Drug-Coated Balloons for Coronary and Peripheral Interventional Procedures

Endovascular Drug Delivery

Drug-eluting stents (DES) and balloons revolutionize atherosclerosis treatment by targeting hyperplastic tissue responses through effective local drug delivery strategies. This review examines approved and emerging endovascular devices, discussing drug release mechanisms and their impacts on arterial drug distribution. It emphasizes the crucial role of drug delivery in modern cardiovascular care and highlights how device technologies influence vascular behavior based on lesion morphology. The future holds promise for lesion-specific treatments, particularly in the superficial femoral artery, with recent CE-marked devices showing encouraging results. Exciting strategies and new patents focus on local drug delivery to prevent restenosis, shaping the future of interventional outcomes. In summary, as we navigate the ever-evolving landscape of cardiovascular intervention, it becomes increasingly evident that the future lies in tailoring treatments to the specific characteristics of each lesion. By leveraging cutting-edge technologies and harnessing the potential of localized drug delivery, we stand poised to usher in a new era of precision medicine in vascular intervention.

Drug Coated Balloon in the Treatment of De Novo Coronary Artery Disease: A Narrative Review

Drug coated balloons (DCBs) are currently indicated in guidelines as a first choice option in the management of instant restenosis, whereas their use in de novo lesions is still debated. The concerns raised after the contrasting results of the initial trials with DCBs in de novo lesions have been more recently overcome by a larger amount of data confirming their safety and effectiveness as compared to drug-eluting stents (DES), with potentially greater benefits being achieved, especially in particular anatomical settings, as in very small or large vessels and bifurcations, but also in selected subsets of higher-risk patients, where a 'leave nothing behind' strategy could offer a reduction of the inflammatory stimulus and thrombotic risk. The present review aims at providing an overview of current available DCB devices and their indications of use based on the results of data achieved so far.

A Multilayer Functionalized Drug-Eluting Balloon for Treatment of Coronary Artery Disease

Drug-eluting balloons (DEBs) have been mostly exploited as an interventional remedy for treating atherosclerosis instead of cardiovascular stents. However, the therapeutic efficacy of DEB is limited due to their low drug delivery capability to the disease site. The aim of our study was to load drugs onto a balloon catheter with preventing drug loss during transition time and maximizing drug transfer from the surface of DEBs to the cardiovascular wall. For this, a multilayer-coated balloon catheter, composed of PVP/Drug-loaded liposome/PVP, was suggested. The hydrophilic property of 1st layer, PVP, helps to separate drug layer in hydrophilic blood vessel, and the 2nd layer with Everolimus (EVL)-loaded liposome facilitates drug encapsulation and sustained release to the targeted lesions during inflation time. Additionally, a 3rd layer with PVP can protect the inner layer during transition time for preventing drug loss. The deionized water containing 20% ethanol was utilized to hydrate EVL-loaded liposome for efficient coating processes. The coating materials showed negligible toxicity in the cells and did not induce pro-inflammatory cytokine in human coronary artery smooth muscle cells (HCASMCs), even in case of inflammation induction through LPS. The results of hemocompatibility for coating materials exhibited that protein adsorption and platelet adhesion somewhat decreased with multilayer-coated materials as compared to bare Nylon tubes. The ex vivo experiments to confirm the feasibility of further applications of multilayer-coated strategy as a DEB system demonstrated efficient drug transfer of approximately 65% in the presence of the 1st layer, to the tissue in 60 s after treatment. Taken together, a functional DEB platform with such a multilayer coating approach would be widely utilized for percutaneous coronary intervention (PCI).

A Prospective Multicenter Randomized Trial to Assess the Effectiveness of the MagicTouch Sirolimus-Coated Balloon in Small Vessels: Rationale and Design of the TRANSFORM I Trial

AIMS

The objective of the study is to assess the efficacy and safety of the novel Magic Touch sirolimus coated-balloon (SCB) when compared to the SeQuent Please Neo paclitaxel coated balloon (PCB) for the treatment of de-novo small vessel coronary artery diseases (SVD).

STUDY DESIGN

The TRANSFORM I study is a randomized, multicenter, non-inferiority trial with the intent to enroll a total of 114 patients with a de-novo SVD (≤2.5 mm). Vessel size will be pre-screened by on-line QCA. After successful pre-dilatation without major coronary dissections (type C-F) nor Thrombolysis In Myocardial Infarction trial [TIMI] grade flow ≤2, patients will be enrolled in a 1:1 randomization to receive treatment with either the novel SCB balloon or the comparative PCB balloon. The balloon sizing will be selected according to the lumen-based approach derived from optical coherence tomography (OCT). The primary endpoint is 6-month mean net lumen diameter gain (6-month minimum lumen diameter [MLD] minus baseline MLD) assessed by quantitative coronary analysis (QCA) with non-inferiority margin of 0.3 mm in per-protocol analysis. The clinical follow-up will be conducted up to 1 year. The enrollment started in September 2020 and will complete in April 2021.

CONCLUSIONS

The TRANSFORM I trial will assess the efficacy of novel SCB in terms of non-inferiority to conventional PCB with a novel OCT measurement approach in patients with a de-novo SVD. Clinical Trial Registration URL: https://clinicaltrials.gov. Unique identifier: NCT03913832.

Advances in Percutaneous Therapies for Peripheral Artery Disease: Drug-Coated Balloons

PURPOSE OF REVIEW

This review paper provides a summary on the use of drug-coated balloons in peripheral artery disease. It covers the main drug-coated balloon (DCB) trials. It is divided into categories of lesions: superficial femoral artery and popliteal lesions, infra-popliteal lesions and in-stent restenosis. It also includes an overview of the future of DCBs, highlighting the main ongoing trials.

RECENT FINDINGS

The latest research on DCB focuses on newer types of DCBs, mainly paclitaxel-coated but with lower doses. Another area of latest DCB research is its use in superficial femoral artery and popliteal artery in-stent restenosis, with superior outcomes. Drug-coated balloons produce better outcomes than percutaneous transluminal angioplasty alone in de novo and in-stent restenosis lesions of superficial femoral artery and popliteal arteries. More data are needed to demonstrate efficacy and safety of DCBs in infrapopliteal disease. Newer DCBs and adjunctive therapy may provide improved outcomes for peripheral artery disease interventions.

Bilayered Nanoparticles with Sequential Release of VEGF Gene and Paclitaxel for Restenosis Inhibition in Atherosclerosis

Complete reendothelialization followed by inhibition of smooth muscle cell (SMC) proliferation is considered as an effective therapeutic option to prevent restenosis. We have designed poly(lactide-co-glycolide)-loaded bilayered nanoparticles (NPs) with the ability to sequentially release vascular endothelial growth factor (VEGF)-encoding plasmids from the outer layer and paclitaxel (PTX) from the core to promote endothelial regeneration as well as prevent restenosis. Comparing with conventional NPs, which release VEGF plasmid and PTX simultaneously, we expect that the bilayered NPs could release the VEGF plasmid more rapidly, followed by a delayed release of PTX, resulting in an efficient VEGF gene transfection, which ideally could promote reendothelialization and inhibit excessive SMC growth. Indeed, in the present study, we have observed efficient gene transfection using a model plasmid as well as cell growth attenuation in vitro using Chinese hamster ovary cells. Therapeutic efficacy of the bilayered NPs on restenosis was further evaluated in vivo using a rabbit model of atherosclerosis. The bilayered NPs were administered locally via balloon angioplasty to the injured aortic wall through perfusion. Twenty-eight days after the NP administration, rabbits treated with the bilayered NPs exhibited rapid reendothelialization and inhibition of restenosis, as demonstrated by histological analysis. Increased level of VEGF and decreased level of C-reactive protein, a biological marker that is closely related to atherosclerosis, were also observed from animals treated with the bilayered NPs, implicating ameliorated atherosclerosis. Our results suggest that the VEGF plasmid-/PTX-loaded bilayered NPs exert a beneficial impact on atherosclerotic restenosis by sequentially releasing VEGF and PTX in vivo.

Drug-Eluting Balloons in the Treatment of Coronary De Novo Lesions: A Comprehensive Review

Drug-eluting balloons (DEBs) have emerged as a new application in percutaneous coronary intervention. DEBs have proven successful in the treatment of in-stent restenosis, but their role in de novo lesions is less clear. This paper provides a review of the current studies where DEBs have been used in coronary de novo lesions, either as part of a DEB-only strategy or in combination with another device, mainly a bare metal stent (BMS). By searching Pubmed and Embase we were able to identify 52 relevant studies, differing in design, intervention, and clinical setting, including patients with small vessel disease, bifurcation lesions, complex long lesions, acute myocardial infarction, diabetes mellitus, and elderly. In 23 studies, a DEB was combined with a BMS, 25 studies used a DEB-only strategy with only provisional BMS implantation, and four studies combined a DEB with a drug-eluting stent (DES). In the vast majority of studies, DEB in combination with BMS does not seem to improve clinical or angiographic outcome compared with DES, whereas a DEB-only strategy seems promising, especially when predilatation and geographical mismatch are taken into account. A lower risk of recurrent thrombosis with DEB compared with DES is not evident from the current studies. In conclusion, the main indication for DEB seems to be small vessel disease, especially in clinical scenarios in which a contraindication to dual antiplatelet therapy exists. The main approach should be a DEB-only strategy with only provisional bailout stenting, which has shown interesting results in different clinical scenarios. In general, larger randomized controlled studies with prolonged follow-up comparing DEB with best in class DES are warranted. Technical developments of DEBs including the use of different drugs might potentially improve the efficacy of such treatment.

In vitro evaluation of paclitaxel coatings for delivery via drug-coated balloons

Lately, drug-coated balloons have been introduced in interventional cardiology as an approach to treat occluded blood vessel. They were developed for the rapid transfer of antiproliferative drugs during the angioplasty procedure in stenosed vessels with the intent to reduce the risk of restenosis. In this study five different paclitaxel (PTX) balloon coatings were tested in vitro in order to examine how solvents and additives influence coating stability and drug transfer rates. PTX-coated balloons were advanced through a guiding catheter and a simulated coronary artery pathway under perfusion and were then inflated in a hydrogel acceptor compartment. The fractions transferred to the gel, remaining on the balloon and the PTX lost in the simulated coronary pathway were then analysed. The results obtained suggest that the solvent used for the coating process strongly influences the surface structure and the stability of the coating. Ethanol/water and acetone based PTX coatings showed the lowest drug transfer rates to the simulated vessel wall (both <1%) due to their high drug losses during the prior passage through the coronary artery model (more than 95%). Balloons coated with PTX from ethyl acetate-solutions showed smaller drug loss (83%±9%), but most of the remaining PTX was not transferred (mean balloon residue approximately 15%). Beside the solvent, the use of additives seemed to have a great impact on transfer properties. The balloon pre-treatment with a crosslinked polyvinylpyrrolidone (PVP) film was able to increase the PTX transfer rate from less than 1% (without PVP) to approximately 6%. The best results in this study were obtained for balloon coatings with commercially available SeQuent© Please balloons containing the contrast agent iopromide. For this formulation drug transfer rates of approximately 17% were determined. Fluorescence microscopic imaging could visualize the particulate transfer of labelled PTX from the balloon surface during dilatation. The findings of this study underline the importance of drug adhesion and coating stability for the efficiency of PTX transfer.

Direct Pulmonary Vein Ablation With Stenosis Prevention Therapy

INTRODUCTION

The dominant location of electrical triggers for initiating atrial fibrillation (AF) originates from the muscle sleeves inside pulmonary veins (PVs). Currently, radiofrequency ablation (RFA) is performed outside of the PVs to isolate, rather than directly ablate these tissues, due to the risk of intraluminal PV stenosis.

METHODS

In 4 chronic canine experiments, we performed direct PV muscle sleeve RFA ± postablation drug-coated balloon (DCB) treatment with paclitaxel/everolimus. Of the 4 PVs, 2 PVs were ablated and treated with DCB, 1 PV was ablated without DCB treatment (positive control), and 1 PV was left as a negative control. Local electrograms were assessed in PVs for near-field signals and were targeted for ablation. After 12-14 weeks survival, PVs were interrogated for absence of near-field PV potentials, and each PV was assessed for stenosis.

RESULTS

All canines survived the study period without cardiorespiratory complications, and remained ambulatory. In all canines, PVs that were ablated and treated with DCB remained without any significant intraluminal stenosis. In contrast, PVs that were ablated and not treated with DCB showed near or complete intraluminal stenosis. At terminal study, PV potentials remained undetectable. A blinded, histologic analysis demonstrated that ablated PVs without DCB treatment had extensive thrombus, fibrin, mineralization, and elastin disruption.

CONCLUSION

Our chronic canine data suggest that direct PV tissue ablation without subsequent stenosis is feasible with the use of postablation DCBs.

Paclitaxel Drug-eluting Balloons to Recurrent In-stent Stenoses in Autogenous Dialysis Fistulas: A Retrospective Study

Purpose

To assess the effect of the Medtronic paclitaxel drug-eluting balloon (DEB) on re-intervention to in-stent stenoses in autogenous dialysis arteriovenous fistulas (AVFs).

Background

AVF is the optimum haemodialysis access. The commonest problem is stenosis, preventing maturation, causing inadequate dialysis or precipitating occlusion. Conventional angioplasty has a high recurrence rate. Successful drug elution in the coronary circulation led us to use DEBs in recurrent AVF stenoses since 2010.

Methods

This is a retrospective study, based on prospective audit data, using DEBs on recurrent in-stent stenotic lesions in the AVF circuit of our haemodialysis population. To analyse the effect of DEBs on re-intervention, we created two Kaplan–Meier curves. The first curve compares the last “disease-free-interval” pre-DEB intervention to the first “disease-free interval” post-DEB, giving us “re-intervention-free percentage at 12 months” pre- and post-DEB. The second curve takes into account the multiple pre- and post-DEB interventions to the index lesion, and uses a marginal proportional hazards model to estimate the hazard ratio for “DEBpresent vs. DEBabsent”.

Results

From 1 September 2010 to 1 December 2013, we treated 625 AVF stenoses with endovascular techniques. In 86 of these stenoses, DEBs were used. Of the 86 DEB interventions, 37 were included for this study, 49 were excluded. In the study group, there was a significant difference in “re-intervention-free percentage at 12 months” before and after DEB: 19% vs. 69%. The hazard ratio for “DEBpresent” vs. “DEBabsent” was 0.23 (95% CI 0.14 to 0.36, p<0.001).

Conclusions

This retrospective study suggests that DEBs significantly reduce re-intervention on recurrent in-stent AVF stenoses.

The Eternal Tale of Dialysis Access Vessels and Restenosis: Are Drug-Eluting Balloons the Solution?

In dialysis access fistulas and grafts, percutaneous transluminal angioplasty (PTA) is frequently followed by restenosis development, which results in repeated periodical re-interventions. The technique of drug-eluting balloon (DEB) angioplasty has shown promising results in the treatment of femoropopliteal arteriosclerotic lesions. In contrast to arteriosclerotic arteries, dialysis access vessels host unfavorable hemodynamics due to the direct conduction of high-pressure fluid into a low-pressure system. Hence, the beneficial effect of DEB angioplasty may be limited in this system. However, a first prospective randomized trial on 40 patients with arteriovenous fistula or graft stenoses exhibited a significantly higher 6-month primary patency of the treated lesions after DEB angioplasty than after uncoated balloon angioplasty. Despite such a positive reference, general recommendations regarding the value of DEBs in dialysis access vessels cannot be considered as serious unless large randomized controlled trials have been performed.

In vitro determination of drug transfer from drug-coated balloons

Drug-coated balloons are medical devices designed to locally deliver drug to diseased segments of the vessel wall. For these dosage forms, drug transfer to the vessel wall needs to be examined in detail, since drug released into the blood is cleared from the site. In order to examine drug transfer, a new in vitro setup was developed combining the estimation of drug loss during advancement to the site of application in a model coronary artery pathway with a hydrogel compartment representing, as a very simplified model, the vessel wall. The transfer of fluorescent model substances as well as the drug paclitaxel from coated balloons to the simulated vessel wall was evaluated using this method. The model was suitable to quantify the fractions transferred to the hydrogel and also to qualitatively assess distribution patterns in the hydrogel film. In the case of fluorescein sodium, rhodamin b and paclitaxel, vast amounts of the coated substance were lost during the simulated passage and only very small fractions of about 1% of the total load were transferred to the gel. This must be attributed to good water solubility of the fluorescent substances and the mechanical instability of the paclitaxel coating. Transfer of the hydrophobic model substance triamterene was however nearly unaffected by the preliminary tracking procedure with transferred fractions ranging from 8% to 14%. Analysis of model substance distribution yielded inhomogeneous distributions indicating that the coating was not evenly distributed on the balloon surface and that a great fraction of the coating liquid did not penetrate the folds of the balloon. This finding is contradictory to the generally accepted assumption of a drug depot inside the folds and emphasizes the necessity to thoroughly characterize in vitro performance of drug-coated balloons to support the very promising clinical data.

Local drug delivery to prevent restenosis

INTRODUCTION

Despite significant advances in vascular biology, bioengineering, and pharmacology, restenosis remains a limitation to the overall efficacy of vascular reconstructions, both percutaneous and open. Although the pathophysiology of intimal hyperplasia is complex, a number of drugs and molecular tools have been identified that can prevent restenosis. Moreover, the focal nature of this process lends itself to treatment with local drug administration. This article provides a broad overview of current and future techniques for local drug delivery that have been developed to prevent restenosis after vascular interventions.

METHODS

A systematic electronic literature search using PubMed was performed for all accessible published articles through September 2012. In an effort to remain current, additional searches were performed for abstracts presented at relevant societal meetings, filed patents, clinical trials, and funded National Institutes of Health awards.

RESULTS

The efficacy of local drug delivery has been demonstrated in the coronary circulation with the current clinical use of drug-eluting stents. Until recently, however, drug-eluting stents were not found to be efficacious in the peripheral circulation. Further pursuit of intraluminal devices has led to the development of balloon-based technologies, with a recent surge in trials involving drug-eluting balloons. Early data appear encouraging, particularly for treatment of superficial femoral artery lesions, and several devices have recently received the Conformité Européene mark in Europe. Investigators have also explored the periadventitial application of biomaterials containing antirestenotic drugs, an approach that could be particularly useful for surgical bypass or endarterectomy. In the past, systemic drug delivery has been unsuccessful; however, there has been recent exploration of intravenous delivery of drugs designed specifically to target injured or reconstructed arteries. Our review revealed a multitude of additional interesting strategies, including >65 new patents issued during the past 2 years for approaches to local drug delivery focused on preventing restenosis.

CONCLUSIONS

Restenosis after intraluminal or open vascular reconstruction remains an important clinical problem. Success in the coronary circulation has not translated into solutions for the peripheral arteries. However, our literature review reveals a number of promising approaches, including drug-eluting balloons, periadventitial drug delivery, and targeted systemic therapies. These and other innovations suggest that the future is bright and that a solution for preventing restenosis in peripheral vessels will soon be at hand.