 °C, respectively, whereas paclitaxel and dexamethasone led to cold crystallization. Cyclosporine A did not affect matrix thermal properties. Altogether, our data provide a contribution towards an understanding of the complex interaction between PLLA and different drugs. Our results hold implications regarding the necessity of target-oriented thermal treatment to ensure the shelf life and performance of stent coatings.

Drug-Eluting Stents and Balloons-Materials, Structure Designs, and Coating Techniques: A Review

Controlled drug delivery is a matter of interest to numerous scientists from various domains, as well as an essential issue for society as a whole. In the treatment of many diseases, it is crucial to control the dosing of a drug for a long time and thus maintain its optimal concentration in the tissue. Heart diseases are particularly important in this aspect. One such disease is an obstructive arterial disease affecting millions of people around the world. In recent years, stents and balloon catheters have reached a significant position in the treatment of this condition. Balloon catheters are also successfully used to manage tear ducts, paranasal sinuses, or salivary glands disorders. Modern technology is continually striving to improve the results of previous generations of stents and balloon catheters by refining their design, structure, and constituent materials. These advances result in the development of both successive models of drug-eluting stents (DES) and drug-eluting balloons (DEB). This paper presents milestones in the development of DES and DEB, which are a significant option in the treatment of coronary artery diseases. This report reviews the works related to achievements in construction designs and materials, as well as preparation technologies, of DES and DEB. Special attention was paid to the polymeric biodegradable materials used in the production of the above-mentioned devices. Information was also collected on the various methods of producing drug release coatings and their effectiveness in releasing the active substance.

Ten things to know about ten cardiovascular disease risk factors ("ASPC Top Ten - 2020")

Preventive cardiology involves understanding and managing multiple cardiovascular disease (CVD) risk factors. Given the rapid advancements in medical science, it may be challenging for the busy clinician to remain up-to-date on the multifaceted and fundamental aspects of CVD prevention, and maintain awareness of the newest applicable guidelines. The "American Society for Preventive Cardiology (ASPC) Top Ten 2020" summarizes ten essential things to know about ten important CVD risk factors, listed in tabular formats. The ten CVD risk factors include unhealthful nutrition, physical inactivity, dyslipidemia, hyperglycemia, high blood pressure, obesity, considerations of select populations (older age, race/ethnicity, and gender), thrombosis/smoking, kidney dysfunction and genetics/familial hypercholesterolemia. For the individual patient, other CVD risk factors may be relevant, beyond the CVD risk factors discussed here. However, it is the intent of the "ASPC Top Ten 2020" to provide a succinct overview of things to know about ten common CVD risk factors applicable to preventive cardiology.

One-year clinical results of the NANO registry: A multicenter, prospective all-comers registry study in patients receiving implantation of a polymer-free sirolimus-eluting stent

OBJECTIVES

We aimed to evaluate the safety and efficacy of Nano+™ (Lepu Medical, Beijing, China) stent implantation in all-comer patients at the 1-year follow-up.

BACKGROUND

The Nano+™ stent is a novel polymer-free sirolimus-eluting stent polymer that employs nanoporous stent surface technology to control drug-delivery. The Nano+™ stent is one of the most widely used drug-eluting stent (DES) in China.

METHODS

A total of 2,481 consecutive patients were included in the multicenter and prospective NANO registry. In this study, the primary endpoint was target lesion failure (TLF) at 1-year follow-up, defined as a composite of cardiac death, target vessel nonfatal myocardial infarction (TV-MI), and clinically driven target lesion revascularization (TLR). The safety endpoint was the occurrence of definite or probable stent thrombosis (ST).

RESULTS

Up to 40.2% of patients presented with acute myocardial infarction (AMI). A total of 63.9% of the 2,904 lesions were American College of Cardiology/American Heart Association (ACC/AHA) type B2 or C lesions. One-year follow-up data were available for 98.4% of patients. The 1-year rate of TLF was 3.1% with rates of 1.3, 1.8, and 0.4% for clinically driven TLR, cardiac death, and TV-MI, respectively. ST occurred in 0.4% of patients. Diabetes mellitus, AMI, left ventricular ejection fraction <40% and long lesions (>40 mm) were independent predictors of 1-year TLF.

CONCLUSIONS

The 1-year clinical outcomes were excellent for Nano+™ polymer-free SES implantation in an all-comer patient population. Follow-up will be extended up to 5 years, to further elucidate the potential long-term clinical benefits.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02929030.