AGA Medical Holdings, which provides minimally invasive devices for the treatment of heart defects and vascular diseases, announced terms for its IPO on Thursday. The Plymouth, MN-based company plans to raise $275 million by offering 13.8 million shares at a price range of $19 to $21. At the mid-point of the proposed range, AGA Medical Holdings will command a market value of $961 million. AGA Medical Holdings, which was founded in 1995 and booked $180 million in sales over the last 12 months, plans to list on the NASDAQ under the symbol AGAM. Citi, BofA Merrill Lynch, and Deutsche Bank are the lead underwriters on the deal. Timing for the IPO has yet to be announced.