What is enhanced external counterpulsation?
Enhanced External Counterpulsation (EECP) is a treatment for angina (also called angina pectoris), or chest pain. Angina occurs when the muscle cells of the heart do not get enough blood to properly maintain their pumping function. The lack of blood supply is most likely to cause pain during physical activity, when the heart pumps fastest and needs the most oxygen. In most people, angina is caused by coronary artery disease.
Results of clinical trials show that EECP is a safe and effective choice for people who are considered at high risk for bypass surgery and angioplasty. The procedure is administered in an outpatient setting, does not require any surgery or anesthetic, and is relatively comfortable for patients.
When applied over time, EECP can reduce the frequency of angina episodes, improve exercise capacity, and may even reduce the need for medications. EECP is not meant to replace bypass surgery or angioplasty, but is an additional treatment for those patients who can no longer benefit from additional surgery or angioplasty.
How does EECP work?
EECP enhances blood flow to the heart and coronary arteries by squeezing blood out of the lower parts of the body up towards the heart. Sometimes referred to as a "natural bypass," EECP stimulates the growth of new blood vessels around blocked arteries.
While EECP is performed, you will be lying on a special treatment table wrapped in three sets of cuffs (like large blood pressure cuffs) around your calves, lower thighs and upper thighs (including the buttocks). The EECP treatment system includes an air compressor that inflates and deflates these cuffs, starting with the calf cuffs, then the lower thigh cuffs, and then the cuffs at the upper thigh and buttocks.
The pressure moves the blood from your lower limbs toward your heart. Each wave of pressure is timed to your heartbeat so that the increased blood flow is delivered to your heart at the time that it is relaxed and blood flow to the heart arteries is at its peak. When the heart pumps again, all the cuffs deflate at the same time. This lowers the resistance in the blood vessels of your legs, and decreases the amount of work for your heart to pump blood to your body.
What can I expect during the procedure?
The initial course of EECP therapy involves 35 consecutive one-hour sessions, once or twice each day, for approximately 7 weeks. During an EECP clinic visit, you will lie on a bed and the treatment supervisor will wrap blood pressure-type cuffs around your calves and lower and upper thighs. Cardiac monitoring wires will be attached to your chest to record your heartbeat. The cuffs are then inflated and deflated in sequence, placing pressure on your legs. The pumping action helps blood flow from the lower limbs to your heart, while reducing your heart's workload.
How can I prepare for this procedure?
During each visit and before the treatment begins, the treatment supervisor will measure and record your blood pressure, pulse and respiratory rates. The supervisor will also look at your legs to check for areas of redness, broken blood vessels, or signs of other vascular problems.
Before your treatment, try to urinate so that you won't experience discomfort during the session. To prevent irritation or skin chafing during the procedure, try to wear tight-fitting, seamless leggings or bicycle pants made of elastic material.
If the pulsating sensation from the cuffs becomes uncomfortable, tell the treatment supervisor immediately so that the treatment can be stopped.
Your treatment supervisor might recommend that you keep a daily diary of your angina symptoms during the course of your treatment. For example, record each angina attack, its time of occurrence, duration, severity, its relationship to precipitating factors, and the number of nitroglycerin tablets you used to ease the attack.
You should continue to take your angina medication at regular prescribed dosages throughout the course of treatment, and talk to your doctor and pharmacist as required.
How will EECP help me?
EECP can benefit the heart in two ways: First, the pumping action of the leg cuffs increases the blood flow to the coronary arteries. Because the coronary arteries receive blood from the heart after each heartbeat, the inflation of the cuffs helps more blood flow into the coronary arteries with each heartbeat.
Second, just as the heart begins to beat, EECP deflates the cuffs and creates a vacuum-like action in the arteries. This reduces the work of your heart muscle in pumping blood into the arteries.
Based on the results of clinical trials, therapy with EECP can help relieve symptoms of angina, reduce the need for angina medications, and reduce the frequency and intensity of chest pain. The procedure can also increase your ability to exercise and give you more independence in daily activities.
Because EECP helps reduce the frequency and intensity of chest pain for the short and long-term, many people who undergo treatment experience an improved sense of well-being and overall improvement in their quality of life.
Since individual conditions differ, there is no specific time when you might expect to feel better. Most people experience some improvement after 10-12 sessions. Others require a longer period of time to notice a difference in their angina symptoms.
What evidence is there that EECP can be beneficial?
Published reports have found that EECP is a relatively safe and effective option for certain people with angina. The Multicenter Study of Enhanced External Counterpulsation (MUST-EECP) randomly assigned 139 people with angina from seven US hospitals to receive either active EECP or a placebo (inactive) procedure for 35 hours over four to seven weeks.
About two-thirds of the people receiving EECP benefited from the treatment. Compared with the people who received the placebo procedure, those who completed the active EECP sessions had significantly less angina and tended to need less nitroglycerin. Also, people who received the active EECP were able to exercise longer before experiencing chest pain. Ten people dropped out of the study because of adverse events - half of them because of leg pain or chafing. The study was published in the June 1999 issue of the Journal of the American College of Cardiology.
EECP appears to have both short-term and long-term benefits. A study published in the April 2000 issue of Clinical Cardiology reported results in 33 patients with coronary heart disease who received EECP. After five years, 64 percent did not need bypass surgery or balloon angioplasty and did not have a major adverse cardiovascular event. This rate is similar to that found in many people who are treated with bypass surgery or angioplasty.
A more recent study showed that the procedure relieves angina and improves perfusion (blood flow to the heart) during stress in patients with coronary artery disease. The research was published in the April 1, 2002 issue of the American Journal of Cardiology.
Doctors are uncertain exactly how EECP helps ease angina. The procedure may stimulate the growth of tiny blood vessels in the heart and help bypass blocked blood vessels. This would increase blood flow and oxygen to deprived areas of the heart. EECP may also improve the function of existing blood vessels.
Am I a potential candidate for EECP? What conditions can be treated with EECP?
People who suffer with chronic angina are candidates for EECP. The procedure is particularly well suited for people who are not candidates for invasive procedures or who do not want to undergo them.
EECP should not be used for the treatment of patients with, or who develop the following disorders during the course of treatment with EECP:
- Uncontrolled congestive heart failure
- Severe heart valve disease
- Uncontrolled arrhythmia
- Coagulopathy (a condition where the blood doesn't clot adequately)
- Inflammation and blood clots in the veins in the legs, or poor circulation to the legs
Patients with blood pressure higher than 180/110 mm Hg or a heart rate of more than 120 beats per minute should have these conditions brought under control before treatment begins.
Are there any side effects or risks?
Most people who have EECP tolerate the therapy with no major discomfort, side effects or complications. The most common side effects are mild headache, mild dizziness, fatigue or muscle aches. A small number of people develop pressure sores, skin irritation or bruising from the cuff inflation.
Ask your doctor if you think you might benefit from EECP.
EECP - Enhanced External Counterpulsation. Univ of California, San Francisco, Cardiology Division. Accessed January 7, 2003.
EECP for Patients. North Suburban Cardiology Group, University of Chicago. Accessed January 7, 2003.
Enhanced External Counterpulsation. Discussed during the Cardiology Update 1997, October 16-18, 1997, at the Carmel Valley Ranch Resort, Carmel, CA. Directed by Parmley WW, MD, FACC, Chatterjee K, MBBS, FRCP, FACC.
EECP: A New Treatment for Angina. John Hopkins Health After 50. Accessed January 7, 2003.
Stys TP, Lawson WE, Hui JCK, et al. Effects of enhanced external counterpulsation on stress radionuclide coronary perfusion and exercise capacity in chronic stable angina pectoris. Am J Cardiol. 2002;89:7:822-824.
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