Everything You Need To Know

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You Need To Know


Cardiac Catheterization


Coronary Intervention

A Patient’s Guide



David Brill, MD

Director, Cardiac Catheterization Laboratory Washington Adventist Hospital

7600 Carroll Avenue

Takoma Park, Maryland 20912 Editor

Susan Brill Kay, B.S.N, RN, CVNS

Copyright© 2004 Kay-McKenna Enterprises, Inc. Copyright© 1996 All rights reserved.

9935 Potomac Manors Drive Potomac, Maryland 20854

Phone and/or Fax Number: (301) 983-4733 www.kmheart.com


You Need To Know


Cardiac Catheterization


Coronary Intervention

A Patient’s Guide


Table of Contents

Introduction . . . .1

Cardiac Catheterization—What is it and Why is it done? . . . .1

How Your Heart Works The Heart—A Muscular Pump . . . .2

The Heart’s Blood Supply: Coronary Arteries . . . .3

Diseases of the Heart Atherosclerosis . . . .4

Plaque Rupture . . . .5

Myocardial Infarction . . . .5

Valvular Disease . . . .6

Congestive Heart Failure . . . .7

Congenital Heart Problems . . . .7

Cardiac Catheterization What to do to Prepare for a Cardiac Catheterization . . . .8

Where is Your Catheterization Performed? . . . .9

What Happens Before Your Catheterization? . . . .10

How Does Catheterization Work? . . . .10-11 What Happens During Catheterization? . . . .11

What is Angiography? . . . .12

After the Catheterization: Sheath Removal/Closure Devices . . . .13

At Home . . . .14

When to Call Your Doctor . . . .14

Risks Involved with Cardiac Catheterization . . . .15

Angioplasty/Stent The Reasons for Intervention/Angioplasty . . . .16

How Angioplasty Works . . . .17-18 Stents . . . .19-20 Drug-eluting or Drug-coated Stents . . . .20

Other Methods of Intervention Rotational Atherectomy . . . .21

Directional Atherectomy . . . .22

Thrombectomy . . . .22

Laser Angioplasty . . . .22

Cutting Balloon . . . .23

Radiation Therapy or Brachytherapy . . . .23

Embolization Prevention Devices . . . .24

After Coronary Intervention Recurrence or Restenosis after Angioplasty . . . .25

Coronary Intervention: Success and Complication Rates . . . .26

Sheath Removal/Closure Devices . . . .27

Activity . . . .28

Testing . . . .29

Your Care after Your Interventional Procedure What is Normal after Intervention? . . . .30

What You Should Report to Your Doctor . . . .30

Ten Rules for Taking Medication . . . .31

Medications . . . .32-36 What You Can do to Help . . . .37

Conclusion . . . .38 Glossary . . . .39-40




ardiac catheterization and coronary intervention (angioplasty) are two wonders of medical tech-nology which have improved the lives of millions of patients. Your doctor has recommended that you should undergo a cardiac catheterization or an interventional procedure. Do not be intimidated or frightened by these procedures. They are safely and comfortably performed in thousands of hospitals on a daily basis. The information in this booklet will help you understand how your heart works, how cardiac catheterization helps to diagnose problems with your heart, and how intervention (angioplasty) can success-fully treat problems with your heart’s blood supply. If you have any special concerns or questions after reading this booklet, please discuss them promptly with your doctor. Your doctor wants you to be well-informed and comfortable with the catheterization or interventional procedure. That is why your doctor gave this booklet to you!



Cardiac catheterization, also called an angiogram, is a test that uses long, thin, hollow tubes called catheters to make x-ray pictures of your heart and its blood vessels. The test also determines how well your heart muscle and its valves are performing. Cardiac catheterization helps your physician to diagnose diseases of your heart—clogged arteries, heart valve defects, or heart muscle damage. Sometimes, a cardiac catheterization confirms that the heart is normal and provides reassurance that symptoms are not related to the heart. If problems are identified by the catheterization procedure, the test will help your physician develop a treatment plan. To better under-stand why the test is being performed, you need to know the basic workings of the heart and understand the diseases that can affect and threaten your heart.




The heart is actually two muscular pumps or ventricles located side by side in the center and left half of your chest. These muscles circulate the blood through your body. The right side of the heart receives blood from your veins and pumps it into the blood vessels of your lungs. There, the blood picks up oxygen and releases carbon dioxide, a waste product. The left side of the heart receives the blood with fresh oxygen

from the lungs and pumps the oxygenated blood to your vital organs (brain, kidneys, gut) and skeletal muscles. Once it has traveled through your body, the blood returns to the right side of your heart to repeat its cycle of exchanging carbon dioxide for oxygen. There are ante-chambers/small chambers on top of the ventricles called atria that fill with blood and then empty into the ventricles to fill them completely before each heart beat. The heart also has four valves that keep the blood moving in only one direction as it pumps the blood.



To the body Pulmonary artery Pulmonary veins Aorta

Pulmonary artery (blood To the lungs)

Left atrium

Pulmonary veins (blood from lungs to the heart)

Left ventricle

Right ventricle Blood from

veins to the heart Right



To provide enough energy to keep its pumping action going, the heart needs an excellent blood supply. Blood is supplied to the heart muscle through the coronary arteries, tubular blood vessels that divide into smaller and smaller branches like the branches of a tree. The large trunk arteries and major

branches run on the outer surface of the heart muscle. The smaller branches penetrate deep into the heart delivering fresh, oxygenated blood to the muscle. There are two main coronary arteries that originate from the base of the aorta, the left coronary artery and the right coronary artery. The left coronary artery divides almost immediately into two branches. The left anterior descend-ing coronary artery supplies the front side of the heart with blood and the

circumflex artery supplies the left outer wall and back side of the heart with blood. The right coronary artery supplies the right side and under surface of the heart with blood.




Left main coronary artery

Right coronary artery

Left circumflex coronary artery

Left anterior descending coronary artery



Atherosclerosis is a build-up of choles-terol, scar tissue, blood clot and fatty material in the walls of your arteries. As this material builds up in the walls of the arteries it narrows the channel of an artery and forms a plaque.

Coronary artery disease refers to ather-osclerosis or cholesterol obstruction in the coronary arteries. Coronary artery disease is the most common problem leading to a recommendation for a cardiac catheterization. The conditions that increase the risk of developing plaques are called coronary risk factors.

You are susceptible to developing cholesterol plaques if:

• You have high blood pressure.

• You have diabetes.

• You have a cigarette smoking habit.

• You have high blood cholesterol level and a low HDL (the good cholesterol).

• You have a family history of early-onset coronary artery disease.

Symptoms or problems develop when plaque partially or completely blocks the channel of a coronary artery. If an artery is partially blocked, there can be a reduction in blood flow to your heart muscle. This reduction in blood flow may create problems when the heart is stressed by physical exertion or emo-tional upsets. Inadequate blood flow through the partially obstructed artery can cause discomfort in the chest called angina pectoris. Angina is a warning sign or symptom that the blood flow to the heart muscle through an obstructed artery is not sufficient.



Cholesterol plaque obstructing blood flow in a coronary artery Plaque




The cholesterol plaque in a coro-nary artery can undergo rapid transformation with sudden narrowing of the channel of the artery. The cholesterol plaque in the wall of the coronary artery can trigger a reaction from the body’s immune system resulting in inflammation. This inflammatory reaction can weaken the inner lin-ing of the artery, causlin-ing the linlin-ing to tear and expose the cholesterol plaque directly to the blood inside the artery. This process is referred to as plaque rupture and can cause rapid accumulation of blood clot material on the exposed plaque. The sudden build-up of clot at a plaque rupture can narrow an artery to the point of causing a heart attack or a prolonged bout of chest pain (unstable angina).



When an artery is completely obstructed, a heart attack may occur. A total obstruction of a coronary artery typically occurs when a clot (thrombus) closes off a segment in an artery that is already narrowed with a plaque. A heart attack occurs when part of the heart muscle (myocardium) has no blood flowing to it for a half hour or longer. The heart muscle supplied by that particular artery becomes damaged and is turned into scar tissue.

Occasionally, if an artery narrows gradually over time, your body can compensate by growing auxiliary, small blood vessels around the obstructed segment of the artery. These small blood vessels are called collaterals and may protect the heart from damage if an artery closes off.


Complete obstruction of an artery resulting in damage (heart attack)

Clot Endothelium Plaque




When the heart circulates the blood, its valves must open and close fully to allow the proper flow of blood through the heart’s pumping chambers. When a valve does not open completely, this condition is called stenosis. The oppo-site problem, regurgitation, occurs when a valve leaks, causing blood to flow in the reverse direction. In adults, the two valves most commonly affected by these problems are the valves in the left side of the heart, the aortic and mitral valves. When a valve has severe stenosis or regurgitation, the heart can

be weakened and its pumping function impaired. Aortic stenosis obstructs blood flow out of the left ventricle. This occurs mostly in older patients. This condition can weaken the heart and may require heart surgery for treat-ment. Mitral regurgitation results in blood flowing backward from the left ventricle (main pumping chamber) into the left atrium and the blood vessels of the lungs. Mitral regurgitation can also reduce the pumping function of the heart and is sometimes due to a “floppy” valve (mitral valve prolapse) or damage to the valve attachment from a heart attack.


Aortic stenosis Aortic valve Pulmonary valve

Normal valves Mitral

regurgitation Mitral

valve Tricuspid




Septal defect


Congestive heart failure is a condition that occurs when the heart has become weakened and cannot pump enough blood to meet your body’s needs. When the heart does not circulate the blood vigorously enough, fluid can back up into your lungs or legs. The symptoms of congestive heart failure are breathlessness, fatigue and swollen ankles.

The most common causes of congestive heart failure are:

1) heart attacks that damage the heart muscle

2) high blood pressure that hinders the heart from filling and pumping the blood forward.

Occasionally, congestive heart failure results from excess thickness and stiff-ness of your heart muscle. In

this case, the pumping chamber of the heart muscle has difficulty filling with blood between heart beats.

This condition is called diastolic dysfunction.


Cardiac catheterization can also be useful in diagnosing congenital heart problems that are present at birth. Septal defects are “holes in the heart” that allow the blood to move abnormally from the left side of the heart to the right side (or vice versa). Valve problems can also be congenital.




he catheterization procedure is performed by a cardiologist, an expert in the diag-nosis and treatment of heart disease. Your cardiologist wants your catheteriza-tion procedure to be safe, comfortable, and easy for you. You can help by getting yourself ready ahead of time and by understanding the procedure. A well-prepared patient is a calm, informed patient who expects a successful procedure.





1. Understand the procedure, the reasons for doing it, and the potential risks.

2. Do not eat or drink anything after dinner the day before the procedure. Continue to take any regular medicines with a small sip of water unless instr

ucted otherwise by your doctor.

3. Inform your doctor at least one day before the

proce-dureif you are allergic to x-ray dye. Allergy to x-ray dye can appear as a skin rash, hives, swelling of

the face or tongue, difficulty breathing or wheezing,

and on rare occasions as collapse of the circulation (shock or low blood pressure with faintness). Fortunately

, serious allergic reactions are very rare. If you ar

e allergic to the x-ray dye, your doctor will pre-tr

eat you with Prednisone and an antihistamine, like Benadryl, to prevent the allergic reaction.

4. Inform your doctors if you are taking Coumadin. This medication slows blood clotting and may need to be stopped before the procedure.

5. If you are diabetic, ask your doctor for specific instructions about your insulin dosage or your

diabetic pills. Some physicians will ask their patients to stop Glucophage (metformin) prior to the procedure.

6. Stay calm. Millions of patients have undergone cardiac catheterization. Almost all patients went through the procedure safely and comfortably






You will go to the catheterization laboratory to have your procedure. The catheteriza-tion laboratory is a specially designed room with an x-ray camera and monitor ( a TV screen) which will display pictures of your heart and blood vessels. There is a padded table for you to lie on during the procedure.






• Before the procedure— sometimes earlier that day or several days in advance—you will need to have blood tests to check your blood count, kidney function, and blood’s ability to clot.

• You are also asked to fast on the day of the procedure.

• An IV line is inserted into a vein in your arm so that you can be given fluids and medications easily.

• You will receive enough medication to feel relaxed and comfortable.

• You will be awake enough during the procedure to communicate with the physician and the staff.

• If you become nervous before or dur-ing the procedure, additional medi-cine to help you relax can be given through the intravenous line.



Your doctor will use a catheter to per-form your heart examination. The catheter is a long, thin, flexible hollow plastic tube. Your cardiologist will insert the catheter into a blood vessel (artery) in the groin area or the arm. The catheter then follows the course of the blood vessels to reach the heart. The movement of a catheter inside a blood vessel cannot be felt by a patient and is therefore painless. The size of the catheter is relatively small com-pared to the size of the blood vessel into which it is introduced.

Most commonly, the blood vessels in the right groin area are used for inser-tion of the catheters to the heart. The femoral artery and vein are located in the skin fold in the groin area that is formed by bending the hip. In the arm, on the inside of the elbow or wrist are two arteries (brachial and radial arter-ies) that can also be used for catheter insertion.

A special needle to puncture the femoral (or radial) artery or vein is used, and through this needle a thin metallic guidewire is threaded into the blood vessel. An introducer sheath is then inserted over the guidewire into the artery or vein. The sheath has a special rubber valve through which a catheter can be introduced into the blood vessel. An x-ray camera is used to guide the catheter from the groin (or arm) area to your heart. When the catheter is positioned at your heart, a




special dye that shows up during x-ray procedures is injected through the catheter. Your cardiologist observes this dye making its way through the coronary arteries and the heart by viewing the x-ray monitor. The catheter can also be used to measure the pressures in the various chambers of your heart and to examine the function of your heart valves. This procedure helps your physician identify clogged arteries, heart valve defects or heart muscle damage.




Once you are adequately medicated and at ease, your cardiologist will:


Numb your groin (or arm/ wrist) by using a small needle to inject lidocaine, a local anesthetic under your skin.


Puncture the femoral (or radial) artery or vein with a needle specially designed to allow entry of the catheter.


Insert the catheter through a sheath that is threaded into the artery over a guidewire passed through the needle.


Guide the catheter from the groin (or arm) to your heart.


Inject through the catheter a special dye that visualizes your heart’s blood vessels and pumping chamber.


Use the catheter to measure the pressure in the chambers of your heart.

Radial artery

Catheter in the Femoral artery





An angiogram is a picture of your blood vessels or arteries. A coronary angiogram (or arteriogram) is an x-ray picture of the arteries of your heart that demonstrates any obstructions or plaques narrowing the coronary arter-ies. The x-ray picture is made by inject-ing x-ray dye into the blood vessels. X-ray dye (radiographic contrast agent) is a clear liquid, containing iodine, that shows up on x-ray pictures. When the dye is injected and the x-ray beam pass-es through the heart, your arteripass-es appear on the x-ray image as a silhou-ette in black against a background of white. The x-ray image is recorded as a digital image or is recorded on 35 mm film. The digital image can be stored on a CD-rom format.

Most people do not feel the small injec-tions of x-ray dye into the arteries of the heart. However, a few experience minor chest discomfort which lasts only a few seconds. A few patients may note a mild sensation of nausea or lightheadedness at times during the angiogram.

Another picture of your heart is made by injecting x-ray dye into the main pumping chamber of your heart and observing the pumping action of the heart muscle as it beats. This procedure may produce a hot and flushed sensa-tion. This feeling lasts for 10 seconds and is not painful.






• In order to prevent bleeding, it is very important for you to lie still and neither bend your leg nor raise your head, if the catheter was inserted in the groin.

• Most patients need to lie still for 2 to 6 hours after a sheath is removed. • Some physicians use closure devices

to close up or seal the arterial punc-ture. Biologic materials that promote rapid clot formation at the puncture hole are used, such as collagen or thrombin (a clot forming enzyme). Some closure devices close the punc-ture hole with supunc-ture material.

Immediately after the procedure, your physician will have some information available about your condition. More information will be forthcoming after your physician has had a chance to review the x-ray pictures and study the data in more detail. Coronary intervention (angioplasty or stent procedure) is occasionally performed immediately after the angiogram. Interventional procedures are described later in this booklet.

The angiogram part of the catheteriza-tion procedure takes between 15 and 45 minutes. After the procedure, you are taken to a holding area to recover. A short tube, called a sheath, is removed from the groin area (or arm area). The sheath is the plastic tube through which the catheters were inserted into the blood vessel.

As soon as the sheath is taken out: • Pressure is applied to the insertion

site for about 20 minutes to prevent bleeding.

• When the pressure is released, the insertion site is inspected very care-fully to be certain there is no oozing or bleeding.

• Then, a dressing is applied to the skin and a 10 pound weight (sandbag) may be placed over the insertion site.




Once you are home, in the hours and days following a catheterization, you may notice a small bruise in the area where the catheter was inserted. Bruising is caused by a small amount of blood that escapes from the blood vessels under the skin during or after the test. In a few cases a larger bruise will develop that can extend many inches beyond the insertion site. In a few patients a hard swelling (hematoma) may appear in the groin area.


Please report to your doctor any of the following:

• Painful swelling at the catheter insertion site that gets worse rather than better.

• Bleeding from the insertion site.

• Swelling in the calf or thigh that occurs days after the procedure. • Fever of 101 or higher.

• Drainage of pus from the insertion site.

• Numbness or weakness of the extremity into which the catheter was inserted.

You do not need to report to your doc-tor if there is skin discoloration around the insertion site, even if it is relatively large. The discolored bruise is caused by the leakage of blood from the artery after the procedure. This old blood works its way to the surface over a period of days. The discolored area may enlarge over time, but will resolve in 1 to 3 weeks.




Cardiac catheterization is a safe

procedure but as with any procedure

there are risks involved:

• In very rare cases—one in 1,000 patients—a stroke or heart attack can occur. Although it is possible that either of these two serious com-plications could occur, the likelihood is very, very rare.

• In addition, some patients are aller-gic to the x-ray dye. It is very impor-tant to inform your doctor immedi-ately if you have this kind of allergy. Medications can prevent most allergic reactions if they are given before the procedure. Some allergic reactions cannot be anticipated and may occur for the first time only after the x-ray dye is injected. The most common reactions are minor such as skin rashes and itching. The chance of a life-threatening allergic reaction is very, very small—one in 10,000 or less. • Patients with weak kidney function,

especially as a result of diabetes or high blood pressure, have an

increased risk of further weakening kidney function from a toxic effect of the x-ray dye. However, this deterio-ration in kidney function is usually only a temporary problem. Special precautions are taken to reduce this

risk. It is very rare for x-ray dye to produce serious or permanent injury to the kidneys, especially if kidney function is normal beforehand. • Finally, the insertion of the catheter

into a blood vessel can sometimes result in injury to the vessel or signi-ficant bleeding around the artery. On rare occasions, the blood vessel does not seal properly or a blood clot forms in the vessel. A minor procedure can repair the blood vessel in these cases.




Coronary interventions are treat-ments or procedures that open up blockages in the blood vessels. Angioplasty is a type of coronary intervention that uses a catheter with a balloon affixed to it to open up a blocked artery. The term angioplasty also will be used as a general term indicating any type of intervention.

The majority of patients have a stent (see page 19) implanted during the angioplasty procedure.


When a build-up of plaque significantly narrows a coronary artery, patients can experience chest pain (angina) or have a heart attack if the artery becomes completely obstructed. Angioplasty is a treatment that can relieve chest pain, reduce the likeli-hood of a heart attack in the future, and can stop a heart attack if rapidly performed during a heart attack.

For the majority of patients, the procedure permanently eliminates the severe blockage. Angioplasty and related procedures are the only techniques that actually reduce an obstruction and “fix” the artery.




Angioplasty balloon catheter Angioplasty balloon catheter inflated Guide catheter




The angioplasty procedure is similar to cardiac catheterization.

• In both procedures, your cardiologist inserts a catheter in the femoral artery in your groin (or an arm artery) and directs it to your heart. • With angioplasty, the catheter which

extends from your groin (or arm) area to the heart is called the guiding catheter.

• Local anesthesia is always used so that the insertion of the catheter is painless. After the guiding catheter is positioned at the opening of your coronary artery, x-ray dye is injected to make pictures of the artery that needs angioplasty.

• Inside the guiding catheter, the angioplasty device, called a balloon catheter, is then inserted. This balloon catheter is a long, very thin, delicate plastic tube that is equipped with a small plastic balloon at its end. When the balloon is deflated, the tube is very thin and can be squeezed across an obstructed segment of an artery. The balloon part of the catheter is used to open up the blockage in your artery. • The narrowed segment of the artery

must first be crossed with a guidewire. A guidewire is a thin, delicate, hair-like strand of metal. The thickness of the guidewire is usually fourteen thousandths of an inch (0.014”).




• After the guidewire is successfully passed through the blocked area, the balloon catheter slides over the guidewire like a train on a rail. The guidewire allows the balloon

catheter to safely follow twists and bends in the artery.

• The balloon segment of the angio-plasty catheter is then positioned across the blockage. The balloon is inflated with a mixture of water and x-ray dye.

• When the balloon is fully expanded, the obstructive plaque is pushed off to the side. The procedure works by stretching the wall of the artery and compressing the plaque. There is some minor tearing and cracking of the plaque that extends into the wall of the artery. This is a normal part of the procedure and is necessary for success.

• During the brief balloon inflations, blood flow through your artery stops. When the balloon is inflated, many patients experience brief discomfort in the chest that is similar to angina. If any significant discomfort occurs, pain medication is given immediately.

• After the balloon has been inflated and deflated, x-ray pictures are again taken to be certain that the obstruc-tion has been eliminated. The balloon catheter is then removed and final x-ray pictures are made. • The patients are observed after the procedure to be certain that delayed problems do not occur.


Artery after angioplasty

Narrowing of coronary artery before angioplasty




Stents are small metal strands that are woven or fashioned into a tubular shape. Most stents are made of thin strips of stainless steel and look like a minature tube of chicken wire. Stents are used to improve upon angioplasty results and provide a more durable treatment of the cholesterol blockage. Stents can reduce the likelihood of recurrent blockage (restenosis) by at least 10% when compared to balloon angioplasty. Some types of blockages are not well suited to stent implantation and are best treated with simple angio-plasty or other techniques. Small arter-ies, very stiff and calcified arterarter-ies, and arteries with blockages involving major branch points may not yield good results with stents. Usually, stenting achieves an excellent result even in complex blockages.


The majority of patients (at least 80%) now receive a stent implant during a coronary intervention:

• A stent is first loaded onto an angio-plasty balloon catheter by crimping and compressing the tubular piece of metal firmly against the plastic bal-loon material.

• The stent-angioplasty balloon unit can then be inserted into the coro-nary artery using standard angio-plasty techniques.

• The metal structure of the stent has a “memory” and will retain the shape that the expanded balloon catheter forces on the stent.

• Many times a blockage is first stretched open with an angioplasty balloon to allow sufficient room for the catheter with the stent to pass through the obstructed segment.

Stent on angioplasty balloon before expansion in the artery Stent on angioplasty balloon expanding in the artery



Stents may also be helpful in opening up blocked arteries on an emergency basis during a heart attack. Stents can be implanted into diseased bypass grafts and can reopen an artery that has developed a delayed narrowing after angioplasty (restenosis). Also, when an artery is forced open by the stretching action of an angioplasty bal-loon, rough surfaces or “flaps” fre-quently are created on the inside of the artery. Stents “tack up” and press together these jagged inner edges of the artery and therefore are useful for fixing an initially unsatisfactory angio-plasty result.

After a stent is inserted, there is a ten-dency for blood to try to form a clot on the metallic surface inside the artery. Special care is needed to prevent a clot from forming and cutting off blood flow through the stented vessel. All patients are treated with antiplatelet agents, medications that keep platelets (small clotting cell fragments in the blood stream) from adhering to the stent. Failure to take the antiplatelet medications (such as aspirin, Plavix, and/or Ticlid) can cause the stent to clot and provoke a heart attack. If a patient properly takes the antiplatelet medications, the likelihood of a serious clotting event occurring is 1 in 200.


Stents are a great technologic improve-ment in the angioplasty procedure. Their increased use among cardiologists is due to the extra safety, reliability, and durability that they add to the coronary intervention.

Drug-eluting or drug-coated stents:

New stents are being developed that are coated with drugs that are slowly released from the stent and that can block the body's ability to form scar tissue at the site of the stent implant. These new stents slowly release the drug into the wall of the coronary artery. The drugs are targeted to stop the ingrowth of smooth muscle tissue from the blood vessel wall. These drug-coated stents have lowered dramatically the recur-rence rate after stenting. The most promising drug so far tested appears to be sirolimus (rapamycin), although other agents are being tested and demonstrate effectiveness in early trials. A stent coated with sirolimus (Cypher stent) is available. There is strong evidence that this type of stent dramatically lowers the risks of recurrent blockage and reduces the likelihood of needing a repeat procedure to keep the treated artery open.

Drugs being slowly released from stent




Rotational atherectomy is performed with the Rotablator, a long metallic catheter with an olive-shaped burr at its tip. This device is useful for treating blockages that are very hard with calcium deposits or resistant to stretching with an angioplasty balloon catheter. The Rotablator can be used to remove obstructive scar tissue that can form inside stents. The Rotablator spins rapidly at approximately 150,000 to 180,000 RPM. The burr is coated with tiny diamond fragments that abrade and pulverize plaque as the burr spins against the plaque material. The micro-scopic debris generated by the Rotablator harmlessly washes out of your coronary arteries and is absorbed by your body. In a small number of patients, the microscopic debris can slow down blood flow in the treated artery. 21

Rotational atherectomy Rotablator burr Plaque ROTO ROTATOR





Directional atherectomy is a technique that allows your physician to remove the plaque from the artery using a spe-cial device known as an atherectomy catheter. When the atherectomy

catheter is positioned over the plaque, a rotating cutting blade advances

through the cutting chamber in the catheter and slices off thin slivers of the plaque. The plaque material is collect-ed in a conical chamber in the front of the catheter and then removed from the body. The cholesterol material there-fore is not allowed to break off or to obstruct the artery. Like angioplasty, the atherectomy catheter is inserted through a larger guiding catheter from the groin and is passed over a guide-wire in the artery. Atherectomy is performed less frequently than balloon angioplasty or stenting, because only certain types of blockages are best suit-ed for this procsuit-edure. Atherectomy is recommended for blockages in the beginning and middle segments of large arteries, blockages at branch points, and blockages with complex configurations.


Thrombectomy devices such as the Angiojet can remove blood clots from the arteries. The Angiojet device aspi-rates clot by “sucking” clot into a high speed jet of salt water sprayed from the tip of the device into a collection cham-ber in the shaft of the instrument. The Transluminal Extraction Catheter (TEC) is a device with rotating cutting blades attached to a suction line. The TEC device also can be used to remove clot or soft cholesterol material.


Excimer laser angioplasty is a technique that opens up obstructed arteries using laser fibers in a catheter. The laser energy at the catheter tip cuts through the plaque and converts the cholesterol material and any adherent clot to water vapor and carbon dioxide. Laser angio-plasty may be recommended to treat complex blockages or to remove obstructive material that can block stents. Directional atherectomy Laser angioplasty Laser catheter Plaque Cutting blades Plaque Conical collection chamber





The scar tissue or tissue proliferation after coronary intervention can negate the bene-ficial effects of an intervention. The growth of scar tissue can be blocked by applying very low doses of radiation directly to the inside of the treated artery at the time of the angioplasty or interventional procedure. The direct application of radiation to an artery is referred to as brachytherapy. Brachytherapy is a new treatment that is very effective for treating restenosis that has occurred at a site previously treated with a stent. The radiation source is applied to the blocked stent for a period of several minutes and then removed. The obstructed stent is usually first treated with angio-plasty or atherectomy to reopen the blocked channel.

At the present time, brachytherapy is the most effective treatment for blocked stents.

Brachytherapy may also prove to be useful in preventing restenosis in patients with blockages that are anticipated to have a high recurrence rate at the time of the first procedure.


The cutting balloon is a balloon catheter with 3 sharp, very short cutting blades attached to the balloon material. As the balloon inflates, the cutting blades shallowly incise the plaque resulting in a more complete and precise opening of the artery. The cutting balloon may be useful for blockages that form inside stents or for plaques that resist stretching properly with an angioplasty balloon catheter.

Radiation brachytherapy Radioactive “seeds”




Blood vessels with large amounts of clot (thrombus) at the site of the block-age are more likely to develop compli-cations with coronary interventions. The clot can travel down the blood vessel and obstruct smaller branches near the termination of the artery. This process is referred to as embolization and may result in heart attack damage (myocardial infarction). Intervention performed on vein grafts implanted at the time of the bypass operation can also be complicated by embolization, but the material embolized is frequently cholesterol plaque that is poorly adherent to the vein graft wall. Fortunately, new devices have been developed and are

being developed to trap embolic material during these complicated interventions. The only approved device so far is the Percusurge Guardwire which captures embolic debris behind a soft retaining balloon mounted on a guidewire. The debris then is aspirated with a special catheter after the intervention. The final step is the deflation of the retaining balloon to allow restoration of normal blood flow. The Guardwire has been demonstrated to reduce the complication rate in patients undergoing intervention on vein graft blockages. Other filter type devices are being developed to capture dislodged debris during interventions.


Embolization device for capturing debris Retaining ballon

Debris Clot breaking off in endothelium






In a minority of patients who undergo a successful angioplasty procedure, the blockage recurs:

• This recurrence, called restenosis, usu-ally is caused by the build up of scar tissue at the site of the original angio-plasty or stent procedure. Restenosis is not due to a reaccumulation of choles-terol or plaque at the treatment site. • Other causes of restenosis are recoil of

the artery wall and negative remodel-ing (“shrinkage” of the vessel wall). Recoil means that the artery wall reas-sumes its original narrowed configura-tion because the vessel wall is very elastic like a rubber band. Negative remodeling refers to contraction and actual shrinkage of the entire artery as it heals and scars after angioplasty. These processes occur only after balloon angioplasty and are not involved in restenosis after stenting. Restenosis occurs in 10 to 35% of patients (1 in 10 patients to 1 in 3 patients), usually between two and six months after angio-plasty or stenting. It is unlikely to occur in the first month or beyond one year after the procedure. Restenosis is sus-pected when symptoms return or if a stress test to evaluate the result of an intervention is abnormal. Restenosis can occur after any of the intervention procedures previously described. In some patients, the narrowing that recurs with restenosis is not as severe as

the original blockage. If the patient has minimal or no symptoms, a mild restenosis is not treated with repeat intervention and instead is managed with medication. When a restenosis is severe or is associated with severe symptoms, the intervention can be repeated. If a stent was not originally implanted, a stent is frequently used to treat restenosis after balloon angioplasty. A restenosis in a stent is due to scar tis-sue build-up occurring through the open space between the metal “struts” of the stent. In-stent restenosis is more difficult to treat than a restenosis after balloon angioplasty and may require an atherec-tomy device to remove the scar tissue or treatment with radiation (brachy-therapy). A small number of patients experience repetitive restenosis and do not have long lasting symptom relief with coronary intervention. The like-lihood of repetitive restenosis is less than or equal to one out of six patients. Some patients require bypass surgery to treat repetitive restenosis.




Coronary intervention and angioplasty have a very high success rate. It is very likely that your physician will be able to open up the obstructed artery during the procedure. Angioplasty is successful in 95% to 98% of patients. This means that in a group of 100 patients, 95 to 98 patients have a successful outcome. The high suc-cess rate of coronary interventions is responsible for its popular use as a treat-ment and is attributable to the technologi-cally advanced equipment used, especially stents, and newer medications that have reduced complications. The success rate is less for arteries that have been obstructed for several months or longer.

The major complications of coronary intervention include:

• Acute closure of the artery or one of its branches. Acute closure can be due to a portion of the cholesterol plaque or artery wall protruding into the channel of the blood vessel. Acute closure can damage the heart and cause a heart attack, but can usually be corrected by implanting a stent. Rarely, a stent can clot off causing the pro-cedure to fail.

• Clot formation or embolization (the breaking off of a fragment of clot that obstructs smaller branches of an artery). Clot formation can be treated with power-ful antiplatelet medications (IIbIIIa platelet inhibitors) and clot dissolving medications (thrombolytics) or a thrombectomy device. • Even with the best equipment and the most experienced hands, a very small number of patients will require emergency

open heart surgery (bypass operation) to treat complications resulting from a failed intervention. The likelihood of this occur-ring varies according to the type of block-age, its severity, complexity, and location in the artery. The occurrence of emer-gency bypass surgery now averages less than one in two hundred patients (<0.5%). • Bleeding from the catheter insertion site can also occur due to the anticoagulant medications administered during the pro-cedure. These medications prevent clots from forming on the equipment or in the artery. Bleeding around the sheath or catheter insertion site is usually control-lable and not dangerous. Rarely, bleeding can be severe at the catheter insertion site or can develop internally. Your cardiolo-gist is an expert who can manage bleeding difficulties by adjusting medications or in very rare cases referring you to a surgeon who can repair the artery into which the catheter was placed.

• Because angioplasty and intervention are a type of cardiac catheterization, the complications detailed in the first part of this booklet for the angiogram also apply to angioplasty. They include allergy, stroke, kidney injury, blood vessel damage and nerve damage.

It is important to remember that complica-tions from angioplasty occur infrequently. Your cardiologist has recommended a coronary intervention because the likeli-hood of success is very high and the risk of a complication is small. In other words, the benefits of the procedure out-weigh the risks.






After the angioplasty procedure:

• You will be taken to your room or to a holding area.

• Usually, you will still have the sheath in the groin (or arm) artery.

• In many patients, the sheath is removed several hours after the procedure. • Sometimes, a closure device such as a collagen plug system, collagen-thrombin

system, or suture device is used to close the artery in the catheterization laboratory immediately after the procedure.

• You are given pain medicines and sedatives so that the sheaths can be removed without causing discomfort.

• Once the sheath is removed, a sandbag is sometimes applied to the groin area to help prevent bleeding.

• You will be asked to lie still for several hours.

• You should not bend your leg or raise your head. These restrictions are necessary to allow the insertion site to seal and to prevent bleeding.

• For patients who have had the catheter inserted into the radial or brachial artery, a compressive dressing is applied to the puncture site after sheath removal. There is less confinement to bedrest after a radial procedure.






ost patients are discharged from the hospital 12 to 24 hours after the sheath is removed. You are able to walk, climb stairs, perform routine daily activities and take care of your personal hygiene. You should try to minimize physi-cal activities for one to two days after the coronary intervention.

• Restrict yourself to light activity for the first five days after angioplasty. • Do not do any heavy lifting or very

strenuous physical exertion for at least 3-4 weeks after the angioplasty.

• Do not push yourself to the point of significant fatigue, shortness of breath or chest pain.

• Walking is an excellent activity.

• You can resume moderate activities five days after the coronary intervention. • You should not engage in strenuous activity or manual labor until a stress test has been performed or you have been given clearance by your doctor. • Always follow your doctor’s specific





• A treadmill exercise test, or stress test, is occasionally performed 3-6 weeks after the intervention. Generally, the results of this test are favorable and help to guide your doctors in prescribing an activity level for you.

• An additional stress test may be done 6 months after the intervention to be certain that you have not experienced a recurrence (restenosis).

• For some patients, after the first stress test, your physician may recommend that you enroll in a regular exercise program. Supervised exercise can be provided through a cardiac rehabilitation program. Please ask your doctor about this if you are interested in cardiac rehabilitation.






• Bruising or discoloration in your groin area where your catheters were inserted. The bruise (“black and blue”) may extend along the inner thigh and up toward the abdomen. The bruise will disappear in 1-3 weeks.

• A small lump where the catheter was inserted. The lump should not

expand in size.

• Soreness over the catheter insertion site when you apply pressure there. • Slight oozing of thin yellow or pink liquid from the catheter hole in the first day following the intervention. The amount of oozing should only be a drop or two at most.

• Tiredness and fatigue that lasts for one or two days after the procedure. You have been through a lot! You are entitled to be tired. If your interven-tion was performed in the first two weeks after a heart attack, you may have more fatigue. This added tired-ness is from the effects of the heart attack. It takes 6 weeks for the heart to heal and “remodel” after a heart attack.



• Chest pain or discomfort that is simi-lar to what you felt before the inter-vention or similar to the discomfort that you may have felt when the balloon catheter was inflated in your artery during the procedure. Very brief, fleeting chest discomfort that lasts for a few seconds is probably not from the heart. Brief pains that last for 1-2 seconds usually are mus-cular in origin. Most patients when questioned about this type of pain will observe that it is different from the discomfort that they felt during the intervention or that they felt with their typical attacks of angina.

• A lump in the groin area that increases in size and/or is painful when no pressure is applied. Such a lump may indicate that the puncture hole in the artery in the groin has not sealed properly or has leaked blood. • Fever or drainage of pus (thick

yellow-brown material) from the puncture site; redness of the skin around the puncture site.

• Swelling, with or without pain, in the thigh or calf of the leg in which the catheters were inserted.



Now that you have had a successful intervention, you and your physician need to keep a watchful eye on your heart to be sure that your good results last. The following is what to expect after your procedure and what to report to your physician.




1. Know the name, purpose, dosage, and precautions of all medications you are taking. Take only medica-tions that have been prescribed for you at the time of discharge. If you were on other medications before your procedure, discuss them with your cardiologist before leaving the hospital.

2. Do not take any over-the-counter drugs or previously prescribed medications without checking with your physician. These drugs may interact or interfere with one another.

3. Take the medicine at the same time each day and in the amount prescribed. This is necessary to ensure a consistent amount of medicine in your blood stream.

4. Do not skip a dose, stop the medicine, or take an extra dose without first consulting your physician.

5. Do not give your medicine to anyone, even though he/she may seem to have the same medical problem.

6. Some medications may produce an allergic or unanticipated reaction such as rash, fever, vomiting, bruising, or diarrhea. Report any such problems to your physician.

7. Keep all medicines out of the reach of children.

8. Outdated medications can become ineffective. If the medicine is more than several months old, ask the pharmacist if it is still safe and effective.

9. Do not remove medicines from their original bottles or mix different kinds in the same container. The color and material of the containers are designed to protect the medications from sunlight and other hazardous conditions. Switching to a different con-tainer might decrease the medicine’s effectiveness.

10. Carry a card with you with the names of your medicines and their dosages written on it.

Ten Rules For

Taking Medication





Purpose: ACE inhibitors

(captopril/Capoten, enalapril/Vasotec, Prinivil/Zestril, Lotensin, Monopril, ramipril/Altace, etc.) and angiotensin receptor blockers (Cozaar, Avapro, Diovan, etc.) block the effects of angiotensin, a hormone that raises the blood pressure and constricts blood vessels. The actions of angiotensin are sometimes harmful in patients with weakened hearts, especially after heart attacks. ACE inhibitors are frequently prescribed after heart attacks.

How Taken: Take the medication as pre-scribed by your physician and do not stop taking it unless your physician instructs you to do so.

Major Side Effect: ACE inhibitors can cause a dry cough; angiotensin receptor blockers do not tend to cause a dry cough as a side effect.



Purpose: Calcium channel blocking drugs (diltiazem/Cardizem/Dilacor/ Cartia, verapamil, nifedipine/

Procardia/Adalat, amlodipine/Norvasc) are medications that prevent spasm of the blood vessel wall at the angioplasty site. They also control high blood pres-sure. Calcium channel blocking drugs are occasionally administered after interventions.

How Taken:Take the medication as

pre-scribed by your physician and do not stop taking it unless your physician instructs you to do so.

Major Side Effects: Some patients may develop flushing headaches or constipation with certain calcium channel blocking drugs.



Purpose: Coumadin (warfarin) is a powerful “blood thinner” that inhibits or slows clotting. Your blood will still be able to clot if you are on this medica-tion, but the time that it takes for a clot to form will be longer.

How Taken: Coumadin should be taken at the same time each day. Your blood will need to be tested regularly (up to twice a week in the beginning and then every 2 to 4 weeks) in order to regulate the dosage of the medication to a safe and effective level.

Major Side Effect: This medication can be associated with internal bleeding. Call your doctor immediately if you notice excess bruising or bleeding, black tarry stool, blood in the stool or urine, or vomiting of blood or coffee-ground appearing material.

Do not use Coumadin with arthritis medications. Coumadin can be taken with aspirin, but a patient should be monitored very closely for bleeding.





You may be asked to take one or

more of these medications,

depending on your situation.



Purpose: Aspirin is an antiplatelet agent, a medication that prevents platelets from sticking together and from sticking to the inside of the artery at the angioplasty or stent site.

Platelets are small cell fragments that bind to tears or areas of trauma in blood vessels. Platelets help form clots that stop bleeding. Aspirin prevents platelets from forming harmful clots at the site of the intervention on your heart’s artery.

How Taken: Aspirin should be taken indefinitely after an intervention unless you are instructed otherwise. Aspirin is available in low dose strength (81 mg), adult strength (325 mg), and in an enteric coated variety to help protect the stomach lining from bleeding. Major Side Effects:The major possible side effect from aspirin is bleeding. Another side effect can be gastrointesti-nal distress.


Purpose:Plavix is an antiplatelet agent that has a different mechanism of action as compared to aspirin. Plavix is always combined with aspirin to prevent clot formation in a stented artery.

How Taken: This medication is prescribed usually for 4 weeks after intervention. It should be taken in combination with aspirn unless you are instructed otherwise. Failure to take these medications can increase the chance of a dangerous clot in the stent (subacute stent thrombosis). Occasionally, you may receive instructions from the pharmacist to not take both aspirin and Plavix; these instructions usually should

not be applied to patients with stents. Always check with your cardiologist if you are given conflicting instructions. Your cardiologist may instruct you to take Plavix for a longer period of time, up to one year after your procedure. There is evidence that Plavix can pre-vent vascular epre-vents such as heart attacks if taken on a regular basis. Ticlid is an alternative antiplatelet agent that can be substituted for Plavix. Major Side Effects: Ticlid can cause the white blood cell count to drop below the normal level; patients on Ticlid should have a CBC blood test 2 to 4 weeks after starting this medication.

With both these medications it is important to know that it will take longer to stop bleeding if you cut yourself. All your physicians and dentist should be aware that you are taking these medications.




Foods high in cholesterol.


Purpose: Cholesterol-lowering medications are vital to prevent additional cholesterol build-up in your arteries. Statins, such as Pravachol, Zocor, or Lipitor may also prevent inflammation in your heart’s arteries where cholesterol plaque has formed. This inflammation-quieting effect may prevent clot formation and future problems with chest pain or heart attacks in patients with coronary artery disease, even if their cholesterol level is not very high.

Fibric acid derivatives, such as gemfibrozil/Lopid and Tricor, have a greater effect on elevated triglyceride levels. Niacin is used in some patients to raise the HDL cholesterol (“good cholesterol”) level.

How Taken: The statins are usually well tolerated and are given once a day at bedtime. Lopid is usually given twice a day, thirty minutes before the morning and evening meals. Tricor is usually given once a day. Niacin should be taken ½hour after aspirin. Any of these drugs should be taken as prescribed by your physician.

Major Side Effects: These drugs infrequently can cause aching of the muscles.

Patients on cholesterol-lowering medications should have blood tests done to monitor the function of their liver. Niacin can cause flushing, headache, or stomach upset. Fibric acid derivatives, such as gemfibrozil/Lopid and Tricor, should not be used while taking any Statin drugs (Pravachol, Zocor, Lipitor) because of the possibility of seri-ous side effects.





Purpose: Beta blocker drugs (meto-prolol/Toprol, atenolol/Tenormin, propanolol/Inderal, nadolol/Corgard) slow the pulse and lower the blood pressure. These medications reduce the workload of the heart, control high blood pressure, and reduce the risk of death and other problems after heart attacks. Some beta blockers (carvedilol/ Coreg, metoprolol, bisoprolol) are use-ful in patients with weakened hearts. How Taken:These medications should be taken as prescribed by your physi-cian. They should be taken at the same time each day.

Major Side Effect: Beta blockers can cause fatigue or breathing problems, including asthma or wheezing.



Purpose: Nitroglycerin-type medica-tions (nitroglycerin patch, isosorbide dinitrate, isosorbide mononitrate/ Imdur/Ismo) prevent spasm of the arteries of your heart and reduce the work of your heart.

How Taken: There are many nitroglyc-erin medications and they should be taken as prescribed by your physician. Major Side Effect: Some patients note headaches with these medications. The headaches usually improve or disappear over time and frequently respond to Tylenol.






Purpose: Antisecretory medications such as Prilosec, Prevacid, Protonix, Pepcid, ranitidine/Zantac, Axid, cimetidine/Tagamet reduce the stomach’s output of acid and can lower the risk of bleeding from antiplatelet agents like aspirin or Plavix and anticoagulants like Coumadin.

How Taken: These medications are usually taken once or twice a day. Major Side Effects: Some people may develop a headache, consti-pation, and abdominal discomfort or pain.


Purpose: Nitroglycerin tablets are used for chest discomfort that is from your heart. How Taken: Nitroglycerin should be placed under the tongue and allowed to dissolve. Nitroglycerin is rapidly absorbed from under the tongue and can provide very quick relief from angina pain. You should lie down or at least sit when you take nitroglycerin. A second or even third nitro-glycerin can be taken, if you wait 5 to 15 minutes between each tablet and under-stand that more doses of nitroglycerin can produce significant lightheadedness by lowering your blood pressure.

Major Side Effect: This medication can cause lightheadedness and can make you faint if you stand up quickly after taking a tablet. Nitroglycerin usually produces a brief headache.

You should call 911


go to the hospital, and call your physician if you have any prolonged episodes of chest discomfort (greater than 15 to 20 minutes). If you are unsure how to respond to an episode of chest discomfort, it is always appropriate to come to an emergency room and to call your physician.






• If you smoke, stop immediately. Cigarette smoking causes

cholesterol deposits to build up in the arteries by damaging the lining

of the heart’s arteries. This allows the cholesterol to move from the bloodstream

into the wall of the artery. Smoking increases the likelihood of a second heart attack

in heart attack survivors and also increases the chances of bypass grafts closing of

f after bypass surgery. • Consume a low-cholesterol, low-fat diet. Excess

carbohydrate intake is also harmful and can raise the triglyceride level. A nutritionist or

your physician can instruct you further on the correct diet.

• If you are diabetic, stick to your diet and keep

your blood sugar well controlled. You should have your diabetic control assessed with

a hemoglobin A1C level. If this level is significantly elevated, you are not doing enough

to treat your diabetes. Consult with your primary care physician who may

refer you to an endocrinologist, a diabetes expert, who can

help adjust your medications to improve your diabetes


• Lose weight if you are overweight. Weight

loss will improve your body’s cholesterol metabolism, improve your control of diabetes (if you are diabetic), and

help lower your blood pressure.

• Exercise as prescribed by your doctor. Aerobic

exercises (brisk walking, swimming, running, bicycling, etc)

help condition the heart and blood vessels. Exercise

can help control your blood pressure and cholesterol level.

A cardiac rehabilitation program may be useful to help

you learn to exercise safely and effectively. Cautious weight training

can build muscle strength, but probably has no direct benefit to the heart.

• Alcohol may be consumed, but in moderation. Alcohol can raise the triglyceride level and should be avoided

in patients with high triglyceride levels.

• Pay attention to yourself and your symptoms. Report any questionable symptoms to your doctor

. Try not to over-react, but when in doubt, always





ow that you have finished this booklet, you should be more confident about undergoing your heart procedure. Although the technology appears to be complicated, most procedures are much simpler and easier than you imagine.

Hopefully, this booklet has helped to increase your understanding and has answered your questions about cardiac catheterization and interventions. Of course, your doctor can answer any questions that this booklet did not address.

If your doctor’s instructions differ from some of the statements in this booklet, always follow your doctor’s instructions.

Remember, stay calm!

Success and safety are what

your doctor expects and what

you should focus upon.




Anginapectoris is inadequate blood flow through the partially obstructed artery causing chest discomfort. P.4 Angiogramis an x-ray picture of the coronary arteries. P.12

Angioplastyis a type of coronary inter-vention that uses a catheter with a balloon affixed to it to open up a blocked artery. P.16

Aortic stenosisobstructs the blood flow out of the left ventricle. P.6

Aortic valveis the valve between the left ventricle and the aorta which allows the blood to be pumped out to the rest of the body. P.6

Atherosclerosisis a build-up of choles-terol, scar tissue, blood clot and fatty material in the walls of arteries. P.4 Atriaare the two small chambers located on top of the ventricles that fill with blood and then empty into the ventri-cles to completely fill them before each heart beat. P.2

Brachytherapyis a treatment using radiation to treat restenosis of a stent. P.23

Cardiac catheterizationor angiogramis a test that uses catheters, (long, thin hol-low tubes) to take x-ray pictures of the heart and its blood vessels (coronary arteries). P.1

Catheterization laboratoryis a specially designed room with an x-ray camera and monitor which will display pic-tures of the heart and blood vessels that is used to perform the catheteri-zation procedure. P.9

Cathetersare long, thin, flexible, hollow plastic tubes that are used to perform the catheterization. P.10

Collateralsare auxiliary small blood vessels that develop over time to compensate for narrowed or obstructed vessels. P.5

Congenital heart problemsare heart problems that are present at birth. P.7 Congestive heart failureoccurs when the heart has become weakened and cannot pump enough blood to meet the body’s needs. P.7

Coronary arteriesare tubular blood ves-sels that divide into smaller branches like branches of a tree and supply the heart muscle with oxygenated blood. P.3

Coronary risk factorsare those conditions that increase the risk of developing plaques. P.4

Directional atherectomyis a technique that removes plaque from the artery by using rotating cutting blades on the catheter that slices off thin slivers of the plaque when advanced through the artery. P.22

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