American Heart Association CEO Nancy Brown on Thursday sent a letter to House Speaker Paul Ryan and House Minority Leader Nancy Pelosi expressing the AHA’s opposition to the American Health Care Act, the GOP’s proposed replacement for the current Affordable Care Act often called “Obamacare.”

Brown wrote that she was disappointed that the bill would reduce coverage of vulnerable populations, cut state funding and shift costs to achieve savings rather than implement sustainable, long-term policies that contain cost growth over the long run.

She noted that if passed in its current form the bill would reduce coverage for millions, make health care less affordable, weaken health care programs and undermine efforts to prevent disease.

“We know that heart disease and stroke patients who are uninsured are far less likely to receive appropriate and timely medical care and suffer worse medical outcomes, including higher mortality rates than their insured counterparts,” Brown wrote.

However, Brown said the AHA remains open to potential modifications to the bill and will continue to rely on the association’s longstanding nonpartisan principles that health insurance must be accessible, affordable and adequate for all Americans in evaluating future legislation.

The letter was sent as discussions continued among Republicans on a vote for the measure. But on Friday afternoon, House Republican leaders pulled the legislation after coming up short on the number of votes needed, and it is now unclear when Congress will again pursue a repeal and it what form.

President Donald Trump campaigned heavily on a promise to repeal and replace the Affordable Care Act.

Read the full letter here.