IMPROVED THROMBOLYSIS IN ACUTE MYOCARDIAL-INFARCTION WITH FRONT-LOADED ADMINISTRATION OF ALTEPLASE - RESULTS OF THE RT-PA APSAC PATENCY STUDY (TAPS)

Thrombolysis with recombinant tissue-type plasminogen activator (rt-PA ) and anisoylated plasminogen streptokinase activator (APSAC) in myoca rdial infarction has been proved to reduce mortality. A new front-load ed infusion regimen of 100 mg of rt-PA with an initial bolus dose of 1 5 mg followed by an infusion of 50 mg over 30 min and 35 mg over 60 mi n has been reported to yield higher patency rates than those achieved with standard regimens of thrombolytic treatment. The effects of this front-loaded administration of rt-PA versus those obtained with APSAC on early patency and reocclusion of infarct-related coronary arteries were investigated in a randomized multicenter trial in 421 patients wi th acute myocardial infarction. Coronary angiography 90 min after the start of treatment revealed a patent infarct-related artery (Thromboly sis in Myocardial Infarction [TIMI] grade 2 or 3) in 84.4% of 199 pati ents given rt-PA versus 70.3% of 202 patients given APSAC (p = 0.0007) . Early reocclusion within 24 to 48 h was documented in 10.3% of 174 p atients given rt-PA versus 2.5% of 163 patients given APSAC. Late reoc clusion within 21 days was observed in 2.6% of 152 patients given rt-P A versus 6.3% of 159 patients given APSAC. There were 5 in-hospital de aths (2.4%) in the rt-PA group and 17 deaths (8.1%) in the APSAC group (p = 0.0095). The reinfarction rate was 3.8% and 4.8%, respectively. Peak serum creatine kinase and left ventricular ejection fraction at f ollow-up angiography were essentially identical in both treatment grou ps. There were more bleeding complications after APSAC (45% vs. 31%, p = 0.0019). Two intracranial hemorrhages (0.9%) occurred in each group ; one of these (in the APSAC group) was fatal. Front-loaded administra tion of 100 mg of rt-PA yields a significantly higher early patency ra te of the infarct-related artery in comparison with that achieved with APSAC. Although more early reocclusions occur after rt-PA than after APSAC treatment, hospital reinfarction rates are similar. The statisti cally significant difference in hospital mortality between the two pat ient groups needs to be confirmed by a further trial with mortality as a primary end point.