Effects of a High-dose Concentrate of n-3 Fatty Acids or Corn Oil Introduced Early After an Acute Myocardial Infarction on Serum Triacylglycerol and High-density Lipoprotein (HDL)- Cholesterol

Results of epidemiologic studies and clinical trials indicate that moderate doses of n-3 unsaturated fatty acids reduce the risk of cardiovascular disease(CVD) and may improve prognosis. N-3 fatty acids have several beneficial cardiovascular properties (1-3), including antiatherothrombotic, antiarrhythmic, and antihypertensive effects, and are especially noted for their triacylglycerol-reducing ability (3-7). These effects may translate into an improved clinical outcome in patients with coronary artery disease (CAD) (8).

The pronounced effect obtained of moderate doses of n-3 fatty acids supplementation may suggest an even stronger effect of pharmacologic doses.

The object of this study was therefore to assess the effect of a high-dose ethylester concentrate of n-3 fatty acids as compared to corn oil administered early (4-8 days) after an acute myocardial infarction (MI), on fatal and non-fatal subsequent cardiac events (cardiac death, resuscitation, recurrent myocardial infarction (MI) or angina pectoris), during 2 ys follow-up (median 18 months). We hypothesized that a high-dose of n-3 fatty acids would improve serum lipids in this population, and beneficially influence several markers of coagulation, endothelial dysfunction and inflammation.

Three hundred patients with an acute myocardial infarction (MI) were recruited at one hospital center (Central Hospital in Rogaland, Stavanger, Norway) from September 1995 until December 1996. All patients were included between the fourth and the eighth day after an acute myocardial infarction (MI). All patients were randomly assigned to receive 2 gelatin capsules of Omacor-R (Pronova AS, Oslo) or corn oil twice a day. Each capsule contained either 850-882 mg eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as ethylesters in the average ratio of eicosapentaenoic acid (EPA) to docosahexaenoic acid (DHA) of 1:2 or the same amount of corn oil. α-Tocopherol (4 mg) was added to all capsules. The capsules were administered in a double-blind manner over 12-24 months. A detailed patient history was recorded and a clinical examination was performed. The electrocardiogram was scrutinized for infarct location. The recent injury was classified as an anterior or inferior Q-wave infarction or any non-Q-wave infarction. Treatment was initiated immediately after inclusion and collection of baseline blood samples. The study was approved by the Regional Ethics Committee for Western Norway.

Clinical follow-up, including blood tests and electrocardiogram recordings, was repeated at 6 wk, 6 mo, 1 y, 18 mo, and, for some patients, 2 ys after the start of treatment. A deviation of 2 wk at the first follow-up and ≤1 mo at later follow-ups was allowed. All cardiac events and ongoing medication were recorded. Cardiac events were defined as cardiac death, resuscitation, recurrent myocardial infarction (MI), and unstable angina. Revascularization and death from other causes were also recorded. The study was closed at the end of 1997. The median follow-up time (ignoring events except deaths) was 1.5 y.