Abiomed (NASDAQ: ABMD), a medical-device maker focused on minimally invasive heart pumps, reported its fiscal second-quarter earnings on Thursday, Oct. 26. The company once again reported strong growth in sales of its Impella family of heart pumps and raised guidance. Let's take a closer look at the company's results. Image source: Getty Images. Abiomed's fiscal second quarter: The raw numbers Metric Q2 2018 Q2 2017 Year-Over-Year Change Revenue $132.8 million $103.0 million 29% GAAP net income $24.5 million $8.9 million 175% GAAP earnings per share $0.54 $0.20 170% Adjusted earnings per share $0.44 $0.20 120% Data source: Abiomed. GAAP = generally accepted accounting principles. What happened with Abiomed this quarter? Total revenue grew 29% to $132.8 million. That exceeded market watchers' expectations by $2 million. Worldwide Impella heart pump sales grew 30% to $127.4 million. That number was derived from 27% sales growth in the U.S. and 61% sales growth in international markets. The company grew its U.S. installed base for all of its Impella heart pump products. Gross margin expanded by 1 percentage point to 84% for the quarter. Operating margin expanded 10 percentage points to 24%. After adjusting for an accounting change, EPS came in at $0.44. That exceeded Wall Street's estimate by $0.07. Cash generation during the quarter was $30 million. Abiomed ended the quarter with $319 million in cash and no debt. Beyond the financial details, Abiomed also announced that the first patient has been treated with an Impella heart pump in Japan. What management had to say CEO Michael Minogue was optimistic about the company's quarterly performance, commenting: "This quarter, we set new records for supporting patients in the U.S. and Germany, and we continue to observe improved clinical outcomes with our education and training initiatives. I am proud of the team's ability to consistently adapt and execute as we transform the standard of care and build the Field of Heart Recovery." Looking forward The strong quarterly growth caused management to increase the lower end of its fiscal-year 2018 revenue guidance. The company now expects revenue to land between $565 million to $575 million, which represents growth of 27% to 29% from the prior year. Turning to profitability, management also increased its fiscal-year guidance for GAAP operating margin. The new range is 23% to 25%, up from its prior outlook of 22% to 24%. Investors looked upon this better-than-expected report favorably and bid up shares by about 5% following this report. Looking beyond the short-term price action, Abiomed's results clearly show that its products are winning over healthcare providers both domestically and abroad. Furthermore, the official launch of the products in Japan should enable the company's rapid growth rates to continue for some time. 10 stocks we like better than AbiomedWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the 10 best stocks for investors to buy right now… and Abiomed wasn't one of them! That's right -- they think these 10 stocks are even better buys. Click here to learn about these picks! *Stock Advisor returns as of October 9, 2017Brian Feroldi has no position in any of the stocks mentioned. The Motley Fool recommends Abiomed. The Motley Fool has a disclosure policy.