Background: Randomized trials have demonstrated coronary artery bypass surgery (CABG) to be superior to percutaneous coronary intervention with respect to long-term mortality and morbidity from myocardial infarction within specific high-risk cohorts. The purpose of this study was to analyze the spatial distribution of coronary artery bypass graft anastomoses relative to acute thromboses in native coronary arteries. We hypothesized that insertion sites of bypass grafts are located distal to sites of acute thrombosis and consequently decrease cardiac morbidity and mortality associated with plaque rupture.
Methods: We analyzed 168 patients with prior CABG and 208 patients with ST-segment elevation myocardial infarctions (STEMI) presenting to the Brigham and Women's Hospital who underwent coronary angiography. We constructed a spatial map of the coronary arterial bypass graft insertion sites and compared these locations to sites of acute thrombosis leading to STEMI.
Results: Graft insertion sites were consistently located distal to acute thrombosis sites (left anterior descending artery median graft insertion versus median thrombosis site = 72 versus 34 mm, right coronary artery 91 versus 42 mm, left circumflex artery 44 versus 37 mm). Greater than 97% of thrombosis sites were located proximal to 75% of graft insertion sites.
Conclusions: Coronary arterial bypass grafts provide the coverage of anatomic zones at risk for STEMI. The superior performance of CABG in high risk patients may be attributed to targeting of proximal coronary locations where thrombosis risk is clustered.
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