PATHOLOGIES OF CORONARY ARTERIES
The coronary arteries surround the myocardial muscle and allow the transportation of oxygen to the heart.
Coronary artery disease is caused by fatty lesions that narrow the coronary artery’s inside diameter (stenosis), consequently reducing blood flow and depriving the heart muscle of oxygen. The dramatic consequence of this blockage is angina pectoris, or pain that spreads from the chest to the arms and neck; and it can also lead to an often-lethal myocardial infarction.
A coronary stenosis can be treated efficaciously with a stent - a small, metal, spring-like tube that opens up the artery.
There are two pathologies for which a stent can be used to treat coronary disease:
RECURRENT CHEST PAIN (ANGINA PECTORIS)
This disease results from the progressive build up of cholesterol and calcium that gradually clogs the artery and limits the oxygen supply to the heart. The stent opens the artery, prevents future narrowing and hence treats the pain.
HEART ATTACK (ACUTE MYOCARDIAL INFARCTION)
This syndrome is caused by a sudden obstruction of the artery caused by plaque rupture and a blood clot that stops the supply of blood to the heart. It results in a sudden, intense pain, which if left untreated could result in permanent heart muscle damage and even death.
The stent is implanted in an emergency setting to quickly restore blood flow and heart function to save the patient’s life.
ACUTE MYOCARDIAL INFARCTION
Myocardial Infarction (MI) is the leading cause of death in most industrialized nations throughout the world. Approximately 800,000 people in the United States are affected and, in spite of an improvement in the awareness of manifesting symptoms, 250,000 die before reaching a hospital.
Most MIs are caused by a disruption in the vascular endothelium associated with an unstable atherosclerotic plaque that stimulates the formation of an intracoronary thrombus, resulting in coronary artery blood flow occlusion. If such an occlusion persists long enough (20 to 40 minutes), irreversible myocardial cell damage and cell death will occur.
Current treatment of artery bifurcations, representing one coronary intervention in five, still remains a challenge : procedures are long and complex, the outcome of which is often difficult to predict since one patient in four later suffers from restenosis (recurrence of the narrowing). This leads to a high number of re-interventions, which too often involve a by-pass surgery.