"The Congressional Budget Office (CBO) has estimated that full repeal of the ACA would increase Medicare spending by $802 billion from 2016 to 2025.1 Full repeal would increase spending primarily by restoring higher payments to health care providers and Medicare Advantage plans. The increase in Medicare spending would likely lead to higher Medicare premiums, deductibles, and cost sharing for beneficiaries, and accelerate the insolvency of the Medicare Part A trust fund. " - KFF
The Republican battle cry about the Affordable Care Act has been "repeal and replace". But they have never said what they would replace it with. Of course there are some rightist think tanks that have developed plans but the GOP leadership has never put one forward.
Many people think only of the three types of individual policies of insurance offered at healthcare.gov or state exchanges (Bronze, silver, platinum) But the Act makes big changes in Medicare too. The Kaiser Family Foundation has studied the impact.
Kaiser Family Foundation Brief
Impact on Medicare of Repeal of Affordable Care Act