Current approaches in small diameter vascular grafts for coronary artery bypass surgeries fail to address physiological variations along the graft that contribute to thrombus formation and ultimately graft failure. An interlayer drug delivery system can sustain delivery of heparin through the graft with a high degree of temporal and spatial control. A heparin-loaded gelatin methacrylate interlayer sits between a biohybrid composed of decellularized bovine pericardium and poly(propylene fumarate) and UV crosslinking is controlled via 3D printed shadow masks. The masks enable control of the resultant gelMA crosslinking and properties by modulating the incident light intensity on the graft. High doses of heparin have detrimental effects on endothelial cell function. When exposed to heparin in a slower, more sustained manner consistent with the masks, endothelial cells behave similarly to untreated cells. Slower release profiles cause significantly more release of tissue factor pathway inhibitor, an anticoagulant, than a faster release profile.