Platelet function in patients with acute coronary syndrome (ACS) predicts recurrent ACS.
BACKGROUND
Platelet hyperfunction contributes to acute coronary syndromes (ACS). Thus, we hypothesized that platelet function under high shear stress predicts recurrent ACS during long-term follow-up of ACS patients.


METHODS
Consecutive ACS patients (n = 208) were prospectively followed-up for an average of 28 months. Platelet function was measured with the platelet function analyzer (PFA-100; Dade Behring, Marburg, Germany) at baseline for collagen/adenosine diphosphate closure times (CADP-CT) and for collagen/epinephrine closure times (CEPI-CT) after infusion of a uniform dose of 250 mg aspirin.


RESULTS
Of the conventional risk factors, only the prevalence of diabetes was higher in ACS patients with re-events. However, use of clopidogrel and use of beta blockers were also slightly lower in patients with re-events (P < 0.05). The unadjusted risk hazard ratio (HR) for re-events was 3.3 [95% confidence interval (95% CI): 1.4-7.4; P = 0.005] in those patients with the shortest CADP-CT values (lowest quartile). Similarly, the risk was 2.0-fold higher (95% CI: 1.1-3.6; P = 0.02) in ACS patients with CEPI-CT < 300 s as compared with CEPI-CT >or = 300 s. Inclusion of diabetes, clopidogrel and beta blockers in a multivariate Cox regression model enhanced the predictive value of CEPI-CT (HR: 2.7). Inclusion of von Willebrand factor levels did not alter the HR for recurrent ACS (HR: 2.1; 95% CI: 1.1-5.2; P = 0.03) for CEPI-CT < 300 s, but reduced the HR for CADP-CT (HR: 2.8, 95% CI: 0.8-9.8; P = 0.11).


CONCLUSIONS
Shortened CT values reflect biologically relevant platelet hyperfunction in patients with ACS because they predict recurrent ACS.
Fuchs
I
I
Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
Frossard
M
M
Spiel
A
A
Riedmüller
E
E
Laggner
A N
AN
Jilma
B
B
D000208:Acute Disease; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D001241:Aspirin / Q000494:pharmacology; D000077144:Clopidogrel; D003327:Coronary Disease / Q000097:blood* / Q000188:drug therapy / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D048909:Diabetes Complications / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D010979:Platelet Function Tests; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012107:Research Design; D018570:Risk Assessment; D013314:Stress, Mechanical; D013577:Syndrome; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D013997:Time Factors; D014841:von Willebrand Factor / Q000378:metabolism
D000319:Adrenergic beta-Antagonists; D010975:Platelet Aggregation Inhibitors; D014841:von Willebrand Factor; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin