Cook’s Zilver PTX Compared to Polymer-Coated DES for Long-Term Vascular Response in Porcine Study

November 15, 2021—Cook Medical announced the publication of a study comparing healthy porcine vessels treated with the company’s polymer-free Zilver PTX paclitaxel-coated drug-eluting stent (DES) versus those treated with a permanent polymer-coated DES.

The purpose of the study was to compare the long-term vascular healing responses of different DESs. The study was performed by the nonclinical testing team at Cook Research Incorporated, with histopathologic analyses performed by CVPath Institute at the University of Maryland in Gaithersburg and Baltimore, Maryland. Aloke Finn, MD, Medical Director at the CVPath Institute, served as Principal Investigator of the study.

Atsushi Sakamoto, MD, et al published the findings in Journal of Vascular and Interventional Radiology (2021;32:792-801).

According to Cook, the results showed that the porcine vessels treated with the polymer-free Zilver PTX DES exhibited a more complete vessel healing compared to the permanent polymer-coated DES.

Specific findings included the following:

• Vessels treated with the Zilver PTX DES experienced less inflammation relative to the permanent polymer-coated DES.
• Vessels treated with the permanent polymer-coated DES sometimes exhibited malapposed struts with excessive fibrin deposition, which was not observed in vessels treated with Zilver PTX DES.
• Aneurysmal vessel wall degeneration and medial layer disruption was observed exclusively in vessels treated with the permanent polymer-coated DES.

The company noted that these distinct features in the results should be confirmed by pathology and in vivo imaging of the human superficial femoral artery to further elucidate their clinical impact. Additionally, the company stated that definitive conclusions regarding the safety or effectiveness of DESs in humans cannot be directly drawn from the results of this animal study.

Cook highlighted that it has published 5-year clinical data on paclitaxel-coated stents (Michael D. Dake, MD, et al. Circulation; 2016;133:1472-1483), which showed that, “Zilver PTX DES provided sustained safety and clinical durability in comparison with standard endovascular treatments.” Because Zilver PTX does not have a polymer coating, patients do not have the risks associated with polymer delamination, polymer degradation, or other polymer-related complications, noted the company.