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.

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PEECH

In the Prospective Evaluation of EECP in Congestive Heart Failure (PEECH) trial, EECP improved exercise duration, symptom status, and QOL in patients with mild-to-moderate heart failure who were already receiving optimal medical therapy. The PEECH trial, reported at the 2005 ACC meeting by Arthur M. Feldman, MD, PhD, FACC, enrolled 187 patients with ischemic or nonischemic heart failure and New York Heart Association (NYHA) class II or III symptoms. All patients had LVEF ≤35% (mean, about 26%) despite optimal medical therapy. Patients were randomized to EECP plus optimal pharmacologic therapy for 7 weeks (n = 93) or optimal pharmacologic therapy alone (n = 94). Patients could not be blinded to their randomized therapy, of course, but the study controlled for researcher bias by creating two investigating teams. One team supervised or performed daily EECP treatments; the other team, which was blinded to randomization, performed patient evaluations. The study's primary endpoint was one of two measures of change in exercise capacity. The first of these, the percentage of patients with at least a 60-second increase in exercise duration from baseline to 6 months, was significantly higher in the EECP group than in the control group (p = 0.016). The second measure, the percentage of patients with at least a 1.25 ml/min/kg increase in peak VO2 from baseline to 6 months, was statistically similar in both groups (Figure 5). The study also demonstrated significant improvements in several secondary endpoints (Figure 6), including mean change in exercise duration, NYHA classification, and QOL, although the latter improvement was not sustained over the long term. Andrew D. Michaels, MD, FACC, of the University of California, San Francisco, was the discussant for Dr. Feldman's presentation. Although he said the PEECH results are "mixed," he added "there is still reason for optimism that EECP may be a positive addition to patients with heart failure treated with optimal medical therapy." However, he acknowledged it was "somewhat concerning" that the only endpoints in PEECH significantly improved by EECP were those subject to a placebo effect. Peak VO2, which is likely not subject to the placebo effect, was unchanged by the therapy. This interview with Dr. Feldman reviews the results of the PEECH trial and evidence suggesting that the benefits observed were not a placebo effect.

Figure 5.

PEECH Trial Results: Primary Endpoints

Figure 6.

PEECH Trial Results: Secondary Endpoints

Dr. Conti: This is Richard Conti, here at the American College of Cardiology 54th Annual Scientific Sessions in Orlando, Florida. With me is Dr. Arthur Feldman, who is Magee Professor of Medicine and chair of medicine at Jefferson Medical School in Philadelphia. We're going to discuss the "Prospective Evaluation of EECP in Congestive Heart Failure" or PEECH trial. Let's start off with a little background about why we're even doing EECP in heart failure.

Dr. Feldman: EECP is an interesting technology that uses a group of cuffs around the lower extremities, which inflate and deflate in time with the electrocardiographic signal; timed to rapidly inflate at the beginning of diastole and deflating at the beginning of systole (Figure 1). In so doing, they provide hemodynamic benefits consistent with the benefits found for many years to occur with intra-aortic balloon counterpulsation.

Dr. Conti: Most of us in cardiology know what the intra-aortic balloon does and now we are going to learn what the external counterpulsation does.

Dr. Feldman: Correct. And early studies using EECP determined that it was very beneficial in the treatment of patients with coronary artery disease and angina. In that group of patients, in a fairly large randomized clinical trial, MUST-EECP, this approach was shown to decrease the use of nitroglycerin, improve exercise tolerance, and improve functional classification.[2]

Dr. Conti: Did these patients have normal or abnormal ventricular function?

Dr. Feldman: It was in patients with normal ventricular function and at the end of that study a registry was started that sought to enroll a large number of patients; currently, the registry contains data from about 5,000 patients. The purpose was to document what was happening to the patients being treated with this new technology. About 20% of the patients enrolled in the registry have left ventricular dysfunction. When the data were analyzed separately for this group of patients, it was determined that they responded very well to EECP therapy. This led to the hypothesis that EECP might be beneficial in a group of patients with heart failure, either due to ischemic events or due to idiopathic dilated cardiomyopathy.

Dr. Conti: So, the registry really set the tone for the PEECH trial, which is what a good registry should be: hypothesis generating. Then what happened?

Dr. Feldman: We randomized a group of 200 patients with stable heart failure symptoms, New York Heart Association class II or class III, an ejection fraction less than or equal to 35% - in other words, they all had systolic dysfunction - and were optimally medicated with an ACE inhibitor and a beta-blocker to receive either EECP or no EECP. As the primary endpoint, we assessed these patients over a 6-month period looking for changes in exercise performance or peak VO2.

Dr. Conti: Before we get to the results, why don't you tell us how many treatments were given to each patient? What was the protocol for EECP?

Dr. Feldman: The standard treatment for EECP, since its inception almost 2 decades ago, has been 35 1-hour sessions 5 days a week.

Dr. Conti: What were the results?

Dr. Feldman: I should make the point that we used an either/or situation for the primary endpoint. If the two endpoints were positive at a p value of <0.05, then the trial would be considered positive. Or it would be considered positive if either of the two endpoints was positive at a p value of 0.025. And this is based on exercise duration and peak VO2; specifically, the percentage of patients who increased their exercise duration by greater than 60 seconds or the percentage of patients who increased their peak VO2 by greater than 1.25 ml/kg/min.

Dr. Conti: And what did you find?

Dr. Feldman: There was a highly statistically significant difference between the percentage of patients who improved in the EECP group and the control group based on exercise performance or exercise time (Figure 5), with the greater increase seen in the EECP group. However, when we looked at peak VO2, there was no significant difference at 6 months in peak VO2. That led us look at some of our secondary endpoints, such as change in exercise time at 1 week, 3 months, and 6 months after initiation of the study (Figure 6). When we looked at those two groups, there was again a statistically significant benefit to EECP and the change in exercise time was substantially more robust in the EECP group than in the control group at each time point. However, consistent with the primary endpoint, when we looked again at peak VO2 there was no difference at any of the three time points.

Dr. Conti: Why do you think that is, if you got increased exercise duration?

Dr. Feldman: One possibility is that there was a placebo effect. We can't ignore that possibility; certainly the patients getting EECP knew they were getting EECP and the patients in the control group were certainly aware they were in the control group.

Dr. Conti: Do you think it was a placebo effect?

Dr. Feldman: No, we think there was a true benefit, not a placebo effect. That is based on some of our secondary endpoints, such as New York Heart Association classification, which was physician-derived, and the Minnesota Living with Heart Failure questionnaire. The New York Heart Association classification was substantially better in the EECP group versus the controls at 1 week, 3 months, and 6 months. And the Minnesota Living with Heart Failure score also was better in the EECP group compared with the controls at 1 week and 3 months, with a trend - although it did not reach statistical significance - at 6 months.

Dr. Conti: Overall, were the patients happy with the results of this therapy?

Dr. Feldman: I think they were. It's interesting because if you compare the robustness of the effect that we saw in PEECH with similar measurements, such as that reported for resynchronization therapy, for example, you see similar improvements with EECP: an increase in exercise time, an improvement in New York Heart Association classification, and an improvement in quality of life. The degree of improvement is greater among patients who receive resynchronization therapy than in our group who received EECP, but the EECP patients in PEECH were much less sick than the patients in the RESYNC trial. Remember, all our patients who received EECP had class II or class III symptoms - most were class II - and had an average ejection fraction of 26%; 95% of them were on a beta-blocker; and they were all optimally medically treated. Therefore, it's conceivable that in the EECP treatment group, we didn't have as far to go to make people feel better as you would with a population of patients with class III or IV symptoms.

Dr. Conti: We haven't talked about etiology: Were most of your patients being treated because of ischemic heart disease? Coronary artery disease? Old infarction?

Dr. Feldman: About 70% of the patients in the study had ischemic heart disease.

Dr. Conti: Which is the usual cause of heart failure in the United States.

Dr. Feldman: It is, and it's the group that has been shown previously to respond very well to EECP therapy. The big difference, at least compared to earlier studies, is this group didn't have angina.

Dr. Conti: What about evidence of diastolic dysfunction in these patients?

Dr. Feldman: Diastolic dysfunction is a huge issue these days, but usually we don't measure it. And, in fact, we did not look to see whether patients had diastolic dysfunction.

Dr. Conti: It sounds like it really was a positive trial. We look forward to perhaps using it a little bit more in patients with heart failure. We've been using it for years in people with ischemic heart disease and it's been a really successful treatment in patients who are not candidates for revascularization.

Dr. Feldman: I agree. It's particularly effective in that group of patients with coronary artery disease and heart failure.

Guidelines: Gibbons RJ, Abrams J, Chatterjee K, et al. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina - summary article: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on the Management of Patients With Chronic Stable Angina). J Am Coll Cardiol 2003;41:159-68.

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