This past year was a particularly frenetic one in the health care industry.

It was punctuated by repeated efforts in Washington to repeal and replace the federal Affordable Care Act — which, if successful, could have spelled turmoil for one of Massachusetts’ biggest economic sectors.

And 2018 could bring more of the same.

Health care industry watchers told the Globe that they expect the uncertainty to linger into the new year, as President Trump and Congress continue to target the federal health care system.

Health care executives and politicians in Massachusetts worry that Republicans in Washington are not finished trying to repeal, or at least weaken, the law known as Obamacare.

“I think that’s a big threat in 2018,’’ said Lora M. Pellegrini, president of the Massachusetts Association of Health Plans, which represents health insurers. “I don’t think we’re done with total repeal of the ACA . . . or chipping away at it, like death by a thousand cuts.’’

The Affordable Care Act, passed in 2010, allowed millions of Americans to gain access to insurance coverage. Massachusetts relies on the law to help pay for health coverage for many low-income residents, and the law has wide support from Democrats and Republicans here. But nationally, many conservatives consider it government overreach and blame it for driving up costs. Trump has expressed loathing for the law in public remarks and on Twitter.

So far, Republicans in Congress have failed to find the votes to repeal and replace the law. But in their big tax bill approved in December, they gutted the national requirement for individuals to obtain health insurance. (Massachusetts still has a state mandate for residents to be covered.)

Also, in October, the White House halted federal payments to insurance companies that are used to subsidize coverage for lower-income Americans. This widely criticized move led to higher-than-expected insurance rate increases for thousands of Massachusetts consumers.

Trump also signed an executive order to allow for the sale of some cheaper and less comprehensive insurance plans.

“Certainly, 2017 was the big year as it relates to challenges to the ACA, but we should remain vigilant in trying to protect remaining pieces of the law, and we should certainly expect there will be more challenges federally to the overall success and continuation of the ACA,’’ said Steve Walsh, president of the Massachusetts Health & Hospital Association.

In addition, health care industry observers said the Trump administration and Congress could target Medicaid, the government program that covers low-income families. Funding changes to that program could affect the flow of federal dollars to Massachusetts.

John E. McDonough, professor at the Harvard T.H. Chan School of Public Health, said the Trump administration could change Medicaid unilaterally by allowing states to test conservative ideas such as work requirements for Medicaid recipients.

“There’s going to be a significant continuation of the effort to destabilize and undermine Medicaid as a broad safety net,’’ McDonough said.

Joshua Archambault, senior fellow at the Pioneer Institute, a free-market-oriented think tank in Boston, also expects Medicaid funding to be a topic of debate in the new year and said changes are necessary because the current pace of spending on public health care is not sustainable.

“I think Medicaid has to be in that discussion,’’ he said. “Whether it’s next year, or in the future, it has to happen.’’

Medicaid is likely to generate debate not just in Washington but in Boston, where state officials are grappling with the costs of the state Medicaid program, known as MassHealth.

In 2017, Governor Charlie Baker proposed a series of ideas to rein in MassHealth spending — including by changing certain eligibility rules — but legislators rejected them. The governor and the Legislature agreed, however, to impose new fees on employers to help cover the costs of MassHealth. The new assessments begin this month.

Massachusetts is also poised to tackle health care spending more broadly. The state Senate passed a bill in November that includes new rules to contain hospital and prescription drug spending. The House is expected to draft a bill in 2018 but take a more conservative approach. Then the two chambers would have to negotiate a compromise bill.

But just as they did in 2017, elected officials in Massachusetts will closely watch what happens with health care in Washington, said state Representative Jeffrey Sánchez, a Democrat who serves as the House budget chief.

“Congress wants to flip health care on its head as we know it now,’’ Sánchez said.

Andrew Dreyfus, chief executive of Blue Cross Blue Shield of Massachusetts, the state’s largest health insurer, expects to see ongoing attempts in Washington to repeal or undermine the Affordable Care Act in 2018.

“But I think there will be well organized forces to preserve it,’’ Dreyfus said, “and we certainly will play a role in that.’’

Priyanka Dayal McCluskey can be reached at priyanka.mccluskey@globe.com. Follow her on Twitter @priyanka_dayal.