Addition of paclitaxel to contrast media prevents restenosis after coronary stent implantation

Meta-Analysis Comparing Drug-Coated Balloon Versus Plain Old Balloon Angioplasty for In-Stent Restenosis of Coronary Arteries

Despite the advent of newer stents, in-stent restenosis has been a persistent and formidable challenge. Trials have demonstrated the superiority of drug-coated balloons over plain old balloon angioplasty. A recent AGENT IDE PRESTO (Prevention of REStenosis with Tranilast and its Outcomes) trial highlighted the need for a more comprehensive understanding; therefore, we conducted a meta-analysis to elucidate their respective clinical outcomes. A literature search was conducted by 2 investigators (SS and MH) using MEDLINE (EMBASE and PubMed) using a systematic search strategy by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) until November 1, 2023. CRAN-R software was used for statistical analysis. The quality assessment was performed using the Cochrane Risk of Bias tool (Supplementary Table 5). We included 6 studies with a total of 1,171 patients. Our analysis showed decreased odds of multiple outcomes with statistically significant results, including target vessel revascularization (odds ratio [OR] 0.33, confidence interval [CI] 0.19 to 0.57), target vessel failure (OR 0.30, CI 0.09 to 0.99), target lesion revascularization (OR 0.22, CI 0.10 to 0.46), restenosis (OR 0.1343, CI 0.06 to 0.27), and major adverse cardiac events (OR 0.2 CI 0.12 to 0.37). Although myocardial infraction and all-cause mortality showed decreased odds with all-cause mortality at 0.8 (95% CI 0.363 to 2.09), and myocardial infarction at 0.6 (95% CI 0.0349 to 1.07), the reductions did not reach statistical significance. Our analysis by scrutinizing 6 randomized controlled trials favored drug-coated balloons over plain old balloon angioplasty. However, extensive research for deeper understanding cannot be overemphasized.

Coronary Drug-Coated Balloons: A Comprehensive Review of Clinical Applications and Controversies

Drug-coated balloons have emerged as a promising therapeutic option in the treatment of cardiovascular disease. This review article provides an overview of the concept of drug-coated balloons and their clinical applications in both de novo and treated coronary artery disease. A summary of key clinical trials and registry studies evaluating drug-coated balloons is presented for reference. Overall, this article aims to provide clinicians and researchers with a comprehensive understanding of the current state of drug-coated balloon technology and its implications in clinical practice.

Comparative evaluation of local and downstream responses in two commercially available paclitaxel-coated balloons in healthy peripheral arteries of a swine model

OBJECTIVE

To investigate the local, downstream, and systemic effects of 2 different paclitaxel-coated balloons.

DESIGN

Preclinical study in healthy peripheral arteries of a swine model, with randomized allocation of the distribution of the devices: the test paclitaxel-coated balloon (PCB) (LuminorⓇ), a control PCB (IN.PACTⓇ), and a plain angioplasty balloon (OceanusⓇ), considering single (1×) and overlapping (3×) doses with simple blind histologic analysis.

METHODS

Twenty animals underwent balloon angioplasty at 1× or 3× doses in the external and internal branches of both femoral arteries and were followed-up for 28 days. Postprocedural and follow-up angiography were carried out. Comprehensive necropsy and histology were used to evaluate the local, downstream and systemic effects.

RESULTS

Angioplasty was successfully carried out in all animals. Significant protocol deviations appeared in 3 arteries (treated with Oceanus®) without clinical relevance. Those samples were excluded from the analysis. All the animals survived the follow-up period without major clinical issues. Local signs of drug toxicity were less marked with Luminor® than IN.PACT® at 1× dose, including endothelial loss (P = .0828), intima/media inflammation (P = .0004), transmural medial smooth muscle cell (SMC) loss (P = .0016), wall thickness loss (P = .0141), presence of fibrin in the vascular wall (P = .0054), and adventitial inflammation (P = .0080). A similar pattern was observed at the 3× dose for endothelial loss (P = .0011), intima/media inflammation (P < .0001), circumferential SMC loss (P = .0004), medial SMC replacement with proteoglycans (P = .0014), fibrin (P = .0034), and collagen content (P = .0205). Downstream vascular histologic changes were mild although more prevalent in the IN.PACT® 3× group (P = .006). No systemic effects of toxicity were detected in any of the samples analyzed.

CONCLUSION

Luminor® showed better healing pattern (lower inflammation, and endothelial and muscular loss) than IN.PACT® balloon. The effect was evident at single and triple doses. The prevalence of downstream lesions, albeit low, was higher with the triple dose of IN.PACT® compared with Luminor®.

Research progress of drug eluting balloon in arterial circulatory system

The arterial circulatory system diseases are common in clinical practice, and their treatment options have been of great interest due to their high morbidity and mortality. Drug-eluting balloons, as a new type of endovascular interventional treatment option, can avoid the long-term implantation of metal stents and is a new type of angioplasty without stents, so drug-eluting balloons have better therapeutic effects in some arterial circulatory diseases and have been initially used in clinical practice. In this review, we first describe the development, process, and mechanism of drug-eluting balloons. Then we summarize the current studies on the application of drug-eluting balloons in coronary artery lesions, in-stent restenosis, and peripheral vascular disease. As well as the technical difficulties and complications in the application of drug-eluting balloons and possible management options, in order to provide ideas and help for future in-depth studies and provide new strategies for the treatment of more arterial system diseases.

A New Frontier for Drug-Coated Balloons: Treatment of "De Novo" Stenosis in Large Vessel Coronary Artery Disease

Background: Drug-coated balloons (DCB) are a well-established option for treating in-stent restenosis endorsed by European Guidelines on myocardial revascularization. However, in recent years, a strategy of "leaving nothing behind" with DCB in de novo coronary stenosis has emerged as an appealing approach. Methods: We performed a systematic review to evaluate the current literature on the use of drug-coated balloons in the treatment of de novo stenosis in large vessel disease. Results: Observational studies, as well as randomized studies, demonstrated the safety of DCB percutaneous coronary interventions (PCI) in large vessel disease. The rate of major adverse cardiac events is even lower compared to drug-eluting stents in stable coronary artery disease. Conclusions: DCB PCI is feasible in large vessel disease, and future large, randomized studies are ongoing to confirm these results.

Comparison of Efficacy and Safety Between Drug-Coated Balloons Versus Drug-Eluting Stents in the Treatment of De Novo Coronary Lesions in Large Vessels: A Study-Level Meta-Analysis of Randomized Control Trials

BACKGROUND

Drug-coated balloons (DCB) can be used as an alternative to drug-eluting stents (DES) in patients with de novo small vessel coronary artery disease. This study aims to assess the efficacy and safety of solely using DCB versus DES in percutaneous coronary intervention (PCI) for de novo coronary lesions in large vessels.

METHOD

A database search was conducted using PubMed, EMBASE, Cochrane Library, and http://Clinicaltrials.gov for trials comparing DCB only with DES in treating de novo coronary lesions in large vessels. Efficacy outcomes included coronary angiography (CAG), follow-up minimal lumen diameter (MLD), and late luminal loss (LLL). Safety outcomes included target lesion failure [TLF: cardiac death, myocardial infarction (MI), target lesion revascularization (TLR)] and their individual components.

RESULTS

We included seven randomized control trials (RCTs) with 816 patients, of which 422 and 394 patients were in the DCB and DES groups, respectively. MLD measured during the 6-12 months follow-up in the DCB group was statistically significantly smaller than in the DES group (MD -0.21, 95% CI -0.34 to -0.07, P = 0.003, I2 = 52%). LLL measured at 6-12 months follow-up was statistically significantly lower in the DCB group than in the DES group (MD -0.13, 95% CI -0.22 to -0.05, P = 0.003, I2 = 60%). TLF, cardiac death, MI, and TLR, were not statistically significantly different between the two groups.

CONCLUSION

Use of DCB was associated with less LLL at 6-12 months than DES and was not associated with any increase in adverse clinical events. This data suggests DCB are as effective in treating de novo coronary lesions in large vessels as DES.

The evolution and revolution of drug coated balloons in coronary angioplasty: An up-to-date review of literature data

European Society of Cardiology (ESC) guidelines gave class I A indication for use of DCB in in-stent restenosis. However, no indication exists for the usage of DCB in de novo lesions. Although the current generation DES offer excellent results, as we embark more complex lesions such as calcified lesion and chronic total occlusion, restenosis and stent thrombosis are higher and tend to increase within the years. There is increasing desire to leave nothing behind to abolish the risk of restenosis and stent thrombosis and hence the absorbable scaffolds were introduced, but with disappointing results. In addition, they take several years to be absorbed. Drug coated balloons offer an alternative to stents with no permanent implant of metal or polymer. They are already in use in in Europe and Asia and they have been approved for the first time in the United States for clinical trials specifically for restenotic lesions. There is emerging data in de novo lesions which have shown that DCB are noninferior and in some studies maybe even superior to current generation DES especially in small vessels. In this article, we provide a comprehensive review of the literature on this expanding technology focussing on the evidence in both re-stenotic and de novo lesions.

Coronary Drug-Coated Balloons for De Novo and In-Stent Restenosis Indications

Drug-coated balloons are approved outside the United States, not only for the treatment of peripheral arteries but also for coronary arteries. This review describes the technological basics, the scenarios of clinical application, and the current available data from clinical trials for the different coronary indications.

Novel application of drug-coated balloons in coronary heart disease: A narrative review

The incidence of coronary heart disease (CAD) has soared over the years, and coronary intervention has become an increasingly important therapeutic approach. The past decade has witnessed unprecedented developments in therapeutic medical instruments. Given that drug-coated balloons bring many benefits, they are indicated for an increasing number of conditions. In this article, we review the results of current clinical trials about drug-coated balloons and summarize their safety and clinical progression in different coronary artery diseases, laying the groundwork for basic research, and clinical therapeutics of this patient population.

The factors influencing the efficiency of drug-coated balloons

The drug-coated balloon (DCB) is an emerging percutaneous coronary intervention (PCI) device that delivers drugs to diseased vessels to decrease the rate of vascular stenosis. Recent clinical studies have demonstrated that DCBs tend to have both good safety and efficacy profiles, leading to extended application indications in the clinic, including in-stent restenosis (ISR) for metal stents such as drug-eluting stents (DESs), small vascular disease, bifurcation disease, large vascular disease, acute coronary syndrome (ACS), and high bleeding risk. However, some previous clinical data have suggested that DCBs performed less effectively than DESs. No studies or reviews have systematically discussed the improvement strategies for better DCB performance until now. Drug loss during the process of delivery to the target lesion and inefficient delivery of the coating drug to the diseased vascular wall are two key mechanisms that weaken the efficiency of DCBs. This review is the first to summarize the key influencing factors of DCB efficiency in terms of balloon structure and principles, and then it analyzes how these factors cause outcomes in practice based on current clinical trial studies of DCBs in the treatment of different types of lesions. We also provide some recommendations for improving DCBs to contribute to better DCB performance by improving the design of DCBs and combining other factors in clinical practice.

The Drug Coated Balloon-Only Strategy for Treatment of de Novo Left Main Coronary Artery Bifurcation Lesion: Stentless Strategy

The study aimed to evaluate the efficacy and safety of drug coated balloon-only strategy (DCB-only) in the treatment of de novo left main coronary artery (LM) bifurcation lesions. 85 patients were enrolled in this study and classified them into two groups: DCB-only group (n = 36) and DES group (n = 49). The MLD of target vessels was measured before and immediately after percutaneous coronary intervention (PCI) and late luminal loss (LLL) were also calculated. And the occurrence of major adverse cardiovascular events (MACE) was also evaluated. Compared with that before PCI, the MLD of target lesions significantly increased immediately after PCI (P < .05) and no MACE was recorded during the perioperative period both in two groups. The MLD at follow-up was significantly higher than that before both DCB and DES treatment. Compared with the DES group, the MLD of the DCB group was smaller than immediately after PCI in the LM and LAD (P < .05). The LLL of LAD in DCB group was smaller than that in DES group (P < .05). There was no significant difference in the incidence of luminal restenosis at the target lesion between the two groups, and no significant difference in the incidence of MACE (P > .05). The use of DCB-only to treat de novo LM bifurcation lesions is effective and relatively safe, which provides new ideas for the treatment of LM coronary artery bifurcation lesions in the future.

A prospective trial of a novel low-dose paclitaxel-coated balloon therapy in patients with restenosis in drug-eluting coronary stents Intracoronary Stenting and Angiographic Results: Optimizing Treatment of Drug Eluting Stent In-stent REstenosis 3A (ISAR-DESIRE 3A)

OBJECTIVES

We investigated the clinical efficacy of a paclitaxel-coated balloon (PCB) with a novel matrix coating and reduced drug concentration in comparison with a widely used PCB with iopromide excipient.

METHODS

We prospectively enrolled patients with restenosis in drug-eluting stents. All patients were treated with a novel low-dose PCB with citrate-based excipient (Agent PCB). Angiographic follow-up was scheduled at 6-8 months. Outcomes were compared against those of patients treated with iopromide excipient PCB (SeQuent Please PCB) enrolled in a trial with identical inclusion and exclusion criteria. The primary endpoint was percent diameter stenosis (%DS) at follow-up angiography. The primary hypothesis was that the investigational device would be non-inferior to the control device (ClinicalTrials.gov Identifier: NCT02367495).

RESULTS

One hundred twenty-five patients with 151 lesions were enrolled. Mean age was 68.1 ± 10.2 years, 40.8% had diabetes mellitus and 80.1% had focal morphology in-stent restenosis. Follow-up angiography data at 6-8 months was available for 102 (81.6%) patients. The Agent PCB was non-inferior to the SeQuent Please PCB in terms of the primary endpoint (38.9 ± 17.5 vs. 38.1 ± 21.5%; p _{non-inferiority}  = 0.0056). Late lumen loss was also comparable between the groups (0.35 ± 0.55 vs. 0.37 ± 0.59; p = 0.71). There was no difference between the groups in the incidence of TLR (27.7% vs. 22.1%; p = 0.31), death or myocardial infarction (4.2% vs. 4.4%; p = 0.92) or target lesion thrombosis (1.0% vs. 0.7%; p = 0.93).

CONCLUSION

In patients with DES restenosis, angioplasty with a novel PCB with citrate-based excipient was non-inferior to PCB with iopromide excipient in terms of angiographic outcome.

Do we really understand how drug eluted from stents modulates arterial healing?

The advent of drug-eluting stents (DES) has revolutionised the treatment of coronary artery disease. These devices, coated with anti-proliferative drugs, are deployed into stenosed or occluded vessels, compressing the plaque to restore natural blood flow, whilst simultaneously combating the evolution of restenotic tissue. Since the development of the first stent, extensive research has investigated how further advancements in stent technology can improve patient outcome. Mathematical and computational modelling has featured heavily, with models focussing on structural mechanics, computational fluid dynamics, drug elution kinetics and subsequent binding within the arterial wall; often considered separately. Smooth Muscle Cell (SMC) proliferation and neointimal growth are key features of the healing process following stent deployment. However, models which depict the action of drug on these processes are lacking. In this article, we start by reviewing current models of cell growth, which predominantly emanate from cancer research, and available published data on SMC proliferation, before presenting a series of mathematical models of varying complexity to detail the action of drug on SMC growth in vitro. Our results highlight that, at least for Sodium Salicylate and Paclitaxel, the current state-of-the-art nonlinear saturable binding model is incapable of capturing the proliferative response of SMCs across a range of drug doses and exposure times. Our findings potentially have important implications on the interpretation of current computational models and their future use to optimise and control drug release from DES and drug-coated balloons.

A Non-inferiority, Randomized Clinical Trial Comparing Paclitaxel-Coated Balloon Versus New-Generation Drug-Eluting Stents on Angiographic Outcomes for Coronary De Novo Lesions

Background

Drug-coated balloon (DCB) has been proved efficacy for coronary small vessel disease, but data regarding outcomes of DCB in common de novo lesions (including reference vessel diameter more than 3.0mm) compared with new-generation drug-eluting stent (DES) are lacking. We hypothesized that a DCB-only strategy for coronary de novo lesions would be non-inferior to DES treatment on angiographic outcomes.

Methods

In this randomized controlled trial, we compared the effect of DCB with DES on late lumen loss (LLL) at 9-month angiographic follow-up and 12-month major adverse cardiac events (MACEs), including death, non-fatal myocardial infarction, target lesion revascularization (TLR), and target vessel revascularization (TVR).

Results

From July 2017 to July 2018, 288 consecutive patients with reference vessel diameter (RVD) between 2.25 and 4.0mm were screened. After proper pre-dilation, 170 patients were enrolled and randomized to the DCB and the DES groups at 1:1 ratio. Seven patients withdrew the consent forms during hospital stay (1 in DCB group, 6 in DES group). Two patients in DCB group underwent bailout stenting due to severe dissection after DCB release. The primary endpoint of 9-month LLL was −0.19±0.49mm with the DCB versus 0.03±0.64mm with the DES. The one-sided 97.5% upper confidence limit of the difference was −0.04mm, achieving non-inferiority of the DCB compared with the DES (P=0.019). The 12-month cumulative MACE rate was similar in the DCB and DES groups (2.44% vs. 6.33%, P=0.226).

Conclusions

In this prospective study, the DCB only strategy for de novo lesion was non-inferior to the new-generation DES in terms of 9-month late lumen loss.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10557-021-07172-4.

Abluminus DES+ for the treatment of coronary artery disease in patients with diabetes mellitus

Diabetes mellitus (DM) is a rising global epidemic affecting more than 10% of the world population and predisposes patients to develop highly progressive and complex coronary artery disease. Despite numerous advancements in percutaneous coronary intervention procedural techniques and coronary stent platforms, clinical outcomes in DM patients have improved little compared with non-DM patients. Abluminus DES+, a biodegradable polymer sirolimus-eluting stent deployed with a drug-coated balloon, has been specifically designed to provide adequate coverage for DM patients and reduce adverse clinical outcomes.

Impact of Optimized Procedure-Related Factors in Drug-Eluting Balloon Angioplasty for Treatment of In-Stent Restenosis

OBJECTIVES

The aim of this study was to investigate the impact of optimizing procedure-related factors during drug-eluting balloon (DEB) angioplasty on clinical outcomes of drug-eluting stent in-stent restenosis (ISR).

BACKGROUND

Although DEB angioplasty is recommended as a reasonable option for ISR, recurrent target lesion failure (TLF) still occurs in many patients after DEB angioplasty.

METHODS

Consecutive patients with drug-eluting stent ISR treated with DEB (SeQuent Please) were collected from 4 centers in Korea. The primary outcome was 2-year TLF. Procedure-related modifiable independent predictors for TLF and their best cutoff values were determined.

RESULTS

In a total of 256 patients (309 lesions), TLF occurred in 52 patients (20.3%). Modifiable independent predictors of TLF among procedure-related factors were residual diameter stenosis after lesion preparation (residual percentage diameter stenosis [%DS]), DEB-to-stent ratio (BSR), and DEB inflation time (T_inflation), whose best cutoff values were 20%, 0.91, and 60 s, respectively. TLF rates were significantly higher in groups with residual %DS ≥20% (34.7% vs. 12.5%; adjusted hazard ratio: 2.15; 95% confidence interval: 1.86 to 2.48; p < 0.001), BSR ≤0.91 (46.4% vs. 21.9%; adjusted hazard ratio: 2.02; 95% confidence interval: 1.75 to 2.34; p < 0.001), and T_inflation ≤60 s (26.2% vs. 14.0%; adjusted hazard ratio: 1.82; 95% confidence interval: 1.36 to 2.45; p < 0.001). When classifying ISR lesions by combination of procedure-related factors, TLF occurred in 8.3% in the fully optimized procedure group (residual %DS <20%, BSR >0.91, and T_inflation >60 s) and 66.7% in the nonoptimized group (residual %DS ≥20%, BSR ≤0.91, and T_inflation ≤60 s) (p < 0.001).

CONCLUSIONS

Residual %DS after lesion preparation, BSR, and T_inflation were the only modifiable procedure-related factors in DEB angioplasty. Fully optimized DEB angioplasty with optimal lesion preparation, prolonged inflation, and sufficient dilation may play an important role in reducing TLF after DEB angioplasty.

Drug-coated balloons for coronary artery disease: current concepts and controversies

Drug-coated balloons (DCBs) are a novel development for percutaneous coronary intervention. The first successful application was in-stent restenosis but in recent years, strong evidence has been released for its use in native small-vessels disease. Additional applications such as acute myocardial infarction, chronic total occlusion and bifurcation lesions are still under investigation. This article reviews the key studies evaluating the role of DCBs in several settings and reports on interesting cases where DCBs showed positive results for high-risk patients with neoplasm, as well as with high bleeding risk, planned surgery or renal injury. We also highlight a new biodegradable therapy for coronary bifurcation treatment, in which a bioresorbable vascular scaffold is implanted in the main branch, completed with a DCB angioplasty in the side branch when a treatment is deemed necessary.

IN.PACT™ Admiral™ drug-coated balloons in peripheral artery disease: current perspectives

Endovascular therapy has evolved as a main treatment option especially in patients with short (<25 cm) femoropopliteal lesion. The latest guideline recommends the use of drug-eluting devices (both drug-coated balloons [DCBs] and drug-eluting stents) in short femoro-popliteal lesions as class IIb recommendation. DCB usage is also recommended for in-stent restenosis lesions (class IIb). DCBs are a more attractive treatment option because the lack of metal prosthesis allows for more flexibility in future treatment options including the option of treating nonstenting zones, previously DCB-treated zones with DCBs again. The IN.PACT™ Admiral™ DCB has shown promising clinical performance in several randomized control trials and global registries, and is currently the market DCB leader for the treatment of femoropopliteal lesions with more than 200,000 patients treated thus far. Currently, more than 10 DCBs have received Conformité Européene mark for the treatment of femoropopliteal atherosclerotic disease. Three of these (including IN.PACT Admiral DCBs) have also received Food and Drug Administration approval in the USA. However, some Conformité Européene-marked DCBs have failed to show consistent results in their clinical studies suggesting all DCBs are not created equal. Each DCB is unique (ie, drug type, drug dose, crystallinity, and excipient) with different clinical outcomes. In the current review, we will focus on the preclinical and clinical results of not only IN.PACT Admiral DCB, but also the other currently available DCBs.

In vitro and in vivo Assessment of Keratose as a Novel Excipient of Paclitaxel Coated Balloons

Purpose: Drug coated balloons (DCB) are continually improving due to advances in coating techniques and more effective excipients. Paclitaxel, the current drug choice of DCB, is a microtubule-stabilizing chemotherapeutic agent that inhibits smooth muscle cell proliferation. Excipients work to promote coating stability and facilitate paclitaxel transfer and retention at the target lesion, although current excipients lack sustained, long-term paclitaxel retention. Keratose, a naturally derived protein, has exhibited unique properties allowing for tuned release of various therapeutic agents. However, little is known regarding its ability to support delivery of anti-proliferative agents such as paclitaxel. The goal of this project was to thus demonstrate the feasibility of keratose as a DCB-coating excipient to promote the release and delivery of paclitaxel. Methods: Keratose was combined with paclitaxel in vitro and the release kinetics of paclitaxel and keratose were evaluated through high performance liquid chromatograph-mass spectroscopy (HPLC-MS) and spectrophotometry, respectively. A custom coating method was developed to deposit keratose and paclitaxel on commercially available angioplasty balloons via an air spraying method. Coatings were then visualized under scanning electron microscopy and drug load quantified by HPLC-MS. Acute arterial transfer of paclitaxel at 1 h was assessed using a novel ex vivo model and further evaluated in vivo in a porcine ilio-femoral injury model. Results: Keratose demonstrated tunable release of paclitaxel as a function of keratose concentration in vitro. DCB coated via air spraying yielded consistent drug loading of 4.0 ± 0.70 μg/mm2. Under scanning electron microscopy, the keratose-paclitaxel DCB showed uniform coverage with a consistent, textured appearance. The acute drug transfer of the keratose-paclitaxel DCB was 43.60 ± 14.8 ng/mg at 1 h ex vivo. These measurements were further confirmed in vivo as the acute 1 h arterial paclitaxel levels were 56.60 ± 66.4 ng/mg. Conclusion: The keratose-paclitaxel coated DCB exhibited paclitaxel uptake and achieved acute therapeutic arterial tissue levels, confirming the feasibility of keratose as a novel excipient for DCB.

Percutaneous coronary intervention: balloons, stents and scaffolds

In this review, major achievements in the field of percutaneous coronary interventions are delineated with particular focus on Germany's contribution. The review deals with important developments, including the first heart catheterization and coronary angiography, first coronary balloon angioplasty and refinement of the technique, coronary stenting and optimization of adjunctive antithrombotic treatment, drug-eluting stents and balloons, as well as bioresorbable polymeric and metallic drug-eluting scaffolds.

The use of an occlusion perfusion catheter to deliver paclitaxel to the arterial wall

AIM

Nonstent drug delivery platforms have recently emerged as an alternative treatment of peripheral arterial disease. Perfusion catheters have the potential to directly deliver antiproliferative agents to the medial arterial layer to prevent restenosis. The purpose of this study was to therefore determine the effectiveness of a perfusion catheter to deliver paclitaxel, a proven antiproliferative agent, to combat restenosis.

METHODS

A benchtop model was utilized to determine the varying parameters of a novel occlusion perfusion catheter to maximize paclitaxel delivery using pharmacokinetic evaluation and fluorescent microscopy. Parameters tested included concentration of paclitaxel, delivery pressure, duration of delivery, and the use of an excipient. In addition, bilateral rabbit iliac arteries were treated with the perfusion catheter and pharmacokinetic evaluation performed at 1 hour, 1 day and 3 days.

RESULTS

Benchtop testing demonstrated uniform and circumferential penetration of paclitaxel within the treated arteries. The results of the ex vivo test identified two groups with and without an excipient with similar loading conditions (with excipient: 15.4±8.6 ng/mg vs without excipient: 8.9±6.9 ng/mg, P=.77). The in vivo pharmacokinetic analysis of these two groups demonstrated the use of contrast agent increased arterial paclitaxel levels and maintained initial paclitaxel dosing up to 3 days (With excipient: 1 hour: 107±62 ng vs 3 days: 40±23 ng, P=.824; No excipient: 1 hour: 247±120 ng vs 3 days: 2.92±2.9 ng, P=.009).

CONCLUSIONS

These results demonstrate the feasibility to deliver paclitaxel directly to the medial layer of an artery via a perfusion catheter.

Effect of Interstitial Fluid Flow on Drug-Coated Balloon Delivery in a Patient-Specific Arterial Vessel with Heterogeneous Tissue Composition: A Simulation Study

Angioplasty with drug-coated balloons (DCBs) using excipients as drug carriers is emerging as a potentially viable strategy demonstrating clinical efficacy and proposing additional compliance for the treatment of obstructive vascular diseases. An attempt is made to develop an improved computational model where attention has been paid to the effect of interstitial flow, that is, plasma convection and internalization of bound drug. The present model is capable of capturing the phenomena of the transport of free drug and its retention, and also the internalization of drug in the process of endocytosis to atherosclerotic vessel of heterogeneous tissue composition comprising of healthy tissue, as well as regions of fibrous cap, fibro-fatty, calcified and necrotic core lesions. Image processing based on an unsupervised clustering technique is used for color-based segmentation of a patient-specific longitudinal image of atherosclerotic vessel obtained from intravascular ultrasound derived virtual histology. As the residence time of drug in a stent-based delivery within the arterial tissue is strongly influenced by convective forces, effect of interstitial fluid flow in case of DCB delivery can not be ruled out, and has been investigated by modeling it through unsteady Navier-Stokes equations. Transport of free drug is modeled by considering unsteady advection-reaction-diffusion process, while the bound drug, assuming completely immobilized in the tissue, by unsteady reaction process. The model also takes into account the internalization of drug through the process of endocytosis which gets degraded by the lysosomes and finally recycled into the extracellular fluid. All the governing equations representing the flow of interstitial fluid, the transport of free drug, the metabolization of free drug into bound phase and the process of internalization along with the physiologically realistic boundary and initial conditions are solved numerically using marker and cell method satisfying necessary stability criteria. Simulated results obtained predict that faster drug transfer promotes rapid saturation of binding sites despite perivascular wash out and the concentrations of all drug forms are modulated by the presence of interstitial flow. Such premier attempt of its kind would certainly be of great help in the optimization of therapeutic efficacy of drug.

Positive Vessel Remodelling

Since its introduction, the success of percutaneous transluminal coronary angioplasty (PTCA) has been jeopardised by recoil, neointima proliferation, and luminal renarrowing; however, the benefit of positive remodelling has not gained widespread attention. While vessels will remodel positively up to a certain stage in the development of atherosclerosis, the therapeutic application of this process remains low. The prevention of vessel shrinkage during the healing process, which represents the predominant mechanism of restenosis after PTCA, is a prerequisite of long-term success in PTCA. The antiproliferative drugs that are currently used mainly on stents are known to be capable of this. Primary clinical studies have reported that positive remodelling leads to beneficial effects in coronary and peripheral angioplasty if no foreign body is inserted, and a paradigm change in percutaneous coronary intervention towards far fewer implants is within reach.

Coating and Pharmacokinetic Evaluation of Air Spray Coated Drug Coated Balloons

Drug coated balloons (DCB) are becoming the standard-care treatment for peripheral arterial disease (PAD). DCB use excipients to transfer and retain anti-proliferative drugs, such as paclitaxel. Excipients thus play a vital role in the design and function of DCB, however methods to coat balloons with excipients and anti-proliferative drugs remain unknown. The goal of this study was to thus develop an approach to coat and evaluate DCB for various excipients. An air sprayer method was developed to deposit paclitaxel and various excipients onto non-coated commercially available angioplasty balloons. The coating of the angioplasty balloons was evaluated for drug deposition and coating efficiency using high performance liquid chromatography tandem mass spectrometry. Drug transfer and retention of the coated angioplasty balloons into arterial segments were evaluated ex vivo using harvested pig arteries in a pulsatile flow bioreactor. The air sprayer method successfully delivered varying excipients including bovine serum albumin (BSA), urea and iohexol. The air spray method was configured to coat four angioplasty balloons simultaneously with paclitaxel and iohexol with an average paclitaxel load of 4.0 ± 0.70 µg/mm². The intra-day (within) and inter-day (between) coating precisions, defined as relative standard deviation (RSD), was 17.2 and 15.5%, respectively. Ex vivo deployment of iohexol-paclitaxel DCB yielded an arterial paclitaxel concentration of 123.4 ± 44.68 ng/mg (n = 3) at 1 h, 126.7 ± 25.27 ng/mg (n = 3) at 1 day, and 12.9 ± 12.88 ng/mg (n = 3) at 7 days. This work provides proof-of-concept of a quick, inexpensive approach to coat commercially available angioplasty balloons with paclitaxel and various excipients.

Quantified frequency-domain optical coherence tomography analysis for the thin-high signals on restenotic tissue after paclitaxel-coated balloon angioplasty

Thin-high signals (THS), detectable by optical coherence tomography (OCT), represent the paclitaxel coverage of in-stent restenotic tissue. This study was conducted to assess the relationship between THS and angiographic outcomes by means of quantified post-procedural frequency-domain OCT (FD-OCT) analysis. From January 2014 to July 2016, 41 patients underwent FD-OCT-guided percutaneous coronary intervention using paclitaxel-coated balloon (PCB) to prevent in-stent restenosis. Of these, we retrospectively enrolled 32 patients (38 lesions) who underwent a 6- to 9-month follow-up angiogram. THS were assessed quantitatively, as THS length and lumen perimeter length were measured using semi-automated software; %THS was calculated by the following formula; total THS area/lumen perimeter area × 100. THS were detected in all 38 lesions that had undergone PCB angioplasty. THS and %THS were significantly higher in lesions without binary restenosis (3.34 ± 2.11 vs. 11.48 ± 8.53 mm², p = 0.001 and 1.49 ± 0.73 vs. 4.42 ± 2.71%, p = 0.001, respectively). Values for THS, which indicates the paclitaxel coverage on restenotic tissue, are associated with reducing restenosis after PCB for in-stent restenosis.

Mechanisms Underlying Drug Delivery to Peripheral Arteries

Delivery of drugs onto arterial targets via endovascular devices commands several principles: dissolution, diffusion, convection, drug binding, barriers to absorption, and interaction between the drug, delivery vehicle, and accepting arterial wall. The understanding of drug delivery in the coronary vasculature is vast; there is ongoing work needed in the peripheral arteries. There are differences that account for some failures of application of coronary technology into the peripheral vascular space. Breakthroughs in peripheral vascular interventional techniques building on current technologies require investigators willing to acknowledge the similarities and differences between these different vascular territories, while developing technologies adapted for peripheral arteries.

Drug-Coated Balloons: Current Outcomes and Future Directions

Paclitaxel-coated drug-coated balloons have significantly improved short-term and mid-term clinical outcomes in patients with symptomatic femoropopliteal peripheral artery disease. However, long-term results are awaited. Furthermore, the clinical success of drug-coated balloons in the infrapopliteal peripheral arteries has been more modest and overall similar to traditional balloon angioplasty, and remains an area of unmet clinical need. This article provides an overview of the clinical evidence for paclitaxel-coated balloons in the femoropopliteal and infrapopliteal peripheral artery distributions and future directions in this area.

IN.PACT™ Admiral™ drug-coated balloon: Durable, consistent and safe treatment for femoropopliteal peripheral artery disease

Endovascular management of peripheral artery disease was until recently limited to percutaneous balloon angioplasty, atherectomy, stent grafts, and bare-metal stents. These therapies have been valuable, but plagued by high restenosis and revascularization rates. Important progress has been made with the introduction of combination devices, including drug-eluting stents and drug-coated balloons (DCB), designed to combat restenosis by locally delivering anti-proliferative drugs. In particular, promising clinical performance has been seen with the Medtronic IN.PACT™ Admiral™ DCB, with durable, consistent and safe results. Rigorous, randomized controlled trials have directly compared this and other drug-delivering devices to their non-drug-coated counterparts with data available through two years. Additionally, trials are ongoing to assess use of drug-coated technologies in combination with traditional therapies in hope of synergistic effects. This review gathers data from currently published clinical trials with the IN.PACT Admiral DCB for the treatment of femoropopliteal peripheral artery disease and explores the possible impact on continuing clinical practice.

Serial Morphological Changes of Side-Branch Ostium after Paclitaxel-Coated Balloon Treatment of De Novo Coronary Lesions of Main Vessels

PURPOSE

The effects on the side-branch (SB) ostium, following paclitaxel-coated balloon (PCB) treatment of de novo coronary lesions of main vessels have not been previously investigated. This study was aimed at evaluating the serial morphological changes of the SB ostium after PCB treatment of de novo coronary lesions of main vessels using optical coherence tomography (OCT).

MATERIALS AND METHODS

This prospective, single-center observational study enrolled patients with de novo lesions, which were traversed by at least one SB (≥1.5 mm) and were treated with PCB. The SB ostium was evaluated with serial angiographic and OCT assessments pre- and post-procedure, and at 9-months follow-up.

RESULTS

Sixteen main vessel lesions were successfully treated with PCB, and 26 SBs were included for analysis. Mean SB ostial lumen area increased at 9-months follow-up (0.92±0.68 mm² pre-procedure, 1.03±0.77 mm² post-procedure and 1.42±1.18 mm² at 9-months). The SB ostial lumen area gain was 0.02±0.24 mm² between pre- and post-procedure, 0.37±0.64 mm² between post-procedure and 9-months, and 0.60±0.93 mm² between pre-procedure and 9-months. The ostial lumen area increased by 3.9% [interquartile range (IQR) of -33.3 to 10.4%] between pre- and post-procedure, 52.1% (IQR of -0.7 to 77.3%) between post-procedure and 9-months and 76.1% (IQR of 18.2 to 86.6%) between pre-procedure and 9-months.

CONCLUSION

PCB treatment of de novo coronary lesions of main vessels resulted in an increase in the SB ostial lumen area at 9-months.

An update on the clinical use of drug-coated balloons in percutaneous coronary interventions

INTRODUCTION

Drug-coated balloons (DCB) promise to deliver anti-proliferative drugs and prevent restenosis leaving nothing behind. Although, randomized clinical trials have demonstrated their efficacy for the treatment of in-stent restenosis, clinical evidence supporting their use in other coronary applications is still lacking.

AREAS COVERED

This review summarizes the development status of clinically available DCB technologies and provides an update on the current data for their coronary use.

EXPERT OPINION

Current generation DCB prevent restenosis by delivering paclitaxel particles on the surface of the vessel wall. Although clinically available technologies share a common mechanism of action, important differences in pharmacokinetic behavior and safety profiles do exist. Future technological improvements include the development of coatings displaying: high transfer efficiency; low particle embolization potential; and alternative drug formulations. Optimized balloon-based delivery systems and drug encapsulation technologies also promise to improve the technical limitations of current generation DCB. Although proving clinical superiority against DES may prove to be difficult in mainstream applications (i.e., de novo), new generation DCB technologies have the potential to achieve a strong position in the interventional field in clinical settings in which the efficacy of DES use is not proven or justified (i.e., bifurcations).

Comparison of Paclitaxel-Coated Balloon Treatment and Plain Old Balloon Angioplasty for De Novo Coronary Lesions

PURPOSE

This study compared the angiographic outcomes of paclitaxel-coated balloon (PCB) versus plain old balloon angioplasty (POBA) treatment for de novo coronary artery lesions. At present, there is no available data comparing the efficacy of PCB versus POBA for the treatment of de novo coronary lesions.

MATERIALS AND METHODS

This multicenter retrospective observational study enrolled patients with de novo coronary lesions with a reference vessel diameter between 2.5 mm and 3.0 mm and lesion length ≤ 24 mm who were successfully treated with PCB or POBA. Angiographic measurements and quantitative coronary analysis were performed before and after the procedure, and at 9 months follow-up.

RESULTS

A total of 72 patients (49 receiving PCB and 23 receiving POBA) were enrolled in this study. Late luminal loss was -0.12 ± 0.30 mm in the PCB group and 0.25 ± 0.50 mm in the POBA group (p<0.001). There was a higher percentage of binary restenosis (diameter stenosis ≥ 50%) in POBA, compared to PCB (30.4%, n=7 vs. 4.1%, n=2, p<0.001). Target vessel revascularization was higher in the POBA group (13.0%, n=3 vs. 0%, p=0.033).

CONCLUSION

PCB treatment of de novo coronary lesions showed better 9-month angiographic outcomes than POBA treatment alone.

Local delivery of paclitaxel in the treatment of peripheral arterial disease

BACKGROUND

Despite advancements from balloon angioplasty to drug-eluting stents, primary patency rates after endovascular revascularization of peripheral artery disease have remained inferior compared to surgery. Endovascular revascularization has been limited by restenosis and mechanical stent failure. Thus, there is increased research into other nonstent-based local drug delivery modalities, which can provide an active drug to inhibit restenosis focally and avoid the risk of systemic adverse effects.

METHODS

This review will summarize the unique properties of paclitaxel and studies on paclitaxel local delivery for the treatment of peripheral artery disease. A MEDLINE search for relevant peer-reviewed scientific literature published in English was conducted. Search terms included but were not limited to paclitaxel pharmacodynamics, paclitaxel local drug delivery, and drug eluting balloons, with a focus on the use of paclitaxel in the context of coronary and peripheral vascular disease.

RESULTS

The primary search produced 182 results of which 51 papers were relevant. Of the 51 relevant papers, 27 were original research papers and 24 were either review papers, commentary or opinion papers.

CONCLUSIONS

Paclitaxel has several chemical properties, which make it ideal for local drug delivery including its hydrophobicity, ability to concentrate into the arterial intima layer and prolonged effect on cells even after brief exposure periods. Local delivery of paclitaxel via injection catheters, balloon catheters and coated balloons has shown encouraging results in terms of efficacy and safety in small-scale animal and clinical studies. Additional preclinical and clinical studies are needed to determine the long-term efficacy and safety of these treatments in humans.

A successful experimental model for intimal hyperplasia prevention using a resveratrol-delivering balloon

OBJECTIVE

Restenosis due to intimal hyperplasia is a major clinical problem that compromises the success of angioplasty and endovascular surgery. Resveratrol (RSV) has demonstrated a beneficial effect on restenosis from angioplasty. Unfortunately, the physicochemical characteristics of RSV reduce the practicality of its immediate clinical application. This work proposes an experimental model aiming to setup an intravessel, elutable, RSV-containing compound.

METHODS

A 140 μg/mL RSV sterile injectable solution with a suitable viscosity for intravascular administration by drug-delivery catheter (RSV-c) was prepared. This solution was locally administered in the common iliac artery of adult male New Zealand White rabbits using a dedicated device (Genie; Acrostak, Geneva, Switzerland) after the induction of intimal hyperplasia by traumatic angioplasty. The RSV concentrations in the wall artery were determined, and the thickness of the harvested iliac arteries was measured over a 1-month period.

RESULTS

The Genie catheter was applied in rabbit vessels, and the local delivery resulted in an effective reduction in restenosis after plain angioplasty. Notably, RSV-c forced into the artery wall by balloon expansion might accumulate in the interstitial areas or within cells, avoiding the washout of solutions. Magnification micrographs showed intimal proliferation was significantly inhibited when RSV-c was applied. Moreover, no adverse events were documented in in vitro or in vivo studies.

CONCLUSIONS

RSV can be advantageously administered in the arterial walls by a drug-delivery catheter to reduce the risk of restenosis.

Quantification of scientific output in cardiovascular medicine: a perspective based on global data

AIMS

We sought to explore whether global and regional scientific output in cardiovascular medicine is associated with economic variables and follows the same trend as medicine and as science overall.

METHODS AND RESULTS

We registered the number of documents, number of citations, citations per document and the h-index for the first 50 countries according to the h-index (a measure to evaluate both the productivity and impact of the publications) in cardiovascular medicine. Economic variables (gross domestic product [GDP] per capita, % expenditure of the GDP in research and development [R&D] and health) were obtained from the World Bank, the UNESCO, and the World Health Organization. In total, the scientific output in cardiology showed the same position as in medicine and science overall (mean difference vs. medicine -0.9±5.3º, p=0.25 vs. science -0.7±5.3º, p=0.39). We found significant correlations between the h-index and the % GDP expenditure in R&D (r=0.67, p<0.001), and the % GDP expenditure in health (r=0.71, p<0.0001). Overall, there was a 21.4% (interquartile range 3.7; 55.0) increase in the % GDP expenditure in R&D between 1996 and 2007. Emerging economies showed the larger growth in % GDP expenditure in health and R&D.

CONCLUSIONS

The global situation of scientific output in cardiovascular medicine is highly polarised and closely related to economic indicators. Emergent economies, with higher rates of GDP growth and increasingly larger expenditures for R&D and healthcare, are expected to show a visible escalation in the scientific global picture in the near future.

Mechanisms of tissue uptake and retention of paclitaxel-coated balloons: impact on neointimal proliferation and healing

Background

The efficacy of paclitaxel-coated balloons (PCB) for restenosis prevention has been demonstrated in humans. However, the mechanism of action for sustained drug retention and biological efficacy following single-time drug delivery is still unknown.

Methods and results

The pharmacokinetic profile and differences in drug concentration (vessel surface vs arterial wall) of two different paclitaxel coating formulations (3 µg/mm²) displaying opposite solubility characteristics (CC=crystalline vs AC=amorphous) were tested in vivo and compared with paclitaxel-eluting stents (PES). Also, the biological effect of both PCB formulations on vascular healing was tested in the porcine coronary injury model. One hour following balloon inflation, both formulations achieved similar arterial paclitaxel levels (CC=310 vs AC=245 ng/mg; p=NS). At 24 h, the CC maintained similar tissue concentrations, whereas the AC tissue levels declined by 99% (p<0.01). At this time point, arterial levels were 20-fold (CC) and 5-fold (AC) times higher compared to the PES group (p<0.05). At 28 days, arterial levels retained were 9.2% (CC) and 0.04% (AC, p<0.01) of the baseline levels. Paclitaxel concentration on the vessel surface was higher in the CC at 1 (CC=36.7% vs AC=13.1%, p<0.05) and 7 days (CC=38.4% vs AC=11%, p<0.05). In addition, the CC induced higher levels of neointimal inhibition, fibrin deposition and delayed healing compared with the AC group.

Conclusions

The presence of paclitaxel deposits on the vessel surface driving diffusion into the arterial tissue in a time-dependent fashion supports the mechanism of action of PCB. This specific pharmacokinetic behaviour influences the patterns of neointimal formation and healing.

Peripheral arterial calcification: prevalence, mechanism, detection, and clinical implications

Vascular calcification (VC), particularly medial (Mönckeberg's medial sclerosis) arterial calcification, is common in patients with diabetes mellitus and chronic kidney disease and is associated with increased cardiovascular morbidity and mortality. Although, the underlying pathophysiological mechanisms and genetic pathways of VC are not fully known, hypocalcemia, hyperphosphatemia, and the suppression of parathyroid hormone activity are central to the development of vessel mineralization and, consequently, bone demineralization. In addition to preventive measures, such as the modification of atherosclerotic cardiovascular risk factors, current treatment strategies include the use of calcium-free phosphate binders, vitamin D analogs, and calcium mimetics that have shown promising results, albeit in small patient cohorts. The impact of intimal and medial VC on the safety and effectiveness of endovascular devices to treat symptomatic peripheral arterial disease (PAD) remains poorly defined. The absence of a generally accepted, validated vascular calcium grading scale hampers clinical progress in assessing the safety and utility of various endovascular devices (e.g., atherectomy) in treating calcified vessels. Accordingly, we propose the peripheral arterial calcium scoring system (PACSS) and a method for its clinical validation. A better understanding of the pathogenesis of vascular calcification and the development of optimal medical and endovascular treatment strategies are crucial as the population ages and presents with more chronic comorbidities.

Numerical modelling of the physical factors that affect mass transport in the vasculature at early time periods

Coronary artery disease results in blockages or narrowing of the artery lumen. Drug eluting stents were developed to replace bare metal stents in an effort to combat re-blocking of the lumen. A key element in determining the therapeutic success of a drug eluting stent is an in-depth understanding of the physical factors that affect mass transport of the drug into the arterial wall, over early time periods. The numerical models developed within this study focus on assessing the influence of a host of physical factors that either facilitate or impede therapeutic drug delivery into the arterial wall from the unit cell of an idealised stent. This study demonstrates that model reduction strategies to 2D and 1D can still adequately represent a 3D curved arterial wall and strut polymer coating, respectively, using an idealistic stent geometry. It was shown that the level of strut compression can have a significant impact on therapeutic drug delivery in the arterial wall.