Bypass folowed by EECP

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Can Angiographic Findings Predict Which Coronary Patients Will Benefit from Enhanced External Counterpulsation?
Lawson WE, Hui JCK, Zheng ZS, et al. American Journal of Cardiology 1996;77:1107-09.

We expect a lot from EECP in patients with one or two vessel disease; patients with three vessel blockage may still benefit, but most of the time their nuclear scan will remain abnormal. What about patients with angina related to closure of their bypass grafts? This is a group that we’d really like to help. Often, a second bypass isn’t technically possible, and when it is the risk may be twice that of the first surgery. Will EECP help these people?

To answer this question, Dr. Lawson and his colleagues at Stony Brook Medical Center provided EECP to 25 patients with angina due to clogged bypass grafts, and compared their response to that of 35 never bypassed angina patients. Pre-EECP coronary angiograms were carried out in both groups. Post-bypass one or two vessel disease was said to be present if one or two grafts contained a ³ 70% narrowing; patients with three narrowed grafts were designated as having post-bypass three vessel disease. Pre and post-EECP stress nuclear scans were carried out in all patients. The investigators looked for a relationship between the number of vessels blocked, either native vessels or bypass grafts, and the percentage of patients in each category whose nuclear scans improved. We already know that nuclear scans improve following EECP in less than half of the patients with native three vessel disease, but what will happen in the post-bypass population? The results may s surprise you.

The difference between 88 and 80% was not statistically meaningful, so from this study we learn that patients with narrowings in one or two bypass grafts typically do as well as never bypassed patients with one or two artery blockage - good news. The really good news is that patients with post-bypass three vessel disease seem to do just as well. We aren’t sure why post-bypass triple vessel disease patients do better than never bypassed triple vessel disease patients. It may be that a 70% narrowing in a bypass graft allows more flow than a 70% narrowing in a native artery, allowing us to counterpulse enough pressure through the graft to grow collaterals from the vessel it is attached to. There may be other reasons. I’m supposed to be the local expert, and I really don’t know. What I do know is what I need to know, that post-bypass patients usually respond well to EECP, regardless of the number of vessels blocked. In these patients, we can typ ically omit a pre-EECP coronary angiogram. (Why put the patient through the risk and expense of an angiogram if the results will not alter our treatment; we can always do an angiogram if the patient continues to experience symptoms after completing a course of EECP.

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