| Since its introduction as a conduit for coronary artery bypass graft (CABG) surgery in the early 1960s, the saphenous vein graft (SVG) has remained a centerpiece of the over 260,000 procedures performed annually. During this time, care of the CABG patient has evolved with the emergence of novel technologies, pharmacological agents and improved standards of post-operative care. In spite of these advances, the rate of SVG occlusion within one year of surgery remains 15--30%, a rate similar to that reported three decades ago.;Using data from the multi-centered, prospective Reduction in Graft Occlusion Rates (RIGOR) study, we have considered both traditional and novel risk factors for early SVG occlusion. Following a review of the literature pertinent to each hypothesis, we first consider anatomic, demographic and technical risk factors in the modern era of CABG surgery. We next examine the performance of the Platelet Function Analyzer-100 (PFA-100), a tool designed to identify platelet dysfunction, and consider its relevance in predicting SVG failure. In the fourth chapter, we explore molecular, pharmacological and patient-specific contributors to aspirin-insensitive thromboxane generation, and weigh its contribution to SVG occlusion in the RIGOR patients. Finally, we consider the association between the endogenous erythropoietin (EPO) response to surgical anemia and SVG outcomes, given the numerous non-hematological salutary effects of this hormone.;We find that anatomic and patient-specific risk factors for early SVG failure persist for today's CABG patients. The performance of the PFA-100 is modulated by numerous extra-platelet factors, but may prove useful in predicting SVG occlusion. We provide some insight into factors associated with, and possibly contributing to, aspirin-insensitive thromboxane generation, and demonstrate its bearing on graft occlusion. Finally, we find no association between the endogenous EPO response to post-CABG anemia and SVG outcome, despite many promising former cellular and clinical studies on this hormone.;We conclude that there are some surgeon-dependent factors that may improve SVG outcomes, including patient selection, technical and anatomic considerations. However, improved CABG outcomes will require continued investigations into thromboxane, platelet hyper-reactivity and endothelial dysfunction to counteract these cellular and sub-cellular risk factors for SVG occlusion. |
