Boston Scientific Corp. on Monday said its first-quarter profit fell by 64 percent on weak sales of the medical device maker's top-selling product as well as costs from the company's $27 billion acquisition of Guidant Corp. last spring.

Natick-based Boston Scientific said net income for the January-through-March period was $120 million, or 8 cents per share, compared with a profit of $332 million, or 40 cents per share, in the same period a year ago.

Net sales rose 26 percent to $2.09 billion from $1.62 billion in the year-ago period _ a result boosted in part by the additional business Boston Scientific took on with its Guidant acquisition.

Boston Scientific's profit in the latest quarter was reduced by $26 million, or 2 cents per share, from special charges, mostly from the Guidant acquisition.

First-quarter sales of Boston Scientific's Taxus drug-coated stent fell 26 percent to $468 million from $633 million a year ago. Drug-coated stent sales have fallen off amid concerns that the devices may put patients at slightly higher risk for blood clots than older bare-metal stents.

Taxus had accounted for about 40 percent of Boston Scientific's overall revenue before the company acquired Guidant to diversify its portfolio by adding Guidant's pacemakers and implantable defibrillators.