Covidien agreed to pay $440 million, or $29 per share, for vascular device maker VNUS Medical Technologies Inc.

That’s a 56 percent premium on the San Jose, Calif.-based company’s $18.57 52-week per-share rolling price average and a 36 percent premium on its $21.32 closing price yesterday.

VNUS, which makes medical devices for minimally invasive treatment of venous reflux disease, posted first-quarter sales of $24.7 million, up 30.9 percent compared with $18.9 million during the same period last year.

The company reported first-quarter net income of $1.9 million, compared with a net loss of $400,000 for the first quarter of 2008.

VNUS spent $694,000 on patent litigation during the quarter, related to its lawsuit against Biolitec Inc., Dornier MedTech America Inc. and CoolTouch Inc. over alleged infringements of VNUS patents on endovenous laser ablation technologies.

First-quarter adjusted EBIDTA was 3.7 million, compared with negative EBIDTA of $420,000 during the 2008 first quarter, putting the premium Covidien will pay for VNUS at 99.2 percent of EBIDTA.

Covidien said the deal expands its footprint in the vascular market; VNUS makes a closure system that uses a radiofrequency catheter to heat and close diseased veins in venous reflux disiease, one of the underlying causes of varicose veins.

Vein Clinic specializing in varicose and spider treatments.