* Stent to fix abdominal aortic aneurysm approved by FDA
* Lombard gains access to biggest endovascular repair market
* Shares up 31 pct
LONDON, Feb 15 (Reuters) - Lombard Medical Technologies has won United States approval for its device to treat abdominal aortic aneurysm (AAA), giving it access to the world's largest market for the product and boosting its shares by 31 percent.
The Aorfix stent, a tube that is inserted into a swollen artery to prevent rupture, has been approved for patients with angulations at the neck of the aneurysm up to 90 degrees, the British company said on Friday.
Chief Executive Simon Hubbert said the endovascular repair sector in the United States is worth $600 million, accounting for more than half of the global market.
"Between 20 percent and 30 percent of patients have severe neck angulation when they have this AAA disease, and no one in the US has approval above 60 degrees," Hubbert told Reuters in an interview.
"So there's very clear headroom for us above the competition in the US. It's a very significant opportunity."
The alternative to endovascular repair is major surgery.
Shares in Lombard, which makes the stents in Oxfordshire, southern England, rose 31 percent to a near one-year high of 234.6 pence by 0946 GMT.
Canaccord Genuity analyst Julie Simmonds said the approval would trigger the second 14.1 million pound ($21.9 million) tranche of Lombard's May 2011 fundraising, enabling the company to launch the stent in the United States.
"We believe Aorfix will see rapid adoption in the United States (the device already has an 8 percent market share in the UK) and ultimately bring Lombard to the attention of the medical device majors," she said.