Prior revascularization increases the effectiveness of enhanced external counterpulsation

Background and hypothesis: Enhanced external counterpulsation (EECP) is an effective noninvasive treatment for chronic angina. However, its usefulness has been felt to be limited in patients with angiographically demonstrated triple-vessel coronary artery disease (CAD), in accord with the hypothesis that a patent vessel is necessary for transmission of the EECP-augmented coronary artery pressure and volume to the distal coronary vasculature. Methods: The effect of revascularization [coronary artery bypass grafting (CABG)] prior to EECP was examined in 60 patients with CAD and chronic angina (35 without and 25 with prior CABG). Patients were grouped by the extent of CAD (single-, double-, triple-vessel disease in the unrevascularized group) and by the extent of residual disease (number of stenotic native vessels unbypassed or supplied by a stenotic graft in the CABG group). Significant CAD or graft stenoses were defined as stenoses demonstrating greater than or equal to 70% luminal diameter narrowing. Benefit was assessed by improvement in post-EECP treatment over pretreatment radionuclide stress testing. Results: Radionuclide stress testing demonstrated a comparable favorable response (80 vs. 71%; p = NS) in patients with prior CABG versus unrevascularized patients. Enhanced external counterpulsation was highly and comparably effective in patients with unrevascularized native single- and double-vessel CAD and in patients with CABG with residual single-and double-vessel CAD (88 vs. 80%; p = NS). Most notably, CABG significantly increased the beneficial response to EECP in those patients with triple-vessel CAD and stenotic grafts compared with unrevascularized patients with triple-vessel CAD (80 vs. 22%; p < 0.05 by chi-square test). Conclusion: The results suggest a new role for EECP as an effective treatment for post CABG ischemia, despite extensive CAD and even in the presence of stenotic grafts.