PRIOR REVASCULARIZATION INCREASES THE EFFECTIVENESS OF ENHANCED EXTERNAL COUNTERPULSATION

Background and hypothesis: Enhanced external counterpulsation (EECP) i s an effective noninvasive treatment for chronic angina. However, its usefulness has been felt to be limited in patients with angiographical ly demonstrated triple-vessel coronary artery disease (CAD), in accord with the hypothesis that a patent vessel is necessary for transmissio n of the EECP-augmented coronary artery pressure and volume to the dis tal coronary vasculature. Methods: The effect of revascularization [co ronary artery bypass grafting (CABG)] prior to EECP was examined in 60 patients with CAD and chronic angina (35 without and 25 with prior CA BG). Patients were grouped by the extent of CAD (single-, double-, tri ple-vessel disease in the unrevascularized group) and by the extent of residual disease (number of stenotic native vessels unbypassed or sup plied 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 improvemen t in post-EECP treatment over pretreatment radionuclide stress testing . Results: Radionuclide stress testing demonstrated a comparable favor able response (80 vs. 71%; p = NS) in patients with prior CABG versus unrevascularized patients. Enhanced external counterpulsation was high ly and comparably effective in patients with unrevascularized native s ingle- and double-vessel CAD and in patients with CABG with residual s ingle-and double-vessel CAD (88 vs. 80%; p = NS). Most notably, CABG s ignificantly increased the beneficial response to EECP in those patien ts with triple-vessel CAD and stenotic grafts compared with unrevascul arized patients with triple-vessel CAD (80 vs. 22%; p < 0.05 by chi-sq uare 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.