Long-term effect of enhanced external counterpulsation on endothelial function in the patients with intractable angina

Background: Enhanced external counterpulsation (EECP) is a noninvasive, pneumatic technique that provides favourable effects in patients with coronary artery disease. The objective of this study was to describe the long-term effect of EECP on endothelial function in patients with ischaemic cardiomyopathy. Method: The study was performed in 15 patients with ischaemic cardiomyopathy. All subjects were treated with EECP 1-h per day, 5 days a week, over 7 weeks (totally 35 h). Endothelium-dependent and -independent relaxation was assessed by flow-mediated dilation (FMD) and nitroglycerine-mediated dilatation (NMD). In each patient, FMD and NMD measurements were performed before, at midcourse (day 17th) and after completion of EECP course (day 35th). In addition, FMD index was assessed I month after completion of EECP therapy. Results: Results showed that EECP was associated with a significant improvement in FMD index after 35 hours of EECP (10.95 +/- 4.1% vs. 7.40 +/- 4.9% for baseline, p < 0.05). NMD index didn't significantly alter during the EECP therapy. Also, 1 month after completion of EECP, FMD index returned to baseline (7.51 +/- 4.4%, vs. 7.40 4.9%, respectively, p < 0.05). EECP acutely improved endothelial function in ischaemic cardiomyopathic patients. However, after 1 month completion of treatment, endothelium-dependent vasorelaxation returned to baseline. Conclusion: It seems that improvement of endothelial function is not the main mechanism of long-term EECP treatment and other mechanisms should be considered.