Abbott Laboratories said it agreed to acquire Perclose Inc. in a stock deal valued at $680 million that would bolster its position in the fast-growing medical devices sector. Under the terms of the agreement, Perclose shareholders would receive $54 worth of Abbott stock for each Perclose share. Redwood City, Calif.-based Perclose is the leading arterial closure device maker, a field with an annual growth rate of more than 40%, Abbott said. Separately, Perclose said it would voluntarily recall certain Techstar vascular surgery products because of a problem with deploying their needles. It said the problem has been resolved. Amid recall rumors, Perclose shares plunged $8.50 to $39.50 on Nasdaq before trading was halted. The Abbott announcement followed. Shares of Abbott Park, Ill.-based Abbott lost 69 cents to close at $42.88 on the New York Stock Exchange.