Percutaneous coronary intervention (PCI), commonly known as coronary angioplasty or simply angioplasty, is one therapeutic procedure used to treat the stenotic (narrowed) coronary arteries of the heart found in coronary heart disease. These stenotic segments are due to the build up of cholesterol-laden plaques that form due to atherosclerosis. PCI is usually performed by an interventional cardiologist, though was developed and originally performed by interventional radiologists.
Coronary artery bypass grafting (CABG), which bypasses stenotic arteries by grafting vessels from elsewhere in the body, is an alternative treatment. Most studies have found that CABG is better than PCI for reducing death and myocardial infarction. However, PCI does improve quality of life. PCI has proven to be as effective and less costly than CABG in patients with medically refractory myocardial ischemia.
The term balloon angioplasty is commonly used to describe percutaneous coronary intervention, which describes the inflation of a balloon within the coronary artery to crush the plaque into the walls of the artery. While balloon angioplasty is still done as a part of nearly all percutaneous coronary interventions, it is rarely the only procedure performed.
Other procedures that are done during a percutaneous coronary intervention include:
- Implantation of stents
- Rotational or laser atherectomy
- Brachytherapy (Use of radioactive source to inhibit restenosis.)
Sometimes a small mesh tube, or "stent", is introduced into the blood vessel or artery to prop it open using percutaneous methods. Angioplasty with stenting is a viable alternative to heart surgery for some forms of non-severe coronary artery disease. It has consistently been shown to reduce symptoms due to coronary artery disease and to reduce cardiac ischemia, but has not been shown in large trials to reduce mortality due to coronary artery disease, except in patients being treated for a heart attack acutely (also called primary angioplasty). In acute cases, there is a small but definite reduction of mortality with this form of treatment compared with medical therapy, which usually consists of the administration of thrombolytic ("clot busting") medication
The angioplasty procedure usually consists of most of the following steps and is performed by physicians, physician assistants, nurse practitioners, nurses, radiological technologists and cardiac invasive specialist; all of whom have extensive and specialized training in these types of procedures.
- Access into the femoral artery in the leg (or, less commonly, into the radial artery or brachial artery in the arm) is created by a device called an "introducer needle". This procedure is often termed percutaneous access.
- Once access into the artery is gained, a "sheath introducer" is placed in the opening to keep the artery open and control bleeding.
- Through this sheath, a long, flexible, soft plastic tube called a "guiding catheter" is pushed. The tip of the guiding catheter is placed at the mouth of the coronary artery. The guiding catheter also allows for radiopaque dyes (usually iodine based) to be injected into the coronary artery, so that the disease state and location can be readily assessed using real time x-ray visualization.
- During the x-ray visualization, the cardiologist estimates the size of the coronary artery and selects the type of balloon catheter and coronary guidewire that will be used during the case.Heparin (a "blood thinner" or medicine used to prevent the formation of clots) is given to maintain blood flow.
- The coronary guidewire, which is an extremely thin wire with a radio-opaque flexible tip, is inserted through the guiding catheter and into the coronary artery. While visualizing again by real-time x-ray imaging, the cardiologist guides the wire through the coronary artery to the site of the stenosis or blockage. The tip of the wire is then passed across the blockage. The cardiologist controls the movement and direction of the guide wire by gently manipulating the end that sits outside the patient through twisting of the guidewire.
- While the guidewire is in place, it now acts as the pathway to the stenosis. The tip of the angioplasty or balloon catheter is hollow and is then inserted at the back of the guidewire—thus the guidewire is now inside of the angioplasty catheter. The angioplasty catheter is gently pushed forward, until the deflated balloon is inside of the blockage.
- The balloon is then inflated, and it compresses the atheromatous plaque and stretches the artery wall to expand.
- If an expandable wire mesh tube (stent) was on the balloon, then the stent will be implanted (left behind) to support the new stretched open position of the artery from the inside.