External counterpulsation therapy (ECP) is a procedure that may be performed on individuals with

angina Angina, also known as angina pectoris, is chest pain or pressure, usually caused by insufficient blood flow to the heart muscle (myocardium). It is most commonly a symptom of coronary artery disease. Angina is typically the result of parti ...

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

, or

cardiomyopathy Cardiomyopathy is a group of primary diseases of the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. A ...

Medical uses

The FDA approved the CardiAssist ECP system for the treatment of angina, acute myocardial infarction and cardiogenic shock under a 510(k) submission in 1980 Since then, additional ECP devices have been cleared by the FDA for use in treating stable or unstable angina pectoris, acute myocardial infarction, cardiogenic shock, and congestive heart failure. Studies have found EECP to be beneficial for patients with erectile dysfunction and some COPD patients. Additionally, improvements in exercise endurance in the non-diseased patient has been found in research studies. Some reviews did not find sufficient evidence that it was useful for either angina or heart failure. Other reviews found tentative benefit in those with angina that does not improve with medications. For

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

due to lack of blood flow, a 2012 Cochrane review found significant neurological improvement, but insufficient evidence to make reliable conclusions. External counterpulsation therapy significantly improved the exercise endurance of normal adults, low endurance adults, and COPD patients.

Method

While an individual is undergoing ECP, they have pneumatic cuffs on their legs and is connected to

telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...

monitors that monitor heart rate and rhythm. The most common type in use involves three cuffs placed on each leg (on the calves, the lower thighs, and the upper thighs (or buttocks)). The cuffs are timed to inflate and deflate based on the individual's electrocardiogram. The cuffs should ideally inflate at the beginning of

diastole Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricul ...

and deflate at the beginning of

systole Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. Its contrasting phase is diastole, the relaxed phase of the cardiac cycle when the chambers of the heart are refilling ...

. During the inflation portion of the cycle, the calf cuffs inflate first, then the lower thigh cuffs, and finally the upper thigh cuffs. Inflation is controlled by a pressure monitor, and the cuffs are inflated to about 200

mmHg A millimetre of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high. Currently, it is defined as exactly , or approximately 1 torr = atmosphere = &nb ...

. Of note, therapies are tailored on an individual basis but beginning regimens tend to include daily one-hour treatments that occur 5 days of the week and last 6–8 weeks with an average overall of 35 hours.

Physiological considerations

One theory is that ECP exposes the coronary circulation to increased

shear stress Shear stress (often denoted by , Greek alphabet, Greek: tau) is the component of stress (physics), stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross secti ...

, and that this results in the production of a cascade of growth factors that result in new blood vessel formation in the heart (arteriogenesis and

angiogenesis Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature mainly by processes of sprouting and ...

). To best understand the pathophysiology of the therapy it is easiest to understand what each step does. To begin with, as the cuffs on each leg inflate, starting at the calf and working up to the upper thighs, blood is propelled back to the heart thereby increasing the venous return or preload. This increase in preload occurs simultaneously with diastole which happens to be the time during the cardiac cycle in which coronary perfusion occurs. So, by increasing the coronary perfusion, you allow more oxygen to perfuse the heart and ultimately generate more collateral circulation without actually increasing the work of the heart. Additionally, cardiac output is increased via the Frank-Starling mechanism secondary to the increased venous return. As the cardiac cycle progresses to systole, the cuffs on the extremities deflate, allowing for the increased cardiac output to adequately perfuse all tissues including the extremities.

Medical uses

Method

Physiological considerations

References

See also