Balloon angioplasty (Figure 1) is performed alone or after atherectomy. In this procedure, a guide wire is threaded through the blockage, and a thin, un-inflated balloon is passed to the tip of the wire.
Once properly positioned in the artery, the balloon is inflated for approximately 2 minutes to press open the blockage and create a channel that increases blood flow through the artery. Chest pain may be experienced during the procedure because the artery is completely blocked while the balloon is inflated.
Progressively larger balloons may be used to enlarge the opening. Once a channel has been created, a stent may be implanted to maintain the opening. Typically, balloon angioplasty can reduce a 70–90 percent blockage about 20–30 percent.
Laser atherectomy is commonly used to remove enough plaque to allow balloon angioplasty to be performed. In this procedure, a laser attached to the tip of a thin flexible catheter emits short pulses of light that ablates plaque.
To avoid damaging artery walls with the laser beam, the patient is injected with tagged antibodies that attach to plaque molecules and "guide" the laser pulses to plaque molecules only.
Risks associated with laser atherectomy include the following:
- Artery perforation
- Cardiac arrhythmias
- Genetic mutation caused by UV radiation
- Toxic gas leakage from the equipment
- Vapor bubbles that can damage artery walls
- Vascular spasm
Rotational atherectomy, or rotablation, typically is used to treat arteries with very long, calcified, or solid blockages. This technique also can be employed to remove plaque that has regrown inside a stent.
In this procedure, a burr, or surgical drill bit, tipped with very fine diamond chips (Figure 2) is carefully advanced to the blockage. Compressed air spins the burr to pulverize the plaque and the debris is continually suctioned out. Progressively larger burrs may be used to enlarge the channel in the artery.
After rotational atherectomy, the channel usually is expanded further with an angioplasty balloon, and in many cases a stent is permanently implanted to hold the artery open.
Directional atherectomy employs a catheter tipped with a device consisting of a cup-shaped blade and a container. The blade cuts away plaque from the artery and deposits it into the container. When the catheter and device are withdrawn, the plaque is removed from the body.
Transluminal extraction involves a special catheter tipped with a hollow tube and rotating blades. As the blades cut plaque away from the arterial wall, the debris is suctioned out of the body through the tube.