Looking at revenue growth geographically, compared to last year, first quarter net sales in the U.S. increased 2%, while internationally, we grew an impressive 11%. In Europe, we were up 6% on a constant-currency basis. Japan had a particularly strong quarter, growing 19%, which included some benefit from a competitor's quality issue in stents that John Weiland will address a little later. Our other international businesses grew 15% in constant currency, driven by a 29% growth in our emerging markets.
On the business development front, we don't have any new deals coming up at this time, but I can tell you that the transactions we closed in the fourth quarter last year are proceeding as planned. We told you that we had expected ClearStream and Medivance together to contribute about 200 basis points of growth this year, and that was their impact on the first quarter. Later, you'll hear John DeFord's update at the LEVANT 2 trial from the Lutonix acquisition continues its rapid enrollment and is going according to our plans.
So in summary, I'd characterize the first quarter as a good start to the year. While we still haven't seen much change in the U.S. environment, our increased focused in investments in international markets are providing rapid returns and strengthening our growth profile. We remain focused on daily execution of our product leadership strategy to take advantage of the opportunities in front of us while positioning ourselves for stronger growth in the future.
Before I turn the call over to John Weiland, I wanted to give you an update on the Gore litigation. As most of you know, on February 10, the Court of Appeals for the Federal Circuit affirmed the District Court's decision in our favor. Gore has since filed a petition requesting a rehearing of the case, so we're currently waiting to find out if there will be further hearings or not. In the meantime, we're in the process of evaluating alternatives for the use of these potential funds in the best interest of shareholders.