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 cardiac device manufacturer Thoratec (Nasdaq: THOR) spiked 17% today following the company's report of better-than-expected fourth-quarter results.

So what: This was another cut-and-dried case of top-line beats across the board. Thoratec reported a fourth-quarter profit of $0.38 per share (excluding one-time items) on sales of $109.4 million. This compared favorably to the consensus estimate of $0.33 in EPS on $107.6 million in sales. Thoratec's HeartMate II was the driving force pumping sales higher. The icing on the cake was Thoratec's fiscal 2012 guidance, which easily surpassed Wall Street's projections ($1.58-$1.68 versus $1.51).

Now what: Surgical devices are one of my favorite sectors to invest in because they often offer products in high demand regardless of economic conditions. As the world's population ages, the demand for surgical products is only bound to rise. Companies like Thoratec look well-positioned to take advantage of this long-term trend, and today's results simply emphasize how surprising the growth will be in this sector for decades to come.

Craving more input? Start by adding Thoratec to your free and personalized watchlist so you can keep up on the latest news with the company.