Sept 28 (Reuters) - A federal appeals court said Boston Scientific Corp did not infringe a patent by Johnson & Johnson's Cordis unit related to a stent used to treat coronary artery disease, but could not block the enforcement of two patents.

Wednesday's ruling in the 14-year-old case by the Federal Circuit Court of Appeals is the latest in a long line of litigation over stents between the companies.

The dispute concerned balloon-expandable stents, which are used to treat blocked blood vessels as an alternative to more invasive coronary bypass surgery.

Cordis initially sued Boston Scientific in 1997.

Wednesday's ruling upheld a lower court judge's decision that Boston Scientific's NIR stent did not literally infringe a Cordis patent.

It also said Boston Scientific failed to show that the patent and one other were tainted because the original patentees, when applying for the patents, hid information from the U.S. agency that eventually granted approval.

Boston Scientific has about $1.5 billion of annual stent sales. In June, J&J said Cordis would stop selling drug-coated heart stents, after losing market share to Abbott Laboratories as well as Boston Scientific.

The case is Cordis Corp v. Boston Scientific Corp et al, U.S. Federal Circuit Court of Appeals, Nos. 2010-1311, 2010-1316.

For Cordis: Gregory Diskant of Patterson Belknap Webb & Tyler.

For Boston Scientific: Frank Porcelli of Fish & Richardson.

(Reporting by Jonathan Stempel)

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