The long-term (3.5 yrs) assumption of 1g of polyunsaturated fatty acids (n-3 PUFA) improves significantly the prognosis of patients who have suffered a recent (<3 mos) myocardial infarction; the benefit is 10-15% relative reduction of the events included in the primary end-point (deaths and non-fatal cardiovascular events). This benefit is almost exclusively due to the decrease of total deaths (14-20%).
At variance with the results obtained with n-3 PUFA, those related to the other experimental treatment, vitamin E, 300 mg/day failed to reach formal statistical significance, though the data on mortality could be seen as highly suggestive of a possible beneficial effect to be verified with the information expected from other ongoing trials. The GISSI-Prevenzione provides also evidence that the combined administration of the two treatments does not add to the beneficial effect of n-3 PUFA.
These results have been produced by the GISSI-group (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto), who since 15 years is present in the international scene of cardiology with its large-scale trials, jointly sponsored by the Associazione Nazionale Medici Cardiologi Ospedalieri (ANMCO) and by Istituto Mario Negri- Consorzio Mario Negri Sud.
The GISSI-Prevenzione includes 11,324 patients, recruited by 172 cardiological departments representing up to 2/3 of the structures of the Country National Health Care System. The results of the GISSI trial confirm early epidemiological reports on the protective effect of a diet rich in fish (n-3 PUFA are considered the main active component), and the findings of other much smaller controlled trials, not sufficiently powered to measure the impact of the treatment on cardiovascular and overall mortality. In the GISSI-Prevenzione, an impressive decrease (more than 40%) has been specifically shown on fatal events classified as sudden deaths, which accounts for up to 30% of all CV deaths. It is interesting to note that the exploratory analysis of the same class of events is also suggestive of an important beneficial effect (similar decrease of events in the treated group) of vitamin E.
A further hint on the importance of the findings of GISSI-Prevenzione must be seen in the fact that the beneficial effects of n-3 PUFA have been obtained in a population already maximally protected with recommended secondary prevention treatments (antiplatelet drugs, beta-blockers, ACE-inhibitors), and exposed to a mediterranead diet, which has been confirmed recently to be per se an important protective factor with respect to cardiovascular risks.
Based on the estimates produced by GISSI-Prevenzione, up to 20 lives are expected to be saved per 1,000 pts treated with n-3 PUFA. This 5.7 lives saved per year is a result which compares well with the benefit obtained with statins in the LIPID trial (5 lives / 1,000 pts/yr). The suggested, though statistically not proven benefit of 14 lives saved per 1,000 pts treated with vitamin E is definitely worth of verification.