Typical angina is described as an uncomfortable sense of pressure, fullness, squeezing or pain in the middle of the chest.  The discomfort also may be felt in the neck, jaw, shoulder, back or arm.  Many types of chest discomfort aren't related to angina.  Acid reflux (heartburn) and lung infection or inflammation are examples.

Therapies for angina include medications such as Nitrates (e.g. nitroglycerine), Beta blockers (e.g. metoprol), Calcium channel blockers (e.g. amlodipine) that relieve symptoms and revascularization procedures such as angioplasty and stenting and Coronary artery bypass grafting (CABG).

However, despite the availability of these medications and the widespread use of these revascularization procedures, a growing number of patients have persistent angina and are significantly limited.  Even after successful bypass surgery, only 75% of patients are free of symptoms at 5 years; at 10 years post bypass the number drops to 50%.   In many of these patients, repeat  bypass surgery or angioplasty and stenting are not feasible options.

What is Enhanced External CounterPulsation (EECP)?

EECP is an FDA-approved, effective and completely non-invasive treatment of angina. EECP works by augmenting or increasing blood flow through coronary arteries.  The patient lies on a comfortable bed while three sets of cuffs that wrap around the calves, thighs and buttocks are then inflated serially. The EECP system monitors the patient’s ECG and determines the optimum time to inflate and deflate the cuffs.

How does EECP work?                                                                                                  

When the myocardium or heart muscle contracts, blood is distributed through the rest of the body.  This is referred to as the systolic phase. The myocardium itself however receives blood only during diastolic phase or the time interval between active contractions.  The EECP cuffs are inflated during diastole beginning at the calves and sequentially to the buttocks.  This increases the pressure during early diastole to levels equal to or higher than in systole, which is opposite of their usual relationship. This process is referred to as counterpulsation. During early systole the cuffs immediately deflate, reducing the hearts workload. The net effect of counterpulsation is to increase the blood flow to the myocardium, while the reduced workload imposed on the heart reduces the oxygen requirement by the myocardium.  The increase in coronary pressure and flow also encourages the heart to develop collaterals or small vessels that carry blood around occluded segments. This new therapy is presently approved as a treatment for chronic angina, as well as acute coronary syndromes and congestive heart failure.

The illustrations below demonstrate how the pressure cuffs work.

The process is initiated by inflation of the distal cuff.  The middle cuff is then inflated. At this time in the cycle all cuffs are are inflated with maximum increase in diastolic pressure achieved. All cuffs are now rapidly deflated, then reducing systolic blood pressures.

EECP works to increase the flow of blood through the coronary arteries when the heart is in the relaxed or diastolic phase. EECP compresses the arteries in the lower extremities by inflating the pressure cuffs in sequence from the lowest part of the legs to the highest. When the heart again compresses in the systolic phase, the pressure cuffs deflate immediately, greatly reducing the workload on the heart. During EECP, the diastolic (relaxed) pressure is often higher than the systolic (compressed) pressure. Which is the opposite of the usual relationship.

EECP does involve a commitment

In the course of one treatment the patient receives 35 one hour sessions over a seven-week period.  Patients can go back home or return to work after each session.  There may be some discomfort as the cuffs inflate, and this can be minimized by applying extra padding.

Current experience indicates that EECP poses little if any, danger to patients.  The treatment however must be used with caution inpatients with the following conditions:

• Cardiac catheterization within the preceding 2 weeks (to minimize the risk of bleeding at the catheterization site).

• Arrhythmia such as atrial fibrillation or atrial flutter that might interfere with the triggering of the EECP system.

• Poorly treated congestive heart failure. In some patients, EECP may worsen heart failure.

• Aortic insufficiency or regurgitation where counterpulsation maybe ineffective and increase the severity regurgitation.

• Peripheral vascular disease (PVD) and/or phlebitis.

• Severe hypertension (180/110mmhg

• Bleeding disorders,  or ongoing coumadin therapy, where cuff inflation might cause bleeding in the leg muscles.

• Pregnant women, and women of childbearing potential.  The effect of counterpulsation on the fetus is unknown.

Patients may notice an improvement in their symptoms in as little as a few weeks of treatment. Many patients are able to increase their activity while reducing or eliminating the need for pills. Some patients may not see an improvement and require a second course of treatment before they improve. There is no way to predict how an individual patient will respond.

Unlike surgical procedures that seek to internally modify the circulatory system by removing or bypassing obstructions, EECP seeks to externally influence changes and it does so by using a technique called, "counterpulsation." When the heart is at rest, the EECP system increases the blood flow to the coronary arteries.

Why EECP reduces the pain of angina

To understand why EECP is effective, it is important to see how the heart works. The heart supplies nourishing blood to all of the muscles and organs of the body. Ironically, all of this blood passing through the heart does not nourish the heart itself. Instead, the heart depends upon a special set of arteries to provide the blood that it needs. These are the coronary arteries.

When the heart muscles contract, blood is sent to the muscles and organs of the body to nourish them. Contraction is called the systolic phase. When the heart is at rest for the fraction of a second between contractions it is in the diastolic phase. (This is why your blood pressure is given as two numbers: the systolic and diastolic pressure.)

Most of the body's arteries deliver oxygenated blood during the compression or systolic phase. But because the coronary arteries are compressed and narrowed along with the heart muscles during the systolic phase, they deliver blood only when the heart is at rest and the coronary arteries are open.

The body responds to this increased pressure and flow by developing a path around the obstruction. Doctors refer to this as collateral circulation. Given time, the human body would naturally develop a path around a blockage. Unfortunately, this is a gradual process that takes too long to help. EECP is believed to speed up the natural healing process to encourage the body to create the bypass over weeks instead of years.

EECP does involve a commitment

EECP treatments are usually administered in a set of 35 sessions over a seven-week period, so a commitment of time is needed. The treatments last about an hour and you can go home or back to work after your session. There may be some slight discomfort as the cuffs inflate, but there is no pain.

The results

All people are different so some patients begin to feel an improvement after just a few weeks while others take longer. Many patients are able to return to a more active lifestyle while reducing or eliminating the need for pills. You should be aware that some patients do not see an improvement and some need a second course of treatment before they improve but a significant number of patients do improve. There is no way to predict how an individual patient will respond.