Lower costs and a smaller tax bill helped bolster net income at Medtronic PLC in its fiscal first ­quarter despite a dip in sales.

The company reported unadjusted net income of $929 million, or 66 cents per share, compared with $820 million, or 57 cents a share for the same period a year ago. Its adjusted net income of $1.03 per share beat Wall Street estimates by 2 cents.

Revenue, though slightly lower than a year ago, was nearly in line with what had been expected.

Medtronic shares closed ­Thursday at $85.39, off $1.26 or 1.5 percent on the day.

Analysts with Leerink Partners predicted that Medtronic’s stock performance would be affected by the generally high expectations among investors in the med-tech sector overall this quarter.

Investors on the earnings call Thursday asked about the timing of Medtronic’s announcement earlier in the week that it had completed its $1.1 billion acquisition of HeartWare, whose high-end heart pumps treat advanced heart failure by helping pump blood through the body. The HeartWare deal was originally ­projected to close by October.

“We really felt that we were in a position where we were getting critical mass around our expertise in heart failure,” chief executive Omar Ishrak said. “Where HeartWare was positioned as a company, we felt that we could add immediate value … We felt that this was absolutely the right time.”

Each outstanding share of HeartWare was converted into the right to receive $58 in cash. HeartWare had sales of $277 million last year.

The deal didn’t change ­Medtronic’s revenue or earnings per share outlook for the year, although it is expected to provide increased confidence in the company’s ability to deliver on its fiscal year 2017 revenue growth outlook, the company said in a news release Tuesday. Medtronic intends to offset any dilutive impact of the deal for two years, until the deal turns profitable in the third year.

In the just-concluded quarter, Medtronic’s adjusted net income ­— including charges related to its ­Covidien purchase and other items — dropped to $1.44 ­billion, down 1 percent from the same period last year.

The comparison to last year’s net income was complicated because the same quarter a year ago had an extra week of sales. Adjusting for that difference, Medtronic said its net income in the most recent quarter rose at least 11 percent, while its adjusted revenue grew by only 5 percent.

Revenue was $7.17 billion in the quarter, down 1 ­percent.

Sales in the current quarter declined in three of Medtronic’s four sales groups, including a 2 percent drop to $2.5 billion in its largest division, cardiac and vascular devices. In the diabetes-device group, sales grew by 2 percent to $452 million.

For the quarter that will end in October, Chief Financial Officer Karen Parkhill said company revenue is projected to grow 5 to 6 percent, and earnings per share will finish in the lower half of a range of 12 to 16 percent growth.

Parkhill reiterated that the same guidance ranges apply to the full fiscal year. That implies diluted adjusted earnings between $4.60 and $4.70 per share for the year.