By Ed Susman
NEW ORLEANS -- November 12, 2008 -- There was no significant difference observed between the angiotensin receptor blocker irbesartan and placebo in patients diagnosed with heart failure who have preserved left-ventricular ejection fraction, according to trial results reported at the American Heart Association (AHA) Scientific Sessions.
The study results were published simultaneously in the New England Journal of Medicine.
About 40% to 50% of patients with heart failure have preserved left-ventricular function and are at risk for cardiovascular events -- but there is no recognised treatment for the condition, said investigator Barry Massie, MD, University of California, San Francisco, San Francisco, California.
"These patients have hearts that pump well and are not enlarged, yet still have the classic heart-failure symptoms of fluid retention, shortness of breath, and oedema or swelling," Dr. Massie noted here at a press briefing on November 11.
Several other attempts to treat patients with drugs that interrupt the renin-angiotensin pathway have failed to produce relief for these patients, and Dr. Massie said the Irbesartan in Heart Failure With Preserved Systolic Function (I-PRESERVE) also produced negative trial results.
In I-PRESERVE, researchers enrolled 4,129 people (approximately 60% female, average age of 72 years). The researchers assigned 2,057 patients to receive irbesartan at a starting dose of 75 mg, titrated to 300 mg/day by 8 weeks, and assigned 2,051 patients to placebo.
After a mean of 49.5 months follow-up, irbesartan did not reduce the rate of the primary composite endpoint of all-cause mortality and hospitalisation for a protocol-specified cardiovascular cause compared with placebo. About 36% of patients on irbesartan experienced one of the composites of the primary endpoint compared with 37% of patients on placebo (P = .35).
Similarly, researchers were unable to observe significant differences in secondary endpoints, including overall mortality: 52.6 per 1,000 patient-years for irbesartan patients compared with 52.3 per 1,000 patient-years for placebo (P = .98).
"Our results are consistent with previous trials in patients with heart failure and preserved left-ventricular ejection fraction that did not demonstrate a positive effect," Dr. Massie concluded. "For this large group of patients, there is no specific evidence-based therapy.
The study was supported by Bristol-Myers Squibb Company and sanofi-aventis.
[Presentation title: I-PRESERVE: Irbesartan in Heart Failure With Preserved Ejection Fraction. LBCT-3320]
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