Local delivery of paclitaxel using the double-balloon perfusion catheter before stenting in the porcine coronary artery

Cholesterol modulates the interaction between paclitaxel and Langmuir monolayers simulating cell membranes

The composition of Langmuir monolayers used as cell membrane models is an essential factor for the interaction with biologically-relevant molecules, including pharmaceutical drugs. In this paper, we report the modulation of effects from the antineoplastic drug paclitaxel by the relative concentration of cholesterol in the Langmuir monolayers of ternary mixtures of dipalmitoylphosphatidylcholine, sphingomyelin, and cholesterol. Since the dependence on cholesterol concentration for these monolayers simulating lipid rafts is non-monotonic, we analyzed the surface pressure and compressibility modulus data with the multidimensional projection technique referred to as interactive document mapping (IDMAP). The maximum expansion induced by paclitaxel in surface pressure isotherms was observed for 27% cholesterol, while the compressibility modulus decreased most strongly for the monolayer with 48% cholesterol. Therefore, the physiological action of paclitaxel may vary depending on whether it is associated with penetration in the membrane or with changes in the membrane elasticity.

Combinatorial therapy of sirolimus and heparin by nanocarrier inhibits restenosis after balloon angioplasty ex vivo

Aim: To develop poly(lactide-co-glycolide)-graft-polyethylenimine (PgP) as a dual drug-delivery carrier for sirolimus (SR) and heparin (Hep) to inhibit restenosis after balloon angioplasty. Materials & methods: SR was loaded in the hydrophobic core and negatively charged Hep complexed with the positively charged hydrophilic shell of PgP. SR- and Hep-loaded PgP was tested on rat aortic smooth muscle cells in vitro and injured porcine coronary arteries after balloon angioplasty ex vivo. Results & conclusion: SR and Hep loading efficiency in PgP were approximately 37 and 82%, respectively. SR- and Hep-loaded PgP treatment decreased smooth muscle cell proliferation up to 14 days post-treatment and decreased proliferation, collagen deposition and neointimal thickness and increased patency in porcine coronary arteries after balloon angioplasty ex vivo.

Paclitaxel drug-coated balloon angioplasty for the treatment of failing arteriovenous fistulas: a single-center experience

Objectives: To report our experience of angioplasty with Lutonix (Bard Peripheral Vascular, Inc., Tempe, AZ) drug-coated balloon (DCB) for the treatment of failing arteriovenous fistulas (AVF).Materials and methods: Retrospective, single-center analysis consisting of 14 patients treated with Lutonix paclitaxel DCBs in the period from July 2015 through April 2017. We analyzed technical success, clinical success, primary patency of the target lesion, primary patency of the dialysis circuit, and the rate of complications. Regular follow-up of AVF patency was realized by clinical examination and duplex ultrasonography. The Kaplan-Meier survival method was applied to determine the cumulative primary patency of the target lesion and the dialysis circuit.Results: Technical success was 100% and clinical success 92.9%. There were no major or minor complications. Cumulative target lesion primary patency after DCB was 69.2% at 6 months and 31.6% at 12 months. Cumulative vascular circuit primary patency was 61.5% at 6 months and 31.6% at 12 months.Conclusion: Compared to results reported in literature with plain old balloon angioplasty (POBA), Lutonix paclitaxel DCB angioplasty proved a short-term patency benefit in treatment of dialysis AVF stenosis.

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

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

Local Endovascular Delivery, Gene Therapy, and Cell Transplantation for Peripheral Arterial Disease

Advances in catheter technology, gene identification, and cell biology may provide novel treatment options for patients with peripheral arterial disease (PAD) who are not candidates for standard revascularization procedures. Animal studies and recent results in human beings suggest that transfer of growth factors or regulatory genes and transplantation of progenitor cells may provide novel therapy options by inducing therapeutic angiogenesis or by inhibiting restenosis. This review will discuss the development of a variety of catheters for localized endovascular delivery, as well as the various cellular and genetic strategies that exist to restore blood flow to ischemic tissue and to reduce neointimal hyperplasia.

Local delivery of paclitaxel in the treatment of peripheral arterial disease

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Loco-regional cancer drug therapy: present approaches and rapidly reversible hydrophobization (RRH) of therapeutic agents as the future direction

Insufficient drug uptake by solid tumors remains the major problem for systemic chemotherapy. Many studies have demonstrated anticancer drug effects to be dose-dependent, although dose-escalation studies have resulted in limited survival benefit with increased systemic toxicities. One solution to this has been the idea of loco-regional drug treatments, which offer dramatically higher drug concentrations in tumor tissues while minimizing systemic toxicity. Although loco-regional delivery has been most prominent in cancers of the liver, soft tissues and serosal peritoneal malignancies, survival benefits are very far from desirable. This review discusses the evolution of loco-regional treatments, the present approaches and offers rapidly reversible hydrophobization of drugs as the new future direction.

Paclitaxel coated balloons for coronary artery interventions: a comprehensive review of preclinical and clinical data

After the "mechanical era" in interventional cardiology (represented by balloon angioplasty and bare metal stent implantation), arrived the "local dispensing" era, began with the intracoronary delivery of antithrombotic or antirestenotic drugs. However, even drug eluting stents have some pitfalls and cannot be used in all clinical subsets. In this article we will review the significant data on the paclitaxel-coated balloons for the treatment of coronary artery disease. Particularly, we will review the rationale of this new treatment strategy, the preclinical data and will focus on available clinical studies in humans. After the initial boost of the paclitaxel coated balloons with the Paccocath technology in in-stent restenotic lesions, the experimentation of newer devices in native coronary arteries raised some concerns on their efficacy and safety. We will comment on this topic trying to understand the reasons of this failure, and will discuss on possible future developments and applications for these devices for the treatment of coronary artery disease.

Nanotechnology in interventional cardiology

High-grade atherosclerotic stenoses are reduced to zero or minimal residual stenosis grades by a single or a series of balloon angioplasties. Currently, stents are implanted to prevent immediate vascular recoil and elution of an antimitotic drug from the stent struts minimizes restenosis. An unwanted side-effect of this drug elution is delayed re-endothelialization which requires treatment with two anti-platelet drugs, in many cases for a minimum of 1 year to prevent acute in-stent thrombosis. Advances in stent design and drug elution technology, now in its fourth generation, have not abated this issue. Nanotechnology-based local drug delivery has the potential to achieve restenosis prevention while not impeding endothelial healing. Molecularly targeted drugs can be aimed to specifically bind to epitopes in the injured media and adventitia. Thus, endothelial healing may progress unhindered. To prevent restenosis, this technology may be used with bare metal or biodegradable stents. In this article novel nanoparticulate agents will be compared regarding their potential to deliver drugs to molecular targets within the vascular wall. Potential molecular targets, targeting mechanisms, drug-delivery propensities, and biocompatibility will be reviewed.

Neointima Inhibition: Comparison of Effectiveness of Non–Stent-based Local Drug Delivery and a Drug-eluting Stent in Porcine Coronary Arteries

PURPOSE

To compare the inhibition of neointimal proliferation by using non-stent-based local drug delivery and a drug-eluting stent in porcine coronary arteries.

MATERIALS AND METHODS

Experiments were conducted with permission of the animal protection committee of the local government. Paclitaxel was either dissolved in a nonionic contrast medium or coated on balloons. Stents were crimped on the coated balloons. Effectiveness was tested in 22 pigs. Two coronary stents were placed in each pig, and slight overstretch was applied. The animals were treated as follows: group A (control group), uncoated balloons, bare stents, and "plain" contrast medium; group B, same treatment as group A, but with paclitaxel in the contrast medium; group C, paclitaxel-coated balloons, with premounted bare stents and plain contrast medium; and group D, sirolimus-eluting stents, noncoated balloons, and plain contrast medium. Stenosis was assessed 4 weeks later at angiography and histomorphometry. For exploratory purposes, continuous variables of quantitative coronary angiography and histomorphometry were compared by using analysis of variance.

RESULTS

Results at follow-up angiography indicated a mean of 1.00 mm +/- 0.18 (standard deviation) lumen diameter loss in the control group and 0.14 mm +/- 0.18 loss in the group treated with the paclitaxel-coated balloon (group C; P < .001). Findings at histomorphometry confirmed the effectiveness of drug delivery, with the most impressive inhibition of neointimal proliferation from coated balloons-the neointimal area was 2.4 mm2 +/- 0.3 (P < .01 vs all other groups), compared with 5.2 mm2 +/- 0.3 in group A (control group), 4.3 mm2 +/- 0.3 in group B, and 3.8 mm2 +/- 0.3 in group D.

CONCLUSION

In spite of the short intima contact time, paclitaxel coated on the balloon inhibits neointimal formation in the porcine model of coronary stent placement.

The paclitaxel-eluting Coroflex™ please stent pilot study (PECOPS I): Acute and 6-month clinical and angiographic follow-up

BACKGROUND AND OBJECTIVES

Various active stent coatings significantly reduce restenosis rates and target lesion revascularization compared to bare metal stents. Therefore, the procedural and 6-month performance of the new paclitaxel-eluting Coroflex. Please stent was investigated.

METHODS

Ninety-seven patients (66 +/- 7.6 years, 34/97(35.1%) diabetics, 11/97(11.3%) unstable angina) were enrolled per protocol for elective single stent deployment into native coronary de-novo or post-PTCA restenotic lesions (stenosis: >or= 70%, < 100%; reference diameter >or= 2.25 mm and <3.3 mm; lesion length <or= 16 mm) with 13/97(13.4%) lesion type A, 64/97(66%) type B1, 20/97(20.6%) type B2). The mean reference diameter was 2.88 +/- 0.42 mm, the lesion length 10.03 +/- 2.93 mm, and the minimal lumen diameter 0.64 +/- 0.22 mm.

RESULTS

The success rates of procedure and study stent deployment were 100% and 94.8%, respectively. In 5/97(5.2%) two stents were implanted. Follow-up was performed clinically in 86/87(98.9%) and angiographically in 77/87(88.5%) patients after 6.1 +/- 0.7 months. Major adverse cardiac events occurred in 7/87(8%) 1/87(1.2%) subacute thrombosis 10.3hrs post procedure, 1/87(1.2%) myocardial infarction, 5/87(5.7%) target lesion revascularizations. The in-segment stenosis declined from 78 +/- 7.2% to 9.4 +/- 6.2% after stenting increasing to 31.9 +/- 18.6% at follow-up. The in-segment late loss and the late loss index were 0.47 +/- 0.6 mm and 0.23 +/- 0.29 resulting in 6/77(7.8%) in-segment restenoses three each of which were located either within or beyond the stent structure. The outcome was neither influenced by the prevalence of diabetes ( p = 0.4), hypercholesterolemia ( p = 1), hypertension ( p = 1), overweight ( p = 1), nor by the family history of coronary artery disease ( p = 0.7).

CONCLUSION

The data of the paclitaxel-eluting Coroflex. Please stent tested in PECOPS I are within the range other available paclitaxel-eluting stent.

Local endovascular delivery, gene therapy, and cell transplantation for peripheral arterial disease

Advances in catheter technology, gene identification, and cell biology may provide novel treatment options for patients with peripheral arterial disease (PAD) who are not candidates for standard revascularization procedures. Animal studies and recent results in human beings suggest that transfer of growth factors or regulatory genes and transplantation of progenitor cells may provide novel therapy options by inducing therapeutic angiogenesis or by inhibiting restenosis. This review will discuss the development of a variety of catheters for localized endovascular delivery, as well as the various cellular and genetic strategies that exist to restore blood flow to ischemic tissue and to reduce neointimal hyperplasia.

Sirolimus- or paclitaxel-eluting stents to prevent coronary artery restenosis

The restenosis rate is lower with stent implantation than with balloon angioplasty. Nevertheless, even with the use of stenting, restenosis still occurs in approximately one-third of patients with diabetes, small coronary vessels, and long lesions. The two drugs commonly used in eluting stents are sirolimus and paclitaxel. Systemically administered sirolimus decreased vascular proliferation in animal models. After preliminary trials showing benefit with sirolimus-eluting stents in de novo coronary lesions, the large-scale SIRIUS (Sirolomus-coated Bx Velocity balloon-expandable stent in the treatment of patients with de novo coronary artery lesions) trial was undertaken. SIRIUS showed that sirolimus reduced restenosis and target vessel revascularisation, compared to bare stents. These benefits were also apparent in the diabetic, and small- and long vessel subgroups. The RESEARCH (Rapamycin-eluting Stent Evaluated At Rotterdam Cardiology Hospital) registry have established that sirolimus-eluting stents are superior to bare stents in practice. Thus, the benefits of sirolimus-eluting stents over bare stents have been clearly established, and sirolimus can be considered the benchmark eluting agent for the prevention of coronary artery restenosis. Animal studies with paclitaxel-eluting stents, mainly in endothelium denuded normal vessels, have shown that paclitaxel reduces restenosis in the short-term, and that this may be a delay, rather than a prevention of restenosis. In clinical trials, stents eluting the paclitaxel derivative 7-hexanolytaxol, or paclitaxel without a polymer, delay rather than prevent restenosis. Slowing the release of paclitaxel with a polymer base in the TAXUS (Taxol(trade mark) [paclitaxel]-eluting stent) series of clinical trials reduced the revascularisation rate at 12 and 18 months, indicating that polymer-based paclitaxel is effective for longer. The results of the REALITY trial comparing the sirolimus- and paclitaxel-eluting stents in diabetics and other high-risk patients are eagerly awaited.

Preclinical restenosis models and drug-eluting stents: still important, still much to learn

Percutaneous coronary intervention continues to revolutionize the treatment of coronary atherosclerosis. Restenosis remains a significant problem but may at last be yielding to technologic advances. The examination of neointimal hyperplasia in injured animal artery models has helped in our understanding of angioplasty and stenting mechanisms, and as drug-eluting stent (DES) technologies have arrived, they too have been advanced through the study of animal models. These models are useful for predicting adverse clinical outcomes in patients with DESs because suboptimal animal model studies typically lead to problematic human trials. Similarly, stent thrombosis in animal models suggests stent thrombogenicity in human patients. Equivocal animal model results at six or nine months occasionally have been mirrored by excellent clinical outcomes in patients. The causes of such disparities are unclear but may result from differing methods, including less injury severity than originally described in the models. Ongoing research into animal models will reconcile apparent differences with clinical trials and advance our understanding of how to apply animal models to clinical stenting in the era of DESs.

Clinical trials in restenosis with 7-hexanoyltaxol and paclitaxel-eluting stents

Restenosis rates are lower with stent implantation than with balloon angioplasty. Nevertheless, even with the use of stenting, restenosis still occurs in approximately a third of patients with diabetes, small coronary vessels and long lesions. Animal studies with paclitaxel (Taxol, Bristol-Myers Squibb)-eluting stents, mainly in endothelium-denuded normal vessels, have shown that although paclitaxel reduces restenosis in the short-term, this may only delay rather than prevent restenosis. In clinical trials, stents eluting the paclitaxel derivative, 7-hexanoyltaxol, or paclitaxel without a polymer, also delay rather than prevent restenosis. Slowing the release of paclitaxel with a polymer base in the TAXUS trade mark series of clinical trials reduced the revascularization rate at 12 months, indicating that polymer-based paclitaxel is effective for longer periods of time. Further follow-up is necessary to determine whether polymer-based release of paclitaxel represents a longer delay or prevention of restenosis. To date, paclitaxel is showing promise as an eluting agent to prevent restenosis associated with stenting.

Inhibition of restenosis in stented porcine coronary arteries: uptake of Paclitaxel from angiographic contrast media

RATIONALE AND OBJECTIVES

Paclitaxel added to angiographic contrast medium (CM) has been shown to inhibit restenosis in the porcine coronary overstretch model. This study determined early local tissue concentrations after the administration of different paclitaxel doses and preparations.

MATERIALS AND METHODS

Fifteen pigs received 2 stents each in the left coronary artery. During and/or after the intervention, paclitaxel-containing CM or diluted Taxol was injected. Fifteen minutes after the last intracoronary injection, paclitaxel concentrations in the arterial wall and myocardium were measured by high-performance liquid chromatography.

RESULTS

Mean paclitaxel concentrations in the left coronary arteries reached 3-10 microM. Higher volumes and higher paclitaxel concentrations resulted in higher tissue concentrations. Paclitaxel in CM was better tolerated and led to higher local concentrations than diluted Taxol. Low paclitaxel concentrations in the uninjected right coronary artery and in plasma indicate selectivity.

CONCLUSION

When admixed to CM, paclitaxel results in local tissue concentrations proportional to the amount of the drug injected.

The paclitaxel (TAXUS)-eluting stent: a review of its use in the management of de novo coronary artery lesions

The TAXUSExpress stent contains paclitaxel 1 microg/mm(2). On deployment, paclitaxel is slowly released into the intimal tissue of the coronary artery to prevent cell proliferation and neointimal hyperplasia. When deployed in patients with previously untreated coronary artery lesions, the paclitaxel-eluting stent (PES) effectively reduces the need for revascularization without increasing the risk of in-stent thrombosis. While long-term outcomes data and comparative efficacy and cost-benefit trials versus other drug-eluting stents are required, the PES appears to be an attractive alternative for the management of de novo coronary artery lesions. PHARMACOLOGIC PROPERTIES: The PES comprises a stainless steel stent coated with a non-erodible biocompatible polyolefin matrix containing paclitaxel 1 microg/mm(2). Paclitaxel dose dependently inhibits vascular smooth muscle cell proliferation at therapeutic concentrations as a result of binding to and stabilizing cellular microtubules. This prevents the cascade of events associated with obstructive in-stent neointimal hyperplasia. Paclitaxel was released in a controlled manner from the stent coating in in vitro studies. The higher release rate in the first 2 days after implantation (to reduce response to implantation injury) slows over the next 8-10 days. The drug is rapidly taken up by intimal cells with minimal dispersion in the plasma; it was not detected systemically after stent deployment in clinical trials. Paclitaxel is extensively bound to proteins (88-98%), and is principally metabolized in the liver, undergoing biliary clearance after systemic administration. THERAPEUTIC EFFICACY: The efficacy of the PES was compared with that of a bare-metal stent (BMS) in a number of randomized, double-blind, multicenter trials in patients with de novo coronary artery lesions. The TAXUS I and II trials used the NIR stent, while the pivotal TAXUS IV trial used the Express stent. The primary endpoints of the well designed TAXUS II and IV trials indicated superiority for the PES over the BMS. Twice as many patients receiving the BMS required target vessel revascularization at 9 months postprocedure and, 6 months following the procedure, the in-stent neointimal volume in the PES system was only one-third of that in the BMS. The incidence of cumulative major adverse cardiac events (MACE; cardiac death, myocardial infarction [MI], or target vessel revascularization [TVR]) was also significantly lower in PES than BMS recipients at 9 and 12 months postprocedure. The incidence of cardiac death and MI was low and similar between treatment groups; however, TVR was significantly reduced by the PES versus the BMS. Other secondary endpoints, such as target lesion revascularization, luminal diameter stenosis, minimal luminal diameter, and serial intravascular ultrasound measurements from one or both trials supported these results. Preliminary analysis of the subgroup of patients with diabetes mellitus in the TAXUS IV trial suggested that the PES was also effective in diabetic patients who receive oral medications. The group receiving insulin was too small to draw meaningful conclusions.

TOLERABILITY

Because of the small paclitaxel dosages and the mainly local uptake, systemic adverse events associated with the PES are considered unlikely. The incidences of cardiac death and MI were very low and similar in both groups. Local events such as in-stent aneurysms, incomplete stent apposition, or in-stent thrombosis occurred at a similar rate in PES and BMS recipients. There has been no evidence of late thrombosis in PES recipients followed for 2 years. The rate of late luminal loss in the 5mm of vessel proximal and distal to the stent edges was significantly lower in PES than BMS systems. PHARMACOECONOMIC CONSIDERATIONS: Initial deployment costs associated with the PES are likely to be offset by savings in repeat procedures, according to a cost-effectiveness analysis in the UK.

7-hexanoyltaxol-eluting stent for prevention of neointimal growth: an intravascular ultrasound analysis from the Study to COmpare REstenosis rate between QueST and QuaDS-QP2 (SCORE)

BACKGROUND

Inhibition of neointimal tissue growth has been demonstrated in preliminary human feasibility studies with a stent-based polymer sleeve delivering 7-hexanoyltaxol. The Study to COmpare REstenosis rate between QueST and QuaDS-QP2 (SCORE) trial is a human, randomized, multicenter trial comparing 7-hexanoyltaxol (QP2)-eluting stents (qDES) with bare metal stents (BMS) in the treatment of de novo coronary lesions. The purpose of this substudy was to evaluate the acute expansion property and long-term neointimal responses of qDES compared with BMS as assessed by intravascular ultrasound (IVUS).

METHODS AND RESULTS

A total of 122 (qDES 66, BMS 56) patients were enrolled into the IVUS substudy. All IVUS images (immediately after the procedure and at 6-month follow-up) were analyzed at an independent core laboratory in a blind manner. At baseline, qDES achieved stent expansion similar to BMS. At follow-up, qDES showed reduced neointimal growth by 70% at the tightest cross section and by 68% over the stented segment (P<0.0001 for both), resulting in a significantly larger lumen in qDES than in BMS. Unlike intracoronary brachytherapy, there was no evidence of negative edge effects, unhealed dissections, or late stent-vessel wall malapposition over the stented and adjacent references segments in either group.

CONCLUSIONS

Detailed IVUS analysis revealed that qDES had comparable acute mechanical and superior long-term biological effects to BMS. Although the long-term benefits and limitations of this technology require further investigation, the reduction in neointimal thickenings demonstrated that local delivery of 7-hexanoyltaxol through polymer sleeves augments conventional mechanical treatment of atherosclerotic disease.