Coronary Artery Disease
A coronary artery supplies oxygenated blood to the heart muscle. When fat, cholesterol, calcium and other deposits accumulate on the inner wall of the artery, it builds plaque, which causes coronary arteries to become narrowed and limits the supply of oxygen-rich blood to the heart. Areas of plaque can also rupture, causing blood clots to form on the surface of the plaque. When blood flow to the heart is reduced or blocked, angina (chest pain) or a heart attack can occur. According to the Centers for Disease Control and Prevention, coronary artery disease accounts for one of every six deaths in the United States.
Treatments over the Years
The old-fashioned way of treating a blocked or clogged coronary artery is Coronary Artery Bypass Surgery. Then in the early 1980s, a less invasive procedure called angioplasty was introduced. During angioplasty, specialized medical balloons are inserted and inflated to unclog a blocked or narrowed artery to restore the blood flow to the heart. This procedure is sometimes followed by the implantation of a stent or scaffold (metal framework) to hold the artery open and allow the vessel to heal without the formation of clots or recoiling of the artery. When combined with the insertion of a stent or scaffold, the procedure is referred to as Percutaneous Coronary Intervention (PCI).
The advent of new technology brings new problems. One of the first new problems with stents was a process called restenosis where the stent itself would cause a re-blockage or re-narrowing of the artery (25% risk of re-blockage). Much of this problem was cured with the introduction of drug-eluting stents. Currently the standard of care, these are medicated stents that release medication into the wall of the artery, allowing for the vessel and the blockage to heal. This innovation has greatly advanced the catheter-based treatments for coronary artery disease.
Problems with Current Standard of Care
However advanced, there are still some problems with drug-eluting stents. Some patients continue to experience angina after the placement of the drug-eluting stent, and there remains long-term need for blood thinners. Also, a stent’s framework is necessary for the first 6 months while the vessel wall heals itself. After that time, the structural framework of the stent may no longer be necessary and may even restrict the function of the vessel. These are the challenges that a landmark U.S. pivotal study aims to address with the introduction of bioabsorbable (disappearing) stents called “Absorb.”
The theory behind the bioabsorbable stent is to provide the necessary structural framework of the stent for the first 6 months, and then it will disappear. Studies have shown that without that framework for the rest of the patient’s life, those vessels remain uncaged and have the potential to resume uninhibited function. Potential benefits which are attributed to bioabsorbable stents in general, and are currently being investigated, include:
•The vessel is able to move in response to changes in blood flow
•Lower likelihood of retreatment of the vessel that received a bioabsorbable stent
•Ability to capture CT imaging of coronary vessels after the stents are placed
ABSORB IV Clinical Trial
Holy Cross Hospital is one of the sites participating in the ABSORB IV clinical trial, which will enroll patients with coronary artery disease in a first-of-its-kind trial that will measure the effectiveness of these bioabsorbable stents in reducing chest pain, or angina, and keeping blood vessels open.
The device used in this study is investigational. An investigational device is one that is not approved by the U.S. Food and Drug Administration (FDA).
For more information on the ABSORB IV trial or the Holy Cross Jim Moran Heart and Vascular Research Institute, call 954-229-8400 or visit HolyCrossHeartResearch.com.