Vascular, downstream, and pharmacokinetic responses to treatment with a low dose drug-coated balloon in a swine femoral artery model

Biolimus-coated versus paclitaxel-coated balloons for coronary in-stent restenosis (BIO ASCEND ISR): a randomised, non-inferiority trial

BACKGROUND

The treatment of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation remains challenging in current clinical practice.

AIMS

The study was conducted to investigate a novel biolimus-coated balloon (BCB) for the treatment of coronary DES-ISR compared with the best-investigated paclitaxel-coated balloon (PCB).

METHODS

This was a prospective, multicentre, randomised, non-inferiority trial comparing a novel BCB with a clinically proven PCB for coronary DES-ISR. The primary endpoint was in-segment late lumen loss (LLL) at 9 months assessed by an independent core laboratory. Baseline and follow-up optical coherence tomography were performed in a prespecified subgroup of patients.

RESULTS

A total of 280 patients at 17 centres were randomised to treatment with a BCB (n=140) versus a PCB (n=140). At 9 months, LLL in the BCB group was 0.23±0.37 mm compared to 0.25±0.35 mm in the PCB group; the mean difference between the groups was -0.02 (95% confidence interval [CI]: -0.12 to 0.07) mm; p-value for non-inferiority<0.0001. Similar clinical outcomes were also observed for both groups at 12 months. In the optical coherence tomography substudy, the neointimal area at 9 months was 2.32±1.04 mm2 in the BCB group compared to 2.37±0.93 mm2 in the PCB group; the mean difference between the groups was -0.09 (95% CI: -0.94 to 0.76) mm2; p=non-significant.

CONCLUSIONS

This head-to-head comparison of a novel BCB shows similar angiographic outcomes in the treatment of coronary DES-ISR compared with a clinically proven PCB. (ClinicalTrials.gov: NCT04733443).

Biological differences of three paclitaxel- and sirolimus-coated balloons on coronary lesions in a rabbit model

BACKGROUND

Drug-coated balloons (DCBs) are important treatment options for coronary artery disease; however, randomised controlled trials comparing various DCB technologies are sparse, and further investigations are needed.

AIMS

This preclinical study aimed to histologically and biologically compare the drug effects and safety of a low-dose paclitaxel-coated DCB (PCB; AGENT), a regular-dose PCB (SeQuent Please NEO) and a sirolimus-coated DCB (SCB; MagicTouch).

METHODS

The DCBs were inflated in the healthy iliac arteries of 18 rabbits, which were euthanised after 28 days. The treated iliac arteries and distal skeletal muscles were histopathologically evaluated, and drug concentrations were measured.

RESULTS

In the histopathological evaluation, the medial smooth muscle cell loss score regarding depth, an indicator of drug efficacy, was significantly higher with AGENT and SeQuent Please NEO than with MagicTouch (4.0 [3.6-4.0] vs 3.7 [3.7-4.0] vs 2.2 [2.0-2.4]), with significant differences in comparisons between AGENT and MagicTouch (p<0.01) and between SeQuent Please NEO and MagicTouch (p<0.01). AGENT and SeQuent Please NEO showed comparable drug concentrations in the treated artery (p=0.61). In contrast, the drug concentrations in distal skeletal muscles were the highest for MagicTouch, followed by SeQuent Please NEO and AGENT (28.07 [13.19-52.46] ng/mg vs 0.66 [0.22-3.76] ng/mg vs 0.25 [0.04-3.23] ng/mg, respectively).

CONCLUSIONS

This study demonstrated that PCBs might have higher efficacy and lower drug concentrations in distal skeletal muscles than the MagicTouch SCB. The efficacy of the AGENT low-dose PCB and the SeQuent Please NEO regular-dose PCB was comparable.

Pre-clinical investigation of liquid sirolimus for local drug delivery

Introduction

Sirolimus is currently being explored as an alternative drug to paclitaxel for the treatment of peripheral artery disease (PAD). To date, sirolimus has only been used as drug coatings for stents and balloons and no studies have yet demonstrated the delivery of sirolimus in liquid form. The purpose of this pilot study was to investigate the feasibility of the delivery of liquid sirolimus into arterial segments in a benchtop peripheral artery bioreactor.

Methods

The feasibility to deliver liquid therapy was first tested on four drug delivery devices using a fluorescently tagged liquid drug and an ex vivo porcine artery benchtop model. The four devices included the Bullfrog micro-infusion device, ClearWay RX catheter, Occlusion perfusion catheter (OPC), and the targeted adjustable pharmaceutical administration system (TAPAS). Penetration of the fluorescently tagged drug was measured via microscopic imaging and quantification of the depth of drug penetration into all device-treated tissue. Based on the penetration outcome, we then selected a single device to deliver liquid sirolimus into the ex vivo porcine artery model undergoing physiological flow and pressure conditions. The liquid sirolimus-treated arteries were collected from the ex vivo bioreactor at 1- and 24-hour post-delivery and arterial drug retention analyzed by liquid chromatography-tandem mass spectrometry.

Results

Fluorescent microscopy demonstrated that drug delivery with the OPC had greater drug penetration into the medial wall as compared to other devices (OPC: 234 ± 161 µm; TAPAS: 127 ± 68 µm; ClearWay: 118 ± 77 µm; Bullfrog: 2.12 ± 3.78 µm; p = 0.098). The results of the ex vivo flow-circuit bench top model showed that the OPC device successfully delivered the liquid sirolimus at 1-hour (5.17 ± 4.48 ng/mg) and 24-hour (0.78 ± 0.55 ng/mg).

Conclusions

These results demonstrate for the first time the ability to deliver liquid sirolimus directly to the medial layer of an artery via a liquid delivery catheter.

Local, Downstream, and Systemic Evaluation after Femoral Artery Angioplasty with Kanshas Drug-Coated Balloons In Vitro and in a Healthy Swine Model

PURPOSE

To evaluate the incidence of distal embolism and local vascular responses after treatment with the Kanshas drug-coated balloon (DCB) in a preclinical model.

MATERIALS AND METHODS

A total of 90 femoral arteries from 35 healthy swine were treated with a single-dose (×1) or triple-dose (×3) Kanshas DCB that applies the Unicoat technology with 3.2 μg/mm2 of paclitaxel. An uncoated Kanshas balloon was used as a control. The arterial wall, downstream skeletal muscle, and nontarget organs (kidneys, lungs, lymph nodes, liver, spleen, and heart) were histologically evaluated. For pharmacokinetic evaluation, a total of 40 healthy swine were treated with ×1 Kanshas DCB, and treated vessels were evaluated ex vivo with high-performance liquid chromatography-mass spectrometry.

RESULTS

Arteries treated with the Kanshas DCB showed mild proteoglycan deposition accompanied by the loss of smooth muscle cells (SMCs). These changes increased in a dose-dependent manner (medial SMC loss at 28 days in the ×1 vs ×3 groups, in depth, 1 (0.75-1.38) vs 2 (1.63-2.44); P = .0008; in circumference, 0.83 (0.67-1) vs 1.5 (1.19-1.81); P = .0071). No evidence of distal embolization in skeletal muscles (0 of 210 histological sections) and nontarget organs (0 of 345 sections) was observed. The pharmacokinetic evaluation showed high paclitaxel concentration in the treated artery (912 ng/mg, peaking at 3 minutes), which remained detectable at up to 180 days (0.04 ng/mg).

CONCLUSIONS

The Kanshas DCB showed a local drug effect in treated arteries up to 180 days with a high concentration of paclitaxel and no histological evidence of distal embolization.

The Ranger drug-coated balloon: advances in drug-coated technology for treatment of femoropopliteal segment arterial disease

Paclitaxel drug-coated balloons (DCBs) have been shown to improve patency and lower revascularization rates compared with plain old balloon angioplasty. DCBs continue to evolve by improving balloon-coating techniques that minimize the quantity of particles washed off into the bloodstream while maximizing drug retention and vascular-healing profile. Against this backdrop, it is clear that the future of antiproliferatives for the superficial femoral artery will focus on enhancements in device coating materials that will improve the efficiency of drug delivery. The Ranger DCB system recently gained US FDA approval for use. This review discusses the background of DCBs and how the Ranger DCB builds on these previous platforms based on experimental and clinical data.

Neointimal characteristic changes following drug-coated balloons in lesions with repeated revascularization

BACKGROUND

Since their emergence, drug-coated balloons (DCBs) have been used widely to treat in-stent lesions with coronary artery disease (CAD). However, despite their superior efficacy to balloon angioplasty, how DCBs affect neointimal characteristics is poorly understood.

OBJECTIVES

We aimed to assess the neointimal characteristic changes following DCB treatment.

METHODS

Using optical frequency domain imaging (OFDI), we serially observed the in-stent lesion site just after and 1 year after DCB angioplasty in 12 lesions of 11 patients with repeated revascularization. Neoatherosclerosis was defined as lipid-laden neointima with or without calcification in the stented lesion. Progression or regression of neoatherosclerosis, newly formed neointimal calcification, newly formed uncovered strut and newly formed evagination were assessed. Tiny tissue protrusion was also recorded as mushroom-like protrusion.

RESULTS

Underlying stents were first-generation (n = 5) or newer (n = 7) drug-eluting stents (DESs) with implantation durations ranging from 1 to 15 years (median 8 years). Surprisingly, two-thirds of the lesions (67%, 8 of 12) showed progression of neoatherosclerosis, while a quarter of lesions (25%, 3 of 12) showed regression of neoatherosclerosis. The maximal lipid arc increased from 122° to 174°. Newly formed neointimal calcification was observed in 2 of 12 lesions (16%). Newly formed uncovered struts (33%; 4 of 12) and newly formed evaginations (33%; 4 of 12) were not rare. Mushroom-like protrusion was found in a quarter of lesions (25%; 3 of 12).

CONCLUSION

Our study demonstrated that a considerable number of lesions showed varied neointimal characteristic changes in a small number of patients. Further studies in a larger population are needed to understand the clinical impact of these findings.

Improvement of Outcome for Treatment of ‘Restenosis-prone’ Vascular Lesions? Potential Impact of the Paclitaxel dose on Late Lumen Loss in Porcine Peripheral Arteries

Purpose

Clinical data indicate that the drug density on drug-coated balloons (DCBs) might have a role on treatment effect and durability. The aim of the current study was to investigate inhibition of neointimal formation and potential adverse effects after treatment with a novel double-dose DCB in swine.

Material and methods

A four-week study was performed in peripheral arteries of 12 domestic pigs after vessel injury and stent implantation. The novel double-dose DCB with 6-µg paclitaxel (Ptx)/mm2 balloon surface (1 × 6) was compared to a standard DCB with 3.5 µg Ptx/mm2 (3.5) and uncoated balloons (POBA). Potential adverse effects were stimulated by using three fully overlapping DCBs with 6 µg Ptx/mm2 each (3 × 6). Quantitative angiography, histomorphometry and histopathological analyses were performed.

Results

Higher paclitaxel doses per square millimeter of treated arteries were associated with reduced late lumen loss (LLL) in quantitative angiography 4 weeks after treatment (POBA: 0.91 ± 0.75 mm; 3.5: 0.45 ± 0.53 mm; 1 × 6: 0.21 ± 0.41 mm; 3 × 6: − 0.38 ± 0.65 mm). In histomorphometry, maximal neointimal thickness and neointimal area were the lowest for the 1 × 6 group (0.15 ± 0.06 mm/1.5 ± 0.4 mm2), followed by 3 × 6 (0.20 ± 0.07 mm/1.8 ± 0.4 mm2), 3.5 (0.22 ± 0.12 mm/2.2 ± 1.1 mm2) and POBA (0.30 ± 0.07 mm/3.2 ± 0.7 mm2). Downstream tissue showed histopathological changes in all groups including POBA, in larger number and different quality (e.g., edema, inflammation, vessel wall necrosis, vasculitis and perivasculitis) in the 3 × 6 group, which did not cause clinical or functional abnormalities throughout the study.

Conclusion

Treatment with the double-dose DCB (6 µg Ptx/mm2) tended to increase inhibition of in-stent neointimal formation and to diminish LLL after peripheral intervention in the porcine model compared to a market-approved DCB with 3.5 µg Ptx/mm2.

Local intraluminal delivery of a smooth muscle-targeted RNA ligand inhibits neointima growth in a porcine model of peripheral vascular disease

Anti-proliferative agents have been the primary therapeutic drug of choice to inhibit restenosis after endovascular treatment. However, recent safety and efficacy concerns for patients who underwent peripheral artery disease revascularization have demonstrated the need for alternative therapeutics. The aim of this investigation was to investigate the efficacy of a cell-specific RNA aptamer inhibiting vascular smooth muscle cell proliferation and migration. First, the impact of the RNA aptamer (Apt 14) on the wound healing of primary cultured porcine vascular smooth muscle cells (VSMCs) was examined in response to a scratch wound injury. We then evaluated the effect of local luminal delivery of Apt 14 on neointimal formation in a clinically relevant swine iliofemoral injury model. In contrast with a non-selected control aptamer (NSC) that had no impact on VSMC migration, Apt 14 attenuated the wound healing of primary cultured porcine VSMCs to platelet-derived growth factor-BB. Histological analysis of the Apt 14-treated arteries demonstrated a significant reduction in neointimal area percent diameter stenosis compared with arteries treated with saline and NSC controls. The findings of this study suggest that aptamers can function as selective inhibitors and thus provide more fine-tuning to inhibit selective pathways responsible for neointimal hyperplasia.

The Development of an ex vivo Flow System to Assess Acute Arterial Drug Retention of Cardiovascular Intravascular Devices

Purpose: The goal of this study was to develop an ex vivo system capable of rapidly evaluating arterial drug levels in living, isolated porcine carotid arteries.

Methods: A vascular bioreactor system was developed that housed a native porcine carotid artery under physiological flow conditions. The ex vivo bioreactor system was designed to quantify the acute drug transfer of catheter-based drug delivery devices into explanted carotid arteries. To evaluate our ex vivo system, a paclitaxel-coated balloon and a perfusion catheter device delivering liquid paclitaxel were utilized. At 1-h post-drug delivery, arteries were removed, and paclitaxel drug levels measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Parallel experiments were performed in a pig model to validate ex vivo measurements.

Results: LC-MS/MS analysis demonstrated arterial paclitaxel levels of the drug-coated balloon-treated arteries to be 48.49 ± 24.09 ng/mg and the perfusion catheter-treated arteries to be 25.42 ± 9.74 ng/mg at 1 h in the ex vivo system. Similar results were measured in vivo, as arterial paclitaxel concentrations were measured at 59.23 ± 41.27 ng/mg for the drug-coated balloon-treated arteries and 23.43 ± 20.23 ng/mg for the perfusion catheter-treated arteries. Overall, no significant differences were observed between paclitaxel measurements of arteries treated ex vivo vs. in vivo.

Conclusion: This system represents the first validated ex vivo pulsatile system to determine pharmacokinetics in a native blood vessel. This work provides proof-of-concept of a quick, inexpensive, preclinical tool to study acute drug tissue concentration kinetics of drug-releasing interventional vascular devices.

Understanding the Mechanism of Drug Transfer and Retention of Drug-Coated Balloons

Objective:

The purpose of this study was to determine the impact of varying inflation parameters on paclitaxel delivery and retention using a commercially available DCB.

Background:

Drug-coated balloons (DCB) have become the standard treatment for peripheral artery disease. Clinical data suggest that varying DCB delivery parameters directly impact patient outcome. Differences in delivery parameters can potentially alter the retention of the drug coating on DCBs.

Methods:

Harvested porcine carotid arteries were utilized in an ex vivo pulsatile flow bioreactor system. The DCBs were then deployed at a DCB-to-artery ratio of 1:1 or 1.25:1, an inflation time of 30 seconds or 1 minute and transit time of 30 seconds or 3 minutes. The amount of drug retention in arterial tissue was evaluated by pharmacokinetic analysis at 1 hour and 1 day post DCB deployment.

Results:

Arterial paclitaxel levels were found to be less at an inflation ratio of 1:1 with 3-minute transit time as compared to 30 seconds of transit time at 1 hour (12.3 ± 1.6 ng/mg vs. 391 ± 139 ng/mg, P = .036). At 1-day, DCBs deployed at a ratio of 1:1 resulted in less drug retention as compared to 1.25:1 (61.3 ± 23.1 ng/mg vs. 404 ± 195 ng/mg, P = .013).

Conclusion:

Arterial paclitaxel retention is reduced with extended transit times and sub-optimal expansion of the balloon. Optimization of delivery parameters can serve as an effective strategy to enhance clinical DCB outcomes.

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.

New Ultrasound-Controlled Paclitaxel Releasing Balloon vs. Asymmetric Drug-Eluting Stent in Primary ST-Segment Elevation Myocardial Infarction - A Prospective Randomized Trial

BACKGROUND

Application of drug-coated balloons (DCBs) is popular for the treatment of percutaneous coronary intervention (PCI). A new DCB has been designed as ultrasound-controlled paclitaxel releasing. This study was conducted to determine whether a DCB-only strategy has a similar safety profile and equal angiographic and clinical outcomes to DES implantation in primary ST-elevation myocardial infarction (STEMI) patients, as well as determine the efficiency and safety of this new DCB.Methods and Results:Overall, 184 pretreated STEMI patients were randomized into DCB and DES groups with a 1:1 allocation. The main study end-point was late lumen loss (LLL) during the 9 months after PCI. Late lumen loss was reported to be 0.24±0.39 mm in the DCB group and 0.31±0.38 mm in the DES group (P=0.215). Diameter stenosis was 28.27±15.35% in the DCB group and 25.73±15.41% in the DES group (P=0.312). Major adverse cardiovascular events (MACEs) were reported in 3 patients (3.4%) in the DCB group and 4 patients (4.7%) in the DES group (P=0.718). TLR and TVR in the DCB group was 2.3%, 3.4% and 2.4%, 3.5% in the DES group (P=1.000), respectively. No cardiac death and stent thrombosis (ST) was found in the DCB group at 12 months clinical follow up.

CONCLUSIONS

The DCB-only strategy showed good angiographic and clinical outcomes in the 9- and 12-month follow-up periods, respectively. The VasoguardTM DCB is safe and feasible to treat STEMI patients.

A novel paclitaxel coated balloon with increased drug transfer for treatment of complex vascular lesions

Background

Drug coated balloons (DCB) with paclitaxel (Ptx) dose of 2–3.5 μg/mm² balloon surface inhibit restenosis with different effectiveness and duration of success. A clinical dose finding study is not known for any of the currently marketed products. The aim of the present preclinical trial was to investigate a novel DCB coated with 6 μg Ptx/mm² in a porcine model.

Methods and results

The current study investigated a DCB with a novel, modified iopromide based matrix with 6 μg Ptx/mm². Drug transfer to the vessel wall of peripheral arteries was compared with a dose of 3 μg Ptx/mm² and two fully overlapping DCB with 3 μg Ptx/mm², each.

Ptx concentration in the vessel wall after drug transfer was about twice as high for balloons with 6 μg/mm² (1957±1472 μg/g) and two overlapping DCB with 3 μg Ptx/mm², each (1287±619 μg/g) compared to a single balloon with 3 μg Ptx/mm², (787±738 μg/g), with statistical significant differences for 1x6 μg/mm² vs. 1x3 μg/mm² (p = 0.017) but not for 2x3 μg/mm² vs. 1x3 μg/mm² (p = 0.184) and 1x6 μg/mm² vs. 2x3 μg/mm² (p = 0.178). The proportion of residual Ptx on balloon after treatment was similar for all groups between 6±1% and 10±3% of dose on balloon.

Conclusion

The dose of 6 μg Ptx/mm² was successfully as well as reproducibly coated on conventional balloon catheters. Increased Ptx on balloons resulted in increased drug concentration in the vessel wall. A single balloon with 6 μg Ptx/mm² seems to provide double dose compared to 3 μg Ptx/mm², facilitates the procedure, and may reduce medico-economic cost compared to the use of two standard DCB.

Preclinical Evaluation of the Temporary Drug-Coated Spur Stent System in Porcine Peripheral Arteries

BACKGROUND

Drug penetration into the deeper arterial wall of heavily calcified lesions is one of the limitations of drug-coated balloons and drug-eluting stents in vascular interventions. The Temporary Spur Stent (TSS) system is characterized by a self-expanding nitinol stent that is uniformly covered in radialspikes, which, when coated, should allow a deeper penetration and longer retention of the drug into the diseased artery walls by penetrating through the calcified plaques.

MATERIALS AND METHODS AND RESULTS

Uncoated TSS and paclitaxel (PTX)-coated TSS systems have been deployed in porcine peripheral arteries. Four weeks after the deployment of uncoated TSS systems, no adverse vascular remodeling or neointimal formation in the treated vessel segments were noticed. PTX-coated TSS systems transferred 9%±7% of the drug that was on the device to the targeted vessel area (196±163 ng PTX/mg arterial tissue) and the addition of the fluorescent dye Nile red to the coating showed that the spikes promote the transfer of the coating to the deeper layers of the vessel wall. The PTX-coated TSS systems showed a significant reduction in neointimal proliferation compared to the uncoated TSS systems: quantitative angiography showed a vessel diameter stenosis of 37.2%±11.0% and 16.4%±8.8% 4 weeks after the treatment with uncoated and PTX-coated TSS systems, respectively.

CONCLUSION

The treatment with the TSS system was well tolerated and the spikesfacilitate the transfer of the coating into deeper layers of the vessel wall. Moreover, the PTX-coated TSS systems effectively inhibit neointimal proliferation.

Study on the safety and effectiveness of drug-coated balloons in patients with acute myocardial infarction

BACKGROUND

Drug-coated balloon (DCB) is a new technology that has emerged in recent years and has been proven to be effective and safe in the treatment of in-stent restenosis. The purpose of this article is to observe the safety and effectiveness of drug-coated balloons in patients with acute myocardial infarction.

METHOD

We selected 80 patients admitted to the hospital for STEMI from January 2018 to December 2019. The subjects were randomly divided into a Yinyi (Liaoning) Biotech Bingo Drug Coated Balloon treatment group (balloon group, n  = 38) and a drug-eluting stent (DES) treatment group (stent group, n  = 42). Patients were followed up to understand the incidence of major adverse cardiovascular events (MACE) at 1 month, 6 months and 1 year after surgery. Coronary angiography was rechecked 1 year after surgery to understand the late lumen loss (LLL) in the two groups.

RESULT

During the one-year follow-up, the LLL of the target lesion in the balloon group was -0.12±0.46 mm, while the target lesion in the stent group was 0.14±0.37 mm ( P  <0.05). Within 1 year, the incidence of MACE in the balloon group was 11%, while the incidence of MACE in the stent group was 12%. There was no significant difference between the two groups.

IN CONCLUSION

When PCI is used for STEMI, only DCB therapy is safe and effective, and has shown good clinical effects during a one-year follow-up period.

In Vitro and In Vivo Comparative Evaluation of a Shellac-Ammonium Paclitaxel-Coated Balloon versus a Benchmark Device

Objectives

The present study was designed to compare the characteristics and performance regarding drug delivery of a novel drug-coated balloon (DCB) to a benchmark device (Restore® versus SeQuent® Please) in an in vitro and in vivo model.

Background

Although Restore® and SeQuent® are both paclitaxel-coated, they use different coating excipient, shellac-ammonium salt and iopromide, respectively. Preclinical study comparing these two different commercial DCBs regarding their characteristics and effects on early vascular response is sparse.

Methods

Restore® and SeQuent® DCBs were scanned with electron microscopy for surface characteristic assessment. Both DCBs were transported in an in vitro vessel model for the evaluation of drug wash-off rate and particulate formation. Eighteen coronary angioplasties with either Restore® or SeQuent® DCBs were conducted in 6 swine (three coronary vessels each). Histopathological images of each vessel were evaluated for vessel injury.

Results

The surface of Restore® DCB was smooth and evenly distributed with hardly visible crystal, while SeQuent® DCB showed a rougher surface with relatively larger apparent crystals. Restore® DCB had a lower drug wash-off rate and fewer large visible particles, compared to the SeQuent® DCB. No significant difference in mean injure score was found between Restore® and SeQuent® group.

Conclusion

Our results suggest that Restore® is better in preclinical performance regarding less release of particles and lower drug wash-off rate as compared to SeQuent® Please. The Restore® DCB, using stable amorphous coating and shellac-ammonium salt as an excipient, appears to provide an advantage in drug delivery efficacy; however, further clinical studies are warranted.

Downstream Paclitaxel Released Following Drug-Coated Balloon Inflation and Distal Limb Wound Healing in Swine

•

PCBs are a clinically proven antirestenotic alternative to plain percutaneous transluminal angioplasty of superficial femoral arteries but their application in critical limb ischemia is inhibited by the concern that the downstream release of particulate paclitaxel may negatively impact distal lower limb’s circulation and its tissues already compromised by chronic ischemia.

•

To investigate this concern experimentally, we used an animal model of standardized distal limb wounds to determine the effect of downstream paclitaxel released during PCB treatment of superficial femoral arteries on distal wound healing process.

•

A clinically relevant concentration of paclitaxel in the vicinity of the wound did not impair the healing of preexisting distal cutaneous lesions in healthy swine even after multiple PCB deployments.

The authors evaluated the presence of paclitaxel and healing of distal hind limb wounds created in 27 swine using biopsy punches followed by paclitaxel-coated balloon (PCB) use in the iliofemoral arteries of healthy swine. After 14 and 28 days, no differences were seen in time course, appearance, and histopathology of wound healing between the single or triple PCB and uncoated balloon treatment despite clinically relevant paclitaxel concentrations in the skin adjacent to the healing wounds. Presence of paclitaxel downstream from the PCB treatment site does not impair the wound healing response of preexisting distal cutaneous lesions in healthy swine.

An ultralow dose paclitaxel coated drug balloon with an outer protective sheath for peripheral arterial disease treatment

Use of a drug-eluting coated balloon (DCB) represents a promising therapeutic method for peripheral arterial disease (PAD) due to its advantages such as no implant permanently retained in the patient and no inflammatory reaction and endothelialization barrier caused by a permanent stent. However, there is still a huge challenge of controlling the release of drugs from the DCB into vessel tissue. The uncontrolled release of drugs and high drug loading amounts could potentially lead to distal embolization and mortality events. In our study, an ultralow dose paclitaxel (PTX) coated DCB appended with an outer protective sheath was designed to treat peripheral vessel stenosis. An in vitro study demonstrated that the sheath could significantly reduce the drug loss during the delivery process and the meglumine matrix could effectively promote the transfer of PTX into vessel tissue. The pharmacokinetics study in the swine model also demonstrated that the PTX amount remaining in the vessel after being treated by our DCB was comparable to similar products on market although only less than a third of the PTX was used. The safety study indicated that the DCB treatment did not have any adverse impact on the physiological function of the vessel. Therefore, our ultralow dose PTX coated DCB could provide an effective and safe treatment for PAD.

Microcrystalline paclitaxel-coated balloon for revascularization of femoropopliteal artery disease: Three-year outcomes of the randomized BIOPAC trial

The aim of the BIOPAC trial was to determine long-term safety and efficacy of a novel microcrystalline paclitaxel-coated balloon (mcPCB) with a biocompatible polymer as an excipient in the treatment of occlusive femoropopliteal lesions. In this first-in-human prospective controlled randomized trial, 66 patients with femoropopliteal, symptomatic (Rutherford stages 2B to 5) occlusive arterial disease were randomized to either mcPCB (study group) or POBA (plain old balloon angioplasty) (control group) on a 1:1 basis. Late lumen loss (LLL) at 6 months was the primary endpoint of the study and serious adverse events (SAE: death, amputation, repeated revascularization) were considered a composite secondary endpoint. Routine angiography was scheduled for all study subjects at 6-month follow-up; outpatient appointments were scheduled at 12 and 36 months after intervention. At 6 months, the LLL was 63% lower in the mcPCB group compared to the POBA group (0.52 ± 1.2 vs 1.39 ± 1.1 mm; psup < 0.01). Binary restenosis occurred in 23% vs 52% of patients ( p = 0.02). At 3 years, the prevalence of SAE was significantly lower in the mcPCB group (33.3 vs 63.3%; p = 0.02), which mainly resulted from a twofold reduction in target vessel revascularization rate (28.6 vs 59.3%; p = 0.02). The difference in mortality was nonsignificant (7.4 vs 14.3%; p = 0.42). Patients with mcPCB were less symptomatic and less likely to adhere to secondary prevention measures. In this pivotal trial, a novel mcPCB proved superior to POBA concerning LLL at 6-month follow-up, and SAE at 12 months. This result was sustained up to 3 years. There was no difference between groups regarding mortality. ClinicalTrials.gov Identifier: NCT02145065

Efficacy and safety of a magnesium stearate paclitaxel coated balloon catheter in the porcine coronary model

BACKGROUND

Local administration of growth-inhibiting substances such as paclitaxel or sirolimus could reduce the risk of restenosis. In the drug coated balloon (DCB) technology the coating and the applied dose seem to play a major role. The aim of the present preclinical studies was to investigate the efficacy and safety of a specific DCB with paclitaxel as active ingredient and magnesium stearate as excipient.

METHODS

Evaluation of the coating, drug release and transfer was done ex vivo and in vivo on peripheral arteries. A porcine coronary stent model was chosen to provoke intimal thickening. Conventional uncoated balloons were compared with paclitaxel urea and paclitaxel magnesium stearate coated balloons. QCA and histomorphometry was performed on treated vessels. Three areas of the heart were histologically examined for pathological changes.

RESULTS

QCA and histomorphometry revealed no differences in baseline data between treatment groups. All DCB groups showed a significant reduction of angiographic and histologic parameters describing neointimal formation 4 weeks after treatment (e.g. mean angiographic late lumen loss all coated 0.31 ± 0.18 mm versus 0.91 ± 0.37 mm in the uncoated balloon group). There were no device-related animal deaths or clinical abnormalities. In spite of very slight-to-slight microscopic findings limited to small arterial vessels in downstream tissue there was no change in left ventricular ejection fraction or angiographic presentation of small side branches of treated arteries.

CONCLUSION

Paclitaxel DCB using stearate as excipient show a high efficacy in reducing neointima formation after experimental coronary intervention. No evidence of myocardial damage resulting from distal embolization was found.

Pre-Clinical Investigation of Liquid Paclitaxel for Local Drug Delivery: A Pilot Study

The purpose of this pilot study was to investigate the feasibility of a perfusion catheter to deliver liquid paclitaxel into arterial segments. A clinically relevant rabbit ilio-femoral injury model was utilized to determine the impact of liquid paclitaxel delivered locally into the vessel wall using a perfusion catheter at 1 h to 14 days. Treatment by two clinically available forms of liquid paclitaxel, a solvent-based (sb) versus an albumin-bound (nab), along with a control (uncoated balloons), were investigated. Pharmacokinetic results demonstrated an increase in the retention of the sb-paclitaxel versus the nab-paclitaxel at 1 h; however, no other differences were observed at days one, three, and seven. Histological findings at 14 days showed significantly less neointimal area in the sb-paclitaxel treated arteries as compared with the nab-paclitaxel and the uncoated balloon-treated arteries. Additionally, percent area stenosis was significantly less in the sb-paclitaxel group. These results support the concept of local liquid delivery of paclitaxel into the arterial segments.

No Difference in Mid-term and Long-Term Mortality After Vascular Paclitaxel Exposure

BACKGROUND

Concern has been raised over potential paclitaxel-related increase in mortality following treatment with drug-coated balloons. We report mid-term and long-term patient-level mortality in three trials from our institution.

METHODS

Patient data from the DRECOREST I and II trials, as well as the FINNPTX-trial, were included for analysis. The DRECOREST I involved patients with stenosis in a bypass vein graft, and the DRECOREST II included patients with stenosis in a dialysis fistula. The FINNPTX-trial randomized patients to either a prosthetic bypass or drug-eluting stent for long femoropopliteal lesions. Since the present retrospective study addressed mortality related to intravascular paclitaxel exposure and population data in Finland are comprehensive, we were able to include all patients exposed to paclitaxel in the three trials. Mortality data were extracted from the population registry, as well as patient records. Survival rates were analyzed for all trials pooled and separately. Late mortality was retrospectively analyzed and cross-referenced with national registry data.

RESULTS

A total of 142 patients were included, 76 treated with paclitaxel-eluting device, and 66 without. The mean follow-up time for survivors was 3.9 years. Overall all-cause mortality was 31.7% during follow-up. In the DRECOREST I-trial, 35.5% of patients died in the paclitaxel group and 37.9% in the control group (P = 0.84). In the DRECOREST II, overall mortality was 55.6% in the paclitaxel group and 44.4% in the control group (P = 0.51). In the FINNPTX-trial 22.2% died in the paclitaxel group and 10.5% in the control group during follow-up (P = 0.30). No single cause of death was overrepresented. The most common causes of death in both groups were cardiovascular death, 59.3% in the paclitaxel group and 52.4% in the control group (P = 0.733), followed by malignancy (14.8% vs. 14.3% in the groups respectively).

CONCLUSIONS

No significant difference was seen in the overall analysis between the paclitaxel and the control group. A statistically nonsignificant elevated late mortality in the FINNPTX-trial after paclitaxel exposure was observed. However, the numbers in the individual trials are small and should be interpreted in the context of future patient-level meta-analysis.

Diffuse Cutaneous Manifestations after Drug-Coated Balloon Angioplasty

We present here a case of an uncommon cutaneous manifestation after paclitaxel-coated balloon angioplasty. In this case, the patient underwent drug-coated balloon angioplasty for stenosis of a prior vein bypass graft. The patient subsequently developed extensive cutaneous lesions not confined to a single arterial distribution. This case represents a rare complication related to paclitaxel-eluting balloons and provides a cautionary tale as well as clinical acumen for providers in using such devices in their practice.

Pre-Clinical Investigation of Keratose as an Excipient of Drug Coated Balloons

BACKGROUND

Drug-coated balloons (DCBs), which deliver anti-proliferative drugs with the aid of excipients, have emerged as a new endovascular therapy for the treatment of peripheral arterial disease. In this study, we evaluated the use of keratose (KOS) as a novel DCB-coating excipient to deliver and retain paclitaxel.

METHODS

A custom coating method was developed to deposit KOS and paclitaxel on uncoated angioplasty balloons. The retention of the KOS-paclitaxel coating, in comparison to a commercially available DCB, was evaluated using a novel vascular-motion simulating ex vivo flow model at 1 h and 3 days. Additionally, the locoregional biological response of the KOS-paclitaxel coating was evaluated in a rabbit ilio-femoral injury model at 14 days.

RESULTS

The KOS coating exhibited greater retention of the paclitaxel at 3 days under pulsatile conditions with vascular motion as compared to the commercially available DCB (14.89 ± 4.12 ng/mg vs. 0.60 ± 0.26 ng/mg, p = 0.018). Histological analysis of the KOS-paclitaxel-treated arteries demonstrated a significant reduction in neointimal thickness as compared to the uncoated balloons, KOS-only balloon and paclitaxel-only balloon.

CONCLUSIONS

The ability to enhance drug delivery and retention in targeted arterial segments can ultimately improve clinical peripheral endovascular outcomes.

Long-term performance and biocompatibility of a novel bioresorbable scaffold for peripheral arteries: A three-year pilot study in Yucatan miniswine

AIMS

Peripheral arteries are constantly exposed to deformation (elongation, twisting, shortening, compression) making bioresorbable scaffolds (BRS) a potentially attractive therapeutic alternative to metallic stents. We conducted a long-term pilot preclinical study of a novel sirolimus-eluting BRS in peripheral arteries.

METHODS AND RESULTS

Fourteen BRS were deployed in iliofemoral arteries of seven healthy Yucatan miniswine and examined with imaging, pharmacokinetic, histopathologic, and polymer degradation techniques at 0, 30, 90, 180 days, 1, 2, and 3.3 years. Angiographic late luminal loss remained unchanged at 30 and 180 days but significantly decreased from 1 to 3.3 years. optical coherence tomography (OCT) showed late increase in lumen area (1 year: 14.70 ± 3.58 mm² , 2 years 22.04 ± 3.81 mm² , and 3.3 years 23.45 ± 7.07 mm² ; p < .05) primarily due to scaffold area enlargement between 1 and 3.3 years, while there was no difference in the percent area stenosis at all time points. Histologic evidence of scaffold degradation was observed starting at 2 years, with minimal inflammatory reaction. At 3.3 years, BRS struts were rarely discernible by OCT, confirmed by a nearly complete polymer degradation by molecular weight analysis.

CONCLUSIONS

In this pilot study, novel sirolimus-eluting BRS showed promising acute and chronic performance in the iliofemoral arteries of Yucatan miniswine.

Ultrasound controlled paclitaxel releasing system-A novel method for improving the availability of coronary artery drug coated balloon

OBJECTIVES

The aim of this study is to improve local-drug delivery efficiency and tissue absorption using the ultrasound (US)-responsible drug coating based on a newly developed US-controlled paclitaxel release balloon.

BACKGROUND

Low availability of the drug coating remains a major concern of the current drug coated balloon (DCB). The goal of this study is to develop a method to use an US-responsible paclitaxel-loaded microcapsules (PM) as the main content of balloon drug coating to enhance bioavailability of DCB.

METHODS

An US-controlled paclitaxel release balloon is designed and fabricated based on the US-responsible paclitaxel-loaded poly (lactic-co-glycolic acid) (PLGA) microcapsules. Rapid exchange percutaneous transluminal coronary angioplasty (PTCA) balloon catheters were coated with the PM. The deployment processes of the paclitaxel-loaded microcapsules coated balloons (PMCB) under US, PMCB without US and a homogenous matrix of paclitaxel and iopromide coated balloon (PICB) were then placed in healthy and stent implanted porcine coronary arteries.

RESULTS

In vitro release assay demonstrated an ability of US (1 MHz, 1.22 W/cm² , 1 minute) to affect the release kinetics of paclitaxel from PM by inducing a 76 ± 5.4% increase in the rate of release. The paclitaxel content in target vessels are 203 ± 37 μg/g for PMCB under US, 85 ± 23 μg/g for PMCB without US, and 107 ± 31 μg/g for PICB 1-hr post-surgery. The availability of the drug for the PMCB reaches 27% under US.

CONCLUSIONS

The US-controlled paclitaxel release balloon significantly improved the drug content of the target vessels in the porcine model.

Provisional Stenting Using the Zilver PTX Drug-Eluting Stent After Drug-Coated Balloon Angioplasty: Initial Experience From the Double Drug Dose "3D" Study

Purpose: To explore the provisional use of a drug-eluting stent (DES) after suboptimal drug-coated balloon (DCB) angioplasty in complex, calcified femoropopliteal lesions. Materials and Methods: A prospective, single-center, investigator-initiated pilot study enrolled 15 patients (mean age 71.3 years; 9 men) with symptomatic stenosis (n=6) or occlusion (n=9) of the native superficial femoral and/or proximal popliteal arteries who experienced suboptimal DCB dilation despite postdilation. Lesion characteristics were evaluated with computed tomography angiography and duplex ultrasound confirmed by intravascular ultrasound. Follow-up included clinical and imaging evaluations as well as blood tests to monitor inflammatory markers. Endpoints included systemic inflammation, acute/chronic thrombosis, aneurysm formation, and mortality. Results: Provisional stenting was required for residual stenosis >50% in 4 cases and flow-limiting dissection in 11. Provisional spot stenting was done using the Zilver PTX DES. Clinical improvement was observed in all cases. After 24-month follow-up all patients were alive and in good clinical condition. One- and 2-year primary patency rates were 93.3% and 92.9%, respectively; secondary patency was 100%. Restenosis required reintervention in 2 cases. No local or systemic complications or toxicity were observed due to the use of a double dose of paclitaxel. No significant increase in any inflammation marker was observed in the perioperative period, and no aneurysm formation was seen over 24 months of follow-up. Conclusion: Combined DCB plus DES therapy seems to be safe and correlated with high primary patency following suboptimal angioplasty. Larger studies are required to confirm the safety and efficacy of this approach.

Taking paclitaxel coated balloons to a higher level: Predicting coating dissolution kinetics, tissue retention and dosing dynamics

Paclitaxel coated balloons (PCBs) are a promising non-implantable alternative to drug-eluting stents, whereby drug is delivered to the arterial wall in solid form as a semi-continuous solid coating or as micro drug depots. To date, it has been impossible to predict or even infer local tissue dosing levels and persistence, making it difficult to compare in vivo performance of different devices in healthy animals or to extrapolate such data to diseased human arteries. Here we derive and analyze a coupled reaction diffusion model that accounts for coating dissolution and tissue distribution, and predicts the concentration of dissolved drug in the tissue during and post dissolution. Time scale analysis and numerical simulations based on estimated diffusion coefficients in healthy animal and diseased human arteries both imply that dissolution of crystalline paclitaxel coating is mass transfer coefficient-limited, and can therefore be solved for independently of the tissue transport equations. Specifically, coating retention is predicted to follow piecewise linear kinetics, reflecting the differential and faster dissolution of lumenal versus tissue-embedded coating owing to a disparity in convective forces. This prediction is consistent with published data on a range of PCBs and allowed for the estimation of the associated dissolution rate-constants and the maximal soluble drug concentration in the tissue during coating dissolution. Maximal soluble drug concentration in the tissue scales as the product of the solubility and ratio of the dissolution and diffusion rate-constants. Thus, coatings characterized by micromolar solubilities give rise to nanomolar soluble concentrations in healthy animal arteries and ~0.1 micromolar in calcified atherosclerotic arteries owing to slower tissue diffusion. During dissolution, retention in porcine iliofemoral arteries is predicted to be dominated by solid coating, whereas post dissolution it is dominated by receptor-bound drug (3.7 ng receptors/g tissue). Paclitaxel coating dissolution and dosing kinetics can now be modeled based upon accepted principles of surface dissolution and tissue transport to provide insights into the dependence of clinical efficacy on device properties and the interplay of lesion complexity and procedural parameters.

Delivery of Cell-Specific Aptamers to the Arterial Wall with an Occlusion Perfusion Catheter

Current strategies to prevent restenosis following endovascular treatment include the local delivery of anti-proliferative agents to inhibit vascular smooth muscle cell (VSMC) proliferation and migration. These agents, not specific to VSMCs, are deposited on the luminal surface and therefore target endothelial cells and delay vascular healing. Cell-targeted therapies, (e.g., RNA aptamers), can potentially overcome these safety concerns by specifically binding to VSMC and inhibiting proliferation and migration. The purpose of this study was to therefore demonstrate the ability of a perfusion catheter to deliver cell-specific RNA aptamer inhibitors directly to the vessel wall. RNA aptamers specific to VSMCs were developed using an in vitro cell-based systematic evolution of ligand by exponential enrichment selection process. Two aptamers (Apt01 and Apt14) were evaluated ex vivo using harvested pig arteries in a pulsatile flow bioreactor. Local drug delivery of the aptamers into the medial wall was accomplished using a novel perfusion catheter. We demonstrated the feasibility to deliver aptamer-based drugs directly to the medial layer of an artery using a perfusion catheter. Such cell-specific targeted therapeutic drugs provide a potentially safer and more effective treatment option for patients with vascular disease.

An Experimental Study of Paclitaxel Embolisation During Drug Coated Balloon Angioplasty

OBJECTIVE

Drug coated balloons (DCB) improve the patency of femoropopliteal angioplasty but their use in infrapopliteal lesions is debateable as paclitaxel (PTX) particle embolisation has been suspected in some trials. The aim of this study was to compare experimentally five DCBs in terms of distal embolism of PTX.

METHODS

Twenty-five New Zealand rabbits were divided into five groups according to the DCB used: Lutonix (Bard), In.Pact (Medtronic), Passeo-18 Lux (Biotronik), Ranger (Boston Scientific), and Stellarex (Spectranetics) (n = 5 in each group). After ligation of the right common iliac artery, a 4 × 40 mm DCB was inflated in the infrarenal aorta for 180 seconds. Rabbits were euthanised two hours after inflation of the DCB. The infrarenal aorta, a blood sample and three left hind leg muscles (tensor fasciae latae [TFL], vastus lateralis [VL], and tibialis anterior [TA] muscles) were harvested for blind measurement of PTX concentrations and histological analysis (PTX emboli count).

RESULTS

In the TA muscle (the most distal), concentrations of PTX were significantly lower for the Ranger (0.067 ng/mg) than for the Lutonix (0.342 ng/mg; p = .008), In.Pact (0.370 ng/mg; p = .012), and Passeo-18-Lux (0.160 ng/mg; p = .021) DCBs. Similarly, concentrations of PTX were significantly lower for the Passeo-18-Lux than for the In.Pact (p = .028). Concentrations of PTX were not significantly different between DCBs in the TFL and VL muscles. Concentrations of PTX were found to be significantly higher in the plasma and lower in the aorta and on the DCBs after use of Lutonix compared with the four other DCBs. Histological analysis revealed evidence of embolised PTX crystals in small arterioles of all muscle tissue samples without any significant difference between the DCBs.

CONCLUSIONS

This study suggests some differences regarding distal embolisation profiles between the five assessed DCBs. Although clinical implications remain to be demonstrated, the present results may have implications when choosing a DCB, especially in a critical limb ischaemia setting.

Balloons and Stents and Scaffolds: Preclinical Evaluation of Interventional Devices for Occlusive Arterial Disease

Atherosclerosis places a significant burden on humankind; it is the leading cause of mortality globally, and for those living with atherosclerosis, it can significantly impact quality of life. Fortunately, treatment advances have effectively reduced the morbidity and mortality related to atherosclerosis, with one such modality being percutaneous intervention (PCI) to open occluded arteries. Over the 40-year history of PCI, preclinical models have played a critical role in demonstrating proof of concept, characterizing the in vivo behavior (pharmacokinetics, degradation) and providing a reasonable assurance of biologic safety of interventional devices before entering into clinical trials. Further, preclinical models may provide insight into the potential efficacy of these devices with the appropriate study design and end points. While several species have been used in the evaluation of interventional devices, the porcine model has been the principal model used in the evaluation of safety of devices for both coronary and endovascular treatments. This article reviews the fundamentals of permanent stents, transient scaffolds, and drug-coated balloons and the models, objectives, and methods used in their preclinical evaluation.

Risk of Death Following Application of Paclitaxel-Coated Balloons and Stents in the Femoropopliteal Artery of the Leg: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background Several randomized controlled trials ( RCT s) have already shown that paclitaxel-coated balloons and stents significantly reduce the rates of vessel restenosis and target lesion revascularization after lower extremity interventions. Methods and Results A systematic review and meta-analysis of RCT s investigating paclitaxel-coated devices in the femoral and/or popliteal arteries was performed. The primary safety measure was all-cause patient death. Risk ratios and risk differences were pooled with a random effects model. In all, 28 RCT s with 4663 patients (89% intermittent claudication) were analyzed. All-cause patient death at 1 year (28 RCT s with 4432 cases) was similar between paclitaxel-coated devices and control arms (2.3% versus 2.3% crude risk of death; risk ratio, 1.08; 95% CI, 0.72-1.61). All-cause death at 2 years (12 RCT s with 2316 cases) was significantly increased in the case of paclitaxel versus control (7.2% versus 3.8% crude risk of death; risk ratio, 1.68; 95% CI, 1.15-2.47; -number-needed-to-harm, 29 patients [95% CI , 19-59]). All-cause death up to 5 years (3 RCT s with 863 cases) increased further in the case of paclitaxel (14.7% versus 8.1% crude risk of death; risk ratio, 1.93; 95% CI , 1.27-2.93; -number-needed-to-harm, 14 patients [95% CI , 9-32]). Meta-regression showed a significant relationship between exposure to paclitaxel (dose-time product) and absolute risk of death (0.4±0.1% excess risk of death per paclitaxel mg-year; P<0.001). Trial sequential analysis excluded false-positive findings with 99% certainty (2-sided α, 1.0%). Conclusions There is increased risk of death following application of paclitaxel-coated balloons and stents in the femoropopliteal artery of the lower limbs. Further investigations are urgently warranted. Clinical Trial Registration URL : www.crd.york.ac.uk/PROSPERO . Unique identifier: CRD 42018099447.

Comparison of Biologic Effect and Particulate Embolization after Femoral Artery Treatment with Three Drug-Coated Balloons in Healthy Swine Model

PURPOSE

To investigate morphometric characteristics and differences in particulate embolization between 3 drug-coated balloons (DCBs).

MATERIALS AND METHODS

Effects of 3 overlapping DCBs (IN.PACT, Ranger, and Stellarex) were assessed in 24 femoral arteries of 12 swine with 28-day follow-up. Histologic analysis of treated arterial wall site and downstream skeletal muscle and coronary band changes were assessed for evidence of emboli. Paclitaxel concentration for downstream skeletal muscle and coronary band and vessel diameters with downstream changes were also measured.

RESULTS

Signs of drug effect, such as medial smooth muscle cell (SMC) loss in depth and circumference, were not significantly different for all 3 DCBs (IN.PACT vs Ranger vs Stellarex: SMC loss depth, 2.8 [interquartile range [IQR]: 2.1-3.6] vs 3.2 [IQR: 2.3-3.8] vs 3.5 [IQR: 2.6-3.8], P = .7; SMC loss circumference, 1.0 [IQR: 1.0-1.0] vs 1.3 [IQR: 1.0-1.8] vs 1.0 [IQR: 1.0-1.2], P = .08). Percentage of sections with vascular changes in downstream nontarget tissues from arteries was similar in all 3 DCBs (42.9% vs 25.0% vs 28.6%, P = .2). Downstream levels of paclitaxel concentration in skeletal muscle were significantly higher for IN.PACT (216.5 ng/g vs 91.5 ng/g vs 101.9 ng/g, P = .01). Median vessel diameters with evidence of downstream changes were smallest for IN.PACT compared with Ranger and Stellarex (57 μm vs 74 μm vs 64 μm).

CONCLUSIONS

All 3 DCBs exhibited no significant difference in local target site drug effect based on histologic analysis. Downstream effects of paclitaxel and/or downstream emboli were highest for IN.PACT compared with Ranger and Stellarex, whereas vessel diameters with evidence of downstream changes were smaller for IN.PACT vs Ranger and Stellarex.

Two-year longitudinal evaluation of a second-generation thin-strut sirolimus-eluting bioresorbable coronary scaffold with hybrid cell design in porcine coronary arteries

BACKGROUND

The first commercially available bioresorbable scaffold (BRS) had a strut thickness of 156 microns. As such, it had the potential for delivery challenges and higher thrombogenicity. The aim herein, is to evaluate biomechanical performance, pharmacokinetics and vascular healing of a novel thin strut (100 μm) sirolimus eluting BRS (MeRes-100, Meril Life Sciences, Gujarat, India) against the once clinically used BRS (Absorb BVS, Abbott, Santa Clara, CA) in porcine coronary arteries.

METHODS

Following device implantation, angiographic and optical coherence tomography (OCT) evaluation were performed at 45, 90, 180 days, 1 year and 2 years. Histological evaluation was per-formed at 30, 90 and 180 days.

RESULTS

At 2 years, both lumen (MeRes-100 7.07 ± 1.82 mm² vs. Absorb BVS 7.57 ± 1.39 mm2, p = NS) and scaffold areas (MeRes-100 9.73 ± 1.80 mm² vs. Absorb BVS 9.67 ± 1.25 mm², p = NS) were comparable between tested and control scaffolds. Also, the late lumen area gain at 2 years was similar in both groups tested (MeRes-100 1.03 ± 1.98 mm² vs. Absorb BVS 0.85 ± 1.56 mm², p = NS). Histologic examination up to 6 months showed comparable healing and inflammation profiles for both devices.

CONCLUSIONS

The novel sirolimus-eluting BRS with thinner struts and hybrid cell design showed similar biomechanical durability and equivalent inhibition of neointimal proliferation when compared to the first-ever Absorb BVS up to 2 years in normal porcine coronary arteries.

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.

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.

Preclinical evaluation of a paclitaxel-incorporated nanoparticle-coated balloon in rabbit and porcine models

BACKGROUND

The main drawback of current available drug coated balloons (DCB) is that a certain percentage of the coated drug is lost in the bloodstream during its delivery to the target lesion. We integrated the nanoparticle-mediated drug delivery technology and polydimethylsiloxane (PDMS) as a new excipient to facilitate an efficient drug delivery and uptake by endothelial cells. The present study aimed to evaluate the efficacy of the new DCB.

METHOD AND RESULTS

The novel DCB were coated with 5.6mg of paclitaxel-incorporated nanoparticles using PDMS. The efficacy of the new DCB was examined in rabbit iliac stent model (n=12) and in the swine in-stent restenosis model (n=8) by quantitative coronary angiography (QCA) and optical coherence tomography (OCT). At 28days follow-up in the swine in-stent restenosis model, the area stenosis was significantly lower in DCB group as compared with that of the control group in OCT analysis (0.31±0.05 vs 0.49±0.06, p=0.04) though there was no significant differences observed in the rabbit iliac stent model in QCA and OCT analysis.

CONCLUSION

The study results indicated that the paclitaxel-incorporated nanoparticle-coated balloon using PDMS has an inhibitory effect for the proliferation of smooth muscle cell in a swine coronary in-stent restenosis model.

Safety of Zilver PTX Drug-Eluting Stent Implantation Following Drug-Coated Balloon Dilation in a Healthy Swine Model

Purpose: To compare the safety of Zilver PTX drug-eluting stents (DES) following drug-coated balloon (DCB) angioplasty or conventional balloon angioplasty (BA) in a healthy porcine iliofemoral artery model. Methods: DES implantation following DCB (DCB+DES) or BA (BA+DES) was assessed by angiography and histology in the nondiseased iliofemoral arteries of 20 animals, with sacrifice at 1, 3, and 6 months. Safety assessment compared quantitative measures of vessel integrity (eg, preservation of artery geometry, structure, and lumen dimensions; absence of aneurysm; malapposition) and histological parameters (eg, excessive inflammation). The percentage of uncovered struts could not be >30% per section and the endothelial cell loss had to be <50%. The vascular and skeletal muscle changes in the downstream regions were also assessed histologically for evidence of emboli. Results: No significant differences in safety parameters, including inflammation and endothelial cell loss, were observed between the 2 groups at all time points. Percentage of fibrin was significantly higher in DCB+DES at 3 months [20.0% (IQR 11.6, 28.4) vs BA+DES 4.2% (IQR 1.4, 9.6), respectively; p=0.04], with consistent trends between groups at all time points. Medial smooth muscle cell loss peaked at 1 month and was not statistically different between groups at any time point, although the loss was greater in the DCB+DES group. Sections with arterioles exhibiting paclitaxel-associated fibrinoid necrosis in downstream tissues were observed exclusively in the DCB group at 1 month (14.3% of sections) and 3 months (11.5%). Conclusion: This preclinical study suggests that Zilver PTX stent implantation is a safe strategy after DCB angioplasty and might be considered for patients who require stenting after DCB treatment.

Paclitaxel-Coated Balloon for Femoropopliteal Artery Disease

PURPOSE OF THE REVIEW

Percutaneous transluminal angioplasty is an established form of therapy for femoropopliteal artery disease. Currently, percutaneous transluminal angioplasty (PTA) is carried out using standard balloon with or without deployment of a stent but is associated with a high rate of restenosis and stent-related complications. Treatment options for restenosis, especially in-stent restenosis, are limited. Drug-coated balloons promise to reduce the rates of restenosis by effective delivery of antiproliferative agent (paclitaxel) directly to vessel wall without the need for a permanent implant. In this review, we look at the technology and rationale behind drug-coated balloons and examine the evidence available so far.

RECENT FINDINGS

Recently, several studies tested the effectiveness of paclitaxel-coated balloon angioplasty compared to that of standard PTA in both de novo lesions and in-stent restenosis of femoropopliteal artery. Paclitaxel-coated balloon use resulted in reduced rates of restenosis and favourable clinical outcomes in both these lesion groups. However, in complex lesions, there is still lack of data to support the use of these balloons. Paclitaxel-coated balloon is a safe and effective therapeutic option in patients with both de novo lesions and in-stent restenosis involving femoropopliteal artery. In light of the new evidence, it is time to consider incorporation of this effective therapeutic option into clinical practice. However, further research is needed for the use of paclitaxel-coated balloons in complex femoropopliteal lesions like calcified lesions especially as adjuncts to cutting balloons and debulking strategies.

Impact of Fluoropolymer-Based Paclitaxel Delivery on Neointimal Proliferation and Vascular Healing

Background—

A polymer-free peripheral paclitaxel-eluting stent (PES, Zilver PTX, Cook, IN) has shown to improve vessel patency after superficial femoral angioplasty. A new-generation fluoropolymer-based PES (FP-PES; Eluvia, Boston Scientific, MA) displaying more controlled and sustained paclitaxel delivery promise to improve the clinical outcomes of first-generation PES. We sought to compare the biological effect of paclitaxel delivered by 2 different stent-coating technologies (fluoropolymer-based versus polymer-free) on neointimal proliferation and healing response in the familial hypercholesterolemic swine model of femoral restenosis.

Methods and Results—

The biological efficacy of clinically available FP-PES (n=12) and PES (n=12) was compared against a bare metal stent control (n=12; Innova, Boston Scientific, MA) after implantation in the femoral arteries of 18 familial hypercholesterolemic swine. Longitudinal quantitative vascular angiography and optical coherence tomography were performed at baseline and at 30 and 90 days. Histological evaluation was performed at 90 days. Ninety-day quantitative vascular angiography results showed a lower percent diameter stenosis for FP-PES (38.78% [31.27–47.66]) compared with PES (54.16% [42.60–61.97]) and bare metal stent (74.52% [47.23–100.00]; P <0.001). Ninety-day optical coherence tomography results demonstrated significantly lower neointimal area in FP-PES (8.01 mm 2 [7.65–9.21]) compared with PES (10.95 mm 2 [9.64–12.46]) and bare metal stent (13.83 mm 2 [11.53–17.03]; P <0.001). Histological evaluation showed larger lumen areas and evidence of higher biological activity (smooth muscle cell loss and fibrin deposition) in the FP-PES compared with PES and bare metal stent.

Conclusions—

In the familial hypercholesterolemic swine model of femoral restenosis, the implantation of an FP-PES resulted in lower levels of neointimal proliferation and sustained biological effect ≤90 days compared with a polymer-free stent-based approach.

The Lutonix® drug-coated balloon: A novel drug delivery technology for the treatment of vascular disease

Local drug delivery of an anti-proliferative drug from balloon catheter systems to the site of arterial injury has been attempted repeatedly over the years with limited success in drug uptake and retention. Accessibility of the drug at the site is critical to combat the body's response to the procedural trauma of angioplasty. Recently, formulations have been designed which achieve delivery of therapeutic doses of the anti-proliferative drug paclitaxel to arteries with higher efficiency and longer tissue retention. These formulations succeed through formation of a drug reservoir in the artery wall enabling release after the initial angioplasty procedure. These formulations have become the cornerstone of several drug coated balloon (DCB) technologies which have found an initial, broad therapeutic application in the treatment of stenosis of the superficial femoral artery (SFA). DCBs achieve drug delivery while leaving no implant behind and represent a new class of combination products developed at the interface of engineering, chemistry and medical science. This review article summarizes the development of the LUTONIX® drug coated balloon catheter. The introduction of DCB technology has provided clinicians and patients with new SFA treatment options while ongoing clinical evidence in additional vascular beds is generated.

[Drug-coated balloons in the treatment of peripheral artery disease (PAD). History and current level of evidence]

BACKGROUND

Despite initially encouraging technical success after femoropopliteal PTA, restenosis remains the major challenge in patients with peripheral artery disease (PAD). The main cause of restenosis is neointimal hyperplasia which can be suppressed by antiproliferative drugs. Drug-coated balloons (DCB) or drug-eluting stents (DES) are used for the inhibition of restenosis.

OBJECTIVES

The present article gives an overview of DCB development, actual DCB systems for femoro- and infrapopliteal use, displays the outcomes of randomized clinical trials and the discusses the evidence for the DCB treatment in PAD.

METHODS

A systematic literature search was performed in i) medical journals (i. e. MEDLINE), ii) in international registers for clinical studies (i. e. www.clinicaltrials.gov ) and in iii) scientific session abstracts.

RESULTS

The clinical evidence of the PTX-DCB of the first and following generation has been shown in several controlled randomized trials.

CONCLUSIONS

Major advantages of the DCBs lie in leaving no stent scaffold behind, the immediate release of high drug concentrations with a single dosage, their efficacy in areas, where stents have been contra-indicated until now and its use for secondary interventions. As their effect seems to be limited in severely calcified lesions, prior plaque preconditioning or removal could be advantageous. First positive results data supporting this hypothesis do exist.