What medication is administered to prevent spasms of the saphenous vein after harvesting for coronary bypass grafting?

The administration of papaverine is specifically aimed at preventing spasms of the saphenous vein after it has been harvested for use in coronary bypass grafting. Papaverine is a smooth muscle relaxant that works by inhibiting phosphodiesterase, leading to increased levels of cyclic AMP and relaxation of vascular smooth muscle. This helps to reduce the risk of vasospasm, which can compromise the viability of the graft and ultimately affect the outcome of the coronary bypass procedure.

In the context of harvested veins, it is crucial to minimize spasms to ensure adequate blood flow once the graft is in place. While other medications listed may serve different purposes in cardiac care or surgery, they do not specifically address the issue of preventing spasms in the extracted saphenous vein. For instance, aspirin is primarily an antiplatelet agent, heparin is an anticoagulant, and nitroglycerin is a vasodilator that acts more on arterial smooth muscle rather than directly on the harvested vein to prevent spasm in this specific context. Therefore, papaverine stands out as the most appropriate choice for this situation.