Effects of Abciximab on the architecture of platelet-rich clots in patients with acute myocardial infarction undergoing primary coronary intervention.
BACKGROUND
Abciximab plus aspirin improves the TIMI 3 flow rate of the infarct-related artery in patients treated with either percutaneous coronary intervention or thrombolysis. The present study investigated whether the reperfusion efficacy of abciximab relates to modifications of clot architecture in patients admitted for acute myocardial infarction (AMI).


RESULTS
A total of 23 AMI patients in the Abciximab before Direct angioplasty and stenting in Myocardial Infarction Regarding Acute and Long term follow-up (ADMIRAL) trial received, in a double-blind fashion, either abciximab (n=13) or placebo (n=10) before primary stenting. Viscoelastic (G' in dyne/cm(2)) and morphological (mean platelet aggregate surface area [SAG] in micrometer(2)) indexes of ex vivo platelet-rich clots (PRC) were assessed in a double-blind fashion before and after the bolus administration of abciximab or placebo. G' and SAG reflect the mechanical and morphological impact of activated platelets on the PRC fibrin network, respectively. Abciximab administration reduced G' by 63% (P=0.0001) and SAG by 65% (P=0.0007), and no effect was seen in the placebo group. These abciximab-related changes increased fibrin exposure as a consequence of the platelet-aggregate surface reduction and may have improved endogenous fibrinolysis. These effects were identified in all patients, independent of previous heparin administration.


CONCLUSIONS
Abciximab dramatically reduces platelet aggregate size and increases the fibrin accessibility of ex vivo PRC in AMI patients. These modifications could participate in the better coronary artery patency observed with abciximab.
Collet
J P
JP
Department of Cardiology, Pitié-Salpêtrière Hospital, Paris.
Montalescot
G
G
Lesty
C
C
Mishal
Z
Z
Soria
J
J
Choussat
R
R
Drobinski
G
G
Soria
C
C
Pinton
P
P
Barragan
P
P
Thomas
D
D
D000077284:Abciximab; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects*; D001792:Blood Platelets / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D008297:Male; D009203:Myocardial Infarction / Q000097:blood / Q000628:therapy*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome; D014783:Viscosity / Q000187:drug effects
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D010975:Platelet Aggregation Inhibitors; D000077284:Abciximab