Angina Sufferers Find Relief with Noninvasive Technique

June 01, 1999
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Angina patients, whose intense, often suffocating chest pains cann't reliably be relieved by medication or vascular surgery, can gain significant pain reduction from a little-used medical procedure that appears to increase heart blood supply, a new study has found. In the first controlled trial of the painless, non-invasive treatment called enhanced external counterpulsation (EECP), patients experienced less frequent angina pain and had less need for nitroglycerin to control pain than did a control group of angina patients.

The results are published in the June issue of the Journal of the American College of Cardiology. Nationally, about 15 million people suffer from angina, more than 2 million chronically. The number is expected to increase as the population ages. And for almost all of these people, neither drugs nor vascular surgery provide complete relief.

"To find something that is very safe and effective in this group of patients is very gratifying," said Dr. Tony Chou, a cardiologist at UCSF Medical Center and assistant professor of medicine who co-authored the report in the cardiology journal.

Patients undergoing the treatment lie on a table and wear a series of cuffs on their legs. At the precise moment of each heartbeat when the heart relaxes, the cuffs briefly inflate. This is thought to reduce the heart's workload, increase its pumping efficiency and improve cardiac bloodflow. The treatment usually involves 35 one-hour sessions.

"The angina patients we treated with EECP have not found relief from any other treatment -- from medications, angioplasty or surgery. They are a very frustrated group of patients for whom we don't have anything to offer. This treatment functions almost like a very good medication," Chou said.

The technique, largely developed in China, has been tested clinically in various forms over the past 30 years, with many reports of major success. But until now, no rigorous controlled study of the treatment had been undertaken. The multi-center trial was conducted at UCSF, Harvard Medical School, Columbia-Presbyterian Medical Center, Yale University School of Medicine and three other sites.

Seventy-one angina patients with documented coronary artery disease were given 35 one-hour EECP treatments over a four-to-seven-week period, while 69 similar patients were "treated" in EECP cuffs without adequate inflation to affect blood flow. Neither the participating patients nor the physicians who studied their progress knew whether they were receiving the active therapy or the control.

Compared to the control group, the "active" EECP treatment patients experienced significantly fewer angina attacks. Although the two groups were able to exercise on a treadmill for about the same length of time, the EECP-active group did so for longer periods without provoking abnormal electrocardiograms, the researchers reported. Use of nitroglycerin in the active group was lower, but not by a statistically significant degree.

The precise mechanism by which EECP exerts its long-term beneficial effect is unknown. But Chou explains the EECP treatment and its benefits this way: "The heart, unlike the rest of the body, gets its blood flow when it is relaxing. When the heart squeezes, it forces blood throughout the body, but not to itself. It is during the relaxation, or diastole phase, that the coronary arteries are fed. This device times the counterpulsation wave so that it occurs right during the heart's relaxation phase, giving a surge of blood back to the heart that it otherwise would not be able to develop. The thought is, if you do this over and over, patients would be able to achieve improved blood flow."

The research team plans next to undertake studies to clarify if and how much heart blood flow is improved by the EECP technique.

Lead author on the journal report is Dr. Rohit R. Arora, assistant professor of medicine at Columbia University. Co-authors, along with Chou, are Dr. Richard Nesto, MD, associate professor of medicine at Harvard Medical School; Dr. Diwakar Jain of Yale University School of Medicine; Dr. Bruce Fleishman of the Grant/Riverside Methodist Hospital, Columbus, Ohio; Dr. Lawrence Crawford of the Pittsburgh Medical Center; and Dr. Thomas McKiernan of Loyola University Medical Center.

The research was funded by a grant from Vasomedical Inc. which manufactures the EECP device used in the trial.