Norfolk County Cardiologist Association
Chronic Angina and EECP treatment
WHAT IS ANGINA?
Angina pectoris literally means “strangling in the chest.” It is the most common symptom of coronary artery disease. The majority of patients with angina complain of chest discomfort provoked by mental, physical, or emotional stress. The discomfort can vary widely among patients who report shortness of breath, fatigue, indigestion, faintness, pain in the chest, arm, neck, or jaw, and other symptoms.
WHAT CAUSES ANGINA?
Angina signals that a part of the heart muscle is not receiving an adequate supple of blood and oxygen. The heart requires a particularly rich blood supple because of its heavy workload., and receives this nourishing blood supply through the coronary arteries. When narrowed or blocked arteries restrict blood flow, oxygen supply to portions of the heart may at times be insufficient. Increases in oxygen demand can occur during exercise, fever, rises in emotion, periods of hypoglycemia, or after meals, triggering the onset of angina.
HOW DOES ANGINA AFFECT PEOPLE?
Angina often occurs when exertion outstrips the ability of narrowed or blocked coronary arteries to supple blood to the heart muscle. Angina restricts activity for many patients. They are able to walk, but not uphill nor while carrying packages. For some, angina is disabling as it interferes with their ability to work or engage in almost any activity.
HOW IS ANGINA AVOIDED?
Doctors recommend controlling the risk factors that contribute to the underlying coronary artery disease. These risk factors include high blood pressure, diabetes, cigarette smoking, high blood cholesterol levels, and excess weight.
WHAT IS THE FIRST LINE OF TREATMENT FOR ANGINA?
Angina is usually controlled by one or more medications that either increase the supply of oxygen to the deprived heart muscle by dilating coronary vessels, or decrease the heart’s demand for oxygen by slowing the heart rate, decreasing intensity of contraction, or reducing stress within the walls of the heart’s chambers. Unfortunately, in most patients, medication becomes insufficiently effective over time.
WHAT IF MEDICATION FAILS TO CONTROL ANGINA?
Bypass surgery or angioplasty is usually recommended if medication fails to ease angina or if the risk of heart attack is high. For some patients EECP treatment is another option that may relieve or eliminate angina by improving oxygen delivery to the heart muscle.
WHAT IS AN ANGIOGRAM?
Angiograms are used to evaluate the condition of the coronary arteries and nourishment of the heart muscle. A dye which can be imaged by x-ray techniques is injected into the heart’s blood vessels via a catheter, providing a recordable view of blood as it courses through the heart’s arteries.
WHAT IS ANGIOPLASTY?
Precutaneous Transluminal Coronary Angioplasty (PCTA) is an invasive procedure that involves inserting a slim hollow tube through a major artery and into a blocked vessel. A small balloon at the tip of the catheter is inflated alongside the obstructing plaque deposits, flattening them against the vessel wall to restore blood flow. No anesthesia is necessary. The patient often can go home the same day.
WHAT IS AUGMENTATION?
When the heart contracts during its pumping phase (systole), the coronary vasculature is squeezed by the powerful contraction of heart muscle, limiting the flow of blood to and within the muscle (myocardium). The myocardium must therefore receive most of its oxygenated blood during its period of relaxation (diastole), when the coronary arteries are most receptive to flow. Muscles, especially the large weight-bearing ones of the lower body, contain large numbers of blood vessels that cumulatively hold a large volume of blood. During EECP treatment, at the onset of each diastole, compressive air cuffs that surround the muscles of the lower body are quickly inflated in rapid succession: first at the calves, then at the lower thighs, and finally at the upper thighs and buttocks. The rapid and precisely timed “squeezing” of the muscles sends a wave of blood (and pressure) that travels toward the heart through both veins and arteries. The sequential compressions ensures that the waves generated in the more distant calf muscles can pass under the next cuffs (lower thighs) and be reinforced (not trapped) by the second and third compressions of the sequence. The results of the combined compressions is an increase in venous return (delivery of oxygenated blood to the right atrium), and an “augmentation” or enhancement of diastolic pressure, which improves myocardial perfusion (flow of blood through the coronary arteries and to the heart muscle).
WHAT IS BLOOD PRESSURE?
The amount of blood pumped out of the heart (cardiac output), the tone of the walls of the arteries (vascular resistance), and the volume and viscosity of the blood influence the pressure (expressed in millimeters of mercury) of the blood against the walls of the arteries. Each blood pressure measurement has two numbers. The fist or top number is systolic blood pressure (pressure within the arteries during systole, when the heart is contracting). The second or bottom number is diastolic pressure (pressure within the arteries when the heart is relaxing). Normally, systolic pressure is the higher number. During EECP treatment sessions, diastolic pressure is increased and systolic pressure is decreased, usually to a degree that diastolic pressure exceeds systolic pressure.
WHAT IS THE CARDIAC CYCLE?
The cardiac cycle is the period from the beginning of one heartbeat to the beginning of the next. The cardiac cycle includes diastole when the heart relaxes and fills with blood, and systole when the heart contracts and pumps blood out to the body.
WHAT IS COLLATERAL CIRCULATION?
When a blockage (stenosis) within an artery prevents that vessel from delivering an adequate supply of blood to the tissues it serves, the body can sometimes compensate by developing and/or opening small-specialized vessels to transfer blood from “healthier” arteries to the deprived tissues that are downstream of the blockage. The result of these special vascular networks that channel blood from one arterial branch to another is termed collateral circulation. The natural development of collaterals, however, is a gradual process, and heart patients often cannot produce them in the time or quantity necessary to relieve or reduce symptoms.
(A possible explanation for the long-term reduction in angina often associated with one course of EECP treatment is that the procedure may improve the body’s ability to develop collateral channel, which, once established, tend to remain.)
WHAT ARE CORONARY ARTERIES?
Enveloping the heart, these arteries provide the heart with its own nourishing supply of blood.
WHAT IS CORONARY ARTERY BYPASS GRAFTING? (CABG)
In traditional bypass operations, an incision is made along the midline of the chest through the breastbone. During part of the operation, heart and lung functions are assumed by a heart-lung machine. Blood vessels from anther part of the body (usually the leg or chest wall) are harvested or rerouted for grafting to diseased arteries to create conduits around blocked sections of the vessels.
WHAT IS CORONARY ATHEROSCLEROSIS?
Every year one million Americans develop atherosclerosis, partial or total blockage of arteries caused by deposits of fatty substances (plaque) in and on the walls of the vessels. The coronary arteries that supply blood to these heart are especially vulnerable.
WHAT IS AN ELECTROCARDIOGRAM? (ECG)
An electrocardiogram is a recording of the heart’s electrical activity. It is detected by electrodes attached to the skin, and recorded in waves that are displayed graphically. The ECG provides information on heart rate, rhythm and function. ECG may also indicate the presence of heart damage or inadequate blood and oxygen supply to the heart muscle, and abnormalities of heart structure.
WHAT IS RESTENOSIS?
Unfortunately, treatments to clear blockages often result in cell regrowth that can obstruct vessels again. This condition, called restenosis, occurs after about 20 to 30 percent of PTCA procedures. (The Merck Manual of Diagnosis and Therapy, Merck Research Laboratories, 1992). Repeat procedures are not uncommon, and restenosis rates after repeat TPCA are as high as 50 percent. (Cath-Lab Digest, Jan/Feb, 1997).
DOES BYPASS SURGERY OFTEN FAIL?
For patients who have undergone CABG, repeat procedures are sometimes necessary. Six to ten percent of CABG procedures are now re operations. However, reoperative mortality rates are tow to three times those of the initial procedure and range from two to ten percent for second operations and up to 15 percent for third and subsequent operations. Patients undergoing repeat procedures generally have more advanced coronary artery disease, rendering the revascularization process less effective. (Cath-Lab Digest, Jan/Feb, 1997).
WHAT ARE THALLIUM OR SESTAMIBI SCANS?
Coronary perfusion scanning is a nuclear imaging technique used to evaluate coronary blood flow. Agents containing tracers such as thallium-201 or technetium-99m are injected into the blood stream. The material is carried through the coronary arteries and into capillaries of the myocardium (heart muscle), where it can be absorbed by the myocardial cells. Energy given off by the tracers is detected and processed by special computerized camera systems. Images are produced that show how the tracers were distributed within the heart muscle. Tissues that are well supplied with blood absorb more tracers, and record as the light areas on scan images. Portions of the heart muscle receiving diminished supplies of blood record proportionally lower levels of tracers, and are imaged with correspondingly less intensity (darker, or black). By comparing scans made while a patient is physically stressed (by exercise or pharmacologicals) with those recorded following a period of rest, diagnostic information regarding the condition of specific portions of the myocardium can be obtained.
WHAT IS SYSTOLIC UNLOADING?
During EECP treatment, the air cuffs are simultaneously and quickly deflated at the beginning of each systolic (ventricular contraction), relieving the compressive force that was being maintained by the inflated cuffs. This decompression allows vessels that had been “squeezed” by the cuffs to quickly re-conform, reducing resistance to the pumping action of the heart. This ‘unloading” of resistance during the heart’s contraction phase (systole) increases the heart’s output (volume of blood ejected with each contraction). The heart’s oxygen demand is actually lowered as a result of the improved pumping efficiency.
WHAT IS EECP TREATMENT?
EECP treatment is a non-invasive outpatient treatment that may relieve or eliminate angina.
WHAT DOES THE NAME ENHANCED EXTERNAL COUNTERPULSATION (EECP) MEAN?
The term Enhanced External Counterpulsation (EECP) describes what happens during treatment. EECP treatment is “External” because it happens outside of the body and doesn’t require surgery or other invasive procedures. “Enhanced” refers to the equipment that has evolved over decades of research and development to become the state-of-the-art treatment delivery system now used in EECP treatment centers. Counterpulsation occurs between heartbeats. EECP system pumps when the heart is resting (the beginning of diastole) and relieves pressure just before the heart beats (the end of diastole). Counterpulsation increases blood flow to the heart muscle, decreases the heart’s workload, and creates greater oxygen supply while lowering oxygen demand.
WHAT ARE THE ADVANTAGES OF EECP THERAPY OVER OTHER TREATMENTS FOR ANGINA?
Unlike procedures such as bypass surgery and balloon angioplasty, EECP treatments are administered in outpatient sessions carries little or no risk and is relatively comfortable.
Some patients may require bypass surgery. Enhanced External Counterpulsation is an option for patients who are unsuitable for invasive procedures or are unwilling to undergo them. For patients who have undergone multiple invasive procedures and for whom additional surgery carries excessive risk, Enhanced External Counterpulsation may be the only way to obtain relief from crippling angina.
WHAT HAPPENS DURING TREATMENT?
Patients lie on a padded table in a treatment room. Three electrodes are applied to the chest to record a constant ECG reading. A finger sensor, called a plethysmograph, records a tracing that represents blood pressure. A set of cuffs is wrapped around the calves, thighs, and buttocks. The system uses an ECG signal to electronically synchronize inflation and deflation of the cuffs. Patients experience a sensation of a strong “hug” moving upwards from calves to thighs to buttocks during inflation followed by the rapid release of pressure on deflation. During EECP treatment, a display shows an ECG signal and a blood pressure tracing. An EECP therapist uses these readings to time counterpulsation and monitor treatment.
AM I A CANDIDATE FOR EECP TREATMENT?
Ask your physician to evaluate you. You may be a candidate for EECP if you:
· Have chronic stable angina.
· Are not receiving adequate relief from angina by taking nitrates.
· Do not qualify as a candidate for invasive procedures.
· Have exhausted invasive treatments without lasing relief of symptoms.
· Are unwilling to undergo surgery or angioplasty.
· Want to explore alternatives to bypass surgery or angioplasty.
HOW DOES EECP TREATMENT WORK?
Normal heart function depends on maintaining a balance between oxygen supply and demand. Oxygen consumption by the cardiac muscle is determined by how fast your heart is beating and how well it pumps. The amount of oxygen available is determined by blood flow. Approximately 80 percent of the blood flow to the cardiac muscle tissue occurs when the heart is resting.
Clinical studies indicate that EECP treatment may create a “natural” bypass of blocked arteries. EECP treatment encourages blood vessels to open or form small channels that become extra branches. These channels or collaterals may eventually become permanent pathways to the heart muscle that was previously deprived of blood flow and adequate oxygen.
ARE THERE DOWNSIDES TO THE PROCEDURE?
The length of treatment may be a consideration for some people. It can take between four and seven weeks to complete a course of EECP treatment. During that time, patients must visit an outpatient clinic and receive treatment for one to two hours per day. Some patients may require more than one course of therapy to achieve an optimal level of relief.
WHAT HAVE STUDIES SHOWN ABOUT EECP TREATMENT?
Clinical studies have shown that EECP treatment is effective treatment for angina. A randomized, controlled, blind study showed a significant increase in the length of time that participants, who had received active treatment, were able to exercise. Additionally, participants who received active treatment experienced fewer attacks of angina.
Studies have demonstrated benefits including:
· Elimination or decrease in exercise-induced signs of lack of oxygen to heart muscle (ischemia).
· Increased exercise tolerance.
· Elimination or decrease in episodes of angina.
· Decrease in need for anti-anginal medications.
WOULD I FEEL BETTER AFTER HAVING EECP TREATMENT?
· Patins can walk farther, carry heavier packages, and be more active without having angina.
· Patients have fewer attacks of angina.
· Episodes of angina are less painful.
· Patients need less anti-anginal medication.
· Patients can return to work, go out to diner, garden, travel, or enjoy golf, tennis, or bowling once again.
· Patins feel more confident about participating in their social lives, volunteer activities, and exercise without interference from angina.
WHAT ARE THE RISKS?
Some patients have experienced minor skin irritation due to the pressure of the cuffs. You should consult with your physician regarding any risk and complication factors.
DOES EECP THERAPY ELIMINATE THE NEED FOR BYPASS SURGERY?
Unlike procedures such as bypass surgery and balloon angioplasty, EECP treatment is administered in outpatient sessions, carries little or no risk, and is relatively comfortable.
Some patients with more extensive disease or who have disease of the left main coronary artery may require bypass surgery. EECP treatment is an option for patients who are unsuitable for invasive procedures or unwilling to undergo them. For patients who have undergone multiple invasive procedures and for whom additional surgeries carry excessive risk, EECP therapy may be the only way to obtain relief from crippling angina.
HOW OFTEN WILL I BE TREATED?
Patients typically attend one-hour treatment sessions once a day, five days a week, for seven weeks. Many people have continued their employment while receiving treatment by scheduling their sessions before or after work.
Patients with extensive atherosclerotic disease may require more than 35 hours of treatment to achieve optimal benefit.
HOW LONG HAS EECP THERAPY BEEN USED TO TREAT ANGINA?
In 1989, researchers at State University of New York at Stony Brook began clinical studies of EECP treatment. Until the summer of 1995, EECP therapy was only available to patients participating in clinical studies. Today EECP therapy is available at treatment centers throughout the country.