Use of bedside activated partial thromboplastin time monitor to adjust heparin dosing after thrombolysis for acute myocardial infarction: Results of GUSTO-I, , , ,

Background The safety and efficacy of bedside monitors of activated partial thromboplastin time (aPTT) have not been examined in a large population receiving intravenous heparin after thrombolytic treatment for acute myocardial infarction. We compared outcomes among patients monitored with these devices versus standard monitoring methods. Methods and Results Investigators chose the bedside device (n = 1713 patients) or their standard method (n = 26,162) for all aPTT measurements at their sites. Clinical outcomes at 30 days, 1-year mortality rate, and aPTT levels at 6, 12, and 24 hours were compared. Bedside-monitored patients had significantly less moderate/severe bleeding (10% vs 12%, P < .01), fewer transfusions (7% vs 11%, P < .001), and a smaller decrease in hematocrit (5.5% vs 6.7%, P < .001) but significantly more recurrent ischemia (22% vs 20%, P = .01). Fewer bedside-monitored patients had subtherapeutic aPTT levels at 12 and 24 hours. Among patients with subtherapeutic levels at 6 and 12 hours, more bedside-monitored patients had therapeutic levels when next monitored. After adjustment for baseline differences, no significant difference in mortality rate was observed in bedside-monitored patients at 30 days (4.3% vs 4.8%, P = .27) and at 1 year (7.1% vs 7.7%, P = .38). The groups had similar rates of reinfarction, shock, heart failure, and stroke. Conclusions This prospective substudy supports the use of bedside monitoring of heparin anticoagulation after thrombolysis. (Am Heart J 1998;136:868-76.)