Enhanced external counterpulsation for the treatment of stable angina and heart failure: a systematic review and economic analysis

Abstract

To determine the clinical effectiveness and cost-effectiveness of enhanced external counterpulsation (EECP) compared with usual care and placebo for refractory stable angina and heart failure, and to undertake analyses of the expected value of information to assess the potential value of future research on EECP. Major electronic databases were searched between November 2007 and March 2008. A systematic review of the literature was undertaken and a decision model developed to compare EECP treatment with no treatment in adults with chronic stable angina. Five studies were included in the review. In the Multicenter Study of Enhanced External Counterpulsation (MUST-EECP), time to greater than or equal to 1-mm ST segment depression (exercise-induced ischaemia) was statistically significantly improved in the EECP group compared with the control group (sham EECP), mean difference (MD) 41 seconds [95% confidence interval (CI) 9.10-73.90]. However, there was no statistically significant difference between the EECP and control groups in the change in exercise duration from baseline to end of treatment, self-reported angina episodes or daily nitroglycerin use, and the clinical significance of the limited benefits was unclear. There was also a lack of data on long-term outcomes. There were more withdrawals due to adverse events in the EECP group than in the control group, as well as a greater proportion of patients with adverse events [relative risk (RR) 2.13, 95% CI 1.35-3.38]. The three non-randomised studies compared EECP with elective percutaneous coronary intervention (PCI) and usual care. There was a high risk of selection bias in all three studies and the results should be treated with considerable caution. The study comparing an EECP registry with a PCI registry reported similar 1-year all-cause mortality in both groups. In the Prospective Evaluation of EECP in Congestive Heart Failure (PEECH) trial, patients with heart failure were randomised to EECP or to usual care (pharmacotherapy only). At 6 months post treatment, the proportion of patients achieving at least a 60-second increase in exercise duration was higher in the EECP group (RR 1.39, 95% CI 0.89-2.16), but the proportion with an improvement in peak VO2 was similar in both groups. The clinical significance of this is unclear. The proportion of patients in the EECP group with an improvement in New York Heart Association classification was higher (RR 2.25, 95% CI 1.25-4.06) at 6 months, as was mean exercise duration, MD 34.6 (95% CI -4.86 to 74.06). There were more withdrawals in the EECP group than in the control group as a result of adverse events (RR 1.05, 95% CI 0.67-1.66). There were limitations in the generalisability of results of the trial and, again, a lack of data on long-term outcomes. The review of cost-effectiveness evidence found only one unpublished study but demonstrated that the long-term maintenance of quality of life benefits of EECP is central to the estimate of its cost-effectiveness. The incremental cost-effectiveness ratio of EECP was 18,643 pounds for each additional quality-adjusted life-year (QALY), with a probability of being cost-effective of 0.44 and 0.70 at cost-effectiveness thresholds of 20,000 pounds and 30,000 pounds per QALY gained respectively. Results were sensitive to the duration of health-related quality of life (HRQoL) benefits from treatment. The results from a single randomised controlled trial (MUST-EECP) do not provide firm evidence of the clinical effectiveness of EECP in refractory stable angina or in heart failure. High-quality studies are required to investigate the benefits of EECP, whether these outweigh the common adverse effects and its long-term cost-effectiveness in terms of quality of life benefits.