1998


From: University of California - San Francisco

One Year Follow-Up Of Non-Invasive Angina Treatment Suggests A Lasting Benefit

A new non-surgical treatment for heart patients who experience the crushing chest pain of angina appears to confer lasting pain relief for a year or longer for many who undergo one-hour treatment sessions for several weeks, according to a study presented at the recent American College of Cardiology meeting in Atlanta.

Angina, which afflicts an estimated seven million patients in the U.S. with coronary-artery-disease, is a chest pain that strikes when the heart muscle has trouble obtaining sufficient oxygen to fulfill its pumping duties adequately. The pain may recur continually, even in patients who take medications or who have had major bypass surgery or angioplasty to clear arteries that supply the blood-pumping organ with oxygenated blood.

Blood pressure in the arteries and veins normally causes blood to flow toward the heart during its pumping phase, called systole, and also between heartbeats, when the heart is in its filling phase, called diastole. The heart muscle, unlike other organs and tissues, gets most of the oxygen it needs during diastole.

The treatment, called Enhanced External Counterpulsation (EECP), is suitable for many heart patients, and may be used in conjunction with coronary bypass surgery or balloon angioplasty or as a follow-up when angina persists after these procedures, according to Tony Chou, UCSF assistant professor of medicine and acting director of the adult cardiac catheterization laboratories. UCSF Stanford Health Care is the first Bay Area medical center to offer EECP.

"Among patients who complete EECP therapy, episodes of angina were halved, and patients in the study also tended to use less of their nitroglycerin to treat their chest pains," Chou says.

With EECP, pressure cuffs wrapped around the patient's legs and buttocks are used to pump extra blood to the ailing heart muscle while the patient reclines.

Inflation of the EECP pressure cuffs, an event timed with the aid of an electrocardiogram, is used to increase diastolic blood pressure, thereby supplying more oxygen to the coronary arteries that feed the heart. Conversely, when the heart pumps, the cuffs deflate instantaneously, momentarily reducing blood pressure and lessening the heart's workload as it delivers oxygenated blood throughout the body.

Treatment requires 35 one-hour visits to UCSF over four to seven weeks. UCSF was the only medical center outside the East Coast to participate in the first nationwide trial to test the treatment.

In the follow-up study presented today, 80 patients were tracked for a year on average after completion of the treatment. Forty randomly selected study participants who received the active counterpulsation used in EECP were compared to 40 patients who received sham counterpulsation. Fifty-seven percent had previous coronary artery bypass surgery or angioplasty, or both, and 49 percent had previous heart attacks. Neither clinicians nor participants knew which patients received active treatment or placebo treatment until the end of the follow-up study.

A year after treatment, patients who received EECP exhibited better endurance in exercise tests and their hearts took longer to become oxygen-deprived during these tests. In diaries kept for the study, EECP patients reported less chest pain. Hospitalization rates were not significantly different for the two groups, nor did angiographic studies to evaluate blood flow in blood vessels supplying the heart reveal significant differences between the two groups.

Earlier findings from that trial, presented last November at the 70th Annual Scientific Sessions of the American Heart Association, indicated that the therapy is safe and effective in relieving angina.

"Most patients are quite comfortable during treatment," Chou says. "Many read, listen to music or watch television, and some even fall asleep." Some patients experience discomfort in the lower legs, but rarely to a degree requiring cessation of treatment, according to Chou. No serious complications were observed in study participants, he adds. Many researchers believe that EECP treatment fosters growth of new, small blood vessels, called collaterals, which feed the heart additional oxygen, although this has not been proved.

Vasomedical, Inc. of Westbury, N.Y., the manufacturer of the EECP equipment, sponsored the study, which was conducted by physicians at seven academic medical centers.




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