In Vitro Platelet Aggregation Inhibition Activity of Psophocarpus tetragonolobus (L.) Dc Pod Extract

The study aimed to investigate antiplatelet activity of the pods of Psophocarpus tetragonolobus in vitro in search for a new botanical source of a platelet aggregation inhibitor for the prevention of stroke, the second leading cause of mortality in the Philippines. This study utilized maceration with hexane as the extraction method. Four concentrations (4mg/mL, 2mg/mL and 0.5mg/mL) of Psophocarpus tetragonolobus pods were used in the study. Aspirin (2mg/mL) and NSS were the positive and negative controls, respectively. The methods employed in the study were Giemsa Microplate Assay for qualitative analysis and UV-Vis spectrophotometric analysis for quantitative analysis. Giemsa microplate assay findings revealed that the 4.0mg/mL test solution had the least violet gels present to no violet gels visible at all. Furthermore, the UV-Vis Spectrophotometric Analysis corresponded with the results and found that the 4mg/mL concentration contained the least mean absorbance reading (among the pod extracts) of 0.409, the highest average percent platelet aggregation inhibition of 69.58% (± 2.93) and the greatest average percent antiplatelet activity of 75.49% (± 3.07), among the pod extracts. In conclusion, the pod extract, at 4.0mg/mL concentration, was able to inhibit platelet aggregation.

Abstract 10018: High on Aspirin Platelet Reactivity in Children Undergoing the Fontan Procedure

Introduction: Despite routine thromboprophylaxis with aspirin, thromboembolism (TE) continues to be a significant complication after the Fontan procedure. Data suggest that suboptimal ex-vivo aspirin-induced platelet inhibition-known as High on-Aspirin Platelet Reactivity (HAPR) is an independent risk factor for breakthrough TE. The occurrence of HAPR may potentially increase the risk of aspirin prophylaxis failure in children who underwent Fontan procedure. However, HAPR has not been adequately studied in this patient population. Hypothesis: There is a high incidence of HAPR in children after the Fontan procedure. Methods: We conducted a single-center, prospective, observational pilot study of children requiring Fontan procedure. Thromboelastography with platelet mapping (TEG-PM), platelet CD62P expression by flow-cytometry and urinary 11-dehydro-thromboxane B2 (11-dhTxB2) were measured at baseline prior to starting aspirin at 5 mg/kg/day and after at least 5 days of continuous therapy. HAPR was defined as less than 30% Arachidonic Acid (AA)-induced platelet aggregation inhibition as measured by TEG-PM. Results: 17 patients (11 males and 6 females, median age 3 years) were enrolled. HAPR was identified in 9/17 (53%) with 3/9 (33%) patients exhibiting no detectable AA-induced platelet aggregation inhibition. There was no significant effect of aspirin on percentage of activated platelets (i.e.: platelets expressing CD62P marker) in children with or without HAPR. In contrast to children with HAPR, aspirin therapy in children without HAPR led to significant reduction in urinary 11-dhTxB2 levels (Table 1). Conclusions: A significant proportion of children with single ventricle physiology exhibited HAPR in the immediate post-operative period after Fontan procedure. Further studies are needed to examine association of HAPR with increased risk of TE in this patient population.