It's been about a year since the FDA decided to deal with potential safety issues with drug-eluting stents. Now, it looks like the agency is finally ready to toughen the requirements for approval.

The stricter requirements likely will increase the amount of time a stent needs to be tested in clinical trials before it's approved. Depending on how long the trials are extended, the change could substantially increase the development costs for drug-eluting stents. The new requirements won't affect stents from Johnson & Johnson (NYSE:JNJ) and Boston Scientific (NYSE:BSX) that are on the market now, but would affect next-generation stents that they're developing.

The new requirements also shouldn't affect the likelihood of approval for Abbott Laboratories' (NYSE:ABT) XIENCE V or Medtronic's (NYSE:MDT) Endeavor, whose marketing applications are pending with the Food and Drug Administration. However, the requirements could affect the companies' post-marketing requirements, given the FDA's newly ascribed powers.

Sanofi-Aventis (NYSE:SNY) and Bristol-Myers Squibb (NYSE:BMY), the co-marketers of PLAVIX, might actually be winners with the new guidelines. The agency may increase the recommended time that the anti-clotting drug is prescribed after a stent is implanted. That would be welcome news for them after all the patent issues the two have had to deal with.

I'm not sure the new requirements affect whether now is a good time to invest in stent makers. The requirements likely will increase research and development costs for the companies, but they'll also raise the bar for any newcomers that want to break into the market. As a Fool knows, investing in stocks with moats around them is a pretty good way to mend a broken heart.

More Foolishness on the tiny medical devices:

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Johnson & Johnson is recommended in the Income Investor newsletter. The Fool has a disclosure policy.