The higher rate of periprocedural adverse events and lower rate of event-free survival of saphenous vein graft (SVG) intervention compared with native coronary artery intervention is primarily due to distal embolization. Distal embolic protection devices have been shown to reduce the incidence of no flow/slow flow and procedure related myocardial infarction during percutaneous intervention of diseased SVGs. The GuardWire(superscript ?) system is a temporary distal balloon occlusion and aspiration device for distal embolic protection. Inflation of the distal elastomeric compliant balloon of the GuardWire system prevents debris embolization downstream and is supposedly atraumatic to the vessel wall. We report the inadvertent dissection of an SVG by GuardWire balloon inflation.