Enhanced External Counterpulsation (EECP), a non-invasive therapy with minimal side effects, is effective in reducing angina in individuals who suffer from coronary artery disease, according to a new study conducted at seven medical centers nationwide, including the University of California San Francisco.
It is estimated that more than 11 million Americans have blockages of the blood vessels of the heart, or coronary artery disease, which causes more deaths, disability and economic loss in Westernized nations than any other group of diseases. Although many patients can be managed with medicines, others require invasive procedures with either balloons, stents or coronary artery bypass graft surgery. Despite significant advances in the medical and surgical management of the disease, many patients still suffer the symptoms of angina -- which often involves pain or diminished capacity for exercise and daily activities.
Though the idea of increasing blood flow to the heart using external pressure is about 30 years old, the study which is being presented today (Nov. 10) at the American Heart Association Scientific Sessions in Dallas, demonstrates for the first time that treatment in its modern form has been proven effective, said UCSF Stanford Health Care cardiologist Tony Chou, MD, UCSF assistant professor of medicine and director of the UCSF Adult Cardiac Catheterization Laboratories. The study is the first completed human trial testing the benefits of EECP.
The study found that patients who underwent EECP treatment, which has been available and FDA approved for a less than four years in the United States, had better exercise tolerance and fewer angina attacks and, therefore, had an improved quality of life compared to those who did not receive full treatment, Chou said. These findings, Chou said, are an important step in making EECP a more widely available option for patients who suffer from angina.
"This treatment is very safe, does not involve surgery and is well tolerated," Chou said. "This is very low risk."
EECP treatments, which are offered at a limited number of medical centers including the UCSF Medical Center, part of UCSF Stanford Health Care, typically involve 35 one-hour sessions over about seven weeks. During treatments, patients lie on a bed wearing large pressure cuffs around their calves, lower thighs and upper thighs. The cuffs are inflated and deflated with pressure, which moves blood from the patients' lower limbs toward the heart and increases blood flow in the affected areas of the heart. The treatments are painless, with side effects limited to occasional skin irritation, Chou said.
Though the theory has yet to be proven, cardiologists believe that the treatment works because the increased flow of blood to the heart stimulates the heart to grow new arteries to bypass those that are obstructed or blocked, Chou said. The results of the study clearly show that EECP offers angina patients relief from their symptoms, often when nothing else does, Chou said.
The study, called the MUST-EECP Trial, tracked the progress of 139 patients age 21 to 81 with documented coronary artery disease. Half of those patients received EECP treatments and half of them received placebo, or sham, treatments. Though patients in both groups increased their ability to exercise after the course of the treatment, only the individuals who actually received EECP treatments were able to exercise longer before they showed signs of reduced blood flow to the heart. Most significantly, individuals in the EECP group reported a decrease in the number of angina events they experienced. Use of nitroglycerin, a drug commonly used to treat angina, also dropped in the EECP group.
The reason members of both groups experienced at least some improvement could be due to a placebo effect, meaning even patients who did not really receive treatment responded positively because they expected to feel better and had continuous, close contact with health care providers. In addition, there are still lingering questions about EECP treatment, such as whether it is effective with patients with different forms of angina or when, or if, it should be used as an alternative to other forms of treatment.
The finding that patients who had EECP treatments actually experienced a reduction in their angina means that the therapy is a promising option for patients who have not found relief from other procedures or high-risk individuals, such as the elderly or patients with other illnesses, who are not good candidates for surgical treatments, Chou said.
The MUST-EECP Trial was funded by Vasomedical, Inc. of Westbury, N.Y. Other researchers include: Rohit R. Arora, M.D., Columbia-Presbyterian Medical Center, Columbia University; Diwakar Jain, M.D., Yale University School of Medicine; Bruce Fleishman, M.D., Grant/Riverside Methodist Hospitals; Lawrence Crawford, M.D., University of Pittsburgh Medical Center; Thomas McKiernan, M.D., Loyola University Medical Center; Richard Neto, M.D., Beth Israel Deaconess Medical Center (Harvard Medical School).