What is enhanced external counterpulsation (EECP) ?
Enhanced external counterpulsation (EECP) is a noninvasive technique to treat chronic stable chest pain (angina). Angina occurs when the heart muscle does not get enough blood and oxygen to support the work it is doing. Many people experience angina during exertion – when the heart has to work harder and needs more oxygen. EECP is designed to reduce the heart's workload while increasing the amount of oxygen-rich blood reaching the heart, thereby relieving angina pain.
EECP was approved by the FDA in 1997; however, the idea behind it was developed in the 1950s. In EECP, 3 air cuffs are placed on each of your legs – one on the calf, one on the lower thigh, and one on the upper thigh. You lie on a table and are hooked up to an electrocardiogram ( ECG) monitor (small, sticky patches will be placed on your chest). The ECG measures your heart's electrical activity, and the cuffs inflate and deflate in response to these signals. When the heart relaxes between heartbeats (the period known as diastole), the 3 cuffs rapidly inflate in succession from the calf to the upper thigh. This propels blood back to the heart. The cuffs quickly deflate just before the next heartbeat.
This inflation/deflation cycle occurs about 60 to 80 times per minute during an EECP session. Sessions last approximately 1 to 2 hours and are scheduled once a day. A full course of EECP treatment lasts 7 weeks, with about 35 hours of treatment time.
How does EECP work?
Researchers don't exactly know how EECP relieves chest pain, but a few different theories have been proposed. The most supported theory is that EECP triggers the body to create tiny blood vessels (known as collaterals) that act like a natural bypass, carrying blood around larger blocked vessels. Chest pain is then reduced because the heart is again able to receive oxygen-rich blood.
Another theory is that cuff inflation/deflation increases the force of the blood flow to the heart, causing the cells lining the blood vessels to produce chemicals that widen the blood vessels, allowing blood to flow through more freely.
Who might have EECP?
EECP may be considered if you experience angina pain that is not relieved with medication, but are unable to have one of the more traditional treatments—balloon angioplasty or bypass surgery. EECP may also be an option if you have had angioplasty or bypass surgery, but continue to suffer from chest pain.
Who should not have EECP?
You should not undergo EECP if you have any of the following conditions:
- Severe heart failure
- Serious heart valve problems
- Heart rhythm problems (arrhythmias)
- High blood pressure that is not controlled with medication
- Peripheral artery disease or peripheral vascular disorders (blockages in the arteries or veins of the legs)
- A tendency to bleed excessively (including people with ulcers)
- You are pregnant
What are the benefits of EECP?
Studies have shown that EECP is a safe and effective treatment for chronic chest pain.1 The frequency and intensity of angina attacks are reduced, and many patients find that they don't need to take their angina medication (usually nitroglycerin) as often. Men and women treated with EECP report having a higher quality of life after EECP, and many are able to exercise for longer periods without experiencing chest pain.2, 3 EECP seems to work equally well in both genders, with women receiving the same chest pain reduction and quality of life benefits as men from the treatment.4, 5
Even so, EECP is not as well studied or understood as the traditional treatments for persistent chest pain. For now, it is used only if bypass surgery or angioplasty are not possible and standard chest pain medications aren't working well enough.
What are the risks of EECP?
EECP is a noninvasive procedure, meaning that you are not cut open. There are no needle pricks, either. This means that EECP is very low risk. You also don't need to take any special medication before or after the procedure, and you can go home immediately after the treatment. The most common adverse side effects are skin abrasions, bruising, or blistering due to the inflatable cuffs. Some people also feel minor pain in their legs and back.
1. Holubkov R, Kennard ED, Foris JM, et al. Comparison of patients undergoing enhanced external counterpulsation and percutaneous coronary intervention for stable angina pectoris. Am J Cardiol. 2002;89:1182-1186.
2. Arora RR, Chou TM, Jain D, et al. The multicenter study of enhanced external counterpulsation (MUST-EECP): effect of EECP on exercise-induced myocardial ischemia and anginal episodes. J Am Coll Cardiol. 1999;33:1833-1840.
3. Urano H, Ikeda H, Ueno T, Matsumoto T, Murohara T, Imaizumi T. Enhanced external counterpulsation improves exercise tolerance, reduces exercise-induced myocardial ischemia and improves left ventricular diastolic filling in patients with coronary artery disease. J Am Coll Cardiol. 2001;37:93-99.
4. Linnemeier GC, Kennard ED, Soran O, Kelsey SF. 891-3 Enhanced external counterpulsation improves functional capacity and quality of life in women with chronic angina. J Am Coll Cardiol. 2004;43:A308.
5. Lawson WE, Kennard E, Linnemeier G, Holubkov R, Mehra M. Do women with refractory angina respond as well as men to treatment with enhanced external counterpulsation? J Am Coll Cardiol. 2002;39:154.