Paclitaxel-coated balloon for the treatment of drug-eluting stent restenosis: subanalysis results from the Valentines I trial

Influences of Stent Design on In-Stent Restenosis and Major Cardiac Outcomes: A Scoping Review and Meta-Analysis

Thanks to the developments in implantable biomaterial technologies, invasive operating procedures, and widespread applications especially in vascular disease treatment, a milestone for interventional surgery was achieved with the introduction of vascular stents. Despite vascular stents providing a solution for embolisms, this technology includes various challenges, such as mechanical, electro-chemical complications, or in-stent restenosis (ISR) risks with long-term usage. Therefore, further development of biomaterial technologies is vital to overcome such risks and problems. For this purpose, recent research has focused mainly on the applications of surface modification techniques on biomaterials and vascular stents to increase their hemocompatibility. ISR risk has been reduced with the development and prevalent usage of the art technology stent designs of drug-eluting and biodegradable stents. Nevertheless, their problems have not been overcome completely. Furthermore, patients using drug-eluting stents are faced with further clinical challenges. Therefore, the bare metal stent, which is the first form of the vascular stent technology and includes the highest ISR risk, is still in common usage for vascular treatment applications. For this reason, further research is necessary to solve the remaining vital problems. In this scoping review, stent-based major cardiac events including ISR are analyzed depending on different designs and material selection in stent manufacturing. Recent and novel approaches to overcome such challenges are stated in detail.

Drug-eluting balloon: design, technology and clinical aspects

A drug-eluting balloon is a non-stent technology in which the effective homogenous delivery of anti-proliferative drugs is processed by the vessel wall through an inflated balloon. This is done to restore luminal vascularity in order to treat atherosclerosis, in-stent restenosis and reduce the risk of late thrombosis without implanting a permanent foreign object. The balloon technology relies on the concept of targeted drug delivery, which helps in the rapid healing of the vessel wall and prevents the proliferation of smooth muscle cells. Several drug eluting devices in the form of coated balloons are currently in clinical use, namely DIOR^®, PACCOCATH^®, SeQuent^®Please and IN.PACT™. The device varies in terms of the material used for making the balloon, the coating techniques, the choice of coated drug and the release pattern of the drug at the site. This review gives an insight into the evolution, rationale and comparison of the marketed drug-eluting balloons. Here, different coating techniques have been analysed for the application and critical analysis of available DEB technologies, and a technical comparison has been done.

Antiproliferative Drugs for Restenosis Prevention

Cardiovascular disease is a leading cause of death and disability worldwide. Current treatment strategies aimed at treating the symptoms and consequences of obstructive vascular disease have embraced both optimal medical therapy and catheter-based percutaneous coronary intervention with drug-eluting stents. Drug-eluting stents elute antiproliferative drugs inhibiting vascular smooth muscle cell proliferation, which occurs in response to injury and thus prevents restenosis. However, all drugs currently approved for use in drug-eluting stents do not discriminate between proliferating vascular smooth muscle cells and endothelial cells, thus delaying re-endothelialization and subsequent vascular healing.

Biological effect on drug distribution and vascular healing via paclitaxel-coated balloon technology in drug eluting stent restenosis swine model

Objectives

To evaluate the biological effect of a paclitaxel‐coated balloon (PCB) technology on vascular drug distribution and healing in drug eluting stent restenosis (DES‐ISR) swine model.

Background

The mechanism of action and healing response via PCB technology in DES‐ISR is not completely understood.

Methods

A total of 27 bare metal stents were implanted in coronary arteries and 30 days later the in‐stent restenosis was treated with PCB. Treated segments were harvested at 1 hr, 14 days and 30 days post treatment for the pharmacokinetic analysis. In addition, 24 DES were implanted in coronary arteries for 30 days, then all DES‐ISRs were treated with either PCB (n = 12) or uncoated balloon (n = 12). At day 60, vessels were harvested for histology following angiography and optical coherence tomography (OCT).

Results

The paclitaxel level in neointimal tissue was about 18 times higher (P = 0.0004) at 1 hr C_max, and retained about five times higher (P = 0.008) at day 60 than that in vessel wall. A homogenous distribution of paclitaxel in ISR was demonstrated by using fluorescently labeled paclitaxel. Notably, in DES‐ISR, both termination OCT and quantitative coronary angioplasty showed a significant neointimal reduction and less late lumen loss (P = 0.05 and P = 0.03, respectively) post PCB versus post uncoated balloon. The PES‐ISR + PCB group displayed higher levels of peri‐strut inflammation and fibrin scores compared to the ‐limus DES‐ISR + PCB group.

Conclusions

In ISR, paclitaxel is primarily deposited in neointimal tissue and effectively retained over time following PCB use. Despite the presence of metallic struts, a uniform distribution was characterized. PCB demonstrated an equivalent biological effect in DES‐ISR without significantly increasing inflammation. © 2015 Wiley Periodicals, Inc.