Solid implantable devices for sustained drug delivery

Implantable drug delivery systems (IDDS) are an attractive alternative to conventional drug administration routes. Oral and injectable drug administration are the most common routes for drug delivery providing peaks of drug concentrations in blood after administration followed by concentration decay after a few hours. Therefore, constant drug administration is required to keep drug levels within the therapeutic window of the drug. Moreover, oral drug delivery presents alternative challenges due to drug degradation within the gastrointestinal tract or first pass metabolism. IDDS can be used to provide sustained drug delivery for prolonged periods of time. The use of this type of systems is especially interesting for the treatment of chronic conditions where patient adherence to conventional treatments can be challenging. These systems are normally used for systemic drug delivery. However, IDDS can be used for localised administration to maximise the amount of drug delivered within the active site while reducing systemic exposure. This review will cover current applications of IDDS focusing on the materials used to prepare this type of systems and the main therapeutic areas of application.

Second generation drug-eluting stents: a focus on safety and efficacy of current devices

Introduction: Percutaneous coronary intervention (PCI) represents the most frequent procedure performed in medicine. Second generation drug eluting stents (DES) have been developed to reduce the rates of late and very late complications of first generation DES.Areas covered: To improve long-term efficacy and safety of patients undergoing PCI, second generation DES have been developed with novel stent platforms, biocompatible durable and biodegradable polymers and newer antiproliferative agents. In this review we provide an overview of second generation DES and their clinical trials, discussing safety and effectiveness of these devices, and outlining clinical indication for use.Expert commentary: Numerous clinical trials have demonstrated the safety and efficacy of second generation DES over the last decade. These devices represent the gold standard treatment in stable and acute coronary syndromes.

Evolution of drug-eluting biomedical implants for sustained drug delivery

In the field of drug delivery, the most commonly used treatments have traditionally been systemically delivered using oral or intravenous administration. The problems associated with this type of delivery is that the drug concentration is controlled by first pass metabolism, and therefore may not always remain within the therapeutic window. Implantable drug delivery systems (IDDSs) are an excellent alternative to traditional delivery because they offer the ability to precisely control the drug release, deliver drugs locally to the target tissue, and avoid the toxic side effects often experienced with systemic administration. Since the creation of the first FDA-approved IDDS in 1990, there has been a surge in research devoted to fabricating and testing novel IDDS formulations. The versatility of these systems is evident when looking at the various biomedical applications that utilize IDDSs. This review provides an overview of the history of IDDSs, with examples of the different types of IDDS formulations, as well as looking at current and future biomedical applications for such systems. Though there are still obstacles that need to be overcome, ever-emerging new technologies are making the manufacturing of IDDSs a rewarding therapeutic endeavor with potential for further improvements.

Twelve-month clinical outcomes of sirolimus-eluting stent in coronary artery disease: An experience in real-world Indian patients

Objective:

Supraflex (Sahajanand Medical Technologies Pvt. Ltd, Surat, India) is the latest generation of biodegradable polymer-coated sirolimus-eluting coronary stent designed on ultra-thin (60 µm) cobalt–chromium platform with flexible “S-link.” The present study was designed to establish the safety and clinical performance of Supraflex in real-world Indian patients with coronary artery disease.

Methods:

The study included 839 consecutive patients with coronary artery disease who were implanted with Supraflex from January 2014 to August 2017 at six different tertiary care centers in India. Follow-up was performed at 30 days, 6 months, and 12 months after the index procedure. The primary end-point of the study was the incidence of major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction (MI), and target lesion revascularization (TLR) at the 12-month follow-up. The occurrence of stent thrombosis was analyzed as safety end-point.

Results:

A total of 1025 lesions were treated by implantation of 1098 Supraflex stents. At the 12-month follow-up, MACE was 4.92%, including 7 (0.86%) cardiac deaths, 16 (1.97%) MI, and 17 (2.09%) TLR. Only three incidences of stent thrombosis were found at the 12-month follow-up.

Conclusion:

The study results showed excellent safety and clinical effectiveness of Supraflex in a high proportion of high-risk real-world Indian patients with coronary artery disease. (Anatol J Cardiol 2020; 24: 364-9)

Advances in mammalian target of rapamycin kinase inhibitors: application to devices used in the treatment of coronary artery disease

Mammalian target of rapamycin (mTOR) inhibitors have been applied to vascular coronary devices to avoid neointimal growth and have become the predominant pharmacological agents used to prevent restenosis. mTOR inhibitors can affect not only proliferating vascular smooth muscle cells but also endothelial cells and therefore can result in delayed healing of the vessel including endothelialization. Emerging evidence suggests accelerated atherosclerosis due to the downstream negative effects on endothelial barrier functional recovery. The development of neoatherosclerosis within the neointima of drug-eluting stents can result in late thrombotic events. This type of problematic healing response may open the way for specific mTOR kinase inhibitors, such as ATP-competitive mTOR inhibitors. These inhibitors demonstrate a better healing profile than traditional limus-based drug-eluting stent and their clinical efficacy remains unknown.

Safety and Performance of the Orsiro Sirolimus-Eluting Stent in the Treatment of All-Comers Patient Population in Daily Clinical Practice

BACKGROUND

The BIOFLOW-III Canada registry aimed to evaluate the safety and efficacy of Orsiro sirolimus-eluting stents (SES) with biodegradable polymer, in an all-comers patient population.

METHODS

We conducted a prospective, non-randomized, multi-center, observational all-comers registry of patients undergoing percutaneous coronary intervention (PCI) with Orsiro SES at two high-volume Canadian centers. The primary endpoint was one-year target lesion failure (TLF) defined as a composite of cardiac death, target-vessel myocardial infarction (MI), coronary artery bypass grafting and clinically driven target lesion revascularization. Four subgroups were pre-defined: i) diabetic patients; ii) small vessels (≤2.75 mm); iii) chronic total occlusions (CTO) and iv) acute MI.

RESULTS

From May 2014 to July 2016, 250 patients (mean age 66.2 ± 10.8 years, 75.6% males, 30% diabetes) underwent PCI with Orsiro SES for 385 coronary lesions. The mean stent diameter was 2.98 ± 0.50 mm and the mean stent length was 22 ± 8 mm. Clinical device and procedural success rates were with 99.5% and 97.6%, respectively. The overall one-year TLF rate was 2.8% [95% confidence interval (CI) 1.4-5.8%], whereas TLF rates were 4.1% [95%CI 1.3-12.2%], 3.2% [95%CI 1.2-8.4%], 8.3% [95%CI 2.2-29.4%], and 2.6% [95%CI 0.7-9.9%] in patients with diabetes, small vessels, CTO, and acute MI, respectively. One case of possible stent thrombosis (ST) was reported (0.4% [95%CI 0.1-2.8%]), while no cases of definite/probable ST was observed at one year.

CONCLUSION

Our data provide further evidence of the safety and clinical performance of Orsiro SES in an unselected, real-world, complex patient population.

CONDENSED ABSTRACT

The BIOFLOW-III Canada registry is a prospective, non-randomized, multi-center, observational all-comers registry designed to evaluate the safety and performance of the Orsiro SES in non-selected, real-world patients. A total of 250 patients (mean age 66.2 ± 10.8 years, 75.6% males, 30% diabetes) who underwent PCI with Orsiro SES, were enrolled at two high-volume Canadian centers. The overall rate of TLF at one year was 2.8% [95%CI 1.4-5.8%], whereas TLF rates were 4.1%, 3.2%, 8.3%, and 2.6% in patients with diabetes, small vessels ≤2.75 mm, CTO, and acute MI, respectively. No case of definite/probable ST was observed.

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.

Safety and efficacy of a novel abluminal groove-filled biodegradable polymer sirolimus-eluting stent

Late stent thrombosis (LST) following drug-eluting stent (DES) implantation in patients with coronary artery disease (CAD) is often associated with delayed vascular healing, resulting from vascular inflammation and hypersensitivity to durable polymers and drugs. Therefore, DES design, materials, and coatings have been technologically revolutionized. Herein, we designed a novel abluminal groove-filled biodegradable polymer sirolimus-eluting stent (AGF-BP-SES), with a sirolimus content of only about one-third of traditional DES. The mechanical performances of AGF-BP-SES during compression and expansion were investigated. The pharmacokinetic (PK) profile of sirolimus was studied in the swine model. The in vivo efficacy of AGF-BP-SES was compared with that of Xience PRIME^® stent. The results showed that AGF-BP-SES exhibited mechanical properties similar to traditional DES, including the rebound ratio of radial contraction/direction, rebound ratio of axial contraction/direction, and inhomogeneity of compression/expansion. Despite utilizing a reduced dose of sirolimus, AGF-BP-SES delivered sirolimus to the coronary artery in a controlled and efficient manner. The stent maintained a safe and effective local drug concentration without local or systemic risks. In the swine model, histopathological indicators predicted safety and biocompatibility of AGF-BP-SES. In conclusion, AGF-BP-SES maintained similar mechanical properties as other stents while reducing the drug-loading capacity, and showed a favorable safety and efficacy profile of the targeted DES.

Randomized clinical trial comparing abluminal biodegradable polymer sirolimus-eluting stents with durable polymer sirolimus-eluting stents: Nine months angiographic and 5-year clinical outcomes

BACKGROUND

The biodegradable polymer drug-eluting stents (DES) were developed to improve vascular healing. However, further data and longer-term follow-up are needed to confirm safety and efficacy of these stents. This randomized clinical trial aimed to compare safety and efficacy of 2 sirolimus-eluting stents (SES): Cordimax-a novel abluminal biodegradable polymer SES and Cypher Select-a durable polymer SES, at 9 months angiographic and 5-year clinical follow-up.

METHODS

We randomized 402 patients with coronary artery disease to percutaneous coronary intervention with Cordimax (n = 202) or Cypher select (n = 200). Angiographic follow-up was performed at 9 months after the index procedure and clinical follow-up annually up to 5 years. The primary endpoint was angiographic in-stent late luminal loss (LLL). Secondary endpoints included angiographic restenosis rate, target vessel revascularization (TVR), and major adverse cardiac events (MACEs; defined as cardiac death, myocardial infarction, or TVR) at 5-year follow-up.

RESULTS

Cordimax was noninferior to Cypher select for in-stent LLL (0.25 ± 0.47 vs 0.18 ± 0.49 mm; P = 0.587) and in-stent mean diameter stenosis (22.19 ± 12.21% vs 19.89 ± 10.79%; P = 0.064) at 9 months angiographic follow-up. The MACE rates were not different at 1 year (5.9% vs 4.0%, P = 0.376); however, MACE rates from 2 to 5 years were lower in the Cordimax group (6.8% vs 13.1%; P = 0.039).

CONCLUSION

Abluminal biodegradable polymer SES is noninferior to durable polymer SES at 9-month angiographic and 1-year clinical follow-up. However, MACE rates from 2 to 5 years were less in the abluminal biodegradable polymer group.

Antiproliferative Drugs for Restenosis Prevention

Cardiovascular disease is a leading cause of death and disability worldwide. Current treatment strategies aimed at treating the symptoms and consequences of obstructive vascular disease have embraced both optimal medical therapy and catheter-based percutaneous coronary intervention with drug-eluting stents. Drug-eluting stents elute antiproliferative drugs inhibiting vascular smooth muscle cell proliferation, which occurs in response to injury and thus prevents restenosis. However, all drugs currently approved for use in drug-eluting stents do not discriminate between proliferating vascular smooth muscle cells and endothelial cells, thus delaying re-endothelialization and subsequent vascular healing.

Preliminary Evaluation of Clinical and Angiographic Outcomes with Biodegradable Polymer Coated Sirolimus-Eluting Stent in De Novo Coronary Artery Disease: Results of the MANIPAL-FLEX Study

Objective. The objective of the MANIPAL-FLEX study was to evaluate the feasibility, preliminary safety, and efficacy of the Supraflex sirolimus-eluting stent (SES) implantation, in de novo coronary artery disease, using clinical and quantitative coronary angiography (QCA) follow-ups. Methods. This was a prospective, nonrandomized, multicenter, single-arm study that enrolled 189 patients with de novo coronary artery disease who were treated with the Supraflex SES. Of 189 patients enrolled, the first 61 consecutive patients who consented to a 9-month follow-up evaluation by QCA, irrespective of presence of symptoms, were to be followed up with angiography at 9 months. The primary endpoint of the study was target lesion failure (TLF), including cardiac death, myocardial infarction, and target lesion revascularization during 12-month follow-up after the index procedure. Results. The mean age of the study population was 58 ± 11 years, with 51.3% (97/189) of hypertensive patients. Total of 66 lesions, analyzed by offline QCA, showed good scaffolding of the target vessel with in-stent late lumen loss at 9 months of 0.18 ± 0.23 mm. The observed TLF at 30-day, 6-month, and 12-month follow-up were 2 (1.1%), 6 (3.2%), and 10 (5.3%), respectively. Conclusion. This study provides preliminary evidence for the feasibility, safety, and efficacy of the Supraflex sirolimus-eluting stent.

Risk factors for long-term outcome of drug-eluting stenting in adults with early-onset coronary artery disease

OBJECTIVE

We lack data on the long-term outcome of drug-eluting stenting in patients with early-onset coronary artery disease (CAD). Here, we investigated the association of traditional risk factors and major adverse cardiovascular events (MACEs) after drug-eluting stenting in patients with CAD who were < 50 years old.

METHODS

We enrolled 437 consecutive CAD patients < 50 years old who underwent drug-eluting stenting and 132 subjects who were age- and sex-matched and angiographically shown to be disease free as controls. MACEs were analyzed in CAD patients for a median of 24 months [interquartile range 14-34 months].

RESULTS

Male patients accounted for 90.4% of cases. As compared with controls, patients with early-onset CAD had higher body mass index and rates of smoking, family history of CAD, and diabetes and hypercholesterolemia. During the hospital stay, 1 patient died, and the incidence of MACEs was 1.1%. At the end of follow-up, the overall death rate was 0.7%. MACEs were observed in 54 patients (12.4%). On Cox proportional hazard analyses, positive family history and diabetes were independent risk factors of MACEs (HR 2.61, 95% confidence interval 1.29-4.00, p = 0.002; and HR 2.48, 95% confidence interval 0.86-3.14, p = 0.004, respectively).

CONCLUSIONS

Drug-eluting stenting is a reliable treatment for patients with early-onset CAD. Positive family history of CAD and diabetes are independent risk factors of adverse cardiovascular events in this subgroup of patients after drug-eluting stent implantation.

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.

Incidences, Predictors, and Clinical Outcomes of Acute and Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

Background—

We investigated the incidences, predictors, and clinical outcomes of acute and late stent malapposition detected by optical coherence tomography (OCT) after drug-eluting stent implantation.

Methods and Results—

We analyzed the OCT images from 351 patients with 356 lesions who received poststent and follow-up OCT examinations. Acute stent malapposition was observed in 62% of lesions. Approximately half of the acute stent malappositions were located within the edges of the stents. Severe diameter stenosis, calcified lesions, and long stents were independent predictors of acute stent malapposition. Follow-up OCT examinations were performed 175±60 days after drug-eluting stent implantation. Thirty-one percent of lesions with acute stent malapposition remained malapposed (late-persistent stent malapposition) and were typically (72%) located within the edges of the stent. The location within the stent edges and the volume of acute stent malapposition were independent predictors of late-persistent stent malapposition. Acute stent malapposition with a volume >2.56 mm 3 differentiated late-persistent stent malapposition from resolved acute stent malapposition. Late-acquired stent malapposition was detected in 15% of all lesions and was usually (61%) located within the stent body. Late-acquired stent malapposition was more frequently associated with plaque/thrombus prolapse on poststent OCT images (70% versus 42%; P <0.001). Clinical events, including cardiovascular death, nonfatal myocardial infarction, and stent thrombosis, did not occur in patients with late stent malapposition during the follow-up period of 28.6±10.3 months after drug-eluting stent implantation.

Conclusions—

Acute, late-persistent, and late-acquired stent malapposition had relatively high incidences but different predictors. The clinical outcome of stent malapposition was favorable.

A randomised comparison of a novel abluminal groove-filled biodegradable polymer sirolimus-eluting stent with a durable polymer everolimus-eluting stent: clinical and angiographic follow-up of the TARGET I trial

AIMS

The study sought to evaluate the safety and efficacy of FIREHAWK, a novel abluminal groove-filled biodegradable polymer sirolimus-eluting stent (SES) for treating patients with single de novo coronary lesions compared with the durable polymer everolimus-eluting stent (EES) XIENCE V.

METHODS AND RESULTS

A total of 458 patients with single de novo native coronary lesions ≤24 mm in length and a coronary artery ≥2.25 to ≤4.0 mm in diameter were enrolled in the TARGET I study, a prospective, randomised, non-inferiority trial. The primary endpoint was in-stent late lumen loss (LLL) at nine-month follow-up. The secondary endpoint, target lesion failure (TLF), was defined as the composite of cardiac death, target vessel myocardial infarction (TVMI), or ischaemia-driven target lesion revascularisation (iTLR). Patients were centrally randomised to treatment with either biodegradable polymer SES (n=227) or durable polymer EES (n=231). The nine-month in-stent LLL of the biodegradable polymer SES was comparable to the EES group (0.13 ± 0.24 mm vs. 0.13 ± 0.18 mm, p=0.94; difference and 95% confidence interval 0.00 [-0.04, 0.04] mm; p for non-inferiority <0.0001). Cardiac death (0.4% vs. 0.0%), TVMI (1.3% vs. 1.7%), iTLR (0.4% vs. 0.4%) and TLF (2.2% vs. 2.2%) were similar between the biodegradable polymer SES and durable polymer EES groups at 12-month follow-up (all p>0.05). No definite/probable stent thrombosis was observed in both of these groups.

CONCLUSIONS

In the multicentre TARGET I trial, the novel abluminal groove-filled biodegradable polymer SES FIREHAWK was non-inferior to the durable polymer EES XIENCE V with respect to the primary endpoint of in-stent LLL at nine months for treating patients with single de novo coronary lesions. The incidences of clinical endpoints were low in both of the stents at 12-month follow-up. (ClinicalTrials.gov identifier: NCT01196819).

Real-world safety and effectiveness outcomes of a zotarolimus-eluting stent: final 3-year report of the RESOLUTE International study

Objectives

We evaluated the safety and effectiveness of the Resolute™ zotarolimus-eluting stent (R-ZES) in real-world clinical practice through 3 years.

Background

A randomized comparison of the R-ZES and the XIENCE V™ everolimus-eluting stent showed no difference in any outcomes through 3-year follow-up in high-volume academic centers. RESOLUTE International is a confirmatory trial designed to evaluate the R-ZES in real-world clinical practice.

Methods

RESOLUTE International is a single arm, observational trial that enrolled 2,349 patients from 88 centers with only a few inclusion and exclusion criteria. The primary end-point was the composite of cardiac death and target vessel myocardial infarction (TV-MI) at 1 year. Secondary end-points include target lesion failure (TLF), target vessel revascularization (TVR), and their components, and stent thrombosis (ST).

Results

At 3 years 97.2% of patients completed clinical follow-up. The mean age was 63.4 ± 11.2 years, 77.8% were male, and 30.4% had diabetes. The average number of stents per patient was 1.6 ± 1.0; and mean stent length was 30.9 ± 20.5 mm. Dual antiplatelet therapy was used in 91.1% of patients at 1 year, 43.0% at 2 years, and 34.6% at 3 years. Cardiac death and TV-MI occurred in 161 patients (7.0%). There were 6 (0.3%) very late ST events for a total ST rate of 1.1% through 3 years. The rates of clinically driven target lesion revascularization (TLR), TVR, and TLF were 5.7%, 7.4%, and 11.4%, respectively.

Conclusions

The safety and effectiveness of the R-ZES through 3 years in this real-world all-comer study was consistent with previously reported all-comer trials. (J Interven Cardiol 2013;26:515-523)

Risk factors for coronary drug-eluting stent thrombosis: influence of procedural, patient, lesion, and stent related factors and dual antiplatelet therapy

The complication of stent thrombosis (ST) emerged at a rate of 0.5% annually for first-generation drug-eluting stents (DES), often presenting as death or myocardial infarction. Procedural factors such as stent underexpansion and malapposition are risk factors for ST in patients. The type of lesion being treated and lesion morphology also influence healing after treatment with DES and can contribute to ST. Second-generation DES such as the XIENCE V everolimus-eluting stent differ from the first-generation stents with respect to antiproliferative agents, coating technologies, and stent frame. Improvements in stent structure have resulted in a more complete endothelialization, thereby decreasing the incidence of ST. Bioresorbable scaffolds show promise for restoring vasomotor function and minimizing rates of very late ST. Post-PCI treatment with aspirin and clopidogrel for a year is currently the standard of care for DES, but high-risk patients may benefit from more potent antiplatelet agents. The optimal duration of DAPT for DES is currently unclear and will be addressed in large-scale randomized clinical trials.

Oxidative stress and pathological changes after coronary artery interventions

Oxidative stress greatly influences the pathogenesis of various cardiovascular disorders. Coronary interventions, including balloon angioplasty and coronary stent implantation, are associated with increased vascular levels of reactive oxygen species in conjunction with altered endothelial cell and smooth muscle cell function. These alterations potentially lead to restenosis, thrombosis, or endothelial dysfunction in the treated artery. Therefore, the understanding of the pathophysiological role of reactive oxygen species (ROS) generated during or after coronary interventions, or both, is essential to improve the success rate of these procedures. Superoxide O2(·-) anions, whether derived from uncoupled endothelial nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, xanthine oxidase, or mitochondria, are among the most harmful ROS. O2(·-) can scavenge nitric oxide, modify proteins and nucleotides, and induce proinflammatory signaling, which may lead to greater ROS production. Current innovations in stent technologies, including biodegradable stents, nitric oxide donor-coated stents, and a new generation of drug-eluting stents, therefore address persistent oxidative stress and reduced nitric oxide bioavailability after percutaneous coronary interventions. This review discusses the molecular mechanisms of ROS generation after coronary interventions, the related pathological events-including restenosis, endothelial dysfunction, and stent thrombosis-and possible therapeutic ways forward.

A new generation of biodegradable polymer-coated sirolimus-eluting stents for the treatment of coronary artery disease: final 5-year clinical outcomes from the CREATE study

AIMS

The aim of the present study was to evaluate the five-year safety and efficacy of a biodegradable polymer-coated sirolimus-eluting stent with six months dual antiplatelet therapy in daily practice.

METHODS AND RESULTS

Two thousand and seventy-seven daily practice patients, exclusively treated with biodegradable polymer-coated sirolimus-eluting stents (EXCEL; JW Medical Systems, Weihai, China), were prospectively enrolled in the multicentre CREATE study. Clinical follow-up was completed in 1,982 patients (95.4%) at five-year follow-up. The rates of cardiac death, non-fatal myocardial infarction (MI), target lesion revascularisation and overall major adverse cardiac events (MACE) at five-year follow-up were 3.0%, 1.5%, 3.7% and 7.4%, respectively. The rates of definite or probable stent thrombosis (ST) at five years and definite ST from one to five years were 1.1% and 0.3%, respectively. Heart failure (hazard ratio [HR]: 3.324, 95% confidence interval [CI]: 1.729-6.391, p<0.001) and prior MI (HR: 2.664, 95% CI: 1.358-5.227, p=0.004) were independent predictors of ST. Landmark analysis of a propensity score matched patient cohort showed that patients with or without clopidogrel treatment after six months had similar clinical outcomes.

CONCLUSIONS

The present study demonstrates satisfactory and sustained five-year clinical safety and efficacy profiles as evidenced by the low rates of MACE and ST for the EXCEL, a biodegradable polymer-based sirolimus-eluting stent, when patients were treated with six months dual antiplatelet therapy in daily practice.

The Supralimus sirolimus-eluting stent

The use of biodegradable polymeric coatings has emerged as a potential bioengineering target to improve the vascular compatibility of coronary drug-eluting stents (DESs). This review summarizes the main features and scientific facts about the Supralimus sirolimus-eluting stent (Sahajanand Medical Technologies Ltd, Surat, India), which is a biodegradable polymer-based, sirolimus-eluting metallic stent that was recently introduced for routine use in Europe. The novel stent is built on a stainless steel platform, coated with a blend of biodegradable polymers (poly-l-lactide, poly-dl-lactide-co-glycolide and polyvinyl pyrrolidone; coating thickness is 4-5 µm). The active agent is the antiproliferative sirolimus in a dose load of 1.4 µg/mm(2), which is released within 48 days. The Supralimus stent was initially evaluated in the single-arm SERIES-I study, which showed binary angiographic restenosis rates of 0% (in-stent) and 1.7% (in-segment) and an in-stent late lumen loss of 0.09 ± 0.28 mm. The multicenter randomized PAINT trial compared two DESs with identical metallic platforms and biodegradable polymer carriers, but different agents (Infinnium [Sahajanand Medical Technologies Pvt Ltd] paclitaxel-eluting stent or Supralimus sirolimus-eluting stent) against bare stents. After 3 years, the pooled DES population had similar rates of cardiac death or myocardial infarction (9 vs 7.1%; p = 0.6), but a lower risk of repeat interventions (10 vs 29.9%; p < 0.01) than controls with bare stents. The incidence of definite or probable stent thrombosis in the pooled DES group was 2.3% (1st year: 1.8%; 2nd year: 0.4% and 3rd year: 0%). These results demonstrate that the novel Supralimus stents are effective in reducing reintervention, while potentially improving the safety profile by decreasing the risk of late-term thrombosis, even though further studies would be necessary to confirm these findings.

Clinical outcome following stringent discontinuation of dual antiplatelet therapy after 12 months in real-world patients treated with second-generation zotarolimus-eluting resolute and everolimus-eluting Xience V stents: 2-year follow-up of the randomized TWENTE trial

OBJECTIVES

The aim of this study was to assess the safety and efficacy of the implantation of Resolute zotarolimus-eluting stents (ZES) (Medtronic Inc., Santa Rosa, California) and Xience V everolimus-eluting stents (EES) (Abbott Vascular, Santa Clara, California) following strict discontinuation of dual antiplatelet therapy (DAPT) after 12 months.

BACKGROUND

Only limited long-term follow-up data are available from head-to-head comparisons of second-generation drug-eluting stents.

METHODS

The randomized TWENTE (The Real-World Endeavor Resolute Versus Xience V Drug-Eluting Stent Study in Twente) trial is an investigator-initiated study performed in a population with many complex patients and lesions and only limited exclusion criteria. Patients were randomly assigned 1:1 to ZES (n = 697) or EES (n = 694).

RESULTS

Two-year follow-up information was available on all patients. The rate of continuation of DAPT beyond 12 months was very low (5.4%). The primary endpoint of target vessel failure, a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization, did not differ between ZES and EES (10.8% vs. 11.6, p = 0.65), despite fewer target lesion revascularizations in patients with EES (2.6% vs. 4.9%, p = 0.03). The patient-oriented composite endpoint was similar (16.4% vs. 17.1%, p = 0.75). Two-year rates of definite or probable stent thrombosis were 1.2% and 1.4%, respectively (p = 0.63). Very late definite or probable stent thrombosis occurred only in 2 patients in each study arm (0.3% vs. 0.3%, p = 1.00).

CONCLUSIONS

After 2 years of follow-up and stringent discontinuation of DAPT beyond 12 months, Resolute ZES and Xience V EES showed similar results in terms of safety and efficacy for treating patients with a majority of complex lesions and off-label indications for drug-eluting stents. (The Real-World Endeavor Resolute Versus Xience V Drug-Eluting Stent Study in Twente [TWENTE]; NCT01066650).

Clinical efficacy and safety of biodegradable polymer-based sirolimus-eluting stents in patients with diabetes mellitus insight from the 4-year results of the create study

BACKGROUND

Diabetes mellitus is an independent predictor of adverse clinical events after drug-eluting stent implantation.

OBJECTIVES

The objective of this study is to evaluate the long-term clinical efficacy and safety of biodegradable polymer-based sirolimus-eluting stents in diabetic versus non-diabetic patients.

METHODS

A total of 2077 "all comers," including 440 (21.2%) diabetic patients and 1637 (78.8%) non-diabetic patients, were prospectively enrolled in the CREATE study at 59 centers in four countries. The recommended antiplatelet regimen was clopidogrel and aspirin for 6 months followed by chronic aspirin therapy. The primary outcome was the rate of major adverse cardiac events (MACE), defined as a composite of cardiac death, non-fatal myocardial infarction (MI), and target lesion revascularization (TLR).

RESULTS

Diabetic patients had higher risks of all-cause death (8.2% vs. 3.4%, P < 0.001) and cardiac death (4.1% vs. 1.4%, P < 0.001) compared with non-diabetic patients at 4 years. The rates of non-fatal MI (0.2% vs. 0.9%, P = 0.218), TLR (2.0% vs. 2.8%, P = 0.357), MACE (5.9% vs. 4.4%, P = 0.227), and overall stent thrombosis (1.6% vs. 1.6%, P = 0.932) were not significantly different between diabetic and non-diabetic patients. A landmark analysis showed that prolonged clopidogrel therapy (>6 months) was not beneficial in reducing the cumulative hazards of MACE either in diabetic or non-diabetic patients (log rank P = 0.810).

CONCLUSIONS

Biodegradable polymer-based sirolimus-eluting stents for the treatment of diabetic patients had a similar clinical event rate at 4 years compared with non-diabetic patients, except for a higher mortality rate.

Long-term outcomes of percutaneous coronary interventions with stent implantation in patients ≤40 years old

Data on the long-term prognosis of percutaneous coronary intervention (PCI) in young patients are limited. The aim of the present study was to report the immediate and long-term clinical outcomes in a consecutive series of young patients with premature coronary artery disease who underwent PCI with stent implantation. During the study period (2005 to 2010), 214 consecutive patients aged ≤40 years who had undergone PCI with a bare metal stent or drug-eluting stent implantation were retrospectively selected and analyzed. Primary end point of this study was the incidence of major adverse cardiac and cerebrovascular events at short- and long-term follow-up. Mean age was 36.3 ± 3.5 years and 88.3% of patients were men. Three-quarters were active smokers and all patients had ≥1 conventional cardiovascular risk factor. The total number of implanted stents was 272 (154 bare metal stent and 118 drug-eluting stent). During the hospital stay, no patient died, and the incidence of major adverse cardiac and cerebrovascular events was 2.3%. No additional events had occurred at 30 days of follow-up. At a median follow-up of 757 days (interquartile range 365 to 1,818), the overall death rate was 0.9%, and a new revascularization procedure was needed in 12.6% of patients. The major adverse cardiac and cerebrovascular event-free survival rate at the median follow-up point and 1,818 days was 89.6% and 84.2%, respectively. Active smoking and left ventricular ejection fraction <50% were independent predictors of major adverse cardiac and cerebrovascular events. In conclusion, PCI in young patients lead to excellent results in short- and long-term follow-up and should be considered as the treatment of choice. Traditional risk factors are important prognostic determinants of adverse events and might help identify higher risk patients within this cohort.

Stent thrombosis: incidence, predictors and new technologies

Some concerns have been raised regarding the risk of late and very late stent thrombosis (ST) following drug-eluting stent implantation. Despite remaining an uncommon complication of percutaneous coronary intervention, when ST occurs, it can be catastrophic to the individual, commonly presenting as acute ST elevation myocardial infarction or sudden cardiac death. The incidence and predictors of ST have been reported in the literature and the role of dual antiplatelet therapies in the avoidance of such a complication remains vital. Ongoing studies are assessing the role of these therapies including platelet reactivity testing, genetic testing and optimum duration of therapy. In addition, newer polymer-free and bioabsorbable stents are under investigation in the quest to potentially minimise the risk of ST.