Following half a year of debate, including some sharp words in a downtown hotel meeting room Tuesday, medical device giant Medtronic shareholders approved a $48 billion deal that will transform the revered Minnesota company into an international conglomerate based in Ireland.

Fridley-based Medtronic's purchase of Covidien PLC would rank among the largest corporate deals in state history if approved, as is expected, by the Irish High Court in the next several weeks.

The new company, called Medtronic PLC, will keep its executive offices in Minnesota and plans to invest in new jobs in the state. The acquisition will nearly double Medtronic's annual revenue, to $27 billion, and help it expand in smaller and emerging countries, where much of the growth in global health care spending is expected in coming years.

"The completion of the acquisition of Covidien by Medtronic will usher in a historic new chapter in the history of Medtronic and will help us advance our long-standing mission of alleviating pain, restoring health and extending life for patients all over the world," Medtronic chief executive Omar Ishrak told shareholders moments after the votes were tallied.

The deal needed approval from the owners of at least half of the outstanding shares, and with most voting electronically or by mail, 75.2 percent gave their assent. The vote tally came hours after Covidien shareholders in Dublin signed off by a similar proportion.

The promise of a historic new chapter did little to placate dissenting shareholders, who bemoaned the loss of a storied local company founded 65 years ago in northeast Minneapolis.

"Medtronic's turned their backs on shareholders, the United States, the state of Minnesota," said John Hilger, who voted against the deal Tuesday. "Here you've got your typical company that started up in a garage. And now? Boom. It's just not fair."

The deal is structured as a so-called corporate inversion through which Medtronic and Covidien will be rolled together under a parent company based in Ireland, where corporate taxes are about a third of the U.S. rate. Broad political resistance to corporate inversions sparked calls for change in the nation's tax code last fall that derailed other proposed deals. But Medtronic and Covidien executives held firm, arguing that the fundamentals of the deal made sense regardless of changes in tax advantages.

The market rewarded shareholders by boosting the price of Medtronic stock 17 percent since June, and driving up Covidien's by 42 percent. The Standard & Poor's 500 index moved up about 3 percent in that time.

But little of the optimism driving the deal was in evidence Tuesday in the Minneapolis hotel conference room, where the few shareholders opting to vote in person gathered to throw pointed questions at Ishrak.

Longtime shareholders and retirees are upset about paying an unplanned capital gains tax when Medtronic cancels its old shares and issues new ones in Medtronic PLC. Although proponents said a capital-gains tax would be due eventually anyway, several inversion critics said they always planned to avoid such a tax by passing on the stock as inheritance.

Naysayers on hand

Longtime investors like Minneapolis' Clem Duffy, 88, also rejected the suggestion that new shares would gain in value fast enough to make up for the old Medtronic shares they will have to sell to pay the taxes.

"As a friend of mine once said: 'At my age, I don't even buy green bananas,' " Duffy said in an interview.

Ishrak told those at Tuesday's meeting that company executives understood the tax implications for individuals, but judged the inversion to be the right decision regardless.

"We looked at the broader interests of all our stakeholders, of all shareholders around the world, the individual as well as institutional, of government and regulatory authorities, of patients, customers," he said.

Medtronic is paying $35.19 per share and exchanging each Covidien share for 0.956 shares in the new company, representing a premium of nearly 30 percent over Covidien's stock price before the deal was revealed.

Although originally announced with a $42.9 billion price tag, the value of the cash-and-stock deal of the deal has risen to about $48 billion. Such a price would put it just above the inflation-adjusted $47.2 billion combination of Norwest Corp. and Wells Fargo & Co. in 1998, believed to be the biggest deal in state history.

On Tuesday, Medtronic shares dropped 36 cents, to $71.22 a share. Covidien were flat at $102.08 per share.

Together, the companies will have a formidable product catalog. Medtronic is primarily known for its cardiac and coronary devices, including defibrillators, pacemakers, artificial valves and heart stents, as well as its businesses in diabetes care, spinal fusion and neural stimulation. Covidien is known for its hospital and medical supplies, equipment for minimally invasive surgeries, and its vascular therapies. All necessary antitrust approvals have been secured, company officials say.

The move to Ireland will allow Medtronic officials to shave a couple of percentage points off the company's effective global tax rate of 17.3 percent in 2014, while providing more flexibility in handling cash recognized in the future.

Company officials say the deal isn't about avoiding taxes, but driving investment.

"It is a matter of access to cash that we want to invest in the U.S., in Minnesota," Ishrak said. "We have committed to deploying 1,000 more people in Minnesota over the next five years. We have committed to taking $10 billion in cash which otherwise we would not have access to, to invest it in the U.S. for med tech purposes — for growing med tech in Minnesota. We feel that is the right thing for our shareholders, it is the right thing for the U.S., in our perspective."

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson