DES (drug eluting stents) is going to replace bare metal stents just as stents replaced balloons. A drug-eluting stent - Taxus, is a stent coated with a drug paclitaxel. This prevents recurrent blockage or narrowing of a previously treated blood vessel. The Taxus stent system represents a major advance in the treatment of coronary artery disease (CAD). The extremely low restenosis rates in nine months with the paclitaxel-eluting Taxus stent system has shown a proven safety profile, flexibility and deliverability. It now represents a new benchmark for the interventional treatment of patients in coronary angioplasty. The outcomes have been similar across the spectrum of patients studied in the trial, including those with diabetes, small vessels and long lesions.
At a forum organized by Boston Scientific, which focused on the current trends and future prospects in the use of stents, also brought out the positive and negative factors of DES technology in coronary angioplasty.
Dr. Upendra Kaul, director, Interventional Cardiology and cardia-electro physiology, Batra Hospital and Dr. Yaron Almagor, Cardiac Catherisation and Interventional cardiology, Jerusalem, said that it was important to identify the problems of DES and analyse the use of the right drugs, stent design and procedure.
CAD is caused by the build up of fatty deposits and plaque inside the coronary arteries. It causes narrowing of the arteries, which in turn reduces the flow of blood and oxygen to the heart. If a coronary artery becomes completely obstructed a heart attack may occur which can be treated with either medication, a surgical procedure or coronary bypass surgery performed under general anesthesia to create a detour to bypass the blockage by Percutaneous Transluminal Coronary Angioplasty (PTCA).
However when the blockage is complex, a stent is implanted to keep the affected part of the artery open. The stent is placed on the balloon that is inserted in the artery, when the balloon is inflated the stent expands and locks in place along the inner arterial wall. Once in place the balloon is deflated and pulled back. The stent remains in the artery and continues to support the blood vessel, explained the doctors.
Results from Taxus IV clinical trial for PTCA have shown significant improvements in sensitive, quantitative angiographic measurements, with reduced revascularization rates. It has proved to be highly effective in diabetic patients who represent approximately 40 per cent of coronary interventions. The results supported safety as demonstrated by low rates of Major Adverse Cardiac Events (MACE), which include death, myocardial infarction and target vessel revascularization. The stent thrombosis rates were similar between Taxus and control stents indicating comparable safety of drug-eluting stents and bare metal stents. The results offer convincing evidence that polymer-based delivery of paclitaxel is a safe and effective treatment for coronary artery disease, stated the doctors.