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 device company Thoratec (UNKNOWN:THOR.DL) sank 12% today after its quarterly results missed Wall Street expectations.  

So what: The stock is up nicely over the past year on solid sales growth, but a wide first-quarter miss -- adjusted EPS of $0.51 on revenue of $117.73 million versus the consensus of $0.46 and $122.9 million -- suggests that growth is slowing. While management maintained its guidance for 2013, the earnings hiccup triggers some concern among analysts over intensifying competition in the U.S.      

Now what: Thoratec still sees full-year adjusted EPS of $1.76-$1.86 on revenue of $490 million-$510 million, in line with Wall Street's view of $1.81 and $503.9 million. "Although we faced some expected challenges in the first quarter, our team is responding well to our near-term priorities while also staying focused on key longer-term growth drivers, giving us confidence in Thoratec's outlook for 2013 and beyond," CEO Gary Burbach reassured investors. More important, with the stock now off about 20% from its 52-week highs and trading at a forward P/E of 15, it might be a decent enough time to buy into that bullishness.    

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