Platelet reactivity and streptokinase resistance following antecedent streptokinase therapy for myocardial infarction.
OBJECTIVE
To assess the efficacy of second-time administration of streptokinase (SK). First-time thrombolysis with SK in myocardial infarction (MI) is established but the efficacy of subsequent SK is unknown.


RESULTS
Platelet reactivity to shear stress, spontaneous and SK-induced thrombolysis were measured in vitro in 28 patients who had received SK for MI and compared to 15 controls. SK antibody (Ab) titres were inversely related to time from MI. Platelet reactivity was greatly enhanced in patients (p < 0.0001). Spontaneous thrombolysis in patients was poor and in 17 failed to occur. In contrast, thrombolysis occurred in all but 1 control. In patients platelet reactivity was strongly related to thrombolytic activity (r = -0.516; p = 0.0029). SK in vitro was at least 4 times more effective in controls than in patients.


CONCLUSIONS
The chances of achieving patency with second administration of SK are poor. Ab titre is not a reliable predictor of resistance.
Division of Cardiology, Imperial College School of Medicine, Hammersmith Hospital, London, UK.
D A
DA
Gorog
N
N
Ahmed
G J
GJ
Davies
D000328:Adult; D000368:Aged; D000906:Antibodies / Q000097:blood; D001792:Blood Platelets / Q000187:drug effects* / Q000276:immunology; D004351:Drug Resistance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000188:drug therapy*; D019233:Retreatment; D013300:Streptokinase / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D015912:Thrombolytic Therapy; D016896:Treatment Outcome
D000906:Antibodies; D013300:Streptokinase