Prospective Evaluation of EECP in Congestive Heart Failure: The PEECH Trial

Arthur M. Feldman, M.D., Ph.D., F.A.C.C.; C. Richard Conti, M.D., M.A.C.C.

Disclosures

Cardiosource 

In This Article

Introduction

While a number of highly effective medical and interventional treatments are available for chronic angina pectoris, over time patients may develop side effects to medications, have coronary vasculature not amenable to either initial or repeat revascularization, or simply experience diminishing treatment benefit. The search for more therapeutic options for patients with chronic angina has yielded a wide range of new treatment modalities. Enhanced external counterpulsation (EECP) has been shown to be beneficial for patients with chronic, refractory angina due to coronary artery disease (CAD) who are not candidates for revascularization. These patients typically experience sustained decreases in angina, improvement in exercise time, improved myocardial perfusion, and enhanced quality of life (QOL) with EECP. The technique involves the use of a series of inflatable cuffs positioned on the calves, lower thighs, and upper thighs.[1] Rapid inflation of the cuffs on the calves at the onset of diastole initiates a retrograde arterial pulse wave, which is sustained by inflation 50 msec later of the cuffs on the lower thighs, and inflation another 50 msec later of the cuffs on the upper thighs. Rapid deflation of the cuffs at the onset of systole facilitates cardiac unloading (Figure 1). Typically, EECP is administered as a series of 35 1-hour treatment sessions. In patients with stable angina, EECP has shown promise in a small number of studies, improving anginal symptoms, functional capacity, the time to exercise-induced ischemia, and QOL.[2,3] For example, the first randomized Multicenter Study of Enhanced External Counterpulsation (MUST-EECP) suggested that this treatment reduced angina (Figure 2) and extended the time to ischemia on an exercise treadmill test (Figure 3) in patients with symptomatic CAD. In patients with heart failure, the data are sparse, although some evidence suggests that EECP may improve exercise tolerance and QOL in this setting, too.[4] Even though the exact mechanisms by which this technique exerts favorable effects remain unclear, improvement in endothelial function is considered a potential mechanism contributing to the clinical benefit associated with EECP. Indeed, investigators at the Mayo Clinic College of Medicine recently described a young woman with severely symptomatic coronary endothelial dysfunction in the absence of obstructive CAD who "experienced a dramatic and sustained reduction in symptoms in response to a standard 35-hour course of EECP."[5]

Figure 1.

Mechanics of EECP

Figure 2.

MUST-EECP Angina Counts. A trend in angina reduction with EECP was seen in the intention-to-treat analysis and became significant when the analysis included only those subjects completing at least 34 sessions. The authors said this observation suggests that a certain number of treatment hours are required to maximize the antianginal benefit of this device.

Figure 3.

MUST-EECP Exercise Treadmill Test. The MUST-EECP trial randomized 139 patients to 35 hours of outpatient therapy with active EECP (n=60) or sham counterpulsation (n=65) over 4-7 weeks. Overall, 57% of patients had prior revascularization procedures, and 74% were Canadian angina class 2 or 3. The data shown confirm that EECP can reduce exercise-induced ischemia in patients with symptomatic CAD. The lack of a significant treatment effect on exercise duration despite reduction in other measures of ischemia may be due to a training effect or the fact that most study patients were limited by nonanginal symptoms such as fatigue or shortness of breath on the treadmill tests. The authors suggested that this may have produced a fixed exercise duration and account for this observation.

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