A new drug is no more effective at improving the survival rates of people with heart failure than an older, widely used medication, says a recent international study.
There were hopes that the new drug, levosimendan, would improve survival because it uses a special mechanism that makes heart muscle cells more sensitive to the calcium that causes them to contract.
However, the study of 1,347 people with acute decompensated heart failure, done at 75 centers in nine countries, found essentially the same death rate for participants who got levosimendan as those who received an established medication, dobutamine.
"The trial leaves cardiologists without a totally satisfactory treatment for decompensated heart failure," said Dr. Robert Hobbs, a Cleveland cardiologist specializing in treatment of the condition. Some five million Americans have one form or another of heart failure, and about one million of them are hospitalized for it each year.
Decompensated heart failure is one form of the general condition in which the heart progressively loses the ability to pump blood. It is characterized by a set of symptoms including shortness of breath and intolerance to exercise.
The original therapy, which is still basic, is diuretics," Hobbs explained. "They make the body lose water, so people feel better. In the 1980s, ACE inhibitors came along to make people feel better and live longer, and they were added for long-term benefit. The third group of drugs to be used were beta-blockers."
Dobutamine is a beta-blocker that has been found to improve symptoms, but it has also been associated with an increased risk of death and cardiovascular problems. In the latest trial, participants with decompensated heart failure received levosimendan or dobutamine intravenously.
"The common practice has been to give dobutamine in the belief that the heart is like a battery that has lost its charge," Hobbs said. "By giving dobutamine, you would recharge it. That didn't actually happen sin previous studies). It appeared to be associated with complications, longer hospital stays and more mortality."
In another study, careful analysis indicated that levosimendan was associated with a lower risk of death than dobutamine. "It did have the different mechanism of action, and it was felt that might translate into improved safety," Hobbs said. "But it proved to be no better in the new trial."
In the 180 days after drug infusion, the death rate was 26% among patients who got levosimendan and 28% in those getting dobutamine. There was no important difference in reported breathing difficulties and in time spent out of the hospital.
Participants who got levosimendan were less likely to experience cardiac failure but they were more likely to experience the abnormal heartbeat called atrial fibrillation, low blood levels of potassium and headache.
"The bottom line on all of this is that it is hard to show benefit for what we do for acute decompensated heart failure," Hobbs said.