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Cardiac catheterization, which involves threading a thin flexible tube through coronary arteries and into the heart, often is done as a test to evaluate the heart and arteries. But did you know it often is performed as a method of intervention to open blocked arteries and restore normal blood flow to the heart?
“Through diagnostic cardiac catheterization, we can measure pressures, take blood samples and inject contrast material into the coronary arteries or chambers of the heart,” explains Palmetto Health Heart Hospital cardiologist Dr. Rodney Rhinehart. “We watch the movement of the dye through the heart’s chambers and blood vessels to determine whether the coronary arteries are narrowed or blocked by cholesterol or calcium inside the lining, forming a substance called plaque.”
If blockages are discovered, the catheter then is used to perform percutaneous coronary intervention (PCI) to open the blocked arteries and restore normal blood flow to the heart. The three common types of PCI are angioplasty, stenting and atherectomy. These procedures can be performed separately or in combination.
Used to treat coronary artery disease, angioplasty involves the use of a small balloon attached to a catheter. Once the catheter has been guided to the proper location in an artery, the balloon is inflated. The pressure from the inflated balloon presses fat and calcium deposits (plaque) against the wall of the artery to improve blood flow.
In an atherectomy, a cutting device (called a “burr”), a whirling blade (called a rotablator), or a laser beam may be used to remove the fat and calcium buildup from the artery wall once the catheter reaches the narrowed portion of the artery.
Directional Coronary Atherectomy
The catheter tip is equipped with a bladed device the cuts away the plaque and stores the little pieces in a tiny container. The plaque is removed when the catheter is withdrawn from the artery.
A whirling blade called a rotablator is used to quickly grind the plaque into very small particles. Once in place, the rotablator may spin between 140,000 and 200,000 times a minute, pulverizing the plaque into micro-particles. These particles travel harmlessly through the circulatory system and then are excreted by the body.
Transluminal extraction catheters have tiny rotating blades and a hollow tube. As plaque is cut away from the artery wall, it is sucked into the tube through a vacuum.
The Angiojet removes blood clots with a high-velocity stream of saline solution that is directed back into the catheter, dragging the debris with it.
STENTING AND DRUG-ELUTING STENTING
Stenting usually is done along with angioplasty. Once the plaque buildup is compressed using angioplasty, a small expandable wire mesh tube called a stent may be inserted into the artery to hold it open. Reclosure of the artery is less likely to occur with angioplasty followed by stenting than with angioplasty alone.
At Palmetto Health Richland Heart Hospital, cardiologists also are inserting drug-eluting stents into some heart patients’ diseased arteries. These stents carry a special chemotherapy drug on their surface that prevents scar tissue growth in the artery where the stent is placed, markedly reducing the possibility of the artery reclosing.
“Traditionally, catheter-based procedures are less expensive and invasive than the other common procedure that treats coronary artery disease—bypass surgery,” Rhinehart says. “Post-operative hospital stays and recovery time also are reduced.”