Better outcomes for patients treated with ANP after MI

ewenwen2007

26October2007

MedWire News: Patients given atrial natriuretic peptide (ANP) after myocardial infarction (MI) have a smaller infarct size, fewer reperfusion injuries, and improved left ventricular ejection fraction (LVEF) than MI patients who do not receive this treatment, results from two trials indicate.

\"We believe that ANP could be a safe and effective adjunctive treatment in patients with acute MI who receive percutaneous coronary intervention,\" the authors write in The Lancet.

Masafumi Kitakaze (National Cardiovascular Center, Suita, Osaka, Japan) and colleagues conducted two randomized trials to compare the effect of ANP or nicorandil with placebo in 1216 patients who had suffered acute MI and were undergoing reperfusion treatment.

In the ANP trial, 277 patients received intravenous ANP, at a dose of 0.025 礸/kg per min for 3 days, and 292 received the same dose of placebo. In the nicorandil trial, 276 patients were treated with 0.067 mg/kg as a bolus, followed by 1.67 礸/kg per min as a 24-hour continuous infusion, and 269 received the same dose of placebo.

Primary endpoints were infarct size, as estimated from creatine kinase levels, and LVEF, determined by angiography of the left ventricle.

The median follow-up was 2.7 and 2.5 years in the ANP and nicorandil trials, respectively,

Patients given ANP had significantly lower levels of creatine kinase than those in the placebo group (66,459.9 vs 77,878.9 IU/ml per hour), which indicated a 14.7% reduction in infarct size.

Patients in the ANP group had fewer reperfusion injuries than those in the placebo group (hazard ratio[HR]=0.74, p=0.01). Cardiac death and readmission to hospital for heart failure were also less likely in patients given ANP than in controls (HR=0.26, p=0.01).

Intravenous nicorandil did not significantly affect creatine kinase levels, LVEF, reperfusion injuries, cardiac death, or readmission to hospital for heart failure, compared with placebo.

However, oral administration of nicorandil during follow-up increased the LVEF between the chronic phase, at 2-8 weeks, and acute phase, at 6-12 months.

Kitakaze et al conclude: \"Our finding that treatment with ANP in the acute phase reduced the incidence of readmission to hospital for chronic heart failure could help to reduce the physical, medical, and economic burdens on people around the world.\"

Richard Bogle and Martin Wilkins, from Imperial College London in the UK, write in an accompanying comment that as the studies were single-blind, \"use of ANP as a treatment for acute MI needs further investigation in a double-blind study.\"