Recent data documenting the effectiveness of Enhanced External Counterpulsation (EECP) for the treatment of angina has failed to bring this apparently effective procedure into the mainstream of cardiology practice. In this article, DrRich discusses what EECP is, how it works, and why cardiologists are avoiding this safe, noninvasive treatment like the plague.
What is EECP?EECP is a mechanical procedure in which long inflatable cuffs (like blood pressure cuffs) are wrapped around both of the patients legs. While the patient lies on a bed, the leg cuffs are inflated and deflated with each heartbeat. This is accomplished by means of a computer, which triggers off the patients ECG so that the cuffs deflate just as each heartbeat begins, and inflate just as each heartbeat ends. When the cuffs inflate they do so in a sequential fashion, so that the blood in the legs is milked upwards, toward the heart.
EECP has two potentially beneficial actions on the heart. First, the milking action of the leg cuffs increases the blood flow to the coronary arteries. (The coronary arteries, unlike other arteries in the body, receive their blood flow after each heartbeat instead of during each heartbeat. EECP, effectively, pumps blood into the coronary arteries.) Second, by its deflating action just as the heart begins to beat, EECP creates something like a sudden vacuum in the arteries, which reduces the work of the heart muscle in pumping blood into the arteries. Both of these actions have long been known to reduce cardiac ischemia (the lack of oxygen to the heart muscle) in patients with coronary artery disease. Indeed, an invasive procedure that does the same thing, intra-aortic counterpulsation (IACP, in which a balloon-tipped catheter is positioned in the aorta, which then inflates and deflates in time with the heartbeat), has been in widespread use in intensive care units for decades, and its effectiveness in stabilizing extremely unstable patients is well known.
While a primitive form of external counterpulsation has also been around for a long time, it has not been very effective until recently. Thanks to new computer technology that allows the perfect timing of the inflation and deflation of the cuffs, and produces the milking action, modern EECP has been greatly enhanced.
EECP is administered as a series of outpatient treatments. Patients receive 5 one-hour sessions per week, for 7 weeks (for a total of 35 sessions). The 35 one-hour sessions are aimed at provoking long lasting beneficial changes in the circulatory system.
How effective is it?EECP now appears to be quite effective in treating chronic stable angina. A randomized trial with EECP, published in the Journal of the American College of Cardiologyin 1999, showed that EECP significantly improved both the symptoms of angina (a subjective measurement) and exercise tolerance (a more objective measurement) in patients with coronary artery disease. EECP also significantly improved quality of life measures, as compared to placebo therapy.
More recent data show that this improvement in symptoms following a course of EECP seems to persist for up to five years.
Furthermore, there is also preliminary data suggesting that EECP may be useful for treating unstable angina, as adjunctive therapy after revascularization (i.e., with angioplasty, stent, and/or bypass surgery), and even as first-line (instead of last resort) therapy for more routine forms of angina. (Read about EECP as early therapy for angina here.)
Finally, clinical trials have suggested that EECP may be useful in improving symptoms in patients with heart failure. Read about EECP for heart failure here.