A polymer-free dual drug-eluting stent in patients with coronary artery disease: a randomized trial vs. polymer-based drug-eluting stents

Polymer-free stents for percutaneous coronary intervention in diabetic patients: a systematic review and meta-analysis

Aim: To compare the efficacy of polymer-free drug-eluting stents (PF-DES) versus other stents in diabetic patients with coronary artery disease undergoing percutaneous coronary interventions. Materials & methods: A systematic review and meta-analysis were performed to identify pertinent randomized controlled trials. The primary end point was the occurrence of target lesion failure. Results: Eight randomized controlled trials were included for a total of 4854 subjects. The PF-DES group experienced a trend in favor of a lower rate of target lesion failure (Incidence rate ratio = 0.91; p = 0.11) and a significantly lower rate of cardiac mortality, as compared with the control group (Incidence rate ratio = 0.82; p = 0.04). However, statistical significance was lost if bare-metal stent patients were excluded and a trend in favor of the PF-DES strategy was reported only for cardiac mortality. Conclusion: PF-DES could be a valuable strategy in diabetic patients with coronary artery disease undergoing percutaneous coronary interventions.

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.

Safety and Efficacy of Post-Dilation in Percutaneous Coronary Intervention Using Polymer-Free Ultrathin Strut Sirolimus-Probucol Coated Drug-Eluting Stents

Background and Objectives: Polymer-free ultrathin strut sirolimus- and probucol-eluting stents (PF-SES) are recognized as safe and effective in diverse patient populations, although the implications of post-dilation during stent implantation remain underexamined. Materials and Methods: In this study, patients implanted with PF-SES at Gachon University Gil Medical Center between December 2014 and February 2018 were evaluated. Major adverse cardiovascular events (MACE), encompassing nonfatal myocardial infarction (MI), nonfatal stroke, and cardiovascular death were identified as primary outcomes, with secondary outcomes including target vessel revascularization (TVR), target lesion revascularization (TLR), and in-stent restenosis (ISR). Results: Of the 384 initial patients, 299 were considered eligible for analysis. The groups, delineated by those undergoing post-dilation (143 patients) and those not (156 patients), exhibited comparable rates of primary outcomes [hazard ratio (HR), 2.17; 95% confidence interval (CI), 0.40 to 11.87; p = 0.37]. The outcomes remained consistent irrespective of the post-dilation status and were similarly unaffected in multivariate analyses (HR, 2.90; 95% CI, 0.52 to 16.34; p = 0.227). Conclusions: These results suggest that the clinical outcomes of patients with post-dilation were similar to that of those without post-dilation in those with the polymer-free sirolimus- and probucol-eluting stents.

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.

Clinical implications of inflammation in atheroma formation and novel therapies in cardiovascular diseases

Cardiovascular diseases (CVD) are the leading causes of death and disability in the world. Among all CVD, the most common is coronary artery disease (CAD). CAD results from the complications promoted by atherosclerosis, which is characterized by the accumulation of atherosclerotic plaques that limit and block the blood flow of the arteries involved in heart oxygenation. Atherosclerotic disease is usually treated by stents implantation and angioplasty, but these surgical interventions also favour thrombosis and restenosis which often lead to device failure. Hence, efficient and long-lasting therapeutic options that are easily accessible to patients are in high demand. Advanced technologies including nanotechnology or vascular tissue engineering may provide promising solutions for CVD. Moreover, advances in the understanding of the biological processes underlying atherosclerosis can lead to a significant improvement in the management of CVD and even to the development of novel efficient drugs. To note, over the last years, the observation that inflammation leads to atherosclerosis has gained interest providing a link between atheroma formation and oncogenesis. Here, we have focused on the description of the available therapy for atherosclerosis, including surgical treatment and experimental treatment, the mechanisms of atheroma formation, and possible novel therapeutic candidates such as the use of anti-inflammatory treatments to reduce CVD.

A novel polymer-free everolimus-eluting stent with a nitrogen-doped titanium dioxide film inhibits restenosis and thrombosis in a swine coronary model

BACKGROUND

Short-term outcomes regarding the safety and efficacy of a polymer-free everolimus-eluting stent (EES) with a nitrogen-doped titanium dioxide (N-TiO₂) film in a swine coronary model have been reported. However, the long-term results of the use of this type of stent have not yet been evaluated or compared to those of other polymer-free coronary stents. Therefore, this study aimed to determine the mid- to long-term safety and efficacy of a polymer-free EES with an N-TiO₂ film in a swine coronary model.

METHODS

Polymer-free EES with N-TiO₂ films (n = 30) and polymer-free sirolimus-eluting stents (SES; n = 30) were implanted in 30 pigs. Quantitative coronary analysis and optical coherence tomography were conducted immediately and at 1 (quantitative coronary analysis only), 3, and 6 months after stenting. Histopathologic examinations were performed at 1, 3, and 6 months after stenting.

RESULTS

The polymer-free EES group had a lower percentage of neointimal growth than the polymer-free SES group at 3 months (22.5% ± 11.4% vs. 32.1% ± 12.3%; p < 0.001). The polymer-free EES group had a lower fibrin score than the polymer-free SES group at 1 month (1.9 ± 0.45 vs. 2.5 ± 0.54; p = 0.001). The re-endothelialization rates were similar between groups. The polymer-free EES group had a lower percentage of the area of stenosis than the polymer-free SES group throughout the follow-up period.

CONCLUSIONS

The novel polymer-free EES with an N-TiO₂ film has superior safety and efficacy than the polymer-free SES at the 6-month follow-up in a swine model.

Modeling Dual Drug Delivery from Eluting Stents: The Influence of Non-Linear Binding Competition and Non-Uniform Drug Loading

OBJECTIVE

There is increasing interest in simultaneous endovascular delivery of more than one drug from a drug-loaded stent into a diseased artery. There may be an opportunity to obtain a therapeutically desirable uptake profile of the two drugs over time by appropriate design of the initial drug distribution in the stent. Due to the non-linear, coupled nature of diffusion and reversible specific/non-specific binding of both drugs as well as competition between the drugs for a fixed binding site density, a comprehensive numerical investigation of this problem is critically needed.

METHODS

This paper presents numerical computation of dual drug delivery in a stent-artery system, accounting for diffusion as well as specific and non-specific reversible binding. The governing differential equations are discretized in space, followed by integration over time using a stiff numerical solver. Three different cases of initial dual drug distribution are considered.

RESULTS

For the particular case of sirolimus and paclitaxel, results show that competition for a limited non-specific binding site density and the significant difference in the forward/backward reaction coefficients play a key role in determining the nature of drug uptake. The nature of initial distribution of the two drugs in the stent is also found to influence the binding process, which can potentially be used to engineer a desirable dual drug uptake profile.

CONCLUSIONS

These results help improve the fundamental understanding of endovascular dual drug delivery. In addition, the numerical technique and results presented here may be helpful for designing and optimizing other drug delivery problems as well.

Polymer-free biolimus-coated stents versus ultrathin-strut biodegradable polymer sirolimus-eluting stents: two-year outcomes of the randomised SORT OUT IX trial

BACKGROUND

For patients with high bleeding risk, the BioFreedom stent is safer and more effective than a bare metal stent. However, at the one-year follow-up of the SORT OUT IX trial, the BioFreedom stent did not meet the criteria for non-inferiority for target lesion failure (TLF) when compared with the Orsiro stent and had a higher incidence of target lesion revascularisation (TLR).

AIMS

The aim of the study was to compare the two-year outcomes following coronary implantation of the BioFreedom or the Orsiro stents in all-comer patients.

METHODS

The Scandinavian Organization for Randomized Trials with Clinical Outcome (SORT OUT) IX trial is a prospective, multicentre, randomised clinical trial comparing the BioFreedom and the Orsiro stents. The primary endpoint, TLF, was a composite of cardiac death, myocardial infarction (MI; not related to other lesions) and TLR.

RESULTS

A total of 1,572 patients were randomised to treatment with the BioFreedom stent and 1,579 patients with the Orsiro stent. At two-year follow-up, TLF was 7.8% in the BioFreedom and 6.3% in the Orsiro stent groups (rate ratio [RR] 1.23, 95% confidence interval [CI]: 0.94-1.61). Risks of cardiac death, MI and definite stent thrombosis did not differ significantly between the groups, whereas more patients in the BioFreedom group had TLR (5.1% vs 2.6%; RR 1.98, 95% CI: 1.26-2.89) attributable to a higher risk of TLR within the first year (3.5% vs 1.3%; RR 2.77, 95% CI: 1.66-4.62).

CONCLUSIONS

At two years, there were no significant differences between the BioFreedom and Orsiro stents for TLF. TLR was significantly higher with the BioFreedom stent due to higher risk of TLR within the first year.

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.

Drug-eluting stents for the treatment of coronary artery disease: A review of recent advances

INTRODUCTION

Percutaneous coronary intervention is a widely used procedure for the treatment of coronary artery disease to relieve narrowing or occlusion and improve blood supply. Although only balloon angioplasty was performed in the early period, coronary stents were developed later and coronary drug-eluting stents were introduced to decrease in-stent restenosis, which is related to the proliferation and migration of vascular smooth muscle cells.

AREAS COVERED

The drug-eluting stents are composed of a metallic or polymeric platform, specific drug, and polymers or coating for drug release. In this article, the recent advances in drug-eluting stent technologies for the treatment of coronary artery disease and adjunctive antiplatelet therapy after drug-eluting stent implantation will be reviewed.

EXPERT OPINION

The need for further advances in drug-eluting stents or fully bioresorbable coronary scaffolds still exists to improve patient survival or clinical outcomes. The use for different actions or of combinations of drugs with several actions can be potential. Technological refinement and progress in manufacturing to improve mechanical integrity are needed, particularly for fully bioresorbable scaffolds. For antiplatelet therapy after stenting, clinical bleeding reduction strategies, such as a shortened duration of dual-antiplatelet therapy, are in progress.

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).

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.

Bivalirudin and sirolimus co-eluting coronary stent: Potential strategy for the prevention of stent thrombosis and restenosis

Localized drug delivery with sustained elution characteristics from nanocarrier coated stents represents a viable therapeutic approach to circumvent concerns related to coronary stent therapy. We fabricated a Sirolimus (SRL) and Bivalirudin (BIV) releasing nanoparticles (NPs) coated stent for concurrent mitigation of vascular restenosis and acute stent thrombosis. SRL NPs were prepared by nanoprecipitation method whereas the BIV vesicles were generated using hydrophobic ion pair approach followed by micellization phenomenon. MTT assay and confocal microscopic analysis indicated superior anti-proliferative activity and higher cellular uptake of SRL NPs into human coronary artery smooth muscle cells, respectively. DSC and ATR-FTIR techniques confirmed the formation of complex between BIV and phosphatidylglycerol via some weak physical interactions. More than 2 fold rise in log P value was obtained for DSPG-BIV at 3:1 M ratio compared with native BIV solution. The SAXS analysis indicated formation of oligolamellar vesicles of DSPG-BIV complex which was preferentially entrapped into lipophilic lamellae of vesicles. APTT, PT, and TT tests revealed that the BIV vesicles caused significant prolongation of clotting time compared to native BIV solution. The SEM analysis showed uniform and defect free stent coating. In vitro release study demonstrated that SRL and BIV were eluted in a sustained manner from coated stents.

Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials

AIMS

The aim of this study was to investigate the long-term safety and efficacy of biodegradable scaffolds and metallic stents.

METHODS AND RESULTS

We analysed a total of 91 randomised controlled trials with a mean follow-up of 3.7 years in 105,842 patients which compared two or more coronary metallic stents or biodegradable scaffolds and reported the long-term clinical outcomes (≥2 years). Network meta-analysis showed that patients treated with the Absorb bioresorbable vascular scaffold (BVS) had a significantly higher risk of definite or probable scaffold thrombosis (ScT) compared to those treated with metallic DES. The risk of very late ScT was highest with the Absorb BVS among comparators. Pairwise conventional meta-analysis demonstrated that the elevated risk of ScT with Absorb BVS compared to cobalt-chromium everolimus-eluting stents was consistent across the time points of ≤30 days (early), 31 days - 1 year (late) and >1 year (very late) ScT. In addition, target lesion failure rates were significantly higher in the Absorb BVS cohort, driven by both increased risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularisation.

CONCLUSIONS

Absorb BVS implantation was associated with increased risk of long-term and very late ScT compared to current-generation metallic DES. The risk of ScT occurred with a rising trend beyond one year.

Polymer-free drug-eluting stents versus permanent polymer drug-eluting stents: An updated meta-analysis

BACKGROUND

Polymer-free drug-eluting stents (PF-DES) have been demonstrated comparable to permanent polymer drug-eluting stents (PP-DES) during long-term follow-up. As a critical component of drug-eluting stents, antiproliferative drugs may be a confounding factor for the results. Thus, we sought to compare the outcomes of these stents during long-term follow-up, especially in consideration of different stent platforms with the same drugs.

METHODS

A systemic search was performed to identify the related randomized controlled trials comparing PF-DES with PP-DES. Primary outcomes included short (≤1 year) and long-term (>1 year) target lesion revascularization (TLR), short-term in-stent late luminal loss (LLL) and diameter stenosis (DS). Subgroup analyses stratified by the different platforms with the same proliferative drugs were conducted in TLR, LLL, and DS. Standardized mean differences (SMDs) and risk ratios (RRs) were estimated using fixed /random effects models RESULTS:: A total of 6927 patients extracted from 12 RCTs were enrolled in the meta-analysis. No differences were observed in clinical outcomes of short-term and long-term overall mortality, myocardial infarction and stent thrombosis and angiographic outcomes of short-term in-stent LLL and DS between PF-DES and PP-DES for patients with coronary artery lesions. Nevertheless, compared with PP-DES coated with the same proliferative drugs, PF-DES had significantly increased risks of in-stent LLL (SMD, 0.49; 95% confidence interval [CI], 0.25-0.72) and DS (SMD, 0.67; 95% CI, 0.27-1.07), and long-term TLR (RR, 1.64; 95% CI 1.13-2.39). There were no significant differences in other outcomes.

CONCLUSIONS

Under the condition of using same antiproliferative drugs (paclitaxel or sirolimus) in different stent systems, PF-DES are associated with the increased risk of restenosis compared to PP-DES.

Outcomes of the amphilimus-eluting polymer-free stent for chronic total occlusion treatment: a multicentre experience

AIMS

Late stent thrombosis and delayed vessel wall healing remain an important issue in coronary vessels treated with drug-eluting stents (DES), especially when long-vessel segments need to be covered, like in chronic total occlusions (CTO). Avoiding polymer use to avoid chronic inflammatory responses is a potential solution to reduce target vessel failure (TVF). We aimed to validate the clinical safety and efficacy at 1 year of the polymer-free Cre8 DES vs. nonpolymer-free DES for the percutaneous treatment of CTO.

METHODS

Between September 2011 and August 2016, patients were prospectively enrolled in three CTO centres. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), including cardiac death, any myocardial infarction, stent thrombosis, TVF and target vessel revascularization.

RESULTS

A total of 102 Cre8 and 133 non-Cre8 patients were enrolled. At 1 year, a low cumulative MACCE was observed in the Cre8 group (6.9%, respectively). Moreover, a numerical trend towards better MACCE was observed in the Cre8 group vs. the non-Cre8 group (6.9 vs. 14.3%; P = 0.065). The clinically driven TVF rate was not statistically different between Cre8 and non-Cre8 patients (6.9 vs. 9.8%; P = 0.373). A borderline significant difference regarding mortality was observed in favour of Cre8 patients (0 vs. 3.8%; P = 0.049).

CONCLUSION

Low rates of MACCE and TVF up to 1 year were observed in the Cre8 group, supportive of the use of polymer-free DES for lesions with high complexity.

Non-polymer drug-eluting coronary stents

Cardiovascular complications are leading causes of most fatalities. Coronary artery disease and surgical failures contribute to the death of the majority of patients. Advanced research in the field of medical devices like stents has efficiently resolved these problems. Clinically, drug-eluting stents have proven their efficacy and safety compared to bare metal stents, which have problems of in-stent restenosis. However, drug-loaded stents coated with polymers have shown adverse effects related to the stability and deterioration of the polymer coating over time. This results in late stent thrombosis and immunogenicity. These reasons laid the foundation for the development of non-polymeric drug-eluting stents. This review focuses on non-polymer drug-eluting stents loaded with different drugs like anti-inflammatory agents, anti-thrombotic, anti-platelet agents, immune suppressants and others. Surface modification techniques on stents like crystalline coating; microporous, macroporous, and nanoporous coatings; and chemically modified self-assembled monolayers are described in detail. There is also an update on clinically approved products and those under development.

The evolution of coronary stents

INTRODUCTION

Percutaneous coronary intervention (PCI) is 40 years old this year. From its humble beginnings of experimental work, PCI has transitioned over years with coronary artery stenting now a standard medical procedure performed throughout the world. Areas covered: The conversion from plain old balloon angioplasty (POBA) to the present era of drug eluting stents (DES) has been driven by many technological advances and large bodies of clinical trial evidence. The journey to present day practice has seen many setbacks, such as acute vessel closure with POBA; rates of instant restenosis with bare metal stents (BMS) and more recently, high rates of stent thrombosis with bioabsorbable platforms. This work discusses POBA, why there was a need for BMS, the use of inhibiting drugs to create 1^st generation DES, the change of components to 2^nd generation DES, the use of absorbable drug reservoirs and platforms, and possible future directions with Prohealing Endothelial Progenitor Cell Capture Stents. Expert commentary: This paper reviews the evolution from the original pioneering work to modern day practice, highlighting landmark trials that changed practice. Modern day contemporary practice is now very safe based on the latest drug eluting stents and supported by large datasets.

Stent Polymers: Do They Make a Difference?

The necessity of polymers on drug-eluting stent (DES) platforms is dictated by the need of an adequate amount and optimal release kinetic of the antiproliferative drugs for achieving ideal DES performance. However, the chronic vessel wall inflammation related to permanent polymer persistence after the drug has been eluted might trigger late restenosis and stent thrombosis. Biodegradable polymers have the potential to avoid these adverse events. A variety of biodegradable polymer DES platforms have been clinically tested, showing equal outcomes with the standard-bearer permanent polymer DES within the first year of implantation. At longer-term follow-up, promising lower rates of stent thrombosis have been observed with the early generation biodegradable polymer DES platforms compared to first-generation DES. Whether this safety benefit still persists with newer biodegradable polymer DES generations against second-generation permanent polymer DES needs to be explored.

Study protocol for a randomised controlled trial: harmonising optimal strategy for treatment of coronary artery stenosis - coronary intervention with next-generation drug-eluting stent platforms and abbreviated dual antiplatelet therapy (HOST-IDEA) trial

INTRODUCTION

We have recently seen the introduction of newer generation drug-eluting stents with ultrathin struts that use advanced polymer technologies. However, the efficacy and safety of these newest stents have not yet been fully explored. In addition, there are still controversies over the optimal duration of dual antiplatelet therapy (DAPT) after stent implantation, particularly for ultrathin stents with the newest polymer technologies.

METHODS AND ANALYSIS

The HOST-IDEA trial is a randomised, open-label, multicentre, non-inferiority trial and the first study to directly compare two of these ultrathin sirolimus-eluting stents: Orsiro stent with biodegradable polymer, and polymer-free Coroflex ISAR (CX-ISAR) stent. This study has a scheme of 2×2 factorial design according to the stent type and DAPT duration (3 vs 12 months). A total of 2152 patients will be randomised and stratified to demonstrate the non-inferiority of CX-ISAR to Orsiro, or of the abbreviated DAPT duration to the conventional 12 months (both in 1:1 ratio). For the comparison of stent type, the primary endpoint is target lesion failure (TLF), which is a composite of cardiac death, target vessel-related myocardial infarction and clinically driven target lesion revascularisation. For the comparison of DAPT duration, the net adverse clinical event is the coprimary endpoint, which is defined as a composite of TLF, definite/probable stent thrombosis and major bleeding.

ETHIC APPROVAL AND DISSEMINATION

All the institutions involved in this study are required to have ethical approval prior to patient enrolment. This multicentre study will recruit patients through competitive registration, but institutions that have not yet obtained ethical approvals have made it impossible to enrol patients in a centralised web database. The final results will be presented at relevant international conferences and will be materialised in the form of papers.

TRIAL REGISTRATION NUMBER

NCT02601157; Pre-results.

Surface Modification with ECM-Inspired SDF-1α/Laminin-Loaded Nanocoating for Vascular Wound Healing

Surface biomimetic modification with extra-cellular matrix (ECM)-derived biomolecules is an emerging potential method of accelerating the healing of vascular stent lesions. However, insufficient capacity of the constructed biofunctional layer in maintaining its long-term efficiency and preventing thrombus and neointimal hyperplasia continue to be major limitations in clinical application. On the basis of the structure and function of ECM, in this study, we constructed a novel stromal cell-derived factor-1α (SDF-1α)/laminin-loaded nanocoating on the 316L stainless steel (SS) surface to provide improved function in modulation of vascular remodeling. The modified surface was found to control delivery of biomolecules and exhibit promising potential to provide stage-adjusted treatment after injury. An in vitro biocompatibility study suggested that the constructed layer may effectively prevent thrombosis formation by inhibiting platelet adhesion and activation, while accelerating endothelium regeneration by inducing endothelial cell (EC) migration and endothelial progenitor cell (EPC) aggregation. An in vivo animal test further demonstrated that the nanocoating may prevent thrombus and neointimal hyperplasia after implantation for 3 months. Therefore, the ECM-inspired nanocoating described in this study is a promising novel approach for vascular stent surface modification.

Polymer-free dual drug-eluting stents evaluated in a porcine model

BACKGROUND

Although drug-eluting stents have dramatically reduced the rates of restenosis and target lesion revascularization, they are associated with stent thrombosis (ST), a catastrophic event likely due to delayed endothelialization and chronic inflammation caused by the polymer and the metal scaffolds. To increase the safety and efficacy of stents, polymer-free dual drug-eluting stents (DDES) have been developed.

METHODS

A total 160 stents (Bare-metal stents (BMS), polymer-free probucol stents (PrES), sirolimus-eluting stents (SES) and DDES) were randomly implanted in the coronary arteries of 80 pigs. 14, 28, 90 and 191 days after implantation, QCA and OCT evaluations were performed in 20 pigs respectively, and the arteries were harvested for scanning electron microscope (SEM), histomorphology, histopathology analyses and for the relative expression of CD31, CD34 and CD133 on mRNA and protein levels.

RESULTS

At the 14-day time point, there were significant differences in the strut rate coverage (p = 0.011), with greater coverage in the PrES than in the SES group (53.2%vs. 20.3%, p = 0.002). As well, there were no significant differences in the expression of CD31, CD34 and CD133 between groups in mRNA and protein level.

CONCLUSIONS

DDES were as safe as BMS and SES, but they did not further improve the endothelialization of the stented coronary arteries in the porcine model.

Efficacy and safety of polymer-free stent versus polymer-permanent drug-eluting stent in patients with acute coronary syndrome: a meta-analysis of randomized control trials

BACKGROUND

The efficacy and safety of polymer-free stent (PFS) versus permanent polymer drug-eluting stent (PPDES) in patients undergoing percutaneous coronary intervention (PCI) remain controversial. Our meta-analysis was undertaken to evaluate and compare the efficacy and safety of PFS with those of PPDES in patients undergoing PCI.

METHODS

We searched PubMed, Cochrane Library, EMBASE, and Clinical Trials.gov databases for randomized controlled trials (RCTs). The primary endpoints were incidence of stent thrombosis (ST) and target-lesion revascularization (TLR). The secondary endpoints included the incidence of major adverse cardiovascular events (MACE), myocardial infarction (MI), cardiac death (CD), late lumen loss (LLL), and diameter stenosis (DS). Subgroup analyses were also conducted based on the follow-up time.

RESULTS

Eleven RCTs met the including criteria, and 8616 patients were included in the study. No significant differences were observed between PFS and PPDES treatments in the incidence of ST (RR 0.90; 95% CI: 0.62-1.31; P = 0.58; I ²  = 0), TLR (RR 0.87; 95% CI: 0.76-1.00; P = 0.05; I ²  = 37%), CD (RR 0.89; 95% CI: 0.72-1.10; P = 0.28; I ²  = 0), MI (RR 0.87; 95% CI: 0.71-1.05; P = 0.15; I ²  = 0), LLL (SMD 0.01; 95% CI: -0.29-0.30; P = 0.96; I² = 90%), and DS (SMD -0.01; 95% CI: - 0.25 to 0.23; P = 0.93; I² = 83%). Meanwhile, the patients with PFS had a lower incidence of MACE (RR 0.87; 95% CI: 0.78-0.97; P = 0.01; I ²  = 0) than those with PPDES.

CONCLUSION

In the overall analysis, patients with PFS presented a lower risk of MACE versus PPDES, but no significant difference were obtained in the risk of ST, TLR, MI, CD, DDD and DS. In the Short term follow up, patients with PSF presented a lower risk of TLR compared with PPDES.

Three-Year Clinical Outcomes of a Polymer-Free Paclitaxel-Eluting Microporous Stent in Real-World Practice: Final Results of the Safety and Efficacy Registry of the Yinyi Stent (SERY-I)

BACKGROUND

The safety and efficacy of a China-made polymer-free paclitaxel-eluting microporous stent (Yinyi) at 1-year has been previously reported. However, limited evidence exists regarding the long-term performance of this novel drug-eluting stent (DES). This study investigated the 3-year efficacy and safety of the Yinyi stent in the setting of safety and efficacy registry of the Yinyi stent (SERY-I) clinical trial.

METHODS

Between June 2008 and August 2009, a total of 1045 patients undergoing percutaneous coronary intervention (PCI) were implanted with ≥ 1 Yinyi stents at 27 medical centers in mainland China. Thereafter, clinical follow-up was performed for a period of 3 years after enrollment. The primary endpoint was the cumulative rate of composite major adverse cardiac events (MACE) including target lesion revascularization (TLR), the combined incidence of cardiac death, and non-fatal myocardial infarction; the second endpoint was the incidence of stent thrombosis.

RESULTS

Overall, 1376 lesions were treated successfully with 1713 Yinyi stents, and 1019 (98.7%) patients received dual antiplatelet therapy for at least 12 months. At 3 years, a total of 13 (1.33%) patients had suffered cardiac death. The incidence of non-fatal myocardial infarction and TLR was 9 (0.92%) and 58 (5.92%) among the patients. Stent thrombosis occurred in 13 (1.33%) patients, and the rate of Academic Research Consortium (ARC) definite or probable stent thrombosis was 0.82%.

CONCLUSIONS

Given the limitations that SERY-I was a single arm, nonrandomized study and only telephone follow-up was performed without angiographic analysis, the safety and efficacy of Yinyi stent observed in this extended follow-up Registry needs further verification.

Five-year clinical outcomes in patients with diabetes mellitus treated with polymer-free sirolimus- and probucol-eluting stents versus second-generation zotarolimus-eluting stents: a subgroup analysis of a randomized controlled trial

Background

Improved outcomes in patients with diabetes mellitus undergoing percutaneous coronary intervention remain an unmet clinical need. We assessed the long-term efficacy and safety of novel polymer-free sirolimus- and probucol-eluting stent in diabetic patients enrolled in intracoronary stenting and angiographic results: test efficacy of sirolimus- and probucol-eluting versus zotarolimus-eluting stents 5 trial.

Methods

In a pre-specified subgroup analysis, outcomes of diabetic patients treated with a sirolimus- and probucol-eluting stent or a second-generation zotarolimus-eluting stent were compared. The primary endpoint was a device-oriented composite outcome comprising cardiac death, target vessel-related myocardial infarction (MI), or target lesion revascularization (TLR) at 5-year follow-up. Event-free survival was assessed using the Kaplan–Meier method. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated from univariate Cox proportional hazards models.

Results

A total of 870 patients with diabetes mellitus were treated with either a sirolimus- and probucol-eluting stent (n = 575) or a second-generation zotarolimus-eluting stent (n = 295). At 5 years, the rate of device-oriented composite endpoint was comparable between the sirolimus- and probucol-eluting stent and the second-generation zotarolimus-eluting stent (32.9 versus 33.4 %, HR 0.88, 95 % CI 0.76–1.26). No significant differences were observed between the sirolimus- and probucol-eluting stent and the second-generation zotarolimus-eluting stent groups in the incidence of cardiac death (15.6 versus 16.7 % HR 0.92, 95 % CI 0.63–1.32), target-vessel MI (4.6 versus 6.6 %, HR 0.73, 95 % CI 0.40–1.34), and TLR (18.6 versus 18.8 %, HR 1.00, 95 % CI, 0.72–1.41). The rate of definite or probable stent thrombosis was low and similar in both groups (2.5 versus 2.6 %, HR 1.02, 95 % CI, 0.41–2.52).

Conclusions

In patients with diabetes the long-term efficacy and safety of a polymer-free sirolimus- and probucol-eluting stent were comparable to a second-generation durable polymer zotarolimus-eluting stent.

Trial registration ClinicalTrials.gov NCT00598533. Registered 10 January 2008

Five-year follow-up of polymer-free sirolimus- and probucol-eluting stents versus new generation zotarolimus-eluting stents in patients presenting with st-elevation myocardial infarction

BACKGROUND

Patients with ST-segment elevation myocardial infarction (STEMI) undergoing drug-eluting stent (DES) implantation are at increased risk of late adverse events, partly explained by an exaggerated inflammatory reaction to durable-polymer stent coatings.

OBJECTIVES

We sought to investigate whether implantation of polymer-free DES would reduce this risk.

METHODS

In the ISAR-TEST 5 (the Intracoronary Stenting and Angiographic Results: Test Efficacy of Sirolimus- and Probucol- and Zotarolimus-Eluting Stents) trial, patients were randomly allocated to receive a polymer-free sirolimus- and probucol-eluting stent or a new generation durable-polymer zotarolimus-eluting stent. We analyzed late clinical outcomes in the subgroup of patients presenting with STEMI. The primary endpoint was the combined incidence of cardiac death, target vessel-related myocardial infarction or target lesion revascularization at 5 years.

RESULTS

311 patients with STEMI were randomized to receive sirolimus- and probucol-eluting stents (n = 215) or zotarolimus-eluting stents (n = 96). At 5 years, there was no difference in the incidence of the primary endpoint in patients treated with sirolimus- and probucol-eluting stents versus zotarolimus-eluting stents (18.3% versus 20.1% respectively, hazard ratio = 0.87, 95% CI, 0.50-1.51; P = 0.62). Rates of the individual components of the primary endpoint were also comparable in both groups. The incidence of definite/probable stent thrombosis was 1.4% versus 1.0% respectively (hazard ratio = 1.35, 95% CI, 0.14-12.94, P = 0.80).

CONCLUSIONS

Long-term outcomes of patients with STEMI treated with polymer-free sirolimus- and probucol-eluting stents versus durable-polymer zotarolimus-eluting stents were similar. Stent thrombosis rates were low and comparable in both treatment groups, with no events beyond 12 months.

CLINICAL TRIAL REGISTRATION

Registered at ClinicalTrials.gov (Identifier NCT 00598533) © 2016 Wiley Periodicals, Inc.

Primary Stenting of Totally Occluded Native Coronary Arteries III (PRISON III): a randomised comparison of sirolimus-eluting stent implantation with zotarolimus-eluting stent implantation for the treatment of total coronary occlusions

AIMS

We investigated whether sirolimus-eluting stents (SES) are superior to next-generation zotarolimus-eluting stents (ZES) in treating patients with total coronary occlusions (TCO).

METHODS AND RESULTS

In a prospective, randomised trial we compared the SES with the zotarolimus-eluting stent (ZES; Endeavor or Resolute) after successful recanalisation of TCO. During the first phase of the trial, 51 patients were assigned to receive the SES and 46 patients to receive the Endeavor ZES. In the second phase we randomised 103 patients to the SES group and 104 patients to the Resolute ZES group. The primary endpoint was in-segment late lumen loss at eight-month follow-up. At eight months, patients in the SES group had less in-segment and in-stent late loss as compared to the Endeavor group: -0.13±0.3 mm vs. 0.27±0.6 mm (p=0.0002) and -0.13±0.5 mm vs. 0.54±0.5 mm (p<0.0001), respectively. In contrast, the SES and the Resolute ZES showed comparable amounts of in-segment (-0.03±0.7 mm vs. -0.10±0.7 mm, p=0.6) and in-stent (0.03±0.8 mm vs. 0.05±0.8 mm, p=0.9) late loss.

CONCLUSIONS

In the treatment of TCOs, the SES was associated with superior angiographic outcomes compared to the Endeavor ZES. On the other hand, the SES and the Resolute ZES showed comparable angiographic outcomes.

Controlling drug delivery from coronary stents: are we aiming for the right targets?

In this review article, the currently employed or explored delivery concepts for local intravascular drug delivery with drug-eluting stents (DES) are discussed with a special emphasis on clinical evidence regarding the desired release profiles. Traditional concepts to control drug release from DES include diffusion through polymers, polymer degradation and erosion as well as dissolution of particulate drug. Published clinical studies do not always reveal fine mechanistic details. The long duration of release favored for DES and the short duration of release favored for drug-eluting balloons require further investigation in experimental studies and clinical trials.

Polymer-Free Drug-Eluting Stents: An Overview of Coating Strategies and Comparison with Polymer-Coated Drug-Eluting Stents

Clinical evaluations have proven the efficacy of drug-elution stents (DES) in reduction of in-stent restenosis rates as compared to drug-free bare metal stents (BMS). Typically, DES are metal stents that are covered with a polymer film loaded with anti-inflammatory or antiproliferative drugs that are released in a sustained manner. However, although favorable effects of the released drugs have been observed, the polymer coating as such has been associated with several adverse clinical effects, such as late stent thrombosis. Elimination of the polymeric carrier of DES may therefore potentially lead to safer DES. Several technologies have been developed to design polymer-free DES, such as the use of microporous stents and inorganic coatings that can be drug loaded. Several drugs, including sirolimus, tacrolimus, paclitaxel, and probucol have been used in the design of carrier-free stents. Due to the function of the polymeric coating to control the release kinetics of a drug, polymer-free stents are expected to have a faster drug elution rate, which may affect the therapeutic efficacy. However, several polymer-free stents have shown similar efficacy and safety as the first-generation DES, although the superiority of polymer-free DES has not been established in clinical trials.

Effects of probucol on restenosis after percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Restenosis after percutaneous coronary intervention (PCI) is a remained clinical problem which limits long-term success of PCI. Although there was recognition that probucol in treating restenosis after percutaneous transluminal coronary angioplasty, the efficacy of probucol on restenosis after stent-implantation is controversial. So this meta-analysis was conducted to investigate the association between probucol and late restenosis.

METHODS

Articles were assessed by four trained investigators, with divergences resolved by consensus. PubMed, EMBASE, ScienceDirect and the Cochrane Central Register of clinical trials were searched for pertinent studies. Inclusion criteria were random allocated to treatment and a comparison of probucol-treated patients and control patients (not treated with lipid-lowering drug) undergoing PCI.

RESULTS

Fifteen studies with 859 subjects were analyzed. Major outcome, binary angiographic restenosis defined as >50% stenosis upon follow-up angiography, was significantly decreased with probucol treatment (RR = 0.59 [0.43, 0.80] among vessels, P = 0.0007; and RR = 0.52 [0.40, 0.68] among patients, P<0.00001). Probucol also increased the minimal luminal diameter (SMD = 0.45 [0.30, 0.61], P<0.00001) and decreased late loss upon follow-up after 6 months (SMD = -0.41 [-0.60, -0.22], P<0.0001). Moreover, there was a significantly lower incidence of major adverse cardiac events (MACE) in the probucol group than control group (RR = 0.69 [0.51, 0.93], P = 0.01).

CONCLUSION

Probucol is more than a lipid-lowering drug. It is also effective in reducing the risk of restenosis and incidence of MACE after PCI.

Long-term outcome of sirolimus-eluting and zotarolimus-eluting coronary stent implantation in patients with and without diabetes mellitus (a Danish organization for randomized trials on clinical outcome III substudy)

We compared 5-year clinical outcomes in diabetic and nondiabetic patients treated with Endeavor zotarolimus-eluting stents (ZESs; Endeavor Sprint, Medtronic, Santa Rosa, California) or Cypher sirolimus-eluting stents (SESs; Cordis, Johnson & Johnson, Warren, New Jersey) coronary implantation. We randomized 2,332 patients to either ZESs (n = 1,162, n = 169 diabetic patients) or SESs (n = 1,170, n = 168 diabetic patients) stratified according to presence or absence of diabetes mellitus. End points included major adverse cardiac event (MACE), a composite of cardiac death, myocardial infarction, target vessel revascularization (TVR), and definite stent thrombosis. Among diabetic patients, MACE occurred more frequently in patients treated with ZESs than SESs (48 [28.4%] vs 31 [18.5%]; odds ratio [OR] 1.75, 95% confidence interval [CI] 1.05 to 2.93, p = 0.032) because of a higher rate of TVR (32 [18.9%] vs 14 [8.3%]; OR 2.57, 95% CI 1.32 to 5.02, p = 0.006). Among nondiabetic patients, ZES and SES had similar MACE rates at 5-year follow-up but SES was associated with a significantly higher risk of definite stent thrombosis (10 [1.0%] vs 23 [2.3%]; OR 0.43, 95% CI 0.20 to 0.91, p = 0.028). Moreover, during the last 4 years, ZES had fewer MACE, TVR, and stent thrombosis events among nondiabetic patients. In conclusion, SES remains superior to ZES in patients with diabetes throughout the 5-year follow-up, however, among nondiabetic patients, SES demonstrated a highly dynamic performance with favorable initial results followed by a late catch-up that included an overall higher risk of stent thrombosis.

Impact of cytochrome P450 2C19 loss-of-function polymorphism on intra-stent thrombi and lesion outcome after everolimus-eluting stent implantation compared to that after first-generation drug-eluting stent implantation

BACKGROUND

The contribution of clopidogrel response due to cytochrome P450 (CYP) 2C19 loss-of-function polymorphism after drug-eluting stent (DES) implantation is unclear.

METHODS

A total of 196 patients who had undergone optical coherence tomography (OCT) at 8 months following first-generation DES (120 lesions) and current-generation everolimus-eluting stent (EES) implantation (127 lesions) were enrolled. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). OCT findings were compared among the 3 groups. Responsiveness to clopidogrel was assessed by VerifyNow platelet reactivity unit (PRU).

RESULTS

The incidence of intra-stent thrombi was significantly higher after first-generation DES implantation compared with EES implantation (35% vs 13%, respectively; p=0.0001). In the first-generation DES group, the incidence of intra-stent thrombi significantly increased among EMs, IMs, and PMs (21% vs 36% vs 63%, respectively; p=0.007), while there was no significant difference among the 3 groups after EES implantation (10% vs 13% vs 20%, respectively; p=0.55). The PRU significantly increased among EMs, IMs, and PMs in each stent group. In multivariate analyses, although PMs had a 3-fold higher risk of thrombi formation compared with non-PMs after first-generation DES implantation, there were no significant differences in thrombi formation between the 2 groups after EES implantation. The optimal PRU cutoff values for the prediction of intra-stent thrombi with first-generation DES and EES were 234 and 256, respectively.

CONCLUSION

CYP2C19 loss-of-function polymorphism is associated with a higher incidence of intra-stent thrombi after first-generation DES implantation, while the impact is attenuated following EES implantation.

Polymers for Cardiovascular Stent Coatings

Polymers have found widespread applications in cardiology, in particular in coronary vascular intervention as stent platforms (scaffolds) and coating matrices for drug-eluting stents. Apart from permanent polymers, current research is focussing on biodegradable polymers. Since they degrade once their function is fulfilled, their use might contribute to the reduction of adverse events like in-stent restenosis, late stent-thrombosis, and hypersensitivity reactions. After reviewing current literature concerning polymers used for cardiovascular applications, this review deals with parameters of tissue and blood cell functions which should be considered to evaluate biocompatibility of stent polymers in order to enhance physiological appropriate properties. The properties of the substrate on which vascular cells are placed can have a large impact on cell morphology, differentiation, motility, and fate. Finally, methods to assess these parameters under physiological conditions will be summarized.

First-generation versus second-generation drug-eluting stents in current clinical practice: updated evidence from a comprehensive meta-analysis of randomised clinical trials comprising 31 379 patients

Background

First-generation drug-eluting stents (DES) have become the most widely used devices worldwide for management of coronary artery disease. As remote follow-up data were becoming available, concerns emerged in regard to their long-term safety. Second-generation DES were designed to overcome safety issues, but the results of randomised clinical trials remain conflicting.

Methods

We compared the safety and efficacy of first-generation versus second-generation Food and Drug Administration approved DES; the following devices were included: first-generation sirolimus-eluting stent (SES) and paclitaxel-eluting stents (PES); second-generation everolimus-eluting stent (EES), zotarolimus-eluting stent Endeavor and ZES-Resolute (ZES-R). Prespecified safety end points comprised ≤1 and >1 year: overall and cardiac mortality, myocardial infarction (MI), definite/definite or probable ST; efficacy end points were target lesion revascularisation and target vessel revascularisation. Composite end points were analysed as well.

Results

33 randomised controlled trials involving 31 379 patients with stable coronary artery disease or acute coronary syndrome undergoing DES implantation were retrieved. No differences in mortality among devices were found. In the overall class comparison, second-generation DES were associated with a 22% reduction of odds of MI at short-term OR 0.77 (95% CI 0.68 to 0.89) p=0.0002; EES reduced the odds of definite-probable ST compared with PES: OR 0.33 (95% CI 0.15 to 0.73) p=0.006; First-generation SES along with second-generation EES and ZES-R showed similar efficacy in decreasing the odds of repeat revascularisation.

Conclusions

Second-generation EES and ZES-R offer similar levels of efficacy compared with first-generation SES, but are more effective than PES; however, only second-generation EES significantly reduced the incidence of MI and ST, and therefore should be perceived as the safest DES to date.

Differential clinical outcomes after 1 year versus 5 years in a randomised comparison of zotarolimus-eluting and sirolimus-eluting coronary stents (the SORT OUT III study): a multicentre, open-label, randomised superiority trial

BACKGROUND

In head-to-head comparisons of coronary drug-eluting stents, the primary endpoint is traditionally assessed after 9-12 months. However, the optimum timepoint for this assessment remains unclear. In this study, we assessed clinical outcomes at up to 5 years' follow-up in patients who received two different types of drug-eluting stents.

METHODS

We undertook this multicentre, open-label, randomised superiority trial at five percutaneous coronary intervention centres in Denmark. We randomly allocated 2332 eligible adult patients (≥18 years of age) with an indication for drug-eluting stent implantation to the zotarolimus-eluting Endeavor Sprint stent (Medtronic, Santa Rosa, CA, USA) or the sirolimus-eluting Cypher Select Plus stent (Cordis, Johnson & Johnson, Warren, NJ, USA). Randomisation of participants was achieved by computer-generated block randomisation and a telephone allocation service. The primary endpoint of the SORT OUT III study was a composite of major adverse cardiac events-cardiac death, myocardial infarction, and target vessel revascularisation-at 9 months' follow-up. In this study, endpoints included the occurrence of major adverse cardiac events and definite stent thrombosis at follow-up times of up to 5 years. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00660478.

FINDINGS

We randomly allocated 1162 patients to receive the zotarolimus-eluting stent and 1170 to the sirolimus-eluting stent. At 5-year follow-up, rates of major adverse cardiac events were similar in patients treated with both types of stents (zotarolimus-eluting stents 197/1162 [17.0%] vs sirolimus-eluting stents 182/1170 [15.6%]; odds ratio [OR] 1.10, 95% CI 0.88-1.37; p=0.40). This finding was indicative of the directly contrasting results for rates of major adverse cardiac events at 1-year follow up (zotarolimus 93/1162 [8.0%] vs sirolimus 46/1170 [3.9%]; OR 2.13, 95% CI 1.48-3.07; p<0.0001) compared with those at follow-up between 1 and 5 years (104 [9.0%] vs 136 [11.6%]; OR 0.78, 95% CI 0.59-1.02; p=0.071). At 1-year follow-up, definite stent thrombosis was more frequent after implantation of the zotarolimus-eluting stent (13/1162 [1.1%]) than the sirolimus-eluting stent (4/1170 [0.3%]; OR 3.34, 95% CI 1.08-10.3; p=0.036), whereas the opposite finding was recorded for between 1 and 5 years' follow-up (zotarolimus-eluting stent 1/1162 [0.1%] vs sirolimus-eluting stent 21/1170 [1.8%], OR 0.05, 95% CI 0.01-0.36; p=0.003). 26 of 88 (30%) target lesion revascularisations in the zotarolimus-eluting stent group occurred between 1 and 5 years' follow-up, whereas 54 of 70 (77%) of those in the sirolimus-eluting stent group occurred during this follow-up period.

INTERPRETATION

The superiority of sirolimus-eluting stents compared with zotarolimus-eluting stents at 1-year follow-up was lost after 5 years. The traditional 1-year primary endpoint assessment therefore might be insufficient to predict 5-year clinical outcomes in patients treated with coronary drug-eluting stent implantation.

FUNDING

Cordis and Medtronic.

Surface modification with dopamine and heparin/poly-L-lysine nanoparticles provides a favorable release behavior for the healing of vascular stent lesions

Surface biofunctional modification of coronary artery stents to prevent thrombosis and restenosis formation, as well as accelerate endothelialization, has become a new hot spot. However, bioactive coatings on implants are not yet sufficiently developed for long-term activity, as they quickly lose efficiency in vivo and finally fail. On the basis of a novel time-ordered concept of biofunctionality for vascular stents, heparin/poly l-lysine nanoparticle (NP) was developed and immobilized on a polydopamine-coated titanium surface, with the aim of regulating and maintaining the intravascular biological response within the normal range after biomaterial implantation. An in vitro dynamic release model was established to mimic the blood flow condition in vivo with three phases: (1) An early phase (1-7 days) with release of predominantly anticoagulant and anti-inflammatory substances and to a minor degree antiproliferative effects against smooth muscle cells (SMCs); (2) this is followed by a phase (7-14 days) of supported endothelial cell (ECs) proliferation and suppressed SMC proliferation with persisting high antithrombogenicity and anti-inflammatory properties of the surface. (3) Finally, a stable stage (14-28 days) with adequate biomolecules on the surface that maintain hemocompatibility and anti inflammation as well as inhibit SMCs proliferation and promote ECs growth. In vivo animal tests further confirmed that the NP-modified surface provides a favorable release behavior to apply a stage-adjusted remedy. We suggested that these observations provide important guidance and potential means for reasonable and suitable platform construction on a stent surface.