Traumatic injuries that damage an artery or vein. These injuries can be very serious and result in life threatening bleeding. Lacerations, knife wounds, and gunshot wounds are the most common cause of blood vessel damage. Treatment is dependent on the location of the injury. Larger arteries and arteries feeding important areas need emergent repair to prevent death of the tissue the artery was supplying with blood. In general veins are not sewn back together unless they are large.