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Multiple electrode aggregometry and vasodilator stimulated phosphoprotein-phosphorylation assay in clinical routine
Matthias K Freynhofer1, Ivan Brozovic, Veronika Bruno
13rd Department of Medicine, Cardiology and Emergency Medicine, Wilhelminen Hospital, A-1160, Vienna, Austria. matthias.freynhofer@meduniwien.ac.at
Insights
The vasodilator stimulated phosphoprotein-phosphorylation (VASP-P) assay effectively predicts major adverse cardiovascular events (MACE) after coronary stenting in routine clinical practice. This assay is feasible for assessing clopidogrel
Area of Science:
- Cardiology
- Pharmacology
- Clinical Diagnostics
Background:
- Reduced antiplatelet effect of clopidogrel is linked to adverse cardiovascular events post-stenting.
- Previous studies lacked consecutive registries evaluating adenosine diphosphate-based platelet function tests in unselected patients.
- Multiple electrode aggregometry (MEA) and VASP-P assay are known predictors of MACE.
Purpose of the Study:
- To assess the clinical feasibility of MEA and VASP-P assays for routine use.
- To determine if low clopidogrel response, measured by MEA and/or VASP-P, predicts MACE in a real-world stenting population.
Main Methods:
- Prospective registry of 300 consecutive patients undergoing coronary stenting.
- Blood sampling 6-24 hours post-stenting for MEA and VASP-P measurements.
- Receiver Operating Characteristics (ROC) analysis to evaluate VASP-P's predictive performance for MACE.
Main Results:
- VASP-P assay was feasible in all 300 patients; MEA was limited to 196 due to glycoprotein-IIb/IIIa-blocker use.
- The VASP-P assay showed an area under the ROC curve of 0.683 (p=0.014) with an optimal cut-off at 60.2% PRI.
- Patients with PRI >60.2% had a significantly increased risk of MACE at six months (p=0.007).
Conclusions:
- The VASP-P assay is a feasible tool for clinical routine to assess clopidogrel effects and predict post-procedural MACE in unselected patients.
- Standardization of the VASP-P assay is crucial due to differing cut-off values.
- MEA testing is limited in unselected patients due to interference from GP-IIb/IIIa-blockers.
Abstract:
Reduced antiplatelet effect of clopidogrel assessed with multiple electrode aggregometry (MEA) and vasodilator stimulated phosphoprotein-phosphorylation (VASP-P) assay has been proven to predict major adverse cardiovascular events (MACE) after coronary stenting. So far no consecutive registry has evaluated the usefulness of different adenosine diphosphate-based platelet function tests to predict outcome in unselected patients. Hence, our objective was to determine the feasibility of MEA and VASP-P for clinical routine and whether low-response to clopidogrel as determined by MEA and/or the VASP-P assays predicts MACE in a "real-life" population undergoing coronary stenting. Three-hundred consecutive patients were included in this prospective registry. Blood was sampled 6-24 hours after stenting to measure MEA and VASP-P. The use of glycoprotein-IIb/IIIa-blockers limited MEA to 196 measurements. Concerning the VASP-P assay, 300 measurements were achieved. Receiver Operating Characteristics (ROC)-curves of sensitivity and specificity estimates for MACE were plotted for VASP-P assay. The area under the ROC-curve was 0.683 (p=0.014) for the platelet reactivity index (PRI) calculated from median fluorescence intensities (FI) with an optimal cut-off at 60.2% PRI. Patients above 60.2% had a significantly increased risk for MACE at six months follow-up (p=0.007). Estimating the cut-offs for the PRI from mean FI (52%) or from geometric mean FI (56.6%) led to clinically relevant differences. VASP-P assay is feasible for clinical routine to measure clopidogrel effects and to predict post-procedural MACE in unselected patients. With regard to differing cut-offs, exact standardisation of the VASP-P assay is mandatory. The use of GP-IIb/IIIa-blockers prevents MEA testing and limits its usability in unselected patients.
