Enhanced External Counterpulsation
Enhanced External Counterpulsation
Enhanced external counterpulsation (EECP) is a noninvasive procedure in which a set of inflatable cuffs (much like blood pressure cuffs) mechanically compress the blood vessels in the patient’s lower limbs to increase blood flow in the coronary arteries of the heart. The blood pressure cuffs (also called stockings) are wrapped around the patient’s calves, lower thighs, and upper thighs. Computer technology, electrocardiography, and blood pressure monitors enable the pressure cuffs to be inflated and deflated in time with the patient’s heartbeat and blood pressure.
EECP is performed to restore blood flow to the heart and to relieve chest pain (angina pectoris) and ischemia. The goals of the procedure are to relieve the symptoms of coronary artery disease, enable the patient to resume a normal lifestyle, and lower the risk of a heart attack or other heart problems. EECP may encourage blood vessels to open small channels (called collateral blood vessels) to eventually bypass blocked vessels and improve blood flow to the heart.
The concept of counterpulsation is not new; it was first introduced in 1953 at Harvard, and refined in the late 1950s. Early models of EECP, however, used nonsequenced pulsation; that is, compression of the patient’s blood vessels was performed simultaneously along the full length of the body. In the 1970s, researchers in China reported on a sequential compression system in which four sets of pressure cuffs were applied to the patient’s legs, buttocks, and arms. Favorable reports about the effectiveness of sequential compression encouraged a research team at SUNY Stony Brook to develop the three-cuff EECP model in use in the early 2000s. The computerized technology currently available with EECP makes it a relatively new procedure compared to the systems used in the 1960s and early 1970s. As of 2008, it is available in about 200 centers across the United States.
EECP is used to treat patients with chronic stable angina, coronary artery disease, or high blood pressure. The Food and Drug Administration (FDA) approved EECP for the treatment of congestive heart failure (CHF) in the early 2000s. Researchers at the Ohio Heart and Vascular Center reported in 2006 that
EECP improves exercise duration as well as quality of life in patients with CHF. The treatment may be appropriate for patients who are not eligible for such nonsurgical interventional procedures as balloon angioplasty, stent placement, rotablation, atherectomy, or brachytherapy. It may also be used for patients who do not qualify for such surgical treatments as coronary artery bypass graft surgery.
EECP is not the first-line treatment for angina. Rather, it is reserved for patients who have not achieved good results from medication or interventional management of their symptoms. To be eligible for EECP, a patient must have coronary artery disease that includes at least one heart vessel with at least 70% obstruction. In addition, the patient must have evidence of either an infarction or significant ischemia on a stress test with nuclear or echocardiographic imaging.
EECP may benefit patients with such other medical conditions as erectile dysfunction, kidney disease, eye disease, diabetic neuropathy, restless legs syndrome, and other circulatory disorders. More research is needed to evaluate the outcomes of EECP for these patients.
Many insurance providers and Medicare have approved EECP treatment for reimbursement. Medicare pays about $5,500 for the full series of 35 treatments.
EECP is not recommended for patients who have certain types of valve disease, uncontrolled arrhythmias (irregular heart rhythms), severe hypertension, uncontrolled congestive heart failure, significant blockages or blood clots in the leg arteries, or those who have had a recent cardiac catheterization, angioplasty, or bypass surgery. It should also not be given to pregnant women.
While the patient lies on a bed, the leg cuffs are deflated and inflated with each heartbeat. A computer synchronizes the compression of the cuffs with the heartbeat. The electrocardiogram indicates when each heartbeat begins, triggering the cuffs to be mechanically deflated. As each heartbeat ends, the cuffs are mechanically inflated in sequential order, starting with the cuffs on the calves and working upward to the cuffs on the lower and then the upper thighs. The pressure produced by the inflation of the cuffs when the heart is at rest pushes the blood in the legs upward toward the heart. The deflating action that occurs just when the heart begins to beat reduces the work of the heart as it pumps blood to other parts of the body. Inflation is controlled by a pressure monitor that
Angina— Also called angina pectoris; chest pain or discomfort that occurs when diseased blood vessels restrict blood flow to the heart.
Aorta— The main artery that carries blood from the heart to the rest of the body; the largest artery in the body.
Artery— A vessel that carries oxygen-rich blood to the body.
Atherectomy— A nonsurgical technique for treating diseased arteries with a rotating device that cuts or shaves away obstructing material inside the artery.
Atria (singular, atrium)— The right and left upper chambers of the heart.
Balloon angioplasty— A nonsurgical technique for treating diseased arteries by temporarily inflating a tiny balloon inside an artery.
Beta blocker— An antihypertensive drug that limits the activity of epinephrine, a hormone that increases blood pressure.
Brachytherapy— The use of radiation during angioplasty to prevent the artery from narrowing again (a process called restenosis).
Calcium channel blocker— A drug that lowers blood pressure by regulating calcium-related electrical activity in the heart.
Cardiac catheterization— An invasive procedure used to create x rays of the coronary arteries, heart chambers and valves.
Collateral vessel— A side branch or network of side branches of a large blood vessel.
Coronary artery disease— Also called atherosclerosis, it is a buildup of fatty matter and debris in the coronary artery wall that causes narrowing of the artery.
Echocardiogram— An imaging procedure used to create a picture of the heart’s movement, valves and chambers.
Electrocardiogram (ECG, EKG)— A test that records the electrical activity of the heart, using small electrode patches attached to the skin on the chest.
Infarction— An area of dead tissue caused by obstruction of the blood supply to that tissue.
Ischemia— Decreased blood flow to an organ, usually caused by constriction or obstruction of an artery.
Rotablation— A nonsurgical technique for treating diseased arteries in which a special catheter with a diamond-coated tip is guided to the point of narrowing in the artery. The catheter tip spins at high speed and grinds away the blockage or plaque on the artery walls.
Stent— A device made of expandable metal mesh that is placed (by using a balloon catheter) at the site of a narrowing artery. The stent remains in place to keep the artery open.
Stress test— A test that determines how the heart responds to stress.
Vein— A blood vessel that returns oxygen-depleted blood from various parts of the body to the heart.
Ventricles— The lower pumping chambers of the heart that propel blood to the lungs and the rest of the body.
inflates the cuffs to about 300 mm Hg. When timed correctly, the procedure increases the cardiac output.
EECP treatments are performed on an outpatient basis and generally last one to two hours. Treatments must be repeated about five times a week for up to seven weeks to achieve improved circulation. This 35-hour regimen is generally followed because it was used in the first multicenter study of EECP in 1999.
The patient is usually instructed to wear tight-fitting seamless cycling pants or athletic tights to prevent chafing, one of the main adverse side effects.
Before the procedure, the patient’s weight, blood pressure, pulse, and breathing rate are measured and recorded. The patient’s legs are examined for areas of redness and signs of potential vascular problems.
The patient is asked to record his or her symptoms during the course of treatment to determine whether and how symptoms improve over time. The patient should record the severity and duration of troublesome symptoms, the time the symptoms occurred, and any activities that may have triggered the symptoms. This patient record is reviewed before each treatment session.
PATIENT EDUCATION. The healthcare team will ensure that the patient understands the potential benefits and risks of the procedure. Informative and instructional handouts are usually provided to explain the procedure. Because the procedure requires multiple outpatient visits (generally 35 visits over a seven-week period), the patient must be able to meet the treatment schedule.
INFORMED CONSENT. Informed consent is an educational process between healthcare providers and patients. Before any procedure is performed, the patient is asked to sign a consent form. Before signing the form, the patient should understand the nature and purpose of the diagnostic procedure or treatment; the risks and benefits of the procedure; and alternatives, including the option of not proceeding with the test or treatment. During the discussion about the procedure, the healthcare providers are available to answer all of the patient’s questions.
SMOKING CESSATION. Patients who will undergo any procedure to treat cardiovascular disease are encouraged to stop smoking and using any tobacco products before the procedure, and to make a commitment to be a nonsmoker after the procedure. There are several smoking cessation programs available in the community. The patient should ask a healthcare provider for more information if he or she needs help quitting smoking.
Patients report little or no discomfort during the procedure. Some people may feel tired after the first few treatments, but this loss of energy improves over time.
To manage heart disease, the patient needs to make several lifestyle changes before and after the procedure, including:
- Quitting smoking. Smoking causes damage to blood vessels, increases the patient’s blood pressure and heart rate, and decreases the amount of oxygen available in the blood.
- Managing weight. Maintaining a healthy weight, by watching portion sizes and exercising, is important. Being overweight increases the work of the heart.
- Participating in an exercise program. The cardiac rehabilitation exercise program is usually tailored for the patient, who will be supervised by professionals.
- Making dietary changes. Patients should eat a lot of fruits, vegetables, grains, and nonfat or low-fat dairy products, and reduce fats to less than 30% of all calories. Alcoholic beverages should be limited or avoided.
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
EECP is performed by healthcare providers trained in the procedure. Interventional cardiologists, registered nurses, and other healthcare professionals may perform the procedure. Currently, EECP credentialing is being investigated by the International EECP Therapists Association (IETA). EECP is generally performed in an outpatient clinic or hospital.
- Taking medications as prescribed. Aspirin and other heart medications may be prescribed, and the patient may need to take these medications for life.
- Following up with healthcare providers. The patient should visit the physician regularly for follow-up visits to control risk factors.
EECP is a relatively safe and effective treatment, and few adverse side effects have been reported. The main adverse side effect is chafing (skin irritation from the compression of the cuffs). To reduce or prevent this side effect, patients are instructed to wear tight-fitting cycling pants or athletic tights. Leg pain is another adverse side effect.
The benefits of EECP are comparable to the results of angioplasty and coronary artery bypass graft surgery: 70-80% of patients experience significant improvement after EECP treatment for as long as five years. The largest research study on EECP indicates that after receiving treatment, patients used less medication, had fewer angina attacks with less severe symptoms, and increased their capacity to exercise without experiencing symptoms. EECP improves the patient’s sense of well-being and overall quality of life, and in some cases, prolongs the patient’s life. Benefits five years after EECP treatment are comparable to surgical outcomes.
The effects of EECP treatment last from three to five years and sometimes longer.
EECP does not prevent coronary artery disease from recurring; therefore, lifestyle changes are strongly recommended and medications are prescribed to reduce the risk of recurrent disease.
QUESTIONS TO ASK THE DOCTOR
- Why do you recommend this procedure?
- Who will perform the procedure? How many years of experience does this doctor have? How many other EECP procedures has this doctor performed?
- May I take my medications the day of the procedure?
- May I eat or drink the day of the surgery? If not, how long before the surgery should I stop eating or drinking?
- How long do the treatments last?
- What should I do if I experience chest discomfort or other symptoms similar to those I felt before the procedure?
- What types of symptoms should I report to my doctor?
- Will I be able to perform my normal activities during the course of treatment?
- When will I find out if the procedure was successful?
- Will I have any pain or discomfort after the procedure?
- What lifestyle changes (including diet, weight management, exercise, and activity changes) are recommended to improve my heart health?
- How often do I need to see my doctor for follow-up visits after the procedure?
Morbidity and mortality have not been reported with this procedure.
All patients with coronary artery disease can help improve their condition by making lifestyle changes such as quitting smoking, losing weight if they are overweight, eating healthful foods, reducing blood cholesterol, exercising regularly, and controlling diabetes and high blood pressure.
All patients with coronary artery disease should be prescribed medications to treat their condition. Such antiplatelet medications as aspirin or clopidogrel (Plavix) are usually recommended. Other medications used to treat angina may include beta blockers, nitrates, and angiotensin-converting enzyme (ACE) inhibitors. Medications may also be prescribed to lower lipoprotein levels, since elevated lipoprotein levels have been associated with an increased risk of cardiovascular problems.
Treatment with vitamin E is not recommended because it does not lower the rate of cardiovascular events in people with coronary artery disease. Although such antioxidants as vitamin C, beta-carotene, and probucol show promising results, they are not recommended for routine use. Treatment with folic acid and vitamins B6 and B12 lowers homocysteine levels (reducing the risk for cardiovascular problems), but more studies are needed to determine if lowered homocysteine levels correlate with a reduced rate of cardiovascular problems in treated patients.
Such nonsurgical interventional procedures as balloon angioplasty, stent placement, rotablation, atherectomy, or brachytherapy can be performed to open a blocked artery.
Coronary artery bypass graft surgery is a surgical procedure in which one or more blocked coronary arteries are bypassed by a blood vessel graft to restore normal blood flow to the heart. These grafts usually come from the patient’s own arteries and veins located in the leg, arm, or chest.
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Angela M. Costello
Rebecca Frey, PhD