Background The Inhibition of Metallo Protease by BMS-186716 in a Randomized Exercise and Symptoms Study in Subjects With Heart Failure (IMPRESS) clinical trial randomized patients with congestive heart failure to a daily regimen of either omapatrilat or lisinopril. At 24 weeks, patients randomized to omapatrilat had a significant reduction in the combined end point of death, hospitalization, or discontinuation of study drug for worsening heart failure when compared with patients randomized to lisinopril. They also had significantly fewer serious cardiac adverse events. Objective This study sought to determine the economic consequences of the lower event rates of patients who were given omapatrilat. Methods Economic outcomes (major hospitalizations and their associated medical costs) were compared between treatment groups and assessed by use of the societal perspective. Hospitalization information was obtained from the IMPRESS trial's standardized case report and serious adverse event forms. Hospital costs were evaluated by means of assigning each hospital admission a diagnosis-related group and an average cost for physician and hospital services. Emergency department visits were included only when they were made for worsening heart failure and were assigned costs equivalent to the average hospital and physician Medicare reimbursement for these visits in Duke University Medical Center's heart failure program. Drug costs were not assessed. Results Although the typical patient in both treatment groups was event-free, there was a trend toward a greater number of hospitalizations in the patients given lisinopril than in the patients given omapatrilat (P =.07). Differences in the distribution of cardiac hospitalizations between patients given lisinopril and patients given omapatrilat were significant (P =.03). There was a trend toward lower medical costs at 24 weeks in patients given omapatrilat versus patients given lisinopril ($1930 vs $2002, P =.09). Considering only cardiac medical costs, this trend toward reduced medical costs was significant ($1240 vs $1442, P =.03). Conclusions At 24 weeks, patients with heart failure treated with omapatrilat had fewer hospitalizations and lower medical costs than patients treated with lisinopril. However, drug treatment costs were not available for this analysis. (Am Heart J 2002;143:1112-7.)