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ASSENT-3 PLUS. 1,639 patients with STEMI Chest pain < 6 hrs Pt evaluated at home or in ambulance by emergency medical team 12-lead ECG transmitted to ED from the ambulance Pt randomized and treatment started during transport. Treatment Group A Enoxaparin + TNK (n = 818).
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ASSENT-3 PLUS • 1,639 patients with STEMI • Chest pain < 6 hrs • Pt evaluated at home or in ambulance by emergency medical team • 12-lead ECG transmitted to ED from the ambulance • Pt randomized and treatment started during transport Treatment Group A Enoxaparin + TNK (n = 818) Treatment Group B UFH + TNK (n = 821) • Endpoints: • Primary Efficacy– 30 day Death or In-hospital MI or Refractory Ischemia • Primary Efficacy plus Safety - 30 day Death or In-hospital MI, Refractory Ischemia, ICH or Major Bleed Wallentin et al, AHA 2002
ASSENT-3 PLUS: Primary Endpoints Death / MI / Refractory Ischemia/ ICH / Major Bleed Death / MI / Refractory Ischemia P=0.080 P=0.297 n=821 n=818 n=821 n=818 UFH + TNK Enoxaparin + TNK UFH + TNK Enoxaparin + TNK Wallentin et al, AHA 2002
ASSENT-3 PLUS: Individual Endpoints Recurrent MI Death ICH Refractory Ischemia P=0.047 P=0.028 P=0.067 P=0.234 Enoxaparin + TNK Enoxaparin + TNK UFH + TNK Enoxaparin + TNK UFH + TNK UFH + TNK Enoxaparin + TNK UFH + TNK Wallentin et al, AHA 2002
ASSENT-3 PLUS: Bleeding Results Stroke Major Bleed ICH P=0.026 P=0.047 P=0.168 Similar to prior studies Enoxaparin + TNK Enoxaparin + TNK Enoxaparin + TNK UFH + TNK UFH + TNK UFH + TNK Wallentin et al, AHA 2002
ASSENT 3 ICH Subgroups • In subgroup analysis, ICH bleeding was greater in the enoxaparin group in • patients >75 years old (6.71 vs. 0.76% p = 0.04) • females (5.15% vs. 1.09%, p = 0.02), and • low body weight (<60kg) patients (5.17% vs. 0%, p = 0.08) • There was a non-statistically significant trend toward increased major bleeding in the enoxaparin group (4.04% vs. 2.80%, p = 0.168). • Twenty-five percent of the patients in each arm continued on to PCI. None of those patients experienced ICH bleeding, suggesting full-dose TNKase is safe in the cath lab.
Why Was There More Bleeding in the Enoxaparin Group? • Administration of additional enoxaparin was frequent • The heparin bag is “visible”, the bolus of enoxaparin is “invisible” to people caring for the patient subsequently • Occurred more in Europe • This was a higher risk population
ASSENT-3 PLUS: Primary Endpoint by Age Group Age >75 Age <75 Death / MI / Refractory Ischemia Death / MI / Refractory Ischemia P=0.694 P=0.033 UFH + TNK Enoxaparin + TNK UFH + TNK Enoxaparin + TNK Wallentin et al, AHA 2002
ASSENT 3 Plus Supports the Concept that Time is Muscle • Symptom onset to treatment times were reduced by 45 minutes. • Fifty percent of patients were treated within 2 hours which represents a significant improvement over ASSENT-3 in which only 29% of the more than 4,000 patients receiving the same regimens in the hospital setting were treated within the same time period. • Earlier treatment was associated with improved outcomes: 30 day mortality 4.4% (0-2hr), 6.2% (2-4hr), 10.4% (4-6hr). • This data, combined with a meta-analysis of all pre-hospital thrombolysis studies showing a 16% improvement in mortality (Morrison et.al, JAMA May 2000), further supports the concept of “time is muscle” and early treatment. CM Gibson 2002
ASSENT-3 PLUS: Summary • In the pre-hospital setting, treatment with enoxaparin plus TNK did not provide significant additional benefit over treatment with UFH plus TNK for STEMI. • Pre-hospital TNK plus heparin does, however, appear to be safe and lower treatment times • Reduced or weight-adjusted dosing of enoxaparin may be warranted in elderly and low weight patients • Use of reduced dose enoxaparin in addition to TNK will be further investigated in the upcoming EXTRACT-TIMI trial CM Gibson 2002