A very rare complication of an Abdominal Aortic Aneurysm: Primary Aortoduodenal Fistula without gastrointestinal bleeding.

An abdominal aortic aneurism (AAA) is an enlargement of the lower part of the aorta that extends through the abdominal area.The diameter of the aneurismatic vessel is represented by 3 cm or more in either anterior – posterior , or transverse planes. The developpement of Abdominal aortic aneurysm (AAA) is a complex, multifactorial process involving destructive remodeling of aortic wall connective tissue. Four interrelated factors involved in this process include: (1) chronic inflammation associated with neovascularization and increased proinflammatory cytokine production, (2) increased and dysregulated production of matrix-degrading proteinases, (3) destruction of structural matrix proteins, and (4) decreased medial smooth muscle cell (SMC) presence, resulting in impaired connective tissue repair. This understanding has developed from a characterization of human AAA tissue, as well as the use of different animal models that replicate human disease. The mortality of ruptured AAA is set between 40 – 70% in patients that manage to arrive alive in the emergency room, and that of 90% in overall patients confirmed with rAAA in the autopsy results. A ruptured abdominal aortic aneurysm (rAAA) represents a disruption of a dilated aortic wall that leads to blood outside the aortic wall.