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External Counterpulsation |
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Clinical experienceindicates that patients have demonstrated improvement after external counterpulsation treatment such as:
Published studies* have demonstrated total relief from Angina pain and elimination or a significant reduction of the ischemic (oxygen deprived) areas of the heart in approximately 78% of stable angina patients. * Lawson et.al., 1995, 1996, 2000 In a paper* published in March of 2001 in a peer reviewed journal, none of the 58 patients studied died or suffered a major cardiac event. Canadian cardiovascular Society Functional Classification System ("CCSF") classification showed improvement in all three CCSF groups. For the entire group of 58 patients, CCSF class was reduced from 2.67 to 1.71 (36%). Overall, 84% of the patients (49 of 58) experienced a reduction in their CCSF improvement. In addition, 91% of the patients experienced a reduction in their anginal episodes per 24 hour period post-treatment. Of the 24 patients who had been hospitalized in the six months prior to treatment, only one (4%) required hospitalization in the six month period after treatment. Medication consumption also decreased 77.4%. The paper concluded that CardiAssist™ ECP significantly reduces CCSF angina class, the incidence of anginal episodes, hospitalization for angina and anti-anginal medication use. * Weisfogel et.al.2001 External counterpulsation has developed over the past 44 years. It has now become a practical way to increase blood flow to the ischemic myocardium and other organs throughout the body. While it may seem that the theoretical benefits of external counterpulsation are evident, this non-invasive method for treating coronary artery disease had been eclipsed by other technologies until the past few years. The first systems built and tested used water as the compression medium and produced mixed results, however, when augmentation was positive, good results were observed. 1950sKantrowitz and Kantrowitz first described the principle of "phase shift" diastolic augmentation. Soroff, et al,* related this principle to the oxygen consumption difference between flow work and pressure work by the heart. It was this understanding that eventually led to the concept of a mechanically induced counterpulsation to provide assistance to patients with low cardiac output syndromes. Direct counterpulsation techniques first developed by Harken and associates at Harvard resulted in femoral cut-down and external pulse actuation. The technique withdrew and then returned the blood to the arterial system. Studies documented increased coronary flow, decreased coronary AVO2 difference and reduced left ventricular pressure work. * Soroff, et. al., 1965 |
1960sDuring the early 60s, laboratory studies with animals demonstrated the potential efficacy of counterpulsation as a treatment following coronary occlusion. Jacobey and associates* provided the first evidence that counterpulsation could quickly enhance the development of coronary collateral circulation. It also suggested the possible clinical application of counterpulsation to the treatment of patients with coronary insufficiency and angina. During this same period at Harvard, Birtwell and Clauss* produced counterpulsation by introducing a catheter with a balloon into the ascending aorta via the femoral artery. 
The Intra-Aortic Balloon Pump was thus invented. This approach has found clinical application in support of circulation during and after cardiac surgery and in cardiogenic shock. Also in the 1960s, several scientists were involved in the evolution of counterpulsation to a completely non-invasive technique using externally applied pressure generated by hydraulic systems. The system used various materials to encase the patient's lower extremities. It then compressed the vascular bed, displacing arterial and venous blood centrally. Though these devices were somewhat primitive, several studies demonstrated the potential of this approach to increase survival in patients with myocardial infarction and cardiogenic shock as well as relief of angina pectoris. During the late 1960s, scientists at the National Institute of Health believed that results could be improved if the blood was moved from the lower limbs in a sequential manner. The development and testing of sequenced systems determined that they achieved greater cardiac output and increased the ratio of diastolic to systolic pressures. * Jacobey et. al, 1971, Birtwell et. al., 1970 1970sDuring the 1970s a great deal of study was done on external counterpulsation.
Among the distinguished physicians and scientists publishing on this subject
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1980sResults from the 25 institution, 258 myocardial infarction patient, multi-center study* using the Cardiassist device (published in 1980), indicated those patients receiving therapy within the first 24 hours after admission had a mortality rate of 6.5% versus 14.7% in the control group. Zheng and associates* at Sun Yat Sen University in China, reported their studies with a newly designed sequenced pneumatic system which produced excellent results. In trials, effects of the sequenced system were studied producing long-term symptomatic relief from chronic angina. These favorable results caused numerous U.S. scientists to rethink their approach to external counterpulsation. Cardiomedics, Inc. was incorporated under the laws of the state of Nevada on August 25, 1986. On August 29, 1986, the Company acquired the assets of CardiAssist Corporation. CardiAssist Corporation had been engaged in the development and testing of earlier versions of the Company's external counterpulsation system, which it had acquired from Medical Innovations, Inc., one of the original developers of external counterpulsation at Harvard/MIT. Cardiomedics owns patent, manufacturing and marketing rights to CardiAssist™, a non-invasive, external counterpulsation therapy for patients with coronary artery disease. Since its inception, the Company has been engaged in development and marketing of its CardiAssist™ System. In September of 1987, the Company was the first to receive 510(k) marketing clearance from the FDA for its external counterpulsation system. * Amsterdam et. al., 1980, Zhang et. al, 1983 1990sThe Zheng device from China was used extensively at State University at Stony Brook, New York. Studies were performed and published by Lawson and Associates in 1992, 1993, 1995, 1997 and 1998. A New York based company began importing the Chinese device in 1995 following the FDA's clearance to market based on substantial equivalence to the CardiAssist™ device. In order to expand the number of indications and knowledge base regarding ECP, Cardiomedics intends to conduct a minimum of 3 multi-center studies beginning in 2002. Date Published: 2003-05-09 |
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