2-Year Experience with EECP
Abstract & Commentary
By Michael H. Crawford, MD Dr. Crawford is the Professor of Medicine, Chief of Clinical Cardiology, University of California, San Francisco; and is the Editor of Clinical Cardiology Alert.
Synopsis: Decreased angina and improvement in quality of life were maintained at 2 years, with modest repeat EECP and low major cardiovascular event rates.
Source: Soran O, et al. Two-Year Clinical Outcomes After Enhanced External Counterpulsation (EECP) Therapy in Patients with Refractory Angina Pectoris and Left Ventricular Dysfunction (Report From the International EECP Patient Registry). Am J Cardiol. 2006;97:17-20.
Enhanced external counterpulsation (eecp) has been shown to be effective in reducing symptoms in patients with refractory angina and congestive heart failure, but little information exists about its long-term effectiveness in patients with marked left ventricular (LV) dysfunction and refractory angina. Thus, Soran and colleagues queried the International EECP Patient Registry (IEPR) for such patients. The IEPR includes > 5000 patients from > 100 centers worldwide who received EECP for angina and were followed for up to 2 years. There were 363 patients with angina and LV ejection fraction ≤ 35%. After completion of treatment, 77% decreased at least one Canadian Cardiovascular Society Class, 18% had no angina, and 2% worsened. About half of the patients discontinued nitroglycerin use, and quality of life improved. After 2 years, the improvement in angina continued in over half of the patients. Event-free survival was 70%, and survival overall was 83%. Also, freedom from heart failure was 81%. Repeat EECP was performed in 20%, many of whom failed to complete the first treatment course. Improvements in quality of life were also maintained in most. Soran et al concluded that in patients with LV dysfunction and refractory angina, EECP improved quality of life and reduced angina for 2 years.
Since EECP increases venous return during diastole, there has been concern that it may precipitate heart failure in patients with refractory angina and marked LV dysfunction. Pilot studies have shown benefit in heart failure patients and few heart failure events in angina patients with LV dysfunction. In this 2-year study, 81% of the patients were heart failure free. Thus, EECP seems safe in patients with marked LV dysfunction. Also, the beneficial effects seen immediately after EECP seem to persist for 2 years.
This is remarkable when you consider that most got one 32-hour course of therapy. Also, these were very sick patients. Angina class was III or IV in 93%, and 93% were deemed non-revascularizable. During EECP, 12% had a clinical event and 7% quit, but 81% completed the treatment. Noncompleters were a high-risk group that had more heart failure events. The 5% who did not respond to EECP were also a high-risk group who had more unstable angina admissions (28 vs 16%, P = .02) and a lower survival rate (71 vs 85%, P = .001).
The major limitation of this study is that it is observational and there is no control group. However, it is difficult to determine what would constitute an appropriate control group. Randomizing patients with refractory angina to EECP or placebo seems harsh at this point. Since most are non-revascularizable, revascularization does not seem to be the appropriate control. Perhaps in the future, the new anti anginal drug ranolazine would be a good comparison. It is just coming on the market for refractory angina patients.