Visualization and comparison of drug effects after local paclitaxel delivery with different catheter types

Paclitaxel-coated balloon catheter versus paclitaxel-coated stent for the treatment of coronary in-stent restenosis: the three-year results of the PEPCAD II ISR study

AIMS

Treatment of bare metal in-stent restenosis with the paclitaxel-coated balloon catheter based on the PACCOCATH® technology has yielded superior six-month angiographic and one-year clinical results compared to a paclitaxel-eluting stent. The three-year clinical follow-up is presented.

METHODS AND RESULTS

One hundred and thirty-one patients with coronary bare metal in-stent restenosis (>70%, length: <22 mm, vessel diameter: 2.5-3.5 mm) were randomly treated with the paclitaxel-coated balloon (DCB) (3 µg/mm²) or a paclitaxel-eluting stent (DES). Clinical follow-up information was requested from the patients and from their physicians. Quantitative angiographic and demographic baseline data were statistically not different between the groups. Per intention-to-treat analysis at 12 months, the lesion-related rates of major adverse cardiac events were 7.6% and 16.9% (p=0.11) while at 36 months the respective numbers were 9.1% and 18.5% (p=0.14). These differences were primarily due to reduced target lesion revascularisation (TLR) in DCB 4/66 (6.2%) compared to DES patients 10/65 (15.4%) (p=0.10). From 12 to 36 months, 1/65 (1.5%) DCB patients experienced a myocardial infarction while neither TLR nor death occurred in any study patient in either group during that period.

CONCLUSIONS

The six-month superiority of the paclitaxel-coated balloon compared to the paclitaxel-eluting stent in the treatment of bare metal coronary in-stent restenosis persisted throughout the three-year clinical follow-up period indicating stability of the lesions treated. (ClinicalTrials.gov Identifier: NCT00393315).

Ultrasound triggered image-guided drug delivery to inhibit vascular reconstruction via paclitaxel-loaded microbubbles

Paclitaxel (PTX) has been recognized as a promising drug for intervention of vascular reconstructions. However, it is still difficult to achieve local drug delivery in a spatio-temporally controllable manner under real-time image guidance. Here, we introduce an ultrasound (US) triggered image-guided drug delivery approach to inhibit vascular reconstruction via paclitaxel (PTX)-loaded microbubbles (PLM) in a rabbit iliac balloon injury model. PLM was prepared through encapsulating PTX in the shell of lipid microbubbles via film hydration and mechanical vibration technique. Our results showed PLM could effectively deliver PTX when exposed to US irradiation and result in significantly lower viability of vascular smooth muscle cells. Ultrasonographic examinations revealed the US signals from PLM in the iliac artery were greatly increased after intravenous administration of PLM, making it possible to identify the restenosis regions of iliac artery. The in vivo anti-restenosis experiments with PLM and US greatly inhibited neointimal hyperplasia at the injured site, showing an increased lumen area and reduced the ratio of intima area and the media area (I/M ratio). No obvious functional damages to liver and kidney were observed for those animals. Our study provided a promising approach to realize US triggered image-guided PTX delivery for therapeutic applications against iliac restenosis.

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.

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.

Catheter-Based Delivery of Fluid Paclitaxel for Prevention of Restenosis in Native Coronary Artery Lesions After Stent Implantation

Background— Stents eluting antiproliferative drugs reduce the incidence of restenosis but delay healing of the vascular wall. We assessed the safety and efficacy of catheter-based local delivery of fluid paclitaxel in patients with coronary de novo stenoses after implantation of a bare metal stent.

Methods and Results— We conducted a prospective, randomized trial comparing the local delivery of fluid paclitaxel after bare metal stent implantation (group I) with the implantation of a bare metal stent (group II) and the implantation of a paclitaxel-eluting stent (group III) in 204 patients. The primary end point was in-stent late lumen loss. Secondary end points included binary restenosis rate >50%, minimal lumen diameter, diameter stenosis, and a composite clinical end point (major adverse cardiac events and revascularization of the target lesion) 6 months after intervention. At 6 months, angiography showed an in-stent late lumen loss of 0.61�0.44 mm in group I versus 0.99�0.72 mm in group II (I versus II, P =0.0006) and 0.44�0.48 mm in group III (noninferiority of I versus III, P =0.023). The 1-sided 95% CI for the true difference of the means of in-stent late lumen loss in groups I and III was −∞ to 0.3174188. The cumulative overall rate of major cardiac events was 13.4% in group I, 26.8% in group II, and 14.9% in group III. Target lesion revascularization rate was 13.4% (group I), 22.1% (group II), and 13.4% (group III).

Conclusions— Additional antiproliferative treatment of de novo lesions in native coronary arteries with catheter-based delivery of fluid paclitaxel after bare metal stenting was safe and significantly reduced neointimal proliferation, restenosis, and clinical events compared with bare metal stent implantation alone.

Paclitaxel-coated balloon catheter versus paclitaxel-coated stent for the treatment of coronary in-stent restenosis

BACKGROUND

Treatment of in-stent restenosis with paclitaxel-coated balloon catheter as compared with plain balloon angioplasty has shown surprisingly low late lumen loss at 6 months and fewer major adverse cardiac events up to 2 years. We compared the efficacy and safety of a paclitaxel-coated balloon with a paclitaxel-eluting stent as the current standard of care.

METHODS AND RESULTS

One hundred thirty-one patients with coronary in-stent restenosis were randomly assigned to treatment by a paclitaxel-coated balloon (3 microg/mm2) or a paclitaxel-eluting stent. The main inclusion criteria encompassed diameter stenosis of > or =70% and < or =22 mm in length, with a vessel diameter of 2.5 to 3.5 mm. The primary end point was angiographic in-segment late lumen loss. Quantitative coronary angiography revealed no differences in baseline parameters. At 6 months follow-up, in-segment late lumen loss was 0.38+/-0.61 mm in the drug-eluting stent group versus 0.17+/-0.42 mm (P=0.03) in the drug-coated balloon group, resulting in a binary restenosis rate of 12 of 59 (20%) versus 4 of 57 (7%; P=0.06). At 12 months, the rate of major adverse cardiac events were 22% and 9%, respectively (P=0.08). This difference was primarily due to the need for target lesion revascularization in 4 patients (6%) in the coated-balloon group, compared with 10 patients (15%) in the stent group (P=0.15).

CONCLUSIONS

Treatment of coronary in-stent restenosis with the paclitaxel-coated balloon was at least as efficacious and as well tolerated as the paclitaxel-eluting stent. For the treatment of in-stent restenosis, inhibition of re-restenosis does not require a second stent implantation.

Catheter-based local antiproliferative therapy in kissing balloon technique for in-stent stenosis of coronary artery bifurcation lesions

There is currently no promising interventional solution for in-stent stenosis in previously stented bifurcation lesions, even with drug-eluting stents. Rather than being restricted to stent struts, catheter-based local antiproliferative therapy offers the advantage of homogenous drug transfer to the whole vessel wall, and thereby allows for intracoronary pharmacotherapy without adding additional layers of metal into an already stented lesion. The newly developed GENIE catheter (Acrostak Corp, Switzerland), applied in the kissing balloon technique, allows for delivery of liquid paclitaxel into whole bifurcation lesions without repeat stent implantation. After conventional percutaneous transluminal coronary angioplasty, local delivery of paclitaxel using two GENIE catheters in the kissing balloon technique was performed in three patients (left anterior descending, left circumflex and right coronary arteries) with highly symptomatic in-stent bifurcation stenoses. The intervention was feasible and safe in all coronary arteries. Final angiography and control angiography after six months showed good results. No major adverse cardiac events occurred 30 days and six months after intervention. The patients, who represent a group at high risk of recurrent instent restenosis, remained asymptomatic since the local drug delivery. They did not require insertion of a drug-eluting stent or crossover to coronary artery bypass surgery. In conclusion, this new treatment strategy proved to be safe and effective in this first human experience and offers a promising alternative to surgery or implantation of additional stents in these patients.

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.