Influence of heparin on fibrinogen and D-dimer plasma levels in acute myocardial infarction treated with streptokinase

The purpose of this study was to investigate whether, to what extent, and through which mechanisms intravenous heparin, administered before and after streptokinase, affects the plasma levels of D-dimer and fibrinogen in myocardial infarction. Data concerning mortality and incidence of coronary recanalization in patients receiving heparin and thrombolytic therapy after acute myocardial infarction are controversial; furthermore, the mechanisms through which heparin acts in combination with thrombolytic therapy are unclear. Thirty-eight patients with acute myocardial infarction treated with streptokinase were considered. Nineteen of them received, immediately before the beginning of thrombolytic treatment, a bolus of heparin (100 U.kg-1 intravenously) and, 2 h later, intravenous heparin in doses raising the partial thromboplastin time to 2-2.5 times the normal value (Group 1); the remaining 19 did not receive anticoagulant treatment (Group 2). Multiple determinations of plasma D-dimer and fibrinogen levels were obtained in all patients before, and in the seven days following thrombolytic treatment. Six hours after streptokinase, fibrinogen decreased from 304 +/- 34 to 61 +/- 34 mg.dl-1 in Group 1 and from 312 +/- 29 to 38 +/- 21 mg.dl-1 in Group 2 (P < 0.02 versus Group 1). The same difference between groups persisted at the 12th and at the 18th hour. D-dimer values, from 0.5 +/- 0.1 microgram.dl-1 in Group 1 and 0.4 +/- 0.1 microgram.dl-1 in Group 2, increased at the 1st hour to 37.2 +/- 36.5 micrograms.dl-1 and 52.2 +/- 39.8 micrograms.dl-1, respectively. A peak value was reached in both groups at the 6th hour, which was followed by a slow decrease.(ABSTRACT TRUNCATED AT 250 WORDS)