Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of medical equipment maker Edwards Lifesciences (NYSE: EW) dove as much as 11% today, devastated by a new report out of the U.S. Centers for Medicare & Medicaid Services alleging that the company's artificial heart valves pose "high rates of stroke and death" in the patients into which they are implanted.

So what: The valve, still not officially approved by the FDA, is said to be one of the most expensive products currently paid for by Medicare. As such, it's probably not surprising to see the USCMMS looking to cut reimbursement costs.

Now what: Edwards' share price depends heavily on the firm's barnburner expectations for 28% long-term earnings growth to justify the earnings multiple. The risk here, therefore, is that curtailing use of the heart value transplant will curb Edwards' growth prospects. Already pricey at 36 times trailing earnings, Edwards' stock just got a whole lot riskier -- and that explains the sell-off.

Funding cuts aren't a certainty at this point? Will Edwards prevail in its product review, and continue on its past growth trajectory? Add the stock to your Fool watchlist and find out.

Fool contributor Rich Smith does not own shares of any company named above. The Motley Fool has a disclosure policy. Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.