Balloon-based drug coating delivery to the artery wall is dictated by coating micro-morphology and angioplasty pressure gradients

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®.

A Novel In Silico-Ex Vivo Model for Correlating Coating Transfer to Tissue with Local Drug-Coated Balloon-Vessel Contact Pressures

Drug-coated balloons (DCBs) aim to deliver drug-loaded surface coating upon inflation at specific vascular sites, yet the role of inflation pressure remains to be defined. We implement a new approach combining ex vivo stamping experiments with in silico simulations to study acute coating transfer by commercial DCBs. This methodology comprises 3 essential pillars: (I) DCB resin inflation and slicing into cylindrical segments for subsequent stamping onto porcine-excised tissue, (II) Numerical inflation of a full DCB replica in an idealized porcine vessel to predict in vivo interfacial contact pressures (CPs) and subsequent interfacial-level numerical stamping to calculate appropriate benchtop forces that recreate these in vivo CP values, and (III) ex vivo stamping experiments and optical analysis of the stamped surfaces (DCB segment and arterial tissue), using a standard high-resolution camera to visualize coating. High-performance liquid chromatography (HPLC) was employed as a validated assay for quantifying drug in tissue samples post-stamping. HPLC analysis revealed a significant correlation with image processing, confirming the validity of the optical method as a tool to quantify DCB coating. Image and HPLC analysis revealed a statistically significant twofold rise in coating area and drug content to tissue, respectively, when the average CP roughly doubled (0.16-0.35 atm) and a non-statistically significant increase in coating area and drug content with a further rough doubling of average CP (0.35 to 0.75 atm). Imaging of DCB segments pre- and post-stamping showed transfer of partial coating thickness at low CP, contrasting with complete transfer at high CP at the same site. 3D confocal images of DCB surfaces revealed variable thickness in the transferred coating. This study introduces a comprehensive methodology for evaluating the efficacy of commercial DCB coating transfer to arterial tissue-a crucial precursor to drug elution studies-while minimizing the number of DCBs needed and improving variable control and realism.

Current Status of Microneedle Array Technology for Therapeutic Delivery: From Bench to Clinic

In recent years, microneedle (MN) patches have emerged as an alternative technology for transdermal delivery of various drugs, therapeutics proteins, and vaccines. Therefore, there is an urgent need to understand the status of MN-based therapeutics. The article aims to illustrate the current status of microneedle array technology for therapeutic delivery through a comprehensive review. However, the PubMed search was performed to understand the MN's therapeutics delivery status. At the same time, the search shows the number no of publications on MN is increasing (63). The search was performed with the keywords "Coated microneedle," "Hollow microneedle," "Dissolvable microneedle," and "Hydrogel microneedle," which also shows increasing trend. Similarly, the article highlighted the application of different microneedle arrays for treating different diseases. The article also illustrated the current status of different phases of MN-based therapeutics clinical trials. It discusses the delivery of different therapeutic molecules, such as drug molecule delivery, using microneedle array technology. The approach mainly discusses the delivery of different therapeutic molecules. The leading pharmaceutical companies that produce the microneedle array for therapeutic purposes have also been discussed. Finally, we discussed the limitations and future prospects of this technology.

In-stent restenosis

Endovascular arterial recanalization has become the mainstay therapy for peripheral arterial occlusive disease. Although immediate technical success is achieved in greater than 90% of cases, longer-term results continue to vary based on the clinical presentation, and the treated target lesion. In the current era, sustained patency can be expected following intervention in the carotid, coronary, renal, and iliac arteries. However, maintaining patency in the femoropopliteal and tibial arteries continues to be present a significant challenge. Endovascular intervention in the peripheral arteries is met with heavy complex plaque burdens, multiple serial stenoses and occlusions, sluggish blood flow, low mean and oscillatory shear stress, and repetitive axial, radial and torsional deformation that hinder its outcomes. In order to maximize the longevity of endovascular intervention, its therapeutic armamentarium has developed to include vessel preparation, drug delivery, and arterial scaffolding. Nevertheless, in the aggregate of real-world clinical practice, recurrence of stenosis still complicates up to 50% of all infrainguinal endovascular procedures after only one year. Unfortunately, this timeline is often insufficient to reliably address lifestyle limiting symptoms, heal a wound, or save a threatened extremity. The purpose of this review is to discuss the pathophysiology, incidence, risk factors, morphology and treatment of restenosis following peripheral endovascular intervention.

A Strategy for the In-Silico Assessment of Drug Eluting Stents: A Comparative Study for the Evaluation of Retinoic Acid as a Novel Drug Candidate for Drug Eluting Stents

In this work, a methodology for the in-silico evaluation of drug eluting stents (DES) is presented. A stent model developed by Rontis S.A. has been employed. For modeling purposes two different stent parts have been considered: the metal core and the coating. For the arterial models, we used animal specific imaging data and realistic geometries were reconstructed which were used as input to the drug-delivery model. More specifically, optical coherence tomography (OCT) imaging data from two coney iliac arterial segments were 3D reconstructed, and the preprocessed 3D stent was deployed in-silico. The deformed geometries of the in-silico deployed stents and the dilated arterial segments were used as input to the drug elution model. The same reconstructed arteries were used in three different cases: (i) Case A. The coatings contain retinoic acid at an initial concentration 49.2% w/w. (ii) Case B. The coatings contain retinoic acid at an initial concentration 1% w/w. (iii) Case C. The coatings contain sirolimus at an initial concentration 0.85% w/w. In each case, two different coatings were examined: (a) polylactic acid and (b) polylactic-co-glycolic acid. The results proved that retinoic acid is a very promising drug candidate for DES due to its binding time to the smooth muscle cells of the arterial wall that exceeds the corresponding time of sirolimus, while being non-toxic to the smooth muscle cells.

Drug-Coated Balloon in Acute Coronary Syndromes: Ready for the Prime Time?

PURPOSE OF REVIEW

Acute coronary syndromes (ACS) are a major global health concern. Percutaneous coronary intervention (PCI) with new-generation drug-eluting stents (DES) has been endorsed as safe and effective in the management of culprit and non-culprit lesions of ACS. However, permanent metallic implants may have drawbacks, including the need for prolonged dual antiplatelet therapy (DAPT) and the risk of long-term stent-related complications. An alternative approach using drug-coated balloons (DCBs) is gaining growing interest, having the potential of delivering therapy directly to vulnerable plaques, avoiding the need for permanent metallic implants, and potentially allowing for better long-term medical treatment. Despite limited evidence, DCB is being explored in several patients' subgroups. This review aims to discuss the existing evidence regarding DCB in ACS management.

RECENT FINDINGS

DCB appears to be a promising strategy in the management of ACS, showing comparable angiographic and clinical results as compared to new-generation DES in relatively small clinical trials or large prospective registries. The advantage of avoiding permanent implants is particularly appealing in this setting, where DCB has the potential of delivering anti-atherogenic local therapy directly to vulnerable plaques still amenable to atherogenic regression. This review seeks to underline the theoretical background of DCB use and reports the available evidence in its support in the specific setting of ACS. In the context of ACS, the use of DCB is highly attractive, offering a dedicated anti-atherogenic local therapy, capable of addressing a broad range of vulnerable plaques and patients.

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.

Plaque heterogeneity and the spatial distributions of its components dictate drug-coated balloon therapy

Drug-coated balloon (DCB) angioplasty is one of the potential approaches to alleviating in-stent restenosis and treating peripheral artery disease. An in-silico model has been developed for sirolimus drug eluted from an inflated balloon in a patient-specific arterial cross-section consisting of fibrous tissue, fibrofatty tissue, dense calcium, necrotic core, and healthy tissue. The convection-diffusion-reaction equation represents the transport of drug, while drug binding, both specific and non-specific, can be modelled as a reaction process. The Brinkman equations describe the interstitial flow in porous tissue. An image processing technique is leveraged for reconstructing the computational domain. The Marker and Cell, and Immersed Boundary Methods are used to solve the set of governing equations. The no-flux interface condition and convection do amplify the tissue content, and the regions of dense calcium and necrotic core limited to or extremely close to the interface pose a clinical threat to DCB therapy. Simulations predict the effects of the positioning and clustering of plaque components in the domain. This study demands extensive intravascular ultrasound-derived virtual histology (VH-IVUS) imaging to understand the plaque morphology and determine the relative positions of different plaque compositions about the lumen-tissue interface, which have a significant impact on arterial pharmacokinetics.

Investigating Balloon-Vessel Contact Pressure Patterns in Angioplasty: In Silico Insights for Drug-Coated Balloons

Drug-Coated Balloons have shown promising results as a minimally invasive approach to treat stenotic arteries, but recent animal studies have revealed limited, non-uniform coating transfer onto the arterial lumen. In vitro data suggested that local coating transfer tracks the local Contact Pressure (CP) between the balloon and the endothelium. Therefore, this work aimed to investigate in silico how different interventional and device parameters may affect the spatial distribution of CP during the inflation of an angioplasty balloon within idealized vessels that resemble healthy femoral arteries in size and compliance. An angioplasty balloon computational model was developed, considering longitudinal non-uniform wall thickness, due to its forming process, and the folding procedure of the balloon. To identify the conditions leading to non-uniform CP, sensitivity finite element analyses were performed comparing different values for balloon working length, longitudinally varying wall thickness, friction coefficient on the balloon-vessel interface, vessel wall stiffness and thickness, and balloon-to-vessel diameter ratio. Findings indicate a significant irregularity of contact between the balloon and the vessel, mainly affected by the balloon's unfolding and longitudinal thickness variation. Mirroring published data on coating transfer distribution in animal studies, the interfacial CP distribution was maximal at the middle of the balloon treatment site, while exhibiting a circumferential pattern of linear peaks as a consequence of the particular balloon-vessel interaction during unfolding. A high ratio of balloon-to-vessel diameter, higher vessel stiffness, and thickness was found to increase significantly the amplitude and spatial distribution of the CP, while a higher friction coefficient at the balloon-to-vessel interface further exacerbated the non-uniformity of CP. Evaluation of balloon design effects revealed that the thicker tapered part caused CP reduction in the areas that interacted with the extremities of the balloon, whereas total length only weakly impacted the CP. Taken together, this study offers a deeper understanding of the factors influencing the irregularity of balloon-tissue contact, a key step toward uniformity in drug-coating transfer and potential clinical effectiveness.

Cardiovascular Tissue Engineering Models for Atherosclerosis Treatment Development

In the early years of tissue engineering, scientists focused on the generation of healthy-like tissues and organs to replace diseased tissue areas with the aim of filling the gap between organ demands and actual organ donations. Over time, the realization has set in that there is an additional large unmet need for suitable disease models to study their progression and to test and refine different treatment approaches. Increasingly, researchers have turned to tissue engineering to address this need for controllable translational disease models. We review existing and potential uses of tissue-engineered disease models in cardiovascular research and suggest guidelines for generating adequate disease models, aimed both at studying disease progression mechanisms and supporting the development of dedicated drug-delivery therapies. This involves the discussion of different requirements for disease models to test drugs, nanoparticles, and drug-eluting devices. In addition to realistic cellular composition, the different mechanical and structural properties that are needed to simulate pathological reality are addressed.

Drug-loaded balloon with built-in NIR controlled tip-separable microneedles for long-effective arteriosclerosis treatment

Drug-eluting balloon (DEB) angioplasty has emerged as an effective treatment for cardiovascular and cerebrovascular diseases. However, distal embolism and late lumen restenosis could be caused by drug loss during DEB handling and rapid drug metabolization. Here, a drug-loaded balloon equipped with tip-separable microneedles on the balloon surface (MNDLB) was developed. Inbuilt near-infrared (NIR) ring laser inside the catheter inner shaft was introduced to activate the biodegradable microneedle tips for the first time. The drug-loaded tips thus could be embedded in the vasculature and then released antiproliferative drug - paclitaxel slowly via polymer degradation for more than half a year. A significant increase in drug delivery efficiency and superior therapeutic effectiveness compared with the standard DEB were demonstrated using an atherosclerosis rabbit model.

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.

Recent advance in treatment of atherosclerosis: Key targets and plaque-positioned delivery strategies

Atherosclerosis, a chronic inflammatory disease of vascular wall, is a progressive pathophysiological process with lipids oxidation/depositing initiation and innate/adaptive immune responses. The coordination of multi systems covering oxidative stress, dysfunctional endothelium, diseased lipid uptake, cell apoptosis, thrombotic and pro-inflammatory responding as well as switched SMCs contributes to plaque growth. In this circumstance, inevitably, targeting these processes is considered to be effective for treating atherosclerosis. Arriving, retention and working of payload candidates mediated by targets in lesion direct ultimate therapeutic outcomes. Accumulating a series of scientific studies and clinical practice in the past decades, lesion homing delivery strategies including stent/balloon/nanoparticle-based transportation worked as the potent promotor to ensure a therapeutic effect. The objective of this review is to achieve a very brief summary about the effective therapeutic methods cooperating specifical targets and positioning-delivery strategies in atherosclerosis for better outcomes.

3D modelling of drug-coated balloons for the treatment of calcified superficial femoral arteries

Background/Objectives

Drug-coated balloon therapy for diseased superficial femoral arteries remains controversial. Despite its clinical relevance, only a few computational studies based on simplistic two-dimensional models have been proposed to investigate this endovascular therapy to date. This work addresses the aforementioned limitation by analyzing the drug transport and kinetics occurring during drug-coated balloon deployment in a three-dimensional geometry.

Methods

An idealized three-dimensional model of a superficial femoral artery presenting with a calcific plaque and treated with a drug-coated balloon was created to perform transient mass transport simulations. To account for the transport of drug (i.e. paclitaxel) released by the device, a diffusion-reaction equation was implemented by describing the drug bound to specific intracellular receptors through a non-linear, reversible reaction. The following features concerning procedural aspects, pathologies and modelling assumptions were investigated: (i) balloon application time (60–180 seconds); (ii) vessel wall composition (healthy vs. calcified wall); (iii) sequential balloon application; and (iv) drug wash-out by the blood stream vs. coating retention, modeled as exponential decay.

Results

The balloon inflation time impacted both the free and specifically-bound drug concentrations in the vessel wall. The vessel wall composition highly affected the drug concentrations. In particular, the specifically-bound drug concentration was four orders of magnitude lower in the calcific compared with healthy vessel wall portions, primarily as a result of reduced drug diffusion. The sequential application of two drug-coated balloons led to modest differences (~15%) in drug concentration immediately after inflation, which became negligible within 10 minutes. The retention of the balloon coating increased the drug concentration in the vessel wall fourfold.

Conclusions

The overall findings suggest that paclitaxel kinetics may be affected not only by the geometrical and compositional features of the vessel treated with the drug-coated balloon, but also by balloon design characteristics and procedural aspects that should be carefully considered.

Directional atherectomy before paclitaxel coated balloon angioplasty in complex femoropopliteal disease: The VIVA REALITY study

BACKGROUND

Drug coated balloon (DCB) angioplasty significantly reduces reintervention rates in patients with symptomatic femoropopliteal peripheral artery disease (PAD). However, stand-alone DCB use in long, severely calcified lesions is frequently associated with vessel recoil and/or high-grade dissections necessitating provisional stent implantation.

OBJECTIVES

Assess the safety and effectiveness of a vessel preparation strategy with directional atherectomy (DA) prior to DCB angioplasty in patients with symptomatic severely calcified femoropopliteal PAD.

METHODS

REALITY (NCT02850107) prospectively enrolled subjects at 13 multinational centers with 8-36 cm femoropopliteal stenoses or occlusions with bilateral vessel wall calcification treated with DA prior to DCB angioplasty. The primary effectiveness endpoint was 12-month primary patency, and the primary safety endpoint was freedom from major adverse events through 30 days. Independent angiographic and duplex core laboratories assessed outcomes and a Clinical Events Committee adjudicated events.

RESULTS

A total of 102 subjects were enrolled; one lesion was treated per subject. The mean lesion length was 17.9 ± 8.1 cm, 39.0% were chronic total occlusions (mean lesion length 22.6 ± 8.6 cm); 86.2% of lesions exhibited moderate to severe bilateral calcification. Provisional stents were implanted in 8.8% (9/102) of subjects. Twelve-month primary patency rate was 76.7% (66/86) and freedom from CD-TLR rate was 92.6% (87/94). No device or procedure related deaths and one index-limb major amputation were reported.

CONCLUSIONS

Plaque excision with DA in patients with symptomatic severely calcified femoropopliteal arterial disease prior to DCB angioplasty is a safe and effective treatment strategy with a low provisional stent rate.

Vascular Lesion-Specific Drug Delivery Systems: JACC State-of-the-Art Review

Drug delivery is central to modern cardiovascular care, where drug-eluting stents, bioresorbable scaffolds, and drug-coated balloons all aim to restore perfusion while inhibiting exuberant healing. The promise and enthusiasm of these devices has in some cases exceeded demonstration of efficacy and even understanding of driving mechanisms. The authors review the means of drug delivery in each device, outlining how the technologies affect vascular behavior. They focus on how drug retention and response are governed by lesion morphology: lipid displacing drug-specific binding sites, calcium inhibiting diffusion, blocking thrombi or promoting luminal washout, and vascular healing steering hyperplastic developments. In this regard, the authors outline the fundamental impact of vascular structure on drug delivery and review the development of contemporary and future devices for coronary and peripheral intervention. They look toward a future where incorporating information on lesion distribution is central to therapeutic success and envision a transition toward lesion-specific treatment for improved interventional outcomes.