Percutaneous Transluminal Coronary Angioplasty / Stent

What is balloon angioplasty?

Balloon angioplasty of the coronary artery, or percutaneous transluminal coronary angioplasty (PTCA), was introduced in the late 1970's. PTCA is a non-surgical procedure that relieves narrowing and obstruction of the arteries to the muscle of the heart (coronary arteries). This allows more blood and oxygen to be delivered to the heart muscle. PTCA, is now referred to as percutaneous coronary intervention, or PCI, as this term includes the use of balloons, stents, and atherectomy devices. PCI is accomplished with a small balloon catheter inserted into an artery in the groin or arm, and advanced to the narrowing in the coronary artery. The balloon is then inflated to enlarge the narrowing in the artery. When successful, PCI can relieve chest pain of angina, improve the prognosis of patients with unstable angina, and minimize or stop a heart attack without having the patient undergo open heart coronary artery bypass graft (CABG) surgery.

In addition to the use of simple balloon angioplasty, the availability of stainless steel stents, in a wire-mesh design, have expanded the spectrum of patients suitable for PCI, as well as enhanced the safety and long-term results of the procedure. Since the early 1990's, more and more patients are treated with stents, which are delivered with a PCI balloon, but remain in the artery as a "scaffold". This procedure has markedly reduced the numbers of patients needing emergency CABG to below 1%, and particularly with the use of the new "medicated" stents (stents coated with medications that help prevent plaque formation), has reduced the rate of recurrence of the blockage in the coronary artery ("restenosis") to well below 10%. At present, the only patients treated with just balloon angioplasty are those with vessels less than 2mm (the smallest diameter stent), certain types of lesions involving branches of coronary arteries, those with scar tissue in old stents, or those who cannot take the blood thinner medication known as clopidogrel bisulfate (Plavix). Various "atherectomy" (plaque removal) devices were initially developed as adjuncts to PCI. These include the use of theexcimer laser for photoablation of plaque, rotational atherectomy (use of a high-speed diamond-encrusted drill) for mechanical ablation of plaque, and directional atherectomy for cutting and removal of plaque. Such devices were initially thought to decrease the incidence of restenosis, but in clinical trials were shown to be of little benefit, and now are only used in selective cases as an adjunct to standard PCI (precutaneous artery intervention).

How does coronary artery disease develop?

Arteries that supply blood and oxygen to the heart muscles are called coronary arteries. Coronary artery disease (CAD) occurs when cholesterol plaque (a hard, thick substance comprised of varying amounts of cholesterol, calcium, muscle cells, and connective tissue, which accumulates locally in the artery walls) builds up in the walls of these arteries, a process called arteriosclerosis. Over time, arteriosclerosis causes significant narrowing of one or more coronary arteries. When coronary arteries narrow more than 50 to 70%, the blood supply beyond the plaque becomes inadequate to meet the increased oxygen demand during exercise. Lack of oxygen (ischemia) in the heart muscle causes chest pain (angina) in most patients. However, some 25% of patients experience no chest pain at all despite documented ischemia, or may only develop episodic shortness of breath instead of chest pain. These patients have "silent angina" and have the same risk of heart attack as those with angina. When arteries are narrowed in excess of 90-99%, patients often have angina at rest (unstable angina). When a blood clot (thrombus) forms on the plaque, the artery may become completely blocked, causing death of a part of the heart muscles (heart attack, ormyocardial infarction).

The arteriosclerotic process can be accelerated by smoking, high blood pressure,elevated cholesterol levels, and diabetes. Patients are also at higher risk for arteriosclerosis if they are older (greater than 45 years for men and 55 years for women) or if they have a positive family history of coronary heart disease.

How is coronary artery disease diagnosed?

The resting electrocardiogram (EKG) is a recording of the electrical activity of the heart, and can show changes indicative of ischemia or

heart attack. Often, the EKG in patients with coronary artery disease is normal at rest, and only becomes abnormal when heart muscle

ischemia is brought on by exertion. Therefore, exercise treadmill or bicycle testing (stress tests) are useful screening tests for patients with significant coronary artery disease (CAD) and a normal resting EKG. These stress tests are 60 to 70% accurate in diagnosing significant

CAD.If the stress tests are not diagnostic, a nuclear agent (Cardiolite® or 

thallium) can be given intravenously during stress tests. Addition of one of these agents allows imaging of the blood flow to different regions of the heart, using an external camera. An area of the heart with reduced

blood flow during exercise, but normal blood flow at rest, signifies substantial artery narrowing in that region.

Stress echocardiography combines echocardiography (ultrasound imaging of the heart muscle) with exercise

stress testing. It is also an accurate technique for detecting CAD. When a significant narrowing exists, the heart muscle supplied by the narrowed artery does not contract as well as the rest of the heart muscle. Stress echocardiography and thallium stress tests are 80% to

85% accurate in detecting significant CAD.When a patient cannot undergo an exercise stress test

because of neurological or arthritic difficulties, medications can be injected intravenously to simulate the

stress on the heart normally brought on by exercise. Heart imaging can be performed with either a nuclear

camera or echocardiography.

Cardiac catheterization with angiography (coronary arteriography) is a technique that allows x-ray pictures to be taken

of the coronary arteries. It is the most accurate test to detect coronary artery narrowing. Small hollow plastic tubes (catheters)

are advanced under x-ray guidance to the openings of coronary arteries. Iodine contrast "dye" is then injected into the arteries

while an x-ray video is recorded. Coronary arteriography gives the doctor a picture of the location and severity of narrowed artery segments. This information is important in helping the doctor

select medications, PCI, or coronary artery bypass graft surgery (CABG) as the preferred treatment option.

A newer, less invasive technique is the availability of high speed CT coronary angiography. While it still involves radiation and dye exposure, no catheters are needed in the arterial system, which

does decrease the risk of the procedure somewhat. This is a very new modality, and its role in the evaluation and management of

CAD is still evolving. It is important to remember that risk of serious complications from conventional coronary angiography is

very low (well under 1%).

How is CAD treated?

Angina medications reduce the heart muscle's demand for oxygen in order to compensate for the reduced blood supply, and also may partially dilate the coronary arteries to enhance blood flow. Three commonly used classes of drugs are the nitrates, beta blockers, and calcium blockers. Examples of nitrates include isosorbide (Isordil), isosorbide mononitrate (Imdur), and transdermal nitrate patches. Examples of beta blockers include propranolol (Inderal),atenolol (Tenormin), and metoprolol (Lopressor). Examples of calcium blockers include nifedipine (Procardia, Adalat),verapamil, (Calan, Verelan, Verelan PM, Isoptin, Isoptin SR, Covera-HS), diltiazem (Cardizem, Dilacor, Tiazac), and amlodipine (Norvasc). Many patients benefit from these angina medications and experience reduction of angina during exertion. When significant ischemia still occurs, either with ongoing symptoms or with exercise testing, coronary arteriography is usually performed, often followed by either PCI or CABG.

Patients with unstable angina have severe coronary artery narrowing and often are at imminent risk of heart attack. In addition to angina medications, they are given aspirin and the intravenous blood thinner, heparin. A form of heparin, enoxaparin (Lovenox), may be administered subcutaneously, and has been demonstrated to be as effective as intravenous heparin in patients with unstable angina. Aspirin prevents clumping of blood clotting elements called platelets, while heparin prevents blood from clotting on the surface of plaques. Newer potent IV anti platelet agents ("super aspirins") are also available to help initially stabilize such patients. While patients with unstable angina may have their symptoms temporarily controlled with these potent medications, they are often at risk for the development of heart attacks. For this reason, many patients with unstable angina are referred for coronary angiography, and possible PCI or CABG.

PCI can produce excellent results in carefully selected patients who may have one or more severely narrowed artery segments which are suitable for balloon dilatation, stenting, or atherectomy. During PCI, a local anesthetic is injected into the skin over the artery in the groin or arm. The artery is punctured with a needle and a plastic sheath is placed into the artery. Under x-ray guidance (fluoroscopy), a long, thin plastic tube, called a guiding catheter, is advanced through the sheath to the origin of the coronary artery from the aorta. A contrast dye containing iodine is injected through the guiding catheter so that x-ray images of the coronary arteries can be obtained. A small diameter guide wire (0.014 inches) is threaded through the coronary artery narrowing or blockage. A balloon catheter is then advanced over the guide wire to the site of the obstruction. This balloon is then inflated for about one minute, compressing the plaque and enlarging the opening of the coronary artery. Balloon inflation pressures may vary from as little as one or two atmospheres of pressure, to as much as 20 atmospheres. Finally, the balloon is deflated and removed from the body.

Intracoronary stents are deployed in either a self-expanding fashion, or most commonly they are delivered over a conventional angioplasty

balloon. When the balloon is inflated, the stent is expanded and deployed, and the balloon is removed. The stent remains in place in the artery. Atherectomy devices are inserted into the coronary artery over a standard angioplasty guide wire, and then activated in varying

fashion, depending on the device chosen.CABG surgery is performed to relieve angina in patients whose illness

has not responded to medications and are not good candidates for balloon angioplasty. CABG is best performed in patients with multiple

blockages in multiple locations, or when blockages are located in certain arterial segments which are not well-suited for PCI. CABG is

often also used in patients who have failed to attain long-term success following one or more PCI procedures. CABG surgery has been shown to improve long- term survival in patients with significant narrowing of the left main coronary artery, and in patients with

significant narrowing in multiple arteries, especially in those with decreased heart muscle pump function.

PTCA/Stent  Procedure

Pre-Admission and Evaluation

You will first undergo a thorough evaluation by your physician. Any questions you still have before your procedure begins can be answered at this time. You may be permitted clear liquids in the morning of the procedure. However, this should be cleared with your physician first . Otherwise, food and beverages may be withheld after midnight. If you are a diabetic, you will be given special instructions. Your groin area will be washed and shaved in preparation for the PTCA/Stent.

Angioplasty Procedure

If family or friends are with you, they will wait in the waiting room near the catheterization laboratory. The length of the procedure depends on the complexity of each individual's situation, but in general, the duration

is between 1 and 2 hours.An intravenous line will be started in your arm this morning. You will receive various medications in the angioplasty laboratory though this

line. To help you relax, you will be given medication prior to leaving for the lab. You will remain awake, but slightly drowsy.

You will be placed on an x-ray table upon your arrival in the lab. It is the same type of room in which you had your cardiac catheterization. All

personnel in the lab will be wearing surgical attire. You will be covered by sterile sheets, and so will some of the equipment. Your groin (arm) will be cleansed with an antiseptic  (might be cold) and then numbed with an anesthetic. You will feel the sting of the needle, but then your groin (arm) will feel quite numb. Heart monitoring equipment will be

placed on your arms and legs, and you may be given oxygen to breathe. You will be given certain medications through the intravenous line, and

periodically medication will be given to relax you and decrease any restlessness. Remember, you must still be able to talk and follow

directions.

The angioplasty catheter (balloon-tipped) is inserted at the numb area, and advanced to your heart, using x-ray to guide it. When the balloon is inflated at the point of the blockage, you may feel chest

pressure, or discomfort, and this is normal.  It will subside when the balloon is deflated. You may also feel your heart thump or skip, feel flushed, or have a headache. All these sensations are normal. You

will be asked at times to hold your breath for a few seconds. You may also be asked to cough.

After the procedure, you will be moved to a recovery area for a short time, and then taken to your room where your heart can be

monitored. Nurses will closely monitor your vital signs and general well being. They will also frequently check the groin area and

dressing. A small, flexible catheter is routinely left in the groin for 4-6 hours unless a percutaneous suture is used to close the hole. You will be required to remain in bed and keep your leg immobilized.You will be able to eat as soon as you wish after the procedure.

If family or friends are with you, they will wait in the waiting room near the catheterization

laboratory. The length of the procedure depends on the complexity of

each individual's situation, but in general, the duration is between 1 and 2 hours.

An intravenous line will be started in your arm this morning. You will receive various

medications in the angioplasty laboratory though this line. To help you relax, you will be given medication prior to leaving

for the lab. You will remain awake, but slightly drowsy.

You will be placed on an x-ray table upon your arrival in the lab. It is the same type of room in which you had your cardiac catheterization. All personnel in the lab will be wearing surgical attire. You will be covered by sterile sheets, and so will some of the equipment. Your groin (arm) will be cleansed with an antiseptic  (might be cold) and then numbed with an anesthetic. You will feel the sting of the needle, but then your groin (arm) will feel quite numb. Heart monitoring equipment will be placed on your arms and legs, and you may be given oxygen to breathe. You will be given certain medications through the intravenous line, and periodically medication will be given to relax you and decrease any restlessness. Remember, you must still be able to talk and follow directions.

The angioplasty catheter (balloon-tipped) is inserted at the numb area, and advanced to your heart, using x-ray to guide it. When the balloon is inflated at the point of the blockage, you may feel chest pressure, or discomfort, and this is normal.  It will subside when the balloon is deflated. You may also feel your heart thump or skip, feel flushed, or have a headache. All these sensations are normal. You will be asked at times to hold your breath for a few seconds. You may also be asked to cough.

After the procedure, you will be moved to a recovery area for a short time, and then taken to your room where your heart can be monitored. Nurses will closely monitor

your vital signs and general well being. They will also frequently check the groin area and dressing. A small,

flexible catheter is routinely left in the groin for 4-6 hours unless a percutaneous suture is used to close the hole. You will be required to remain in bed and keep your leg

immobilized.You will be able to eat as soon as you wish after the

procedure.

Recuperation

The catheter or sheath will be removed approximately 4-6 hours after theprocedure is over. This waiting period is crucial as the physician uses blood -thinning agents to implant the stent, thus the sheaths cannot be removed until the blood thinning reverted back to normal and firm presssure applied for about 20 minutes. Then a pressure bandage is applied and a small sandbag placed over it. This is to assure proper healing of the artery.   Pain medication is available to you every few hours after the procedure. Please let your nurse know of any pain or discomfort you may feel at any time. The rest of the day is basically for rest, recuperation, and a gradual return to your activities.

POSSIBLE COMPLICATIONS

AND RISK

No invasive procedure occurs without a certain amount of potential risk and complications. You are followed closely by your doctor and nurses,

precisely for the reason that if any of these complications arise, corrective action can be taken immediately. The incidence of

complications is low, but nonetheless, you need to be aware what they can be:

 Severe bruising/bleeding into the groin area of the procedure leg.

Changes in your heart rhythm.Allergic reaction to the contrast or dye or to other medications used.

A tear in the lining of the artery which is being dilated.Possibility of a heart attack during or following inflation of the balloon or stent implantation.. (you are given strong blood thinners to minimize this

risk.)Possibility of a blood clot in the artery in which the catheter is inserted. (If

this occurs, surgical removal may be required.)

PCI, using balloons, stents, and/or atherectomy can achieve effective relief of coronary arterial obstruction in 90% to 95% of patients. In a very small percentage of patients, PCI cannot be performed because of technical difficulties. These difficulties usually involve the inability to pass the guide wire or the balloon catheter across the narrowed artery segments. The most serious complication of PCI results when there is an abrupt closure of the dilated coronary artery within the first few hours after the procedure. Abrupt coronary artery closure occurs in 5% of patients after simple balloon angioplasty, and is responsible for most of the serious complications related to PCI. Abrupt closure is due to a combination of tearing (dissection) of the inner lining of the artery, blood clotting (thrombosis) at the balloon site, and constriction (spasm) or elastic recoil of the artery at the balloon site.

To help prevent the process of thrombosis during or after PCI, aspirin is given to prevent platelets from adhering to the artery wall and

stimulating the formation of blood clots. Intravenous heparin is given to further prevent blood clotting; and combinations of nitrates and calcium

blockers are used to minimize vessel spasm. Individuals at an increased risk for abrupt closure include:

women,patients with unstable angina, and

patients having heart attacks.The incidence of abrupt occlusion after PCI has declined dramatically with the introduction of coronary stents, which essentially eliminate the problem of flow-limiting arterial dissections, elastic recoil, and spasm.

The use of new intravenous "super aspirins", which alter platelet function at a site different from the site of aspirin-inhibition, have dramatically reduced the incidence of thrombosis after balloon

angioplasty and stenting. Examples of these newer agents include abciximab (Reopro) and eptifibatide (Integrilin); these agents represent a major advance in enhancing the safety and efficacy of PCI in selected

patients.

When despite these measures, a coronary artery cannot be "kept open" during PCI, emergency CABG surgery may be necessary. Before the advent of stents and advanced anti-thrombotic strategies, emergency CABG following a failed PCI was required in as many as 5% of patients. In the current era, the need for emergent CABG following PCI is less than 1-2%.The overall acute mortality risk following PCI is less than one percent; the risk of a heart attack following PCI is only about 1-2%. The degree of risk is dependent on the number of diseased vessels treated, the function of the heart muscle, and the age and clinical condition of the patient.

How do patients recover after PCI?

PCI is performed in a special room fitted with computerized x-ray equipment called a cardiac catheterization laboratory. Patients are mildly sedated with small amounts ofdiazepam (Valium), midazolam (Versed), morphine, and other sedative narcotics given intravenously. Patients may experience minor discomfort at the site of the puncture in the groin or the arm. Patients also may experience brief episodes of angina while the balloon is inflated, briefly blocking the flow of blood in the coronary artery. The PCI procedure can last from 30 minutes to two hours, but is usually completed within 60 minutes.

Patients are then brought to a monitored bed for observation. The plastic catheters left in the artery are removed from the groin after four

to 12 hours depending on how long blood thinning is needed to stabilize the opened artery. When these catheters are removed, the

area is compressed by hand or with the aid of a mechanical clamp for about 20 minutes to prevent bleeding. In many instances, the artery in the groin may be sutured or "sealed" in the catheterization laboratory,

and the catheters are immediately removed. This enables the patient to sit up in bed within a few hours after the procedure.

Most patients are discharged home the day after PCI. Patients are advised not to lift anything heavier than 20 pounds or perform vigorous exertion for the first one to two weeks after PCI. This allows the area in the coronary artery as well as the groin or arm arteries to heal. Patients

may return to normal work and sexual activity two or three days after PCI.

Patients are maintained on aspirin indefinitely after PCI to prevent future thrombotic events [(for example, unstable angina or heart attack). In patients

who receive stents, an additional anti-platelet agent (in most instances clopidogrel (Plavix)] is given in conjunction with aspirin for two to

four weeks; this is because the metal in the stents may promote the formation of blood clots in the first couple of weeks after the stent is inserted. After two weeks, the metal of the stent is coated with a natural tissue lining which no longer stimulates platelets to form blood clots. With the newer medicated stents designed to prevent recurrence, the process of forming this natural lining may be delayed, and aspirin and Plavix are generally continued for a year or longer. If you have a stent, always consult your cardiologist before

stopping aspirin or Plavix, even for a few days.Exercise stress testing is sometimes done several weeks after PCI and

signals the beginning of a cardiac rehabilitation program. Rehabilitation can involve a 12 week program of gradually increasing monitored exercise lasting one hour three times a week. Lifestyle changes can help to lower the patient's chance of developing further coronary artery disease. These include stopping

smoking, reducing weight and dietary fat, controlling blood pressure and diabetes, and lowering blood cholesterol levels. Cholesterol reduction is often aided by the addition of medications which may not only

lower cholesterol levels, but may offer protection against future heart attacks.

What are the long-term results of PCI?

Long-term benefits of PCI depend on the maintenance of the newly-opened coronary artery(ies). 30-50% of patients with successful balloon angioplasty (no stent) may develop recurrent narrowing (restenosis) at the site of the balloon inflation, usually within six months following PCI. Patients may complain of recurrence of angina or may have no symptoms. Restenosis is often detected by exercise stress tests performed at four to six months after PCI. Restenosis occurs with a significantly higher frequency in patients with diabetes. The rate of restenosis is greater in vein grafts, at the origins of vessels, in the beginning part of the left anterior descending coronary artery, and in those with suboptimal initial results. The widespread use of intracoronary stents has reduced the incidence of restenosis by as much as 50% or more; this is due to prevention of "elastic recoil" in the artery, as well as providing a larger initial channel in the treated artery. With the newer medicated stents, the restenosis rate is well under 10%.

Restenosis can simply be observed or treated with medications if the narrowing is not critical and the patient is not symptomatic. Some patients undergo a repeat PCI to increase coronary artery blood flow. Second PCI procedures have similar initial and long-term results as first procedures, although certain patterns of restenosis have a very high repeat recurrence rate. Sometimes, CABG surgeries are recommended for those patients who have developed more extensive disease in the restenosed artery as well as in the other coronary arteries. Patients may also choose CABG surgery to avoid the uncertainty of restenosis after the second PCI. In patients with restenosis after balloon angioplasty or stents, the use of intracoronary radiation (brachytherapy) may reduce the risk of future restenosis. If no evidence of restenosis is observed after six to nine months, studies have demonstrated that the treated arterial segment is likely to remain open for many years. "Late restenosis" after one year or more is very uncommon. Symptoms developing more than one year after successful PCI are usually due to blockage in a different segment of the artery, or in a different artery from that which was treated in the initial PCI.

Follow-up Care

Periodic follow-up with your personal physician is quite important. It is important for you to realize that by

angioplasty (PTCA), your immediate problem has been taken care of, but it does not cure coronary artery disease. In some patients, re -narrowing (Restenosis) of the artery may occur over the ensuing 3-6 months. If this happens,

your original symptoms may return, or your stress test will be abnormal.

If you have chest discomfort, stop your activity, sit or lie down, and take nitroglycerine, as instructed. If the chest discomfort does not go away after 3 nitrolycerin tablets in a 15 minute period, DO NOT DELAY SEEKING MEDICAL

ATTENTION.  Either call your doctor, or go to an emergency room.

Coronary Balloon Angioplasty At A Glance

Coronary angioplasty is accomplished using a balloon-tipped catheter inserted through an artery in the groin or arm to enlarge a

narrowing in a coronary artery.Coronary artery disease occurs when cholesterol plaque builds up

(arteriosclerosis) in the walls of the arteries to the heart.Angioplasty is successful in opening coronary arteries in well over

90% of patients.Up to 30-40% of patients with successful coronary angioplasty will

develop recurrent narrowing at the site of balloon inflation.The use of newer devices such as intracoronary stents and

atherectomy, as well as newer pharmacologic agents has resulted in higher success rates, reduced complications, and reduced

recurrence after PCI.