Ultrastructural Analysis of the Saphenous Vein Endothelium in a Patient With Proinflammatory Comorbidities Undergoing Coronary Artery Bypass Grafting.

The saphenous vein (SV) remains one of the most widely used grafts in coronary artery bypass grafting (CABG), and the integrity of the endothelium-a complex structure susceptible to deleterious effects from proinflammatory comorbidities-is a critical factor for graft patency. A 75-year-old patient with hypertension, dyslipidemia, insulin-dependent Type 2 diabetes mellitus, gout, peripheral arterial occlusive disease, and active smoking presented with unstable angina and cardiogenic shock, exhibiting severe coronary artery disease refractory to medical treatment. Emergency CABG was indicated due to the patient's clinical deterioration. During the procedure, the SV was harvested using skin-bridged incisions in an atraumatic manner with minimal handling. Immediately after excision, the SV was maintained at room temperature (∼20°C), and a venous cannula was attached to the distal portion of a 3-cm segment, which was perfused with a fixation solution containing 2.5% glutaraldehyde, 4% paraformaldehyde, and 0.1 M sodium cacodylate buffer (pH 7.4). It was then stored in an isothermal container and transported for scanning electron microscopy (SEM) analysis. SEM revealed significant endothelial damage, with extensive areas of endothelial cell detachment and loss, exposure of the basement membrane and collagen fibers, and-particularly in areas of endothelial denudation-the presence of fibrin aggregates and microthrombi. This case suggests that, in critically ill patients with multiple comorbidities, the SV may exhibit substantial endothelial damage, including microthrombi formation, immediately after surgical excision. These findings are associative and speculative; further studies are needed to explore whether such changes contribute to an increased risk of early venous graft failure. Upon identifying patients at high risk, intensive therapeutic measures should be promptly implemented to address comorbidities and minimize their deleterious effects on the endothelium.