Abstract 15714: Residual Platelet Aggregation is Associated with a Significant Platelet Decrease after Transfemoral Aortic Valve Implantation Which Predicts Poor Outcome
Background: After CoreValve implantation patients (pts) are treated with dual antiplatelet therapy consisting of aspirin (ASA) and clopidogrel (Clp) for 6 months to prevent procedural-related thrombocytopenia. Aim of the study : The aim of this study was to investigate the effect of residual platelet aggregation (RPA) on platelet (plt) decrease after TAVI and its relation to outcome.
Methods: All pts were loaded with 600 mg Clp and 500 mg ASA the day before intervention. Platelet aggregation (Plagg)was evaluated by the Multiplate system (Dynabyte, Munich, Germany) before (T0) and directly after intervention (T1) and on day 1,2,3 and day 4. RPA was defined with a maximal ADP (5mM)-induced Plagg > 50 AUC. Plt activation (PA) was also assessed with immunologic markers of plt activation (SDF1 and PAC-1) by flow cytometry.
Results: Plt function was consecutively analyzed in 132 pts (age 80.4+0.6 years ) with severe aortic stenosis (mean pressure gradient 45+1.2 mmHg, aortic valve area 0.7+0.01 cm2, mean ejection fraction 51+1.0) and high surgical risk (log Euroscore 24.7+1.1) . In our study group 26 (19.6 %) pts with enhanced RPA [median AUC T (25th;75th percentile) = 60 (54-81) ] were classified as Clp low responder (ClpLR). Enhanced RPA was associated with a significant decrease in plt count (93+8.3 versus 67+4.1; p=0.006) between T0 (directly before intervention) and day 3 (T4) compared to pts with decreased RPA and classified as Clp Responder (ClpR). ClpLR showed an enhanced expression of SDF1 and PAC-1 [mean immunoflourescence (25th;75th percentile): SDF-1= 37 (33-55) versus 34 (26-39);p= 0.02 and PAC-1 = 5.3 (4.6-6.4) versus 4.5 (4.1-5.1);p= 0.016 . Endstage renal disease(ESRD)seemed to be associated with RPA, because seven of ten patients with dialysis were ClpLR. In a multivariate logistic regression analysis including age, log Euroscore, left ventricular ejection fraction, plt drop, dialysis , low gradient aortic stenosis and Clp responsiveness, only plt drop and dialysis were independent predictors for poor outcome (30 day mortality was 3.8 %, long term mortality 13.6 % ).
Conclusion: Since RPA is associated with poor outcome, it is tempting to speculate that alternative plt therapy to prevent RPA might be beneficial.
- © 2012 by American Heart Association, Inc.