Aim: Limited data are available regarding the clinical relevance of platelet function measurements in stable patients with coronary artery disease (CAD). Our aim is to evaluate the agreement between multiple electrode aggregometry (MEA) and light transmittance aggregometry (LTA) in detecting clopidogrel low responders and their prognostic value in CAD patients with type 2 diabetes mellitus (T2DM) on dual platelet inhibition.
Methods: LTA and MEA were performed in 122 stable cardiovascular patients with T2DM. The upper quartile of patients according to maximum LTA (LTAmax) and MEA measurements were defined as clopidogrel low responders. Agreement between the two methods was evaluated by kappa statistics. We assessed the potential correlation between antiplatelet response and clinical outcome and the optimal cutoff value according to ROC analysis to predict the occurrence of major adverse cardiovascular events (MACE), during 1-year follow-up period.
Results: Cohen's kappa coefficients (0.214) indicated fair agreement (70.2%) between LTA and MEA. A total of 25 MACE occurred in 108 patients (23.1%). Patients with MACE had higher LTAmax than those without (57.1 ± 16.5 vs 49.3 ± 18.3, respectively, p = 0.023). MEA measurements were similar between patients with and without MACE (30.1 ± 15.4 vs 30.6 ± 20.8, respectively; p = 0.84). Multiple logistic regression showed LTAmax response as an independent predictor of death from cardiovascular causes (Odds Ratio, adjusted:0.2;0.05-0.81). ROC analysis indicated that LTAmax cutoff of 62.5% best predicted death (AUC = 0.67, sensitivity = 78%, specificity = 61.5%).
Conclusions: The assessment of platelet responsiveness remains highly test-specific. Our results support the prognostic role of LTA, but not MEA testing, for death risk evaluation in stable cardiovascular T2DM patients.
Keywords: Clinical prognosis; Coronary artery disease; Diabetes mellitus; Light transmittance aggregometry; Multiple electrode aggregometry.
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