Endologix Inc, a medical device maker, said it has received approval from the US regulatory authority to market an expanded offering of its Powerlink stent graft products. Powerlink, which is an already approved endovascular stent graft, is used in the treatment of abdominal aortic aneurysm. In abdominal aortic aneurysm, the aortic wall weakens, creating a “ballooning” of the blood vessel.