Biodegradable versus durable polymer drug eluting stents in coronary artery disease: insights from a meta-analysis of 5,834 patients

Nanoparticles eluting stents for coronary intervention: Formulation, characterization and in vitro evaluation

Coronary artery disease (CAD) is currently a leading cause of death worldwide. In the history of percutaneous coronary intervention for the treatment of CAD, a drug-eluting stent (DES) is recognized as a revolutionary technology that has the unique ability to significantly reduce restenosis and provide both mechanical and biological solutions simultaneously to the target lesion. The aim of the research work was to design and fabricate DES coated with a nanoparticulate drug formulation. Sirolimus, an inhibitor of the smooth muscle cell (SMC) proliferation and migration, was encapsulated in polymeric nanoparticles. The nanoparticle formulation was characterized for various physicochemical parameters. Cell viability and cell uptake studies were performed using human coronary artery smooth muscle cells (HCASMCs). The developed nanoparticle formulation showed enhanced efficacy compared to plain drug solution and exhibited time-dependent uptake into the HCASMCs. The developed nanoparticle formulation was coated on the FlexinniumTM ultra-thin cobalt-chromium alloy coronary stent platform. The nanoparticle coated stents were characterized for morphology and residual solvent analysis. In-vitro drug release was also evaluated. Ex-vivo arterial permeation was carried out to evaluate the nanoparticle uptake from the surface of the stents. The characterization studies together corroborated that the developed nanoparticle coated stent can be a promising replacement of the current drug-eluting stents.

Targeted therapy with a localised abluminal groove, low-dose sirolimus-eluting, biodegradable polymer coronary stent (TARGET All Comers): a multicentre, open-label, randomised non-inferiority trial

BACKGROUND

The FIREHAWK is a drug-eluting stent with a fully biodegradable sirolimus-containing polymer coating localised to recessed abluminal grooves on the stent surface. We investigated clinical outcomes with this targeted, low-dose, biodegradable polymer, sirolimus-eluting stent compared with XIENCE durable polymer, everolimus-eluting stents in an all-comers population.

METHODS

The TARGET All Comers study was a prospective, multicentre, open-label randomised non-inferiority trial done at 21 centres in ten European countries. Patients with symptomatic or asymptomatic coronary artery disease and objective evidence of myocardial ischaemia who qualified for percutaneous coronary intervention were randomised 1:1 to undergo implantation of a FIREHAWK or XIENCE. Randomisation was web-based, with random block allocation and stratification by centre and ST elevation myocardial infarction. Outcome assessors were masked to treatment allocation, but treating physicians and patients were not. The primary endpoint was target lesion failure at 12 months, a composite of cardiac death, target vessel myocardial infarction, or ischaemia-driven target lesion revascularisation. The control event rate for XIENCE was assumed to be 7%, the non-inferiority margin was 3.5%, and the primary analysis was in the intention-to-treat population, censoring patients who did not have either an event before 365 days or contact beyond 365 days. Late lumen loss was the primary endpoint of an angiographic substudy designed to investigate the non-inferiority of the FIREHAWK compared with the XIENCE stent. This trial is registered with ClinicalTrials.gov, number NCT02520180.

FINDINGS

From Dec 17, 2015, to Oct 14, 2016, 1653 patients were randomly assigned to implantation of the FIREHAWK (n=823) or XIENCE (n=830). 65 patients in the FIREHAWK group and 66 in the XIENCE group had insufficient follow-up data and were excluded from the analyses. At 12 months, target lesion failure occurred in 46 (6·1%) of 758 patients in the FIREHAWK group and in 45 (5·9%) of 764 patients in the XIENCE group (difference 0·2%, 90% CI -1·9 to 2·2, p_{non-inferiority}=0·004, 95% CI -2·2 to 2·6, p_superiority=0·88). There were no differences in ischaemia-driven revascularisation or stent thrombosis rates at 12 months. 176 patients were included in the angiographic substudy, in which in-stent late lumen loss was 0·17 mm (SD 0·48) in the FIREHAWK group and 0·11 mm (0·52) in the XIENCE group (p=0·48), with an absolute difference of 0·05 mm (95% CI -0·09 to 0·18, p_{non-inferiority}=0·024).

INTERPRETATION

In a broad all-comers population of patients requiring stent implantation for myocardial ischaemia, the FIREHAWK was non-inferior to the XIENCE as assessed with the primary endpoint of target lesion failure at 12 months and in-stent late lumen loss at 13 months. The FIREHAWK is a safe and effective alternative stent to treat patients with ischaemic coronary artery disease in clinical practice.

FUNDING

Shanghai Microport Medical.

Three-months optical coherence tomography analysis of a biodegradable polymer, sirolimus-eluting stent

OBJECTIVE

We aimed to assess early neointimal healing by optical coherence tomography (OCT) 3 months after implantation of the ultrathin Orsiro® sirolimus-eluting stent with biodegradable polymer.

BACKGROUND

New generations of drug-eluting stents with biodegradable polymer have been developed to avoid the continued vascular irritation of durable polymers.

METHODS

In this prospective, open-label study, 34 patients received an Orsiro® sirolimus-eluting stent with biodegradable polymer. In a subgroup of patients (n = 15), the intervention was performed under OCT guidance. All patients underwent OCT-examination at three months. The primary endpoint was 3-month neointimal healing (NIH) score, calculated by weighing the presence of filling defects, malapposed and uncovered struts. Secondary endpoint was maturity of tissue coverage at 3 months.

RESULTS

At 3 months, NIH score was 13.7 (5.4-22), covered struts per lesion were 90% (84-97%), malapposed struts were 2.7% (0.8-5.4%) and rate of mature tissue coverage was 47% (42-53%). No target lesion failure occurred up to 12 months. Patients with OCT-guided stent implantation demonstrated a trend toward earlier stent healing as demonstrated by superior NIH scores (angio guided: 17.6% [8.8-26.4]; OCT-guided: 9.8% [4.0-15.5]; mean difference -8, [95%CI: -18.7-2.9], P = 0.123). This group had significantly more covered struts per lesion (angio-guided: 86% [82-90]; 95% [92-99]; mean difference 9% [95%CI: 3-15], P = 0.001).

CONCLUSION

The Orsiro® sirolimus-eluting stent with biodegradable polymer shows early vascular healing with a high rate of strut coverage at 3-month follow-up. OCT guided stent implantation had a positive impact on early vascular healing.

BIOFLOW-III satellite-One-year clinical outcomes of diabetic patients treated with a biodegradable polymer sirolimus-eluting stent and comprehensive medical surveillance

BACKGROUND

Drug-eluting stents with biodegradable polymer might be particularly useful in diabetic patients who are at increased risk for target lesion/target vessel revascularization. We therefore aimed at assessing the safety and performance of a biodegradable polymer sirolimus-eluting stent (BP-SES) in combination with comprehensive optimal medical therapy following coronary interventions.

METHODS

This prospective, multicenter registry was conducted at six centers in Israel. Aside of stent treatment, we aimed for an LDL-C level<70mg/dl; at one and six months post-intervention a diabetic consultancy was required, and follow-up data were collected at six and twelve months. The primary outcome measure was target vessel failure, a composite of cardiac death, target-vessel myocardial infarction and clinically driven target vessel revascularization. Secondary outcomes were target lesion failure, its individual components, and stent thrombosis.

RESULTS

From August 2013 until May 2014, 120 diabetic patients with 158 lesions were treated with a BP-SES. Mean age was 63.9±9.2years, 27.5% were insulin dependent, 28.3% had a history of myocardial infarction, and 47.5% had prior coronary interventions. By visual estimation, lesions were 3.0±0.5mm in diameter and 15.2±7.4mm long; mean stent diameter and length were 3.0±0.5mm and 19.2±6.8mm. Target vessel failure and target lesion failure at 12months occurred in seven (6.4% [95% CI: 3.1-13.0]) and four patients (3.5% [95% CI: 1.3-9.2]), respectively, and definite stent thrombosis in one patient (1.0% [95% CI: 0.1-7.0]).

CONCLUSION

Treatment with a BP-SES demonstrated excellent target-vessel and target-lesion revascularization rates in a high-risk diabetic patient population undergoing catheter-based revascularization followed by intensified medical care.

ANNOTATED TABLE OF CONTENTS

In 120 high-risk diabetic patients with coronary artery stenosis, treatment with the Orsiro sirolimus-eluting stent with biodegradable polymer and comprehensive antidiabetic therapy resulted in excellent clinical outcomes. Target vessel revascularization occurred in 6.4% of patients and target lesion revascularization in 3.5%.

Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study

We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

Polymer-free versus permanent polymer drug eluting stents in coronary artery disease: A meta-analysis of 10 RCTs with 6575 patients

Background

Permanent polymer drug eluting stents (PP-DES) may induce inflammation of the vessel wall due to the existence of the polymer, which may delay intimal healing. Polymer-free DES (PF-DES) that eliminate the polymeric carrier may potentially lead to safer DES. However, the safety and efficacy of PF-DES remains controversial.

Methods

Randomized controlled trials comparing PF-DES with PP-DES were searched in online database including MEDLINE, Excerpta Medica Database (EMBASE) and Cochrane Library. Studies reporting late lumen loss (LLL), all-cause death, myocardial infarction (MI), target lesion revascularization (TLR) and late stent thrombosis (LST) were enrolled and quantitatively analyzed.

Results

Ten studies enrolling 6575 patients were included in this meta-analysis. The PF-DES showed a benefit in reducing all-cause death (OR = 0.77, 95% CI: 0.61 to 0.98, P = 0.03) and long-term LLL (weighted mean difference (WMD) −0.16 mm, 95% CI: −0.22 to −0.11 mm, P < 0.001), while no superiority was found in reducing short-term LLL (WMD 0.03 mm, 95% CI: −0.07–0.13 mm, P = 0.57), MI (OR = 1.12, 95% CI: 0.19 to 23.18, P = 0.39), TLR (OR = 1.19, 95% CI: 0.42 to 3.38, P = 0.83) and LST (OR = 0.92, 95% CI: 0.05 to 5.71, P = 0.74).

Conclusion

PF-DES showed benefits in reducing long-term LLL and mortality compared with PP-DES, but no superiority was found in short-term LLL, MI, TLR and LST. These findings provide a sound basis for the wide application of PF-DES in the future.

Comparison of the Absorbable Polymer Sirolimus-Eluting Stent (MiStent) to the Durable Polymer Everolimus-Eluting Stent (Xience) (from the DESSOLVE I/II and ISAR-TEST-4 Studies)

We compared the outcomes of a novel, thin-strut, cobalt-chromium, absorbable, polymer sirolimus-eluting stent (APSES; MiStent) to the durable polymer cobalt-chromium everolimus-eluting stent (EES; Xience). A propensity-matched analysis was performed comparing data from the DES With Sirolimus and a Bioabsorbable Polymer for the Treatment of Patients With De Novo Lesions in the Native Coronary Arteries (DESSOLVE) I and II studies, evaluating the APSES to the EES arm of the Intracoronary Stenting and Angiographic Results: Test Efficacy of 3 Limus-Eluting Stents-4 study. Target lesion failure (TLF) and its components were evaluated at 12 months and annually to 3 years; 805 patients (APSES = 153; EES = 652) were included with propensity matching in 204 patients (APSES = 102; EES = 102). APSES compared with EES had lower TLF at 1 year (3.0% vs 8.0%, p = 0.12) driven by a difference in target lesion revascularization (TLR; 1% vs 6%, p = 0.05), with no difference in target vessel myocardial infarction (p = 0.56) or stent thrombosis (p = 0.31). At 3 years, TLF (5.0% vs 12.5%, p = 0.07) and TLR (2.0% vs 8.4%, p = 0.04) remained lower with APSES. By landmark analysis, there was no significant difference in TLF between 1 and 3 years (p = 0.36). In conclusion, in a propensity-matched analysis, the APSES demonstrated reduced clinically indicated TLR rates at 1 and 3 years compared with the durable polymer EES, with minimal accrual of events between 1 and 3 years.

Smooth Muscle Cell-targeted RNA Aptamer Inhibits Neointimal Formation

Inhibition of vascular smooth muscle cell (VSMC) proliferation by drug eluting stents has markedly reduced intimal hyperplasia and subsequent in-stent restenosis. However, the effects of antiproliferative drugs on endothelial cells (EC) contribute to delayed re-endothelialization and late stent thrombosis. Cell-targeted therapies to inhibit VSMC remodeling while maintaining EC health are necessary to allow vascular healing while preventing restenosis. We describe an RNA aptamer (Apt 14) that functions as a smart drug by preferentially targeting VSMCs as compared to ECs and other myocytes. Furthermore, Apt 14 inhibits phosphatidylinositol 3-kinase/protein kinase-B (PI3K/Akt) and VSMC migration in response to multiple agonists by a mechanism that involves inhibition of platelet-derived growth factor receptor (PDGFR)-β phosphorylation. In a murine model of carotid injury, treatment of vessels with Apt 14 reduces neointimal formation to levels similar to those observed with paclitaxel. Importantly, we confirm that Apt 14 cross-reacts with rodent and human VSMCs, exhibits a half-life of ~300 hours in human serum, and does not elicit immune activation of human peripheral blood mononuclear cells. We describe a VSMC-targeted RNA aptamer that blocks cell migration and inhibits intimal formation. These findings provide the foundation for the translation of cell-targeted RNA therapeutics to vascular disease.

Comparison of the safety and efficacy of biodegradable polymer drug-eluting stents versus durable polymer drug-eluting stents: a meta-analysis

Background

A meta-analysis was conducted to assess the safety and efficacy of biodegradable polymer drug-eluting stents (BP-DESs).

Methods

PubMed, Science Direct, China National Knowledge Infrastructure, and Chongqing VIP databases were searched for randomized controlled trials comparing the safety and efficacy of BP-DESs versus durable polymer drug-eluting stents (DP-DESs). Efficacy included the prevalence of target lesion revascularization (TLR), target vessel revascularization (TVR), and late lumen loss (LLL), and safety of these stents at the end of follow-up for the selected research studies were compared.

Results

A total of 16 qualified original studies that addressed a total of 22,211 patients were included in this meta-analysis. In regard to efficacy, no statistically significant difference in TLR (odds ratio (OR) = 0.94, P = 0.30) or TVR (OR 1.01, P = 0.86) was observed between patients treated with BP-DESs and those with DP-DESs. However, there were significant differences in in-stent LLL (weighted mean difference [WMD] = −0.07, P = 0.005) and in-segment LLL (WMD = −0.03, P = 0.05) between patients treated with BP-DESs and with DP-DESs. In terms of safety, there was no significant difference in overall mortality (OR 0.97, P = 0.67), cardiac death (OR 0.99, P = 0.90), early stent thrombosis (ST) and late ST (OR 0.94, P = 0.76; OR 0.96, P = 0.73), or myocardial infarction (MI) (OR 0.99, P = 0.88) between patients treated with BP-DESs and with DP-DESs. However, there was a statistically significant difference in very late ST (OR 0.69, P = 0.007) between these two groups. In addition, the general trend of the rates of TVR and TLR of BP-DESs groups was lower than DP-DESs groups after a 1-year follow-up.

Conclusion

BP-DESs are safe, efficient, and exhibit superior performance to DP-DESs with respect to reducing the occurrence of very late ST and LLL. The general trend of the rates of TVR and TLR of BP-DESs groups was lower than DP-DESs groups after a 1-year follow-up.

Clinical performance of biodegradable versus permanent polymer drug-eluting stents: A meta-analysis of randomized clinical trials at long-term follow-up

Several types of biodegradable polymer drug-eluting stents (BPDES) have been used for percutaneous transluminal angioplasty; however, the safety and efficiency of these BPDES have not been fully evaluated. A meta-analysis was, therefore, conducted to compare the clinical performance of BPDES with that of permanent polymer drug-eluting stents (PPDES) in unselected patients with coronary stenosis. PubMed, Web of Science, Medline and The Cochrane Library were searched for randomized clinical trials (RCTs) from January 2005 to January 2014. Trials that compared BPDES with PPDES in patients with coronary stenosis were considered. Twelve RCTs with a total of 15,938 patients with coronary stenosis were included in this meta-analysis. No significant difference was found between the two arms in the incidence of major adverse cardiac events (MACE) and definite or probable stent thrombosis (DpST) at the one-year follow-up (P>0.10). The use of BPDES, however, showed a tendency towards a lower risk of MACE (P=0.09) and a beneficial effect by reducing DpST episodes (P=0.04) at long-term follow-up, particularly when compared with the incidence of DpST at the one-year follow-up. BPDES also tended to be associated with a decreased late lumen loss in patients with coronary stenosis [instrumental variable =−0.04; 95% confidence interval =−0.08–0.00; P=0.05). In conclusion, the one-year outcomes following drug-eluting stent implantation showed BPDES were noninferior to PPDES in unselected patients with coronary stenosis. Long-term clinical outcomes, however, indicated that BPDES appeared to a present a lower risk of MACE and DpST.

Current status of bioresorbable scaffolds in the treatment of coronary artery disease

State-of-the-art drug-eluting metal stents are the gold standard for interventional treatment of coronary artery disease. Although they overcome some disadvantages and limitations of plain balloon angioplasty and bare-metal stents, some limitations apply, most notably a chronic local inflammatory reaction due to permanent implantation of a foreign body, restriction of vascular vasomotion due to a metal cage, and the risk of late and very late stent thrombosis. The development of biodegradable scaffolds is a new approach that attempts to circumvent these drawbacks. These devices provide short-term scaffolding of the vessel and then dissolve, which should theoretically circumvent the side effects of metal drug-eluting stents. Various types of these bioresorbable scaffolds are currently under clinical evaluation. This review discusses different concepts of bioresorbable scaffolds with respect to material, design, and drug elution and presents the most recent evidence.

Clinical outcomes of biodegradable polymer drug-eluting stents for percutaneous coronary intervention: an updated meta-analysis of randomized controlled trials

Biodegradable polymer drug-eluting stents (DES) are innovative concepts in the era of percutaneous coronary intervention. We systematically reviewed the latest randomized evidence on the efficacy and safety of biodegradable polymer DES as compared to durable polymer DES. MEDLINE, Embase, and the Cochrane database were searched in August 2013 for eligible randomized controlled trials (RCTs) comparing biodegradable polymer DES with durable polymer DES. Clinical outcomes of interest were mortality, myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis. A total of 20 RCTs randomizing 20 021 participants were included, of whom 11 045 were allocated to biodegradable polymer DES and 8976 to durable polymer DES. Treatment of biodegradable polymer DES was not associated with a significant reduction of any of the clinical outcomes (all-cause mortality, odds ratio [OR]: 0.94, 95% confidence interval [CI]: 0.80 to 1.10, P = 0.42; cardiovascular mortality, OR: 0.97, 95% CI: 0.79 to 1.19, P = 0.74; MI, OR: 1.07, 95% CI: 0.91 to 1.26, P = 0.41; TLR, OR: 0.87, 95% CI: 0.69 to 1.08, P = 0.20; TVR, OR: 1.05, 95% CI: 0.85 to 1.28, P = 0.67; definite/probable stent thrombosis, OR: 0.80, 95% CI: 0.59 to 1.07, P = 0.14). Current randomized data indicate that clinical efficacy and safety profiles of biodegradable polymer DES are comparable to those of durable polymer DES. Findings from large-scale studies with rigorous methodology and long follow-up duration are needed.

A novel platinum chromium everolimus-eluting stent for the treatment of coronary artery disease

The development of coronary stents represents a major step forward in the treatment of obstructive coronary artery disease since the introduction of percutaneous coronary intervention. The initial enthusiasm for bare metal stents was, however, tempered by a significant incidence of in-stent restenosis, the manifestation of excessive neointima hyperplasia within the stented vessel segment, ultimately leading to target vessel revascularization. Later, drug-eluting stents, with controlled local release of antiproliferative agents, consistently reduced this need for repeat revascularization. In turn, the long-term safety of first-generation drug-eluting stents was brought into question with the observation of an increased incidence of late stent thrombosis, often presenting as myocardial infarction or sudden death. Since then, new drugs, polymers, and platforms for drug elution have been developed to improve stent safety and preserve efficacy. Development of a novel platinum chromium alloy with high radial strength and high radiopacity has enabled the design of a new, thin-strut, flexible, and highly trackable stent platform, while simultaneously improving stent visibility. Significant advances in polymer coating, serving as a drug carrier on the stent surface, and in antiproliferative agent technology have further improved the safety and clinical performance of newer-generation drug-eluting stents. This review will provide an overview of the novel platinum chromium everolimus-eluting stents that are currently available. The clinical data from major clinical trials with these devices will be summarized and put into perspective.

Drug eluting balloons for de novo coronary lesions - a systematic review and meta-analysis

BACKGROUND

The role of drug-eluting balloons (DEB) is unclear. Increasing evidence has shown a benefit for the treatment of in-stent restenosis. Its effect on de novo coronary lesions is more controversial. Several smaller randomized trials found conflicting results.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials (RCT) evaluating the effect of local Paclitaxel delivery/drug eluting balloons (DEB) (+/- bare metal stent) compared to current standard therapy (stenting) to treat de novo coronary lesions. Data sources for RCT were identified through a literature search from 2005 through 28 December 2012. The main endpoints of interest were target lesion revascularization (TLR), major adverse cardiac events (MACE), binary in-segment restenosis, stent thrombosis (ST), myocardial infarction (MI), late lumen loss (LLL) and mortality. A random effects model was used to calculate the pooled relative risks (RR) with 95% confidence intervals.

RESULTS

Eight studies (11 subgroups) and a total of 1,706 patients were included in this analysis. Follow-up duration ranged from 6 to 12 months. Overall, DEB showed similar results to the comparator treatment. The relative risk (RR) for MACE was 0.95 (0.64 to 1.39); P = 0.776, for mortality it was 0.79 (0.30 to 2.11), P = 0.644, for stent thrombosis it was 1.45 (0.42 to 5.01), P = 0.560, for MI it was 1.26 (0.49 to 3.21), P = 0.629, for TLR it was 1.09 (0.71 to 1.68); P = 0.700 and for binary in-stent restenosis it was 0.96 (0.48 to 1.93), P = 0.918. Compared to bare metal stents (BMS), DEB showed a lower LLL (- 0.26 mm (-0.51 to 0.01)) and a trend towards a lower MACE risk (RR 0.66 (0.43 to 1.02)).

CONCLUSION

Overall, drug-eluting balloons (+/- bare metal stent) are not superior to current standard therapies (BMS or drug eluting stent (DES)) in treating de novo coronary lesions. However, the performance of DEB seems to lie in between DES and BMS with a trend towards superiority over BMS alone. Therefore, DEB may be considered in patients with contraindications for DES. The heterogeneity between the included studies is a limitation of this meta-analysis; different drug-eluting balloons have been used.