[Intravenous thrombolysis in myocardial infarction. Influence of the quality of the anticoagulation on the early recurrence rate of angina or infarction].

In this retrospective study the data of 70 patients treated with streptokinase in the acute phase of myocardial infarction were reviewed in search of a possible relation between recurrent ischaemic events and degree of anticoagulation. All patients had received a 30 mn infusion of streptokinase 1.500.000 units within a mean 175 mn period from the initial symptoms. They were followed up clinically (signs of angina or infarction), angiographically (coronary arteriography within 5.5 days on average) and biochemically (daily measurements of TCA values and blood fibrinogen concentrations). Fifteen recurrent ischaemic events (21.4 p. 100), including 6 attacks of angina and 9 myocardial infarctions, were observed. Angiography showed that the artery responsible for the initial infarction was occluded in 23.6 p. 100 (13/55) of patients without recurrent ischaemic accident. This figure rose to 46.6 p. 100 in patients who suffered a new anginal attack (7/15; NS) and up to 77 p. 100 in those who developed a new myocardial infarction (7/9; p less than 0.01). Biochemical data showed that 13 recurrent ischaemic accidents occurred when the APTT values were lower than 1.5 (176 measurements), as against 2 when these values were higher than 1.5 (359 measurements) (p less than 0.01). These two recurrent ischaemic accidents took place when fibrinogen concentrations abruptly rose above 1 g/litre. These results demonstrate that poor quality anticoagulation is responsible for the occurrence of recurrent ischaemic events within days of thrombolysis for acute myocardial infarction. They prompt the authors to recommend anticoagulation with heparin started at an early stage and carefully adjusted by means of repeated biochemical essays.