[Correlation between antiplatelet resistance and recurrent cardiac ischemic events of patients with acute myocardial infarction].

OBJECTIVE

To evaluate the predictive value of antiplatelet resistance assessed by whole blood electronic impedance aggregometry (EIA) for the risk of recurrent cardiac ischemic events in patients with acute myocardial infarction (AMI) who underwent coronary stenting.

METHODS

We enrolled 109 patients with AMI, 72 (66.1%) men and 37 (33.9%) women with mean age (63 ± 12) years, who were treated with aspirin and clopidogrel daily after coronary stenting. EIA used arachidonic acid (AA) and adenosine diphosphate (ADP) as inductors to measure platelet aggregation inhibited by aspirin and clopidogrel respectively. The subjects were divided into four groups: pure aspirin resistant group (AR, electrical impedance > 0 Ω), pure clopidogrel resistant group (CR, electrical impedance ≥ 10 Ω), dual resistant group (DR) and dual sensitive group (DS). The primary outcomes were recurrent cardiac ischemic events during the 12-month follow-up.

RESULTS

Antiplatelet resistance occurred more often in patients with type 2 diabetes (P = 0.027). The platelet counts (PLT) were higher in antiplatelet resistant groups than DS group (P = 0.013). During the 12-month follow-up, the antiplatelet resistant patients had a higher incidence of recurrent cardiac ischemic events and stent thrombosis (ST) than the patients without (12.5%, 10.0%, 50.0% vs 3.8%, P = 0.036; 6.3%, 10.0%, 50.0% vs 1.3%, P = 0.000; respectively). Binary Logistic regression indicated that dual resistance remained an independent predicator of recurrence cardiac ischemic events and ST (OR 5.99, 95%CI 1.05 - 34.34, P = 0.045; OR 6.36, 95%CI 1.13 - 35.78, P = 0.036; respectively).

CONCLUSIONS

As a physiological assessment of platelet reactivity, EIA is a convenient and accurate option for measuring aspirin resistance. Antiplatelet resistance assessed by EIA is paralleled to clinical events. Dual resistance is an independent predicator for ST and recurrence cardiac ischemic events in patients with AMI.