Enhanced external counterpulsation (EECP) is a relatively new and painless treatment for angina and heart failure. The goal of the procedure is to increase oxygen-rich blood flow to the heart and to reduce the heart’s workload. EECP is performed over a series of several weeks, with each session lasting from one to two hours. The procedure has so far been performed in more than 5,000 patients with generally good results. It is usually recommended for patients who are not suitable for other procedures, such as coronary artery bypass graft surgery or a catheter-based procedure.
During each session, air (pneumatic) cuffs are placed on each of the patient’s calves, lower thighs and upper thighs. Precisely timed by a computer to match the heartbeat, these cuffs are rapidly and sequentially inflated from the calves to the upper thighs. As a result, the blood vessels in the leg are gently compressed and blood is forced back to the heart.
This may reduce the pain of angina, increase one’s capacity for exercise and decrease the need for medication. Unfortunately, some patients (e.g., those with pacemakers) may not be appropriate for EECP.
About EECP
Enhanced external counterpulsation (EECP) is a relatively new, noninvasive treatment for angina and heart failure. Angina is a type of temporary chest pain, pressure or discomfort that is the main symptom of coronary artery disease – a chronic disease in which there is a “hardening” (atherosclerosis) of the coronary arteries. The pain associated with angina is caused by a temporary lack of oxygen-rich blood in the heart muscle. Heart failure is a condition when the heart muscle becomes weak and enlarged, and the heart cannot pump enough oxygen-rich blood to satisfy the body.
Enhanced external counterpulsation got its name because it is a sophisticated technique for producing counterpulsation without invading the body. Counterpulsation is a strategy for increasing the blood flow back to the heart during the part of the heartbeat (diastole) when the heart is relaxing between contractions. Not only does the strategy increase the amount of oxygen available to the heart, but it also decreases the heart’s workload, improves circulation and strengthens the cardiopulmonary system.
As a result, patients may experience a reduction in the frequency and intensity of angina and need less medication. Patients may also be able to increase their level of exercise (while under the supervision of a physician). Improvement can also carry over into other areas, such as ability to work, resuming of social activities and general sense of well-being. It has also shown benefit in patients with stabilized heart failure, although this use of EECP is very new and more long-term studies are underway.
Researchers are unclear about exactly how EECP continues to relieve the pain, pressure or discomfort of angina in the long run. The most supported theory appears to be the idea that EECP triggers a natural process in which the body produces tiny blood vessels (collaterals) that carry blood flow around blocked vessels. With more blood vessels available to carry oxygen-rich blood to the heart, angina is relieved.
Unfortunately, only certain patients are candidates for EECP. Patients who may be considered for EECP including those who:
Have chronic, stable angina
Are not receiving relief from medications
Do not qualify for more invasive treatments (e.g., balloon angioplasty, stenting or open-heart surgery)
Patients who do not qualify include those with the following conditions:
Tendency to bleed excessively (including those with ulcers)
Pregnancy
In addition, EECP may not be advised for people with pacemakers, implantable cardioverter defibrillators (ICDs) or patients taking anticoagulants. EECP is not likely to replace the more invasive techniques used to treat angina, but it may provide an option for certain patients who are not appropriate candidates for procedures such as balloon angioplasty or open–heart surgery. It may also provide an alternative for those who had those procedures, or who took medication, but continue to have pain.
History of EECP
The history of EECP begins in the early 1950s, when researchers discovered that the heart was doing two different kinds of work. The first type of work occurred during the pumping part of the heartbeat (systole) during which the heart needed to overcome the blood pressure in the aorta in order to pump blood through it. The second type of work occurred during the relaxed part of the heartbeat (diastole) during which the heart received blood via backflow from the aorta. This was described as the difference between pressure work and flow work.
Counterpulsation was introduced as a strategy by which the blood flow from the aorta back to the heart could be increased during diastole. The increased blood flow to the heart through the coronary arteries would provide the heart with more oxygen, thereby improving circulation and strengthening the cardiopulmonary system.
In 1958, Harvard researchers documented positive results from counterpulsation in laboratory studies, and animal studies in the early 1960s supported these results. From this research, American researchers began to develop a device that could be surgically implanted in the chest to produce counterpulsation (an intra-aortic balloon pump [IABP]). This device is used during open-heart surgery to help wean patients off the heart-lung machine.
While most American physicians were pursuing invasive techniques such as the IABP, Chinese physicians were developing one of the other findings that came from Harvard in the 1960s. The Harvard researchers had discovered that counterpulsation could be achieved without inserting a device into the aorta. Instead, cuffs were applied to the lower legs and timed to fill and empty of water in the same rhythm as the patient’s heartbeat. By gently compressing the blood vessels in the legs, this increased the blood flow to the heart during the diastole phase of the heartbeat.
Chinese physicians pursued this painless, noninvasive technique for achieving counterpulsation and have been developing and refining it over the last 40 years. Today the technique of enhanced external counterpulsation uses a pressure suit that sends counterpulsation waves through computer–controlled pneumatic cuffs located at three points on the leg. This modern version of the technique was introduced in 1983 and continues to be used today.
Precisely timed by computer, these modern cuffs inflate and deflate rapidly between heart beats. The modern cuffs used today fill with air instead of water, for the greater comfort of the patient and the greater ease of the physician. The three cuffs also fill sequentially, one at a time, rather than suddenly filling all at once.
In 1989, researchers from the State University of New York at Stony Brook determined that enhanced external counterpulsation continued to show helpful effects on patients even three years after treatment. There are no reported risks of complication, and as of this time, centers are opening up across the country to provide this service. However, in 2002, the American Heart Association and the American College of Cardiology issued guidelines on treating angina stating that more studies are required on EECP before it can be recommended as a standard treatment for angina. So far, EECP has not been widely accepted in clinical practice.
In 2004, several studies also found that EECP shows some benefit for patients with stabilized heart failure. These study results were confirmed in 2006, with publication of the PEECH (Prospective Evaluation of Enhanced External Counterpulsation in Congestive Heart Failure) study. This study found that patients with mid- to moderate-severe heart failure experienced an improvement in their New York Heart Association (NYHA) class after counterpulsation. However, the long-term safety and effects of EECP are unknown among these patients and more long-term studies are needed.
During and after EECP
The patient puts on a pressure suit with air (pneumatic) cuffs, similar to the cuffs used to measure blood pressure. He or she then lies on a padded table equipped with three sets of electronically controlled inflation and deflation valves. The three valves are connected to the three cuffs, which are firmly wrapped around the calves, lower thighs and upper thighs. The valves are controlled by signals running from an electrocardiogram (EKG), a device that measures the heart’s electrical activity, to a microprocessor.
When the heart is resting (diastole), the three cuffs rapidly inflate in sequential order, from the cuff at the calf to the cuff at the upper thigh, which forces blood back to the heart. Patients will experience a sensation like a strong hug traveling up from their calves to their thighs. Then, just before the next heartbeat, the cuffs quickly deflate. The inflation/deflation cycle occurs between 60 and 80 times each minute during the session. The treatment is relatively painless, although some patients find the cuffs to be somewhat uncomfortable.
Sessions last one to two hours and are usually scheduled once a day. There is a resting period if a patient receives two sessions in a single day. Typically, an entire course of therapy is 35 hours in total. After treatment, the patient may return home. No special medication or invasive technique is required with EECP.
Because it is noninvasive, the risk of complications with this technique is very low. No medication or needles are required.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to enhanced external counterpulsation (EECP):
Could EECP be used to treat my condition?
How successful do you expect EECP to work for me? How much will it decrease my pain?
Am I in any danger from EECP? Are there any risks?
Are there any alternatives to EECP? Are there any medications I could take to treat my pain instead?
Are there any lifestyle changes I can make that might decrease my pain?
Do I need to discontinue any of my medications prior to the EECP procedure?
Will the EECP procedure require me to stay in the hospital? If so, how long?
Where will the procedure take place? Do I need to make any special arrangements to get to or from the site?
Can I safely undergo EECP if I am pregnant?
If EECP does not improve my symptoms, what is the next step?
