NEJM: Irbesartan fails to improve diastolic heart failure

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High-blood pressure medication, irbesartan (Avapro), does not improve a common form of heart failure, according to new results from a large, international study, which was published in the Dec. 4 issue of the New England Journal of Medicine.

The researchers said that the findings are disappointing, but said that they would continue to study other medications in search of a successful treatment for the condition, which predominantly affects older individuals, particularly women.

Barry M. Massie, MD, from the University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, and colleagues recruited 4,128 patients with heart failure from 25 countries.

The patients, all of whom were at least 60 years old, were randomly placed into two groups, according to the authors. One group received 300 milligrams of irbesartan, while the other group was given a placebo. Doctors tracked the patients for five years, documenting their progress and outcomes.

Researchers found that the treatment with irbesartan did not reduce the risk of death or hospitalization for cardiovascular causes among patients, who had diastolic heart failure, nor did it improve any of the secondary clinical outcomes, including quality of life.

The investigators chose irbesartan for the study because previous, smaller studies in humans with diastolic heart failure indicated that the drug may have had a potential benefit, said Dalane Kitzman, MD, a cardiologist in the department of Internal medicine at Wake Forest Baptist Medical Center in Winston-Salem, N.C., and principal investigator for the Wake Forest trial site.

While irbesartan was not successful in treating diastolic heart failure, Kitzman said that the study showed the medication, though powerful, was found to be safe for patients with the condition.

There were fewer bad outcomes than predicted, according to Kitzman. This may have been partly because blood pressure was well controlled from the start of the study by design. While the results were not positive, he said, the study does provide helpful clues to treatment of the disease. "If you have the disease but can control blood pressure with medication, the patient is likely to do pretty well," he said.

The researchers said they are continuing work to find effective treatments. Kitzman and colleagues at Wake Forest are collaborating in another ongoing trial called TOPCAT (Treatment of Preserved Cardiac function heart failure with an Aldosterone anTagonist), testing another medication for treatment of this condition.

Avapro is marketed by New York City-based Bristol-Myers Squibb and the Paris-based Sanofi-Aventis.