distal revascularization and interval ligation distal revascularization and interval ligation distal revascularization and interval ligation (dril) is a surgical method of treating vascular access steal syndrome. distal revascularization and interval ligationspecialtynephrology/vascular medicine history dril was first proposed by harry schanzer and colleagues in 1988. procedure a short distal bypass is created and the artery just distal to the av anastomosis is ligated.