User:Aspezikian/Dual therapy stent

A dual therapy stent is a coronary artery stent that combines the technology of a bioengineered stent and a drug eluting stent. This biotechonology allows the accelerated healing of the vessel and ability to block cell proliferation. The dual therapy stent has potential in becoming a shorter dual antiplatelet therapy alternative.

The COMBO Dual Therapy Stent is the first dual therapy stent that addresses the challenges of vessel healing in drug-eluting stents. It combines the Genous endothelial cell capture technology with an antiproliferative, biodegradable sirolimus drug elution. The COMBO Stent has received CE Mark approval.

Background
The field of interventional cardiology began in the 20th century with the development of the plain old balloon angioplasty, which revolutionized the treatment of cornonary artery disease. However, this procedure carried risks of promoting platelet aggregation, tearing, arterial recoil, and restinosis. Thus, coronary stents were created in order to prevent "restinosis after balloon dilation". There are three types of stents: bare metal stents (BMS), drug-eluting stents (DES), and bioresorbable vascular scaffolds (BRS).

The first stents created were bare-metal stents where they were made from stainless steel and had poor flexibility. Despite its reduced rates of restinosis compared to plain old balloon angioplasty, it still had high rates of [https://www.thecardiologyadvisor.com/home/decision-support-in-medicine/cardiology/stent-thrombosis/#:~:text=Stent%20thrombosis%20is%20a%20thrombotic,often%20results%20in%20anginal%20symptoms. stent thomborosis] and required high dosage of blood thinners. This lead to the development of drug-eluting stents to act as a local drug delivery and vascular scaffold platform in order to reduce in-stent restenosis.

Antiproliferative drugs like sirolimus and paclitaxel were used in the first-generation drug-eluting stents to inhibit the migration of vascular smooth muscle cells and restenosis. The first implanted drug-eluting stent occured in 1999, which revolutionized the course of interventional cardiology. However, despite the drug-eluting stents superiority over the bare-metal stents, drug-eluting stent implantation had possible concerns over platelet aggregation and major blood clotting in localized area.

As a result, improvements of stent material, strut thickness, polymer, and drug choice lead to the development of second-generation drug-eluting stents that showcased overall clinical imporvements to its predecessor. The new stent used more biocompatible molecules like zotarolimus and everolimus with quicker drug elution. However, despite these improvements, concerns persisted on risk of stent thrombosis.

Purpose
The development of dual therapy stents resulted from the health risks of long term use of drug-eluting stents.

Risks in Drug-Eluting Stents
Drug-eluting stents inihibit growth of endothelical cells and vascular smooth muscle cells, which are important in stent endothelialization. Due to inhibition of vital vascular system cells, this causes risk of stent thrombosis, and, thus, patients with drug-eluting stents are required to use dual antiplatelet therapy for approximatley 12 months. Although long term use of dual antiplatelet therapy research showcases reduced risk of cardiovascular deaths, it has increased occurrences of major bleeding events, which has challenges for patients with bleeding disorders.

Development of Dual Therapy Stents
The COMBO Dual Therapy Stent is the first dual therapy stent to combine the biotechnology of the Genous Stent with antiproliferative sirolimus elution.

Genous Stent
The predecessor of the biotechnology used to create a dual therapy stent was the development of the Genous Stent. The Genous Stent is a coronary stent coated with anti-CD3 monoclonal antibodies that bind with circulating endothelial cells to the stent. The coated stent promotes formation of endothelial layer, which protected agaist thrombosis and reduced restenosis. Although this biotechnology promoted rapid vessel healing, it did not "decrease the rate of lesion failure" compared to drug-eluting stents.

COMBO Dual Therapy Stent
The COMBO Stent is a prohealing stent with sirolimus drug elution and anti-CD3 monoclonal antibodies that has enhanced degree of endothelization. The stent has "an abluminal (facing the vessel wall) coating of bioabsorbable polymer matrix formulated with sirolimus (5 mcg/mm of stent length) for sustained release and a luminal anti-CD34 antibody cell capture coating".

The COMBO Stent's enhanced endothelization is due to the sirolimus drug that reduces risk of stent restenosis and the Genous Stent's anti-CD3 antibodies capture biotechnology. The COMBO stent reduces not only the rate of stent restenosis but also the need for dual antiplatelet therapy, which "enables the use of this type of stent in high-risk patient groups (eg, patients who are under long-term anticoagulation regimens or patients with bleeding disorders)".