ST segment resolution in ASSENT 3: insights into the role of three different treatment strategies for acute myocardial infarction.
OBJECTIVE
ASSENT 3 (Assessment of the Safety and Efficacy of a New Thrombolytic) demonstrated that the bolus fibrinolytic tenecteplase (TNK), combined with enoxaparin (ENOX) or abciximab (ABCX), substantially reduced ischemic complications of acute myocardial infarction as compared with unfractionated heparin (UH). We compared ST resolution in each of the three treatment regimens in order to evaluate the speed, extent and stability of ST segment resolution and its relationship to the primary composite endpoint(s) of the trial.


RESULTS
We evaluated ST segment shift and its subsequent resolution i.e. complete (> or =70%), partial (<70-30%) and no resolution (<30%) in 4,304 patients 60 and 180 min after treatment. Sixty minutes after therapy there was a trend for both half-dose TNK/ABCX and TNK/UH to have more frequent complete ST resolution (P=0.072) than TNK/ENOX. Pair-wise comparison at 60 min revealed that patients receiving TNK/ABCX had significantly more complete ST resolution than TNK/ENOX (P=0.026). Further ST resolution had occurred 180 min after treatment: complete ST resolution was greater with TNK/ABCX (59.2%) than the TNK/heparin (50.8%) and TNK/enoxaparin (50.8%) (P<0.001). In the TNK/ENOX group achieving complete ST resolution by 180 min, in-hospital reinfarction was 1.9% vs 4.2% for TNK/UH (P=0.015) representing a 2.3% absolute and 55% relative reduction in reinfarction. Thirty day and one year mortality was greatest amongst those patients with <30% ST segment resolution in the TNK/ABCX group.


CONCLUSIONS
More rapid and complete ST resolution occurs with half-dose TNK/ABCX whereas less reinfarction occurs amongst those patients with > or =70% ST resolution receiving either TNK/ABCX or TNK/ENOX. These data highlight two potentially complementary mechanisms of clinical benefit associated with different pharmacologic regimens in acute myocardial infarction, i.e. more rapid versus more stable coronary patency.
Armstrong
Paul W
PW
University of Alberta, Edmonton, Canada. paul.armstrong@ualberta.ca
Wagner
Galen
G
Goodman
Shaun G
SG
Van de Werf
Frans
F
Granger
Christopher
C
Wallentin
Lars
L
Fu
Yuling
Y
D000077284:Abciximab; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D004562:Electrocardiography; D017984:Enoxaparin / Q000627:therapeutic use*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D012044:Regression Analysis; D000077785:Tenecteplase; D015912:Thrombolytic Therapy / Q000379:methods; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D017984:Enoxaparin; D005343:Fibrinolytic Agents; D007140:Immunoglobulin Fab Fragments; D010975:Platelet Aggregation Inhibitors; D010959:Tissue Plasminogen Activator; D000077785:Tenecteplase; D000077284:Abciximab