MONDAY, March 26, 2007 (HealthDay News) -- The drug tilarginine does not reduce the risk of death for heart attack patients who develop cardiogenic shock (low blood pressure due to impaired cardiac function), a new study finds.
The study, published online March 26 by the Journal of the American Medical Association, is also being presented at the American College of Cardiology's annual conference, in New Orleans.
Cardogenic shock is the leading cause of death among hospitalized heart attack patients, according to background information in the study.
Inflammation -- including the production of an enzyme called nitric oxide synthase (NOS) -- boosts blood levels of nitric oxide, the researchers explained. High levels of nitric oxide can cause vessels to inappropriately widen as they do in persistent cardiogenic shock, they added.
Previous studies suggested that inhibiting NOS might improve survival in patients with cardiogenic shock, they noted.
This new study -- TRIUMPH (Tilarginine Acetate Injection in a Randomized International Study in Unstable MI Patients With Cardiogenic Shock) -- included almost 400 patients in eight countries. Researchers looked at whether using the drug tilarginine to inhibit NOS would reduce the risk of death in this group of patients.
The patients received either 1-milligram per kilogram of tilarginine intravenously followed by 1.0 mg/kg per hour of intravenous infusion for five hours, or a placebo.
At 30 days, death rates were 48 percent for patients who received the drug and 42 percent for those who received the placebo. At six months, death rates were 58 percent for patients in the tilarginine group and 59 percent in the placebo group.
The study also found that tilarginine had no effect on the 30-day rates of recurrent heart attack or heart failure. Among patients with very low blood pressure, those who received the drug showed a greater early rise in blood pressure than those who received the placebo. However, the resolution and duration of cardiogenic shock were similar in both groups.
"Tilarginine, at the dose and duration, studied, had no effect on mortality in patients with [heart attack] complicated by refractory cardiogenic shock," the team wrote. "Additional innovations in therapy and improved health care delivery systems are needed to reduce the high short-term mortality rate of patients who develop cardiogenic shock," they said.
The study was funded by AgriNOx Pharmaceuticals Inc.
The American Heart Association has more about heart attack.