*A Stellium is the term for a natural grouping of planets. This name reflects the coming together of three star-performers to make a revolutionary product: DISA Vascular’s Stellium Drug-Eluting Stent (DES).

Late stent thrombosis (LST) in patients with DES has received considerable attention recently and safety is the key issue currently in the world of Drug Eluting Stents. The third generation Stellium DES combines three proven elements to produce a new generation product which is designed to reduce the current levels of LST:

1. Stent platform: The ChromoFlex

The Stellium delivery platform is the proven ChromoFlex stent which was one of the first cobalt chromium stents, having received European certification in 2004. This product was based on research that showed a direct correlation between the width of the stent struts and the percentage of in-stent restenosis (Pache et al. JACC 2003; 41(8): 1283-8). Through the use of an exotic biocompatible and highly radiopaque alloy, DISA Vascular was able to substantially decrease strut width whilst lowering the delivery profile, improving stent flexibility and increasing scaffold support. This stent is currently sold in Europe, Asia, South America, and is becoming increasingly popular in South Africa.

2. The drug: Paclitaxel

Paclitaxel is a clinically proven anti-restenosis drug. It inhibits vascular smooth muscle proliferation which has been shown to result in in-stent restenosis (Drachman et al. JACC 2001; 38(1): 292-3). The Stellium dosage is as low as a tenth of the current Paclitaxel-based stents. The rationale behind the particular low-dose formulation of the Stellium is to achieve the required moderation of the acute aggressive proliferative response in the first 3 months while avoiding long term healing inhibition and the potential for late thrombosis risks as seen in certain current generation, permanent polymer and high drug dose DES.

This low dosage combined with a well-controlled and gradual release ensures that there is no toxicity to the surrounding tissue, thus avoiding negative remodelling and late stent malapposition. DISA Vascular has recently published a study in the Journal of Invasive Cardiology (Jabara et al. 2006; 18(8): 383-90) which highlights the importance of optimising Paclitaxel dosage and release rate.

3. Biodegradable Polymer

A biodegradable polymer holds and elutes the Paclitaxel from the Stellium stent. The advantage of a totally biodegradable polymer is that the entire drug load is eluted and the polymer disappears within six months, leaving behind a benign bare metal stent in the vessel. The polymer is completely bio-erodible allowing for total drug elution without long-term leaching hence avoiding long-term inhibition of healing and possible polymer thrombogenicity.

The coating process and unique elution properties of DISA Vascular's drug eluting stent have already been developed and tested. Pre-clinical animal trials have shown significant neointimal suppression compared to historical bare metal controls, suggesting a level of efficacy.