Bill Cassidy and Susan Collins said the CBO report showed the House Obamacare replacement was not adequate.
The talks surrounded then-Trump campaign chairman Paul Manafort and campaign advisor Michael Flynn.
Sick Americans and older people could see costs spike under the House-passed Obamacare replacement plan.
Treasury Secretary Steven Mnuchin on Wednesday pushed Congress to raise the federal borrowing limit.
Steven Mnuchin testifies about the White House's proposed budget following earlier testimony from Mick Mulvaney.
Conservative Rep. Mark Sanford has some doubts about the Trump administration's rosy economic growth projections.
"We've got to get tax reform done by then," House Speaker Paul Ryan says.
Mick Mulvaney testifies on Capitol Hill on Wednesday about President Donald Trump's budget proposal.
After Trump's election, Mnuchin told CNBC that wealthy Americans would get no "absolute tax cut."