Arizona Cardiologists, Cardiology Clinics, Cardiology Doctors

What is EECP®

EECPEnhanced External Counterpulsation may stimulate the opening, or formation of, small branches of blood vessels (collaterals) to create natural bypass around narrowed or blocked arteries.

The term “Enhanced External Counterpulsation” describes what will happen during treatment.

Enhanced” refers to the equipment that has evolved over decades of research and development to become the state-of-the-art delivery system now used in EECP® centers.

External” means treatment is applied outside your body and does not require surgery.

CounterPulsation” The EECP® system compresses your lower limbs to increase blood flow toward your heart. Each wave of pressure is electronically timed to your heartbeat, so that the increased blood flow is delivered to your heart at the precise moment it is relaxing. When the heart pumps again, pressure is released instantaneously. This lowers resistance in the blood vessels of your legs so that blood may be pumped more easily from the heart, decreasing the amount of work required of your heart muscle.

During counterpulsation the EECP® system pumps when your heart is resting and releases pressure when your heart is working.

Clinical Benefits

EECP Illustration

Clinical trials have confirmed the benefits of EECP® treatment. They include: symptomatic relief of angina unresponsive to medical therapy, improved blood flow to deprived areas of heart muscle demonstrated by the results of thallium stress testing, elimination or reduction of nitrate use, improved ability to exercise.

In a 3-year, follow-up study, the majority of patients remained free of angina and showed persistent improvements in their thallium scans. Patients and their families usually report noticeably greater ability to engage in daily activity.

Patients usually receive EECP® treatment for 35 hours divided into one or two 60-minute treatment sessions five days per week. Patients who undergo two treatment sessions in one day rest between sessions.

EECP® treatment uses unique equipment to inflate and deflate a series of pneumatic compressive cuffs around the lower extremities. Treatment is administered on a padded table where three sets of electronically controlled inflation and deflation valves are located. These valves are connected to specially designed adjustable cuffs that are wrapped firmly, but comfortably around the patient’s calves, lower thighs, and upper thighs, including the buttocks. The design of the cuffs permits significant pressure to be applied to the arteries and veins at relatively low air pressures. Timing for inflation and deflation is regulated by running electrocardiogram signals through a microprocessor that monitors the treatment process.

While the heart is at rest the cuffs are inflated in rapid sequence from the calves upward, creating a pressure wave that increases diastolic pressure, coronary artery perfusion pressure, and blood flow to the heart muscle. This compression of the blood vessels in the legs also increases the volume of blood returned to the right side of the heart via the venous system. Instantaneous deflation of all cuffs at the onset of the heart’s contraction lowers the resistance the heart must pump against, decreasing the heart’s work load. This latter effect, when coupled with increased venous return, significantly raises cardiac output. The overall effect is to increase the oxygen supply of the heart, while decreasing its oxygen demand.

Significant obstruction in one or more coronary arteries can create a pressure difference between areas of the heart muscle that receive and those that do not receive enough blood. Repeated and pulsed increases in pressure during diastole may stimulate opening of collateral channels across this pressure gradient within the heart muscle, resulting in increased blood supply to deprived tissues.

Answers to Frequently Asked Questions

How does the heart work?
A muscular organ, the heart has two pumps that are divided into an upper chamber (atrium) and lower chamber (ventricle). These chambers are linked by passageways with valves to ensure blood flow in one direction. The lower left ventricle works the hardest, pumping blood into the body through the aorta, the largest artery in the body. In turn, this chamber of the heart has the greatest need for oxygenated blood.

The blood’s cycle through the body begins when oxygen-depleted blood returns to the heart, entering the upper right atrium via the largest veins (venae cavea). Blood passes through a valve from the right atrium to the lower right ventricle. The blood is then pumped through the pulmonary artery into the lungs where it receives oxygen.

Freshly oxygenated blood then flows from the lungs through the pulmonary veins into the left atrium and then into the left ventricle. From the left ventricle, blood is pumped through the aorta to supply the body.

What is angina?
Angina literally means “strangling in the chest”. It is the most common symptom of coronary artery disease, which occurs when vessels that carry blood to the heart muscle become narrowed and blocked by deposits of calcified fatty tissue (atheroma).

Is angina life threatening?
Angina signals heart disease, the number one killer in the industrialized world. Two to four percent of people with angina die from heart disease. More than 7 million people in the United States suffer with angina. An estimated 350,000 new cases occur each year. Of this number, approximately 1 million will have invasive procedures; 6 million patients who are maintained on drug therapy live in varying degrees of discomfort. Angina is frequently crippling and disabling; patients are often unable to maintain their lifestyles.

What does it feel like?
The majority of patients with angina complain of chest discomfort provoked by mental, physical, or emotional stress. Discomfort can vary widely among patients who report shortness of breath, fatigue, indigestion, faintness, jaw pain, and other symptoms. Angina can also feel like a pressing or squeezing pain, usually in the chest under the breast bone, and sometimes in the shoulders, arms, neck, jaws, or back.

What triggers angina?
Angina occurs when the heart needs more oxygen from the blood. Physical activity often triggers angina. Other triggers include emotional stress, extreme cold or heat, heavy meals, alcohol, and cigarette smoking.
How does angina affect people?
Angina restricts the activities of many patients. They are able to walk, but not uphill or carrying packages. For some patients, angina is disabling, interfering with their ability to work or engage in various activities.

How is angina avoided?
Doctors recommend controlling the risk factors that contribute to underlying coronary artery disease. These risk factors include high blood pressure, cigarette smoking, high blood cholesterol levels, and obesity.

What is the first line of treatment for angina?
Angina is usually controlled by medication that helps increase the supply of oxygen to the oxygen-deprived heart muscle by dilating coronary vessels or decreasing the demand for oxygen. Unfortunately, in most patients, medication becomes less effective over time.

When should EECP® treatment be used for patients with angina?
EECP® treatment may be used to treat any patient with chronic stable angina, but it is usually reserved for patients taking medication that is losing its effectiveness.

What is EECP® treatment?
The EECP® procedure is a noninvasive outpatient treatment that is used to relieve or eliminate angina. It is believed to create new pathways around blocked arteries in the heart by expanding networks of tiny blood vessels that help increase blood flow to the heart muscle.

What are the advantages of EECP® treatment?
Unlike procedures such as bypass surgery and balloon angioplasty, EECP® treatment can be administered in outpatient sessions, carries little or no risk, and is relatively comfortable.

Will EECP® treatment eliminate the need for bypass surgery?
No. Some patients with more extensive disease or those who have disease of the left main coronary artery require bypass surgery. EECP® treatment is an option for patients who are unsuitable for or unwilling to undergo, invasive procedures. For patients who have undergone multiple invasive procedures and for whom additional surgery carries excessive risk, EECP® treatment may be the only way to obtain relief from crippling angina.

What are the clinical benefits of treatment?
EECP® treatment can reduce or eliminate the frequency and intensity of chest pain, decrease the need for medication, and greatly improve the ability to participate in activities of daily living. After receiving EECP® treatment, patients often are able to enjoy moderate exercise for the first time since developing angina.

Are there any downsides to the procedure?
The length of treatment may be a consideration for some people. It can take between four to seven weeks to complete a course of EECP® treatment. During that time, patients must visit an outpatient clinic and receive treatment for one to two hours per day. Some patients with more extensive disease may require more than one course of therapy to achieve optimal relief.

What have studies shown about EECP® and its effect on angina?
In 1989, the Health Sciences Center, State University of New York at Stony Brook, began clinical studies with EECP® treatment for patients with chronic angina. These studies demonstrated a number of positive effects that are maintained after treatment for at least three years after completing a full course of EECP® treatment.

How is EECP® treatment performed?
During treatment, patients lie on a padded table in which sets of electronically-controlled inflation and deflation valves are located. These valves are connected to specially designed adjustable cuffs that are wrapped firmly, but comfortably, around the patient’s calves, lower thighs, and upper thighs, including the buttocks. While the heart is in its resting phase, the cuffs are inflated sequentially and rapidly from the calves toward the buttocks. The cuffs are then deflated instantaneously just before the heart beats. This causes the heart muscle to receive an increased blood supply while reducing the heart’s work load.

How does EECP® treatment work?
The body has its own solution to an inadequate blood supply caused by blocked or partially blocked arteries. When an artery is severely narrowed, the body can increase the amount of blood flowing to the heart muscle by opening up small branches of nearby arteries. Known as collateral circulation, these networks of blood vessels create new routes for blood to detour around clogged arteries.

The development of a collateral circulation is particularly important in the heart muscle where it may be life saving. However, the development of collateral circulation is a gradual process, and not everyone has the same ability to develop these networks.

EECP® treatment appears to stimulate the natural process of developing collateral circulation, but there are probably other, yet unexplained, mechanisms that contribute to the long-lasting effects of EECP® treatment.

History

Kantrowitz brothers in 1953

The state-of-the art angina treatment has evolved from a principle described in 1953 by the Kantrowitz brothers at Harvard. The phase-shift, diastolic augmentation principle, led to a better understanding of the myocardial oxygen consumption differences between “flow work” and “pressure work.”

This new understanding on improving blood flow to the ischemic myocardium by increasing coronary perfusion became the research objective.

Many attempts were made to develop effective means of providing mechanical cardiac assistance for patients with low, cardiac output syndromes.

One of the first techniques developed was the Intra-Aortic Balloon Pump (IABP). The IABP consists of an inflatable balloon catheter that is inserted into the femoral artery and advanced to the descending aorta. Modified and refined over the last 40 years, this device remains a primary therapy for assisting the heart function of patients in cardiogenic shock.

Soroff, Birtwell, and others at Harvard in the mid-60s

In the mid-60s, Soroff, Birtwell and others at Harvard developed a device for external counterpulsation. It was a hydraulic system that pumped water in and out of cuffs applied to the lower extremities. It was clear that Soroff and Birtwell’s device had advantages over the IABP. It was noninvasive, and also increased venous return as it boosted coronary perfusion pressure.

Though cumbersome, this early hydraulic device increased survival rates of patients with acute myocardial infarction and cardiogenic shock and relieved angina. However, in the United States, external counterpulsation was eclipsed by the emergence of coronary bypass surgery and angioplasty.

While physicians in the United States turned their attention to these dramatic new developments in invasive treatments, physicians in China adopted the concept of external counterpulsation and refined the technology. Treatment was made easier to administer and more comfortable for patients by using pneumatic cuffs instead of hydraulic cuffs.

Researchers in the 1970s and Late 1980s

In the 1970s, a group of researchers, led by Dr. Zeng Sheng Zheng at the Sun Yat-sen University of Medical Sciences in the People’s Republic of China, began to develop more sophisticated counterpulsation systems. They devised a system in which the pneumatic cuffs inflated sequentially, not simultaneously as they had before.

The Chinese researchers in collaboration with researchers at the State University of New York at Stony Brook continued to refine the technique of external counterpulsation. In 1989, researchers at Stony Brook began clinical studies of enhanced external counterpulsation (EECP®) treatment. These studies demonstrated that the treatment produces a number of positive effects that are maintained for at least three years after a full course of treatment.

Multi-center clinical trials have confirmed the Stony Brook results. The trials also showed the extent of treatment benefit with greater accuracy, determined the patients who gained the most from treatment, and measured the effect of treatment on medication requirements, exercise capability, and quality of life.

EECP® treatment has evolved and is being used with no reported complications as an outpatient treatment of chronic angina patients. References to the treatment appear in medical literature and are presented at medical conferences. EECP® treatment does not require the adoption of new medical practices; it is an improvement of existing medical practices made possible by the advanced technology of a new delivery system.

Treatment

When patients have angina, their bodies are telling them that their heart is not receiving enough oxygen. A treatment, in harmony with patients heart, can improve circulation to the heart muscle. EECP® treatment appears to stimulate the opening of new, natural pathways around narrowed or blocked arteries. After EECP® treatment, patients may find that:

  • they can walk farther, carry heavier packages, and be more active without having angina
  • they have fewer attacks of angina
  • their episodes of angina are less intense
  • they need less anti-anginal medication
  • they can return to work, go out to dinner, garden, travel, or enjoy golf, tennis, or bowling once again
  • they no longer restrict their social lives, volunteer activities, or exercise because they are worried that they will cause angina.

If patients are one of more than seven million people in the United States with angina, they may be all too familiar with angina. Angina signals that a part of the heart muscle is not receiving an adequate supply of blood and oxygen. The heart requires a particularly rich blood supply because of its heavy workload, and receives this nourishment through the coronary arteries. When these vessels are narrowed or blocked, restricting blood flow, they fail to supply adequate oxygen.

Detours around blocked arteries

The body has a response to pain and problems caused by narrowed arteries. The body often can increase the amount of blood flowing to the muscle by opening up tiny branches of nearby vessels. This network of tiny blood vessels –; known as “collateral circulation” –; makes it possible for blood to detour around blocked or narrowed arteries. The development of collateral circulation is particularly important in the heart muscle where it may be life-saving. However, the development of collateral circulation is a gradual process and not everyone has the same natural ability to develop these networks at a rate that will relieve angina.

Enhanced External Counterpulsation may stimulate the opening of small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries.

The term “Enhanced External Counterpulsation” describes what will happen during treatment.

“Enhanced” refers to the equipment that has evolved over decades of research and development to become the state-of-the-art treatment delivery system now used in EECP® treatment centers.

“External” means treatment happens outside of the patient’s body and doesn’t require surgery.

Before we can understand the term “Counterpulsation,” we have to understand the cardiac cycle, the period from the beginning of one heartbeat to the beginning of the next. The cardiac cycle includes diastole when the heart relaxes and fills with blood, and systole when the heart contracts and pumps blood out to the body.

The EECP® system compresses a patient’s lower limbs to increase blood flow toward the heart. Each wave of pressure is electronically timed to a heartbeat, so that the increased blood flow is delivered to the heart at the precise moment it is relaxing. When the heart pumps again, pressure is released instantaneously. This lowers resistance in the blood vessels of the legs so that blood may be pumped more easily from the heart, decreasing the amount of work required of the heart muscle.

During counterpulsation the EECP® system pumps when the heart is resting and releases pressure when the heart is working.

Your doctor will evaluate you to determine if you may be eligible to receive EECP® treatment. You may be a candidate for EECP® treatment if:

  • you have angina
  • nitroglycerin does not provide adequate relief from your angina
  • you have been told that you are not a candidate for bypass surgery or angioplasty
  • you underwent bypass surgery or angioplasty in the past, and angina has returned
  • you want to explore all treatment options

Some people may not be candidates for EECP® treatment because of their medical conditions. Only a physician can make a decision regarding whether or not you are a candidate for EECP® treatment.

Once you are eligible to receive EECP® treatment, it is important that you understand the treatment schedule. Patients typically attend one-hour treatment sessions once a day, five days a week for seven weeks. Many people receive treatment, without interruption to their employment, by scheduling their sessions before or after work.

To make sure the treatment goes smoothly, please follow your Pre-Treatment Instructions, which will be similar to those at the back of this booklet. You may wish to bring a book, a magazine, or a portable CD or tape player with earphones. You also may wish to invite a family member or friend to accompany you.

At the EECP® center, your therapist will explain each step as you go through treatment. You may be given a pair of stretch pants to wear at each treatment session. Although treatment usually takes one hour, you should plan to spend approximately 1-1/2 hours at the treatment center.

Once patients have changed clothes, a therapist will weigh them, and take their blood pressure. Patients will lie on a padded table in a treatment room. Three electrodes will be applied to the patients chest to take a constant ECG reading during treatment. A finger sensor, called a plethysmograph, will be placed over patient’s finger like a thimble. This sensor records tracings that represent blood pressure.

The therapist will wrap a set of inflatable cuffs around patient’s calves, thighs, and buttocks. Patients are likely to feel a sensation of a strong “hug” moving upwards from the calves to thighs to buttocks during inflation followed by the rapid release of pressure on deflation.

Synchronized with your heartbeat
Inflation and deflation are electronically synchronized with the heartbeat using the ECG signal. By monitoring the ECG reading and the plethsmograph (blood pressure) tracing, your EECP® therapist can time counterpulsation accurately.

Clinical studies indicate that EECP® treatment may create a “natural bypass™” around narrowed or blocked portions of arteries. These channels or collaterals may eventually become permanent pathways for blood to reach heart muscle that was previously deprived of adequate nourishment.

A controlled, randomized, blinded study showed a significant increase in the length of time that participants who had received active treatment were able to exercise. Additionally, participants who received active treatment experienced fewer attacks of angina.

Medical research

Studies conducted at numerous university medical centers and published in peer-reviewed medical
journals have demonstrated benefits including:

  • elimination or decrease in exercise-induced signs of lack of oxygen to the heart muscle (ischemia)
  • increased exercise tolerance
  • elimination or decrease in episodes of chest pain
  • decrease in need for anti-anginal medication

Answers to Frequently Asked Questions

What are the clinical benefits of treatment?
For many patients, EECP® treatment can reduce the frequency and intensity of chest pain or eliminate it altogether, decrease the need for medication, and greatly improve the ability to participate in activities of everyday life. After receiving EECP® treatment, patients often are able to enjoy moderate exercise for the first time since they developed angina.

How will I feel after treatment?
You may feel a little tired after your first treatment session, but you are unlikely to experience any unpleasant aftereffects. You may be given an Angina Diary in which you can record any episodes of angina and your use of nitroglycerin. This record may be helpful in tracking your progress.

How soon can I expect to feel an improvement in my condition?
Because each individual’s condition is unique, there is no special time when you can expect to feel an improvement. Experience has shown that some patients tend to report some improvement about halfway through their course of treatment.

Are there any drawbacks to the procedure?
The length of treatment may be a consideration for some people. A course of EECP® treatment typically takes seven weeks to complete. During that time, patients must visit an outpatient clinic and receive treatment for one hour per day. Some patients may require more than one course of therapy to achieve an optimal level of relief.

What are the risks of EECP® treatment?
Some patients have experienced minor skin irritation due to the pressure of the cuffs. You should consult with your physician regarding any risk and complication factors.

What are the advantages of EECP® treatment over other treatments for angina?
Unlike procedures such as bypass surgery and balloon angioplasty, EECP® treatment is administered on an outpatient basis and does not involve any period of post-treatment recuperation.

Are there other treatment options to consider?
There are several other treatment options including bypass surgery, balloon angioplasty, and drug treatments. Discuss options with a physician to determine which course of treatment is most suitable for you.

Are there any drawbacks to the procedure?
The length of treatment may be a consideration for some people. A course of EECP® treatment typically takes seven weeks to complete. During that time, patients must visit an outpatient clinic and receive treatment for one hour per day. Some patients may require more than one course of therapy to achieve an optimal level of relief.

What are the risks of EECP® treatment?
Some patients have experienced minor skin irritation due to the pressure of the cuffs. You should consult with your physician regarding any risk and complication factors.

What are the advantages of EECP® treatment over other treatments for angina?
Unlike procedures such as bypass surgery and balloon angioplasty, EECP® treatment is administered on an outpatient basis and does not involve any period of post-treatment recuperation.

Are there other treatment options to consider?
There are several other treatment options including bypass surgery, balloon angioplasty, and drug treatments. Discuss options with a physician to determine which course of treatment is most suitable for you.

Glossary

Angina pectoris
Angina pectoris — which literally means “pain in the chest” — refers to a set of symptoms, characterized by a “crushing” sensation or pain that may be felt in the chest, back, and sometimes radiating down the left arm. Often referred to as angina, it occurs when regions of the heart muscle do not receive the amount of blood (oxygen) needed when exercise or other forms of stress increase oxygen demand. Usually, the reason for this oxygen deficit is coronary artery disease, in which one or more of the heart’s blood vessels are narrowed or blocked.

Balloon angioplasty
This procedure, known in medical terms as Percutaneous Transluminal Coronary Angioplasty (PTCA), is used to expand blocked arteries by inserting a slim hollow tube (catheter) through a major artery in an arm or leg and into the obstructed vessel. A small balloon at the tip of the catheter is inflated alongside the obstructing tissues, flattening them against the vessel wall, thereby restoring normal blood flow. About 405,000 initial and repeat angioplasties are performed in the United States each year at an average cost of $21,113.

Bypass surgery
Also called Coronary Artery Bypass Graft (CABG), it is the surgical transplant of one or more blood vessels to carry (pipe) blood around the blocked portion of a coronary artery. This is a major operation that involves opening the chest and stopping the heart. About 485,000 such operations take place every year in the United States at an average cost of $32,347.

Collateral circulation
This phrase refers to an auxiliary or supplemental network of tiny channels that usually lie dormant in muscular tissues and can be recruited to carry blood around obstructed main vessels. Collateral vessels begin to open or enlarge when a blockage in an artery produces a pressure differential across the well-supplied and poorly-supplied parts of the muscle. Over time, these accessory vessels can be transformed into significant conduits substituting for the blocked arteries. Probably because pressure differentials are lower, collateral circulations form less readily in the heart but can be life-saving when they do. The clinical benefits of EECP® are believed to stem from enhanced development of collateral circulation to oxygen-deprived regions of the heart.

Diastole
The period in the pumping cycle of the heart when the heart muscle relaxes, the chambers fill with blood, and the heart receives about 80% of its own supply of oxygen and other nutrients.

EECP® – Enhanced External Counterpulsation
A non-surgical procedure that can relieve or eliminate the symptoms of angina pectoris. It is believed to create new pathways around blocked arteries in the heart by expanding networks of tiny blood vessels, therefore increasing the amount of blood flowing to heart muscles.

Systole
The period when the heart contracts to force blood onward. The pumping action of the heart raises the blood pressure throughout the body to increase perfusion of tissues, but the heart muscle itself receives only about 20% of its supply at this time because the heart’s contraction squeezes and closes off many of its own blood vessels.