Cook Medical is removing certain ZENITH ALPHA 2 THORACIC ENDOVASCULAR GRAFT proximal components because PTFE scrapings may enter the stent graft during deployment.

http://www.fda.gov/medical-devices/medical-device-recalls-and-early-alerts/endovascular-graft-recall-cook-medical-removes-zenith-alpha-2-thoracic-endovascular-graft