[Impact of intravenous thrombolysis prior to percutaneous coronary intervention in reperfusion therapy for acute myocardial infarction].

OBJECTIVES: To elucidate the effectiveness and safety of intravenous thrombolysis (IVT) with mutant tissue plasminogen activator prior to percutaneous coronary intervention (PCI) in patients with acute myocardial infarction.

METHODS: Ninety consecutive patients were recruited with the following criteria: acute myocardial infarction with ST segment elevation or bundle branch block on electrocardiography, admission within 6 hr from onset, age of < or = 80 years and without previous PCI or coronary bypass graft surgery. They were divided into two groups. Group IV consisted of 53 patients treated with IVT prior to PCI and Group D consisted of the other 37 patients with direct PCI. Mutant tissue plasminogen activator, monteplase, was administered with a dose of 27,500 U/kg in Group IV (maximum injection dose, 160 x 10(4) U). The clinical features and in-hospital outcome were compared between the two groups.

RESULTS: Patients in Group IV acquired earlier reperfusion estimated by electrocardiography recovery at 60 min after admission and higher Thrombolysis in Myocardial Infaction (TIMI) flow grade on the first coronary angiogram (TIMI 2 or 3 flow rate; Group IV vs Group D = 75% vs 35%, p < 0.0001). The duration from onset to TIMI 3 flow grade was not significantly different between Group IV and Group D (230 vs 260 min, p = 0.15). The incident of ST segment re-elevation with chest pain at recanalization was lower in Group IV than in Group D (23% vs 46%, p < 0.05). The duration from TIMI 3 recognition to peak creatine kinase level was longer in Group IV (466 vs 359 min, p = 0.039). Subacute thrombotic occlusion occurred in two patients in Group IV and three in Group D (NS). One patient in each group died from pump failure (NS). No severe bleeding complication was found in any patient.

CONCLUSIONS: IVT prior to PCI was considered to be a safe, effective and useful therapy in patients with acute myocardial infarction. Different patterns of reperfusion might occur, because of the low frequency of ST re-elevation and elongation of duration from reperfusion to peak creatine kinase level in patients treated with IVT prior to PCI.