Bolus alteplase

An angiographic assessment of alteplase: double-bolus and front-loaded infusion regimens in myocardial infarction. DouBLE Study Investigators. Double Bolus Lysis Efficacy

BACKGROUND

This study was designed to investigate the efficacy of alteplase double-bolus dosing compared with the front-loaded 90-minute infusion regimen in patients with acute myocardial infarction. Recent pilot studies have suggested that bolus dosing may provide improved efficacy in establishing early, complete, and sustained patency of the infarct-related artery in the thrombolytic treatment of acute myocardial infarction.

METHODS AND RESULTS

In this multicenter, randomized, open-label trial, 461 patients with acute myocardial infarction received 100 mg alteplase as a front-loaded 90-minute infusion (15 mg bolus, then 50 mg over a 30-minute period, then 35 mg over a 60-minute period) or double bolus (two 50 mg bolus injections 30 minutes apart). All patients also received intravenous heparin and oral aspirin during and after alteplase treatment. The 90-minute angiographic patency rates were 74.5% in the double-bolus group and 81.4% in the infusion group (p = 0.08). Patency rates were also comparable for the two groups at 60 minutes (76.8% vs 77.5%) and 24 hours (95.5% vs 93.5%) after initiation of treatment. In-hospital mortality rates were 4.5% in the bolus group and 1.3% in the infusion group (p = 0.04); 30-day mortality rates were 4.5% and 1.7%, respectively (p = NS). The two-groups were comparable in frequency of all other adverse events.

CONCLUSIONS

Double-bolus alteplase administration produced reperfusion rates comparable to front-loaded infusion, but in-hospital and 30-day mortality rates were higher in the double-bolus group. These findings are in agreement with those of the COBALT megatrial, which also reported a trend to higher mortality rates with double-bolus dosing.

Evaluation of thrombolytic and systemic effects of the novel recombinant plasminogen activator BM 06.022 compared with alteplase, anistreplase, streptokinase and urokinase in a canine model of coronary artery thrombosis

The thrombolytic and systemic effects of BM 06.022 were evaluated and compared with those of alteplase, anistreplase, streptokinase and urokinase in a canine model of coronary artery thrombosis. BM 06.022 consists of the kringle-2 and protease domains of human tissue plasminogen activator (t-PA) and is unglycosylated because of its expression in Escherichia coli cells. Thrombus formation in anesthetized open chest dogs was induced by electrical injury to the intimal surface of the left circumflex coronary artery at a high level site of obstruction. In heparinized dogs, none of six vehicle-treated animals exhibited reperfusion. Reperfusion was achieved in four of six dogs at 18.3 +/- 6 min after intravenous bolus injection of 140 kU/kg (0.24 mg/kg) of BM 06.022, whereas four of six dogs exhibited reperfusion later (p less than 0.05) at 76.5 +/- 16.1 min during infusion of 1.33 mg/kg of alteplase (0.13 mg/kg as initial bolus injection, followed by 0.66 mg/kg over 1 h and 0.53 mg/kg over 2 h). Significantly later (p less than 0.05) reperfusion than that achieved with BM 06.022 was achieved in five of six dogs at 57.8 +/- 12.1 min after intravenous injection of 0.4 U/kg of anistreplase. Streptokinase (21,000 IU/kg over 60 min) and urokinase (20,000 IU/kg as an intravenous bolus injection, followed by 20,000 IU/kg over 89 min) each induced reperfusion in three of six dogs but at 67 +/- 12 and 84.3 +/- 17.1 min (p less than 0.05 vs. BM 06.022), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effectiveness of double bolus alteplase in the treatment of acute myocardial infarction

Fifty-nine consecutive patients presenting within 6 hours of the onset of symptoms of an acute myocardial infarction were treated with 150 mg of soluble aspirin orally, and either 70 or 100 mg of alteplase divided into 2 intravenous bolus injections separated by 30 minutes. Dosage regimens were either 20 followed by 50 mg (group A), 50 followed by 20 mg (group B), or 50 followed by 50 mg (group C). Coronary angiography 60 minutes after the first bolus showed infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction score 2 or 3) in 13 of 16 (81%) patients in group A, 12 of 17 (71%) in group B, and 10 of 11 (91%) in group C (overall patency rate at 60 minutes: 35 of 44 [80%] patients; 95% confidence interval 68 to 91%). At 90 minutes, patency rates were 15 of 20 (75%) patients in both groups A and B, and 18 of 19 (95%) in group C (overall patency rate 48 of 59 [81%] patients; 95% confidence interval 72 to 91%). Residual thrombus was identified with the 90-minute angiogram in 7 patients in group A, 5 in group B, and 3 in group C. Although there was no statistically significant difference in patency between the 3 dosage regimens at either 60 or 90 minutes there was a trend toward increased patency and more complete thrombolysis at 90 minutes in group C. No episodes of bradyarrhythmia, hypotension or cerebrovascular bleeding were observed after double bolus therapy. There were 7 episodes (12%) of reocclusion, and 3 deaths (5%) within 1-month follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

A pilot study of the efficacy and safety of bolus administration of alteplase in acute myocardial infarction

OBJECTIVE

To examine the efficacy, safety, and the pharmacokinetic profile of a bolus dose administration regimen of alteplase in the treatment of acute myocardial infarction.

DESIGN

An open pilot study.

SETTING

District general hospital.

PATIENTS

33 suitable consecutive patients presenting within six hours of the onset of symptoms who satisfied the electrocardiographic criteria for acute myocardial infarction.

INTERVENTIONS

Two intravenous boluses of 35 mg alteplase, 30 minutes apart.

MAIN OUTCOME MEASURES

Angiographic coronary patency at 90 minutes and 24 hours. Plasma alteplase concentration-time profile and pharmacokinetic analysis.

RESULTS

Coronary patency at 90 minutes: 26 of 30 arteries (87%, 95% confidence interval (CI) 74-99%). Coronary patency at 24 hours: 24 of 29 arteries (83%, CI 69-97%). Mean (SD) plasma tissue plasminogen activator (t-PA) concentration reached 4434.8 (2117.8) and 4233.3 (2217.5) ng/ml within 10 minutes of each bolus and fell to 425.8 (288.3) ng/ml between boluses. The estimated peak concentrations at two minutes after boluses were 12,389 (8580) ng/ml and 10,811 (6802) ng/ml. The derived pharmacokinetic variables were volume of distribution 3.11 (1.89) 1, clearance 21.3 (9.3) 1/h, half life 5.9 (1.7) minutes.

CONCLUSIONS

This simple administration regimen achieved brief, high concentrations of plasma t-PA that were well tolerated. The regimen was associated with a high coronary patency rate at 90 minutes that was well maintained at 24 hours.

A randomized trial of a single bolus dosage regimen of recombinant tissue plasminogen activator in patients with acute pulmonary embolism

Experiments in animals have demonstrated that recombinant tissue plasminogen activator (rt-PA) produces continuing thrombolysis after it is cleared from the circulation and that thrombolysis is both increased and accelerated, and bleeding is reduced when rt-PA is administered over a short period. In previous studies in patients with thrombotic disease, rt-PA has been shown to be an effective thrombolytic agent when administered by continuous infusion over a period between 90 minutes and 8 hours. To determine whether a short course regimen of rt-PA can achieve thrombolysis, a double-blind randomized trial has been conducted in which patients with objectively established acute symptomatic pulmonary embolism who were receiving heparin were allocated to either a 2-minute infusion of rt-PA at a dose of 0.6 mg/kg (33 patients) or saline placebo (25 patients). Perfusion lung scanning was used to assess the change in pulmonary perfusion at 24 hours and seven days post-study drug administration. Thirty-four percent of the rt-PA patients had a greater than 50 percent resolution in the perfusion defect at 24 hours compared to 12 percent of placebo patients (p = 0.026). At 24 hours, the mean relative improvement in the perfusion defect was 37.0 percent in rt-PA treated patients compared to 18.8 percent in the placebo group (p = 0.017). By day 7, no difference in lung scan resolution was detected between the groups. There were no major bleeds in either group nor were there any differences in transfusion requirements between groups. Minor bleeding occurred in 15 of the rt-PA patients mainly at angiogram-catheter insertion and venipuncture sites. These results suggest that a bolus regimen of rt-PA produces accelerated thrombolysis and provides an alternative and convenient approach to thrombolytic therapy in patients with pulmonary embolism.