NEW ORLEANS — The experimental drug ularitide over the long term did not improve survival or lessen the damaging effects of acute heart failure, found a study presented Sunday at the American Heart Association’s Scientific Sessions.

Ularitide is a synthetic form of a natriuretic peptide, a naturally-occurring protein that helps regulate the amount of sodium excreted in the urine. Experts had hoped giving the drug within 12 hours of hospitalization would help patients live longer and result in fewer re-hospitalizations.

The intravenous drug helped, but only during the two days it was being administered.

Despite the lack of post-infusion benefit, ularitide safely lowered blood pressure, reduced stress on the heart wall and dropped the rate of in-hospital worsening of heart failure.

Clyde Yancy, M.D., chief of cardiology at Northwestern University Feinberg School of Medicine, said the news is not all bad.

“At first glance, we might say this is a negative trial, but I would put a pause button on that,” he said.

Other studies have shown some benefit to early acute heart failure treatment, so the results could be due to timing, said Yancy, who was not involved in the study.

More than 2,000 acute heart failure patients ages 18 to 85 received ularitide or a placebo for two days after initial treatment in the hospital. The median time to patients receiving the study treatment was six hours.

That is the earliest time to treatment of any trial of acute heart failure patients, said Milton Packer, M.D., Distinguished Scholar in Cardiovascular Science at Baylor University Medical Center in Dallas, who led the trial, called TRUE-AHF.

But the clock on time to treatment begins when a patient gets to the hospital, Yancy said. So earlier treatment may have to happen before a patient arrives.

“As we continue this pursuit of targeted therapies for acute decompensated heart failure and not finding those, maybe we have to search for new targets or realize that this is all within the continuum of heart failure,” he said.

Acute heart failure occurs when someone suddenly develops symptoms that require hospitalization, said cardiologist Mariell Jessup, M.D., a professor at the University of Pennsylvania, who was not involved in the study. Patients may or may not have been previously diagnosed, she said.

The results may help settle part of the scientific debate over acute heart failure, Packer said. Some theorize that acute heart failure occurs at a specific moment, like a heart attack, with a course that could be changed.

But he disagrees.

“It’s a gradual event that picks up over weeks beforehand,” Packer said. “It has no wonderful window of opportunity for intervention.”

About 5.7 million Americans have heart failure, which in 2013 was the underlying cause of more than 58,000 deaths. Typical causes are heart disease, diabetes and high blood pressure. Trouble breathing, fatigue and swelling are common symptoms.

Yancy said that despite the disappointing results, “it’s reassuring that ultimately what we need to do for heart failure patients is to provide best care.”

Jessup said this isn’t the end of natriuretic peptide therapy for heart failure.

“Hope will spring eternal that these compounds should work in acute heart failure,” she said.