Comparison of abbreviated versus full course of enhanced external counterpulsation in heart failure patients with one-year follow-up

Abstract

Introduction: Enhanced external counterpulsation (EECP) for 30 hrs improves myocardial perfusion, endovascular function, neurohumoral activation in angina patients (pts). However, its optimal dose and effectiveness for CHF has not been elucidated. Methods: The International EECP Registry (IEPR) prospectively tracks treatment and outcomes of sequential pts. Pts with CHF withdrawing early in EECP therapy (<10 hrs of EECP, LD group) were used as controls to evaluate 1-year outcome vs the usual course of therapy (≥ 30 hrs of EECP, FD group). Kaplan Meier survival curves were compared using log-rank test, Chi-square test for other events. Results: There were 701 CHF pts in the IEPR, 65 LD pts (5.0±2.7 hrs of EECP) and 636 FD pts (36.6±4.8 hrs). Demographics were similar in both groups except more men completed therapy (75.1% vs 60%; p<0.01). Baseline LVEF was similar in LD and FD groups (36±13.9% vs 39.6±15.1%). Both groups were high-risk CAD with refractory angina unsuitable for revascularization in >90%, and a high prevalence of DM, HBP, smoking, multivessel CAD, prior MI and revascularization. At baseline 97% of LD and 89.8% of FD pts were Canadian Cardiovascular Society Angina Class (CCS) III or IV. During EECP, there were more MACE in LD than FD groups (7.7 % versus 1.7%, p<0.05). Post therapy CCS angina class improved in 83.7% of FD vs 3.2% of LD pts (p<0.001) with significant parallel improvements in angina frequency and Ntg use. At 1 year significant CCS differences persisted comparing LD versus FD groups (CCS Class III or IV in 50% versus 25.4%), but were less marked than immediately post EECP. Kaplan Meier event rates at 15 mos post initial EECP showed significantly higher MACE in LD versus FD groups (36.9% vs 22.4%; p<0.01), rate of CABG (10.6% vs 1.5%; p<0.001). However, PCI (7.3% vs 6.7%), death (16.1% vs 10.0%), and MI (11.0% vs 7.3%) were not significantly different. Of note 24.6% of LD pts had CHF exacerbations requiring hospitalization vs 12.7% of FD pts during follow-up (p<0.01). Conclusions: Among CHF patients completing a full course, EECP is associated with significant improvement in early and 1-year CCS angina class, reduced MACE rates and fewer CHF exacerbations at one-year post-treatment, compared with patients completing an abreviated course. The randomized PEECH trial will further evaluate the benefit of EECP in treating CHF.