Preliminary clinical data have indicated that the use of radiation in conjunction with widely used interventional treatments like percutaneous transluminal coronary angioplasty (PTCA) and coronary stenting, has the potential to minimise the re-occurrence of blockage in a previously treated artery. This re-occurring blockage, known as restenosis, is one of the biggest clinical challenges in cardiovascular medicine.
The ACS MULTI-LINK Radiation Coronary Stent System is comprised of the world's market leading stent, the ACS MULTI-LINK TRISTAR Coronary Stent System. The stent is implanted with a pure beta-emitting isotope known as Phosphorus 32 (32P). This type of radiation requires minimal shielding to protect clinical personnel, necessitating even less protection than what is required for x-ray technicians. The stent limits the radiation exposure to a specific site within the artery, and delivers a majority of the dose within the first month following implantation.
"The first human implant of the ACS MULTI-LINK Radiated Coronary Stent System is a significant milestone in Guidant's effort to address the important clinical challenge of restenosis", stated Ginger L. Graham, president of Guidant's Vascular Intervention Group. "We believe that the study of radiation stenting, in addition to our other clinical trials, will provide physicians with a solution to address restenosis and help them to more effectively treat their patients with coronary artery disease."
Guidant is one of the leaders in conducting research on the use of radiation to treat coronary artery disease. In addition to the radiation stent trial, the company is currently conducting the INHIBIT trial (INtimal Hyperplasia Inhibition with Beta In-stent Trial), to study the safety and effectiveness of Guidant's Intravascular Radiotherapy System. This randomised, multi-centre trial is being conducted with 310 patients at leading cardiovascular centres throughout the United States. The Guidant system is a 32P beta-emitting system that consists of a source wire, a source-delivery unit, and a centring catheter. The system delivers radiation directly to the diseased area of the vessel that has re-closed following a previous stent procedure.
Enrolment for INHIBIT was completed in November 1999. Once each patient has received nine-month follow-up, Guidant expects to file its Intravascular Radiotherapy System with the United States Food & Drug Administration for marketing approval. Guidant has completed clinical work in its PREVENT (Proliferation Reduction with Vascular Energy Trial) study, which assessed the effectiveness of its Intravascular Radiotherapy System in treating both first-time and re-occurring blockages of coronary arteries.
In addition to its own clinical trials, Guidant is associated with additional research in the study of radiation. Guidant is the provider of catheters for the PARIS Centring Catheter System, which is being used by Nucletron B.V. of The Netherlands in its Peripheral Artery Radiation Investigational Study (PARIS). This clinical trial's purpose aims at studying the feasibility of the Nucletron microSelection HDR afterloader to deliver gamma radiation to specific diseased areas inside the femoral artery, which is the primary vessel of the thigh and the popliteal artery, located behind the knee. An afterloader is an automated system that stores a radioactive-tipped wire and delivers it through a catheter to the therapeutic target area. This system is currently being used in a randomised trial of 300 patients at various centres all over the United States.
A global leader in the medical device industry, Guidant Corporation provides innovative, minimally invasive and cost-effective products and services for the treatment of cardiovascular and vascular disease. Read more about this company's initiatives in our current issue's article Guidant to order Interventional Cardiology Training Simulator from Virtual Presence.