A delivery system for an endoluminal device including an introducer(100), the introducer having a distal end (101) intended to remain outside a patient in use and a proximal end. A stent graft having a first and second end is retained upon the introducer, the stent graft defining a fenestration (52,152) disposed through a wall of the stent graft between the first and second end. A valve arrangement (60,160) is disposed within an interior lumen of the stent graft about the fenestration (52,152). A retention system (64,164) including a trigger wire engages and retains the valve arrangement (60,160) away from the fenestration (52,152). The fenestration is in fluid communication with the interior lumen of the stent graft.
