Introduction:
Enhanced External Counterpulsation (EECP) is a non-invasive Food and Drug Administration approved treatment for patients with chronic stable angina and heart failure. Typical treatment regimen comprises of 35, 1-hour sessions of synchronized compressions of the calf, thigh, and sacral muscles over a seven-week period. Exercise duration measured using an exercise tolerance test is a commonly utilized marker of worsening ischemic disease and is predictive of cardiovascular mortality. Several studies have evaluated the impact of EECP on exercise duration with conflicting results. We sought to determine the magnitude of benefit of EECP on exercise duration.
Methods:
A literature search was performed in MEDLINE, CINAHL, and the Cochrane database along with hand searching of relevant articles limited to those published in the English language. Studies were included for analyses if assessing patients with stable angina and reporting exercise duration data using either the Bruce or modified Bruce exercise treadmill test. Appropriate data were extracted at baseline and after completion of the full course of EECP. Studies were excluded if presenting duplicate data or using a non-Bruce protocol. A weighted mean difference from baseline along with 95% confidence interval was calculated using the DerSimonian-Laird random-effects model. Sub-group analyses, the Cochran Q statistic, and JADAD scores were utilized to assess for heterogeneity, non-combinability, and quality of published studies respectively. Publication bias was assessed using visual inspection of funnel plots and the Egger bias statistic.
Results:
Our search strategy identified 1117 independent studies of which 15 were included for analyses. A total of 484 individual subjects were incorporated in the primary analysis. Exercise duration improved by 55.5 seconds (95%CI 36.1 to 74.9; Cochran Q, p=0.246) from baseline. The benefits were maintained when using a fixed-effects model, excluding small studies and limiting to studies using the Bruce protocol only. While the Egger statistic showed a lack of publication bias (p=0.121), it cannot be ruled out based on visual inspection of funnel plots.
Conclusion:
EECP significantly increases exercise duration by 56 seconds in patients with chronic stable angina. Further studies are needed to determine the impact of EECP on long-term outcomes. The views expressed in this material are those of the authors, and do not reflect the official policy or position of the U.S. Government, the Department of Defense or the Department of the Air Force.
HEALTH-STATUS OUTCOMES WITH ENHANCED EXTERNAL COUNTERPULSATION IN PATIENTS WITH ANGINA
