How Are Stents Placed?
To place a stent, your doctor will make a small opening in a blood vessel in your groin (upper thigh), arm, or neck. Through this opening, your doctor will thread a thin, flexible tube called a catheter with a deflated balloon on its end.
A stent may be placed around the deflated balloon. The tip of the catheter is threaded up to the narrowed section of the artery or to the aneurysm or aortic tear site.
Special x-ray movies are taken of the tube as it's threaded up into your blood vessel. These movies help your doctor position the catheter.
For Arteries Narrowed by Plaque
Once the tube is in the area of the artery that needs treatment:
Coronary Artery Stent Placement
The illustration shows the placement of a stent in a coronary artery with plaque buildup. Figure A shows the deflated balloon catheter and closed stent inserted into the narrowed coronary artery. The inset image on figure A shows a cross-section of the artery with the inserted balloon catheter and closed stent.
In Figure B, the balloon is inflated, expanding the stent and compressing the plaque to restore the size of the artery. Figure C shows normal blood flow restored in the stent-widened artery. The inset image on figure C shows a cross-section of the compressed plaque and stent-widened artery.
A very narrow artery, or one that's hard to reach with a catheter, may require more steps to place a stent. This type of artery usually is first expanded by inflating a small balloon. The balloon is then removed and replaced by another larger balloon with the collapsed stent around it. At this point, your doctor can follow the standard practice of compressing the plaque and placing the stent.
When angioplasty and stent placement are done on carotid arteries, a special filter device is used. The filter helps keep blood clots and loose pieces of plaque from passing into the bloodstream and traveling up to the brain during the procedure.
For Aortic Aneurysms
The procedure to place a stent in an artery with an aneurysm is very similar to the one used for an artery narrowed by plaque. The stent used to treat an aneurysm is different, though. It’s made out of pleated fabric, often with one or more tiny hooks.
Once the stent has been placed and expanded to fit tight against the artery wall, the hooks on the stent latch on to the artery wall. This anchors the stent.
The stent creates a new inner lining for that portion of the artery. Cells in the artery eventually grow to cover the fabric and create an inner layer that looks like the inside of a normal blood vessel.