Persistent Type II Endoleak Unrelated to an Anaconda Aortic Stent Graft Fulfilling the 3Bs Requirements of Biofunctionality, Biodurability, and Biocompatibility

A patient was fitted with an Anaconda stent graft for which there was a persistent type II endoleak. Two subsequent attempts at embolization were unable to resolve the endoleak. The diameter of the aneurysm varied initially from 5.5 cm in diameter down to 4.8 cm but then later re-dilated to 6.1 cm, with evidence of persistent flow into the aneurysmal sac from the inferior mesenteric artery. Results from serial computed tomography scans demonstrated clear evidence of a type II endoleak that originated from the inferior mesenteric artery with outflow to a distal lumbar artery. The harvested stent graft did not show evidence of a device-related failure. The stent graft and its modular segments were found to have been properly deployed. Only a thin external capsule was evident at explantation. The internal wall of the device showed irregular and thin encapsulation with scattered mural thrombi, which were more prominent at the bifurcation of the main body of the device. Blood deposits and tissue development were sufficient to prevent blood oozing through the wall. The explanted Anaconda stent graft was devoid of any construction flaws or damage (fatigue of the textile or corrosion of the Nitinol wires) after implantation.