NON SURGICAL MANAGEMENT OF CORONARY ARTERY DISEASE

What is it?
Coronary heart disease is characterized by the narrowing of the arteries that supply blood and oxygen to the heart muscle. The consequences of coronary heart disease include stable angina (intermittent, but predictable chest pain), unstable angina (angina that is new in onset, occurs at rest, or has a worsening pattern), heart attack (myocardial infarction). There are several treatment options for people with coronary heart disease who have stable angina. These options are classified as

Medical treatment (drugs and lifestyle modifications)
Interventional treatment (angioplasty also known as PTCA, with or without a stent)
Coronary artery bypass graft (CABG) surgery.
Because coronary heart disease is typically a chronic disease requiring long-term treatment, it is very important to learn as much as you can about this disease and about the benefits and risks of the various treatment options. This section essentially deals with non-surgical treatment options like medical management and interventional treatment like angioplasty (PTCA). Write-up about surgical option is available elsewhere.

Goals of Treatment

All of the medical and interventional treatments for people with coronary heart disease have the same goals: to decrease the effects of the disease on quality of life and to alleviate symptoms such as angina. In some patients, these interventions may also delay or stop the progression of the disease and thereby prolong life.

Medical Treatment

Medical treatment for coronary heart disease includes drugs called antianginal drugs, which alleviate symptoms and support heart function. It also includes lifestyle modifications. Medical treatment is usually considered first for all people with coronary heart disease, although certain individual factors may make interventional treatment a better initial choice (see below).

Antianginal drugs

There are currently three major classes of antianginal drugs:

Nitrates
Beta blockers
Calcium channel blockers

For initial treatment, doctors may recommend nitrates for people who have one or fewer anginal episodes per week and beta blockers for people who have two or more anginal episodes per week. If these initial drugs do not control angina, calcium channel blockers may be added to the treatment plan. However, the choice among these classes of drugs and the choice of specific drugs within these classes are made on an individual basis. See Medical Management for CAD for details of the drugs available.

Other drugs and aspirin

Depending upon the severity of heart disease, people with stable angina may also be treated with other drugs, such as angiotensin-converting enzyme (ACE) inhibitors, cholesterol lowering drugs, drugs to lower blood pressure, and diuretics. Aspirin may decrease the risk of heart attack and other serious complications in some people with stable angina, and doctors usually recommend taking aspirin daily.

Lifestyle modifications

Certain lifestyle modifications are often recommended for people with stable angina, including cessation of smoking, the gradual institution of a regular aerobic exercise program, modification of activities that precipitate angina (such as minimizing exposure to the cold, avoiding heavy meals, and eliminating very vigorous exercise), modification of diet and reduction in amount of fats and cholesterol eaten, weight reduction, stress reduction, and behavioral modification.

Treatment of risk factors for coronary heart disease

Risk factors for coronary heart disease include smoking, high blood pressure, and high blood lipids such as cholesterol. Doctors usually try to reduce these risk factors in all people with coronary heart disease, regardless of whether they receive medical or interventional treatment. This is usually accomplished with a combination of the lifestyle modifications, as described above, and medications.

Benefits of medical treatment

Medical treatment with antianginal drugs can effectively reduce the frequency and severity of anginal episodes and improve a person's ability to exercise. In many patients, medical therapy eliminates or delays the need for revascularization (ie, surgery or angioplasty). Two of the drugs commonly used to treat angina (beta blockers and aspirin) may actually reduce the risk of additional heart attacks and of death from cardiac causes in people who have previously suffered a heart attack.

Risks of medical treatment

The primary risks of medical treatment are related to the side effects from the drugs. Your doctor can provide you with detailed information about the possible side effects of specific drugs. However, most people experience tolerable or no side effects when taking drugs commonly used to treat angina. In those who do experience them, side-effects can sometimes be lessened by decreasing the drug dose, changing the timing of drug administration, switching to a different drug within the same class of antianginal drugs, or by switching to an entirely different class of antianginal drugs. These changes should all be made under your doctor's supervision.

Candidates for interventional treatment

A number of invasive techniques are available for treating coronary artery disease. The two standard surgical procedures are coronary artery bypass grafting (commonly called bypass) and percutaneous transluminal coronary angioplasty (commonly called angioplasty) . Studies have generally reported similar effectiveness in the two procedures, although one or the other may be preferable for specific patients.

Advantages with Angioplasty.
Angioplasty has the following advantages for most patients:

It is less invasive than bypass.
It is initially less expensive. (Although the postoperative need for more medications and the high risk for repeat procedures to reopen the artery reduce the long-term difference in cost between the two procedures.)
Advantages of Bypass. Bypass is usually the appropriate procedure, however, in patients with the following conditions:

Three or more blocked arteries.
A left main artery narrowed by 50% or more.
A very long diseased portion of the artery.
Diabetes. (In fact, some experts believe angioplasty should rarely, if ever, be used for these patients.)
The elderly. (Although angioplasty rates are improving in this group, and in one study such patients had a long-term survival rate equal to others.)
Considerations for Women
Women have higher mortality rates than men after surgery no matter what procedure, perhaps because they tend to be older and sicker when they have a heart operation. One study of bypass patients, however, indicated that simply being female was a risk factor for higher mortality regardless of age or health status.

Patients considering surgery should discuss all options and risks with their physician. No surgical procedure cures coronary artery disease, and patients must continue to rigorously maintain a healthy life-style and continue any necessary medications. In general interventional treatment may be recommended over medical therapy for two groups of people with stable angina:

People who have persistent and intolerable symptoms despite adequate medical treatment
People who have specific patterns of arterial narrowing and a high risk of heart attack and death
People who have extensive coronary heart disease, including a large number of narrowed coronary arteries or narrowing of the left main coronary artery and poor pumping function of their left ventricle (lower heart chamber), tend to live longer when they receive coronary artery bypass surgery than when they receive medical treatment.

Percutaneous transluminal coronary angioplasty
Percutaneous transluminal coronary angioplasty (PTCA) involves passing a tiny, deflated balloon through the arterial system (usually through an artery in the leg) to the narrowed coronary artery. The balloon is then inflated, causing the walls of the balloon to dilate (expand) the narrowed artery, thereby restoring blood flow to the heart muscle. A stent (an expandable tube usually made of wire mesh) is often placed to prevent the narrowing from recurring.

The usefulness of angioplasty depends upon the pattern and extent of arterial narrowing. Angioplasty is often recommended over bypass surgery when arterial narrowing is mild or moderate and when only one or two coronary arteries are narrowed. It is more effective in patients who do not have diabetes; people with diabetes appear to have greater benefit from bypass surgery, especially if they have two or three vessels involved.

Benefits
Angioplasty can effectively relieve angina and improve a person's ability to exercise. However, relative to medical treatment, angioplasty does not reduce the risk of heart attack or death in most people over time.Complications — Since angioplasty does not require surgery, complications are relatively infrequent and hospital stay and convalescence are usually brief. The most frequent complications are related to the insertion of catheters in the leg and include pain and bleeding at the puncture site. A small tear (dissection) of the coronary artery due to the catheter may occur in up to 50 percent of patients. However, the tear is usually small and heals by itself, but, if it is large, may cause the artery to become abruptly occluded, which occurs in about 4 percent of patients. This is treated by repeat angioplasty and the insertion of a stent; rarely is there the need for urgent bypass surgery. Approximately 1 percent of patients may have a heart attack as the result of angioplasty.

In most cases, patients are able to walk on the day following the angioplasty and can resume their normal activities, including returning to work, within a week. However, you should discuss this with your doctor.

Limitations
Although angioplasty restores blood flow and relieves symptoms in over 90 percent of patients, there is a substantial rate of recurrent symptoms at six months, usually due to recurrent narrowing (restenosis) of the artery, which may occur in up to 30 percent of patients. Restenosis that causes recurrent symptoms is usually treated by repeat angioplasty. The placement of a stent at the time of the angioplasty can also reduce the rate of restenosis.
Another reason for recurrent symptoms is the inability to dilate all narrowed vessels. Some vessels that are very small, have a total occlusion, or have a very calcified lesion cannot be adequately dilated.
FACTORS AFFECTING THE CHOICE BETWEEN MEDICAL TREATMENT AND INTERVENTIONAL TREATMENT
Several factors can help determine whether medical treatment or interventional treatment is a better choice. You should discuss all of these factors with your doctor before choosing between the treatment options.
Age
Interventional treatments have more risks in older people. For example, the risk of dying from bypass surgery is about 3.3 times greater for people who are 80 years of age or older than for people who are 50 years of age. On the other hand, older people often stand to gain the most from bypass surgery—in older patients (>75 years of age), bypass surgery has a greater life-prolonging benefit relative to medical treatment. Therefore, advancing age does not necessarily rule out angioplasty or bypass surgery as treatment options.

Severity of angina
People who have severe angina tend to derive more benefit from interventional treatment than from medical treatment.

Presence of advanced heart disease
Coronary heart disease may lead to poor pumping function of the left ventricle, (the heart chamber that pumps blood around the body), called low EF and it may even lead to a serious condition called congestive heart failure. People with these advanced types of heart disease may benefit more from interventional treatment, primarily bypass surgery, than from medical treatment. In fact, interventional treatment may even reverse abnormal function of the left ventricle in some cases. Still, interventional procedures are also associated with greater risks in people with advanced heart disease.

Pattern of narrowing of coronary arteries
Interventional treatment is usually more beneficial than medical treatment when the coronary arteries are severely narrowed, when many coronary arteries are narrowed, and when the left main coronary artery (the artery that supplies blood to the left side of the heart) is narrowed. These early patterns of arterial narrowing often predict how severe heart damage would be if a heart attack occurs.
People who have at least three narrowed coronary arteries are usually advised to select interventional treatment, most often bypass surgery. People who have two narrowed coronary arteries may be advised to select interventional treatment. People who have only one narrowed coronary artery are often advised to select medical treatment, unless this treatment fails to control angina; if angina persists with medical treatment, angioplasty is often recommended.

Presence of peripheral vascular disease
Peripheral vascular disease refers to narrowing of arteries in parts of the body other than the heart. For example, arteries that supply blood to the arms and legs or to the brain may be narrowed. Studies suggest that people with peripheral vascular disease have greater risks from angioplasty and bypass surgery, and medical treatment may therefore be a better choice. PRIMARY STENTING IN ACUTE MYOCARDIAL INFARCTION
In acute myocardial infarction, successful restoration of the blood flow in the affected artery by either clot bursting drugs or primary angioplasty, can result in preservation of left ventricular function. The clinical efficacy of primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction is limited by the risks of early restenosis. A number of reports have shown that stenting is of benefit in an acute MI setting when combined with PTCA. Initial trials suggested that that primary stenting in acute myocardial infarction was more effective than PTCA, resulting in a higher rate of successful reperfusion, a lower rate of acute closure, better postprocedural diameter stenosis, and a lower restenosis rate. Direct stenting, without predilation, reduces procedural time, radiation exposure, and costs. In patients with an acute myocardial infarction, direct stenting may also reduce embolization of plaque constituents, lowering the incidence of the no reflow phenomenon, thereby increasing myocardial perfusion and salvage. Although primary stenting improves the short-term outcome of patients, there is growing evidence that the main benefit of stenting is freedom from long-term recurrence of restenosis and myocardial infarction and a reduction in target lesion revascularization. Primary stenting is an effective therapy for some patients with an acute myocardial infarction who have a left main coronary artery stenosis, particularly when associated with cardiogenic shock.

How is PICA done?

Percutaneous transluminal coronary angioplasty (PTCA), usually simply called angioplasty, involved opening the blocked artery. A typical angioplasty procedure involves the following steps:

The cardiologist threads a narrow catheter (a tube) containing a fiber optic camera directly to the blocked vessel.
The physician opens the blocked vessel using balloon angioplasty , in which the surgeon passes a tiny deflated balloon through the catheter to the vessel.
The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
In order to keep the artery open afterwards, surgeons now commonly employ a device called a coronary stent , which is an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage.
Once in place, the stent pushes against the wall of the artery to keep it open. (A number of studies are reporting fewer future heart attacks and restenosis in patients who receive stents compared with those who had angioplasty alone.)

Why Stent ?
Stenting is now used in about 60% of angioplasty procedures. Studies report high survival rates with the use of stents, including their use with multiple blood vessels and as the initial device after a heart attack instead of balloon angioplasty. Recently, however, this widespread use is being questioned. In one study, there was no difference in outcome between balloon angioplasty and coronary stents, except in certain cases. Of additional concern was a 1999 study reporting more injury to the walls of the artery after six months in patients with coronary stents compared to angioplasty or atherectomy. Research is needed to determine which individuals would benefit most from stents. Some experts now recommend they be used only to prevent restenosis in patients with large blood vessels (greater than 3 mm).

After
Recuperation.
Angioplasty is less invasive than bypass surgery, requiring only one night in the hospital. Recuperation takes about a week. It should be pointed out the chest pain after the procedure is very common and usually due to problems other than ischemia. Chest pain is even more common when a stent is used, possibly because the artery is stretched.

Short-Term Complications:
Reclosure During or Shortly after Angioplasty. Reclosure of the artery during or shortly after angioplasty is often but not always due to blood clots. Aspirin, heparin, coumarin, or combinations of anti-clotting drugs are generally used during and after the operation. Aspirin is more effective than heparin. New anti-clotting agents (tirofiban, abciximab, argatroban, clopidogrel, or bivalirudin) may be more effective for preventing reclosure, often when administered in combination with heparin or aspirin. Anti-clotting drugs are not wholly protective, in any case, because reclosure in some cases is due to other, unknown causes.

Long-Term Complications:
Reclosure (Restenosis) Within a Year of Angioplasty. Narrowing or reclosing of the artery (restenosis) occurs within a year of angioplasty in nearly half of angioplasty patients, often requiring a repeat operation. Reclosure, in this case is not due to blood clots and so anti-clotting agents are not useful. Theories for the cause of restenosis include the following:

The release of large amounts of oxidants (damaging unstable particles) at the surgical site may activate damage in certain white blood cells that causes overgrowth in smooth muscles in the blood vessels. With this theory in mind, researchers have tested an antioxidant drug, probucol (Lorelco), with some success. Other drugs that are being investigated for their ability to limit smooth muscle growth include verapamil, a calcium channel blocker, and a protein called angiopeptin.
Some experts argue that other activities, such as scarring, may remodel and narrow the blood vessels.
A number of approaches, including coronary stents, have been developed to prevent restenosis.

Radiation treatment of the site is used to prevent reclosure, although some experts are concerned about its long-term safety. Studies suggest, however, a high rate of late blockage occurring after angioplasty within two to 15 months in patients who receive radiation treatments.
Directional atherectomy has been another attempt to solve the problem of reocclusion of the blood vessels. A balloon catheter is inserted for determining position; then, a tiny cutter spinning at 2,500 rpm removes plaque fragments from the arterial walls. The use of angioplasty with the coronary artery stent, however, is proving to be safer and more effective.