FREVENTION OF MYOCARDIAL REINFARCTION BY LOW DOSE HEPARIN
The effectiveness of low dose heparin in the prevention of myocardial reinfarction was investigated in a multi centric randomized controlled study. After having given their, informed consent to undergo daily subcutaneous heparin adninistratian, 728 patients of both sex aged 50-75 years, who had suffered frcm a transmural myocardial infarction 6-18 months before the enrollment and were in the I or II NYHA class were randomized. 365 patients (control group) were an the therapy usually performed by the 21 experimental canters participating in the study and 363 (heparin group) were treated with subcutaneous calcium heparin (Calciparina®) 12,500 IU daily in addition to the usual therapy of the centers. Curing enrollment the balancement of the two grcups was periodically checked for age, sex, serum cholesterol, cigarette smoking, blood pressure, site of infarction, arrhythmias and drug regimen. The prospect!vely established end-points were: transmural reinfarctioi as primary end-point; general mortality and mortality for cardiovascular events as accessory end-points over a mean follow-up period of 24 nxnths. Statistical analysis was foreseen both on drug efficacy (EE) and intention to treat (IT) basis. Patients of both groups underwent periodical examinations during the study. Acherence to the therapy and bone mineral content (bone density by double isotope technique) were also checked. At the end of the study the balancement for the factors considered was satisfactory and the drop-outs were 7.7% in heparin group and 6.3% in control group (ns). In heparin group the re infarction rate was lcwer by 62.92% than in control group. At life table analysis the difference was statistically significant (p<0.05 DE and p=0.05 IT). Mortality rate was reduced by 47.61% (DE) in heparin group (p<0.05 at life table analysis). Cardiovascular mortality was not significantly reduced (−33.06%), but the mortality attributable to thromboembolism was reduced in heparin group (p<0.05). Sixty patients (16.5%) discontinued heparin treatment, but only in 23 patients (6.3%) suspension was due to side effects.