Background: Aspirin has been routinely prescribed following transcatheter closure of secundum atrial septal defects (ASDs) but its rationale has not been clinically or biologically evaluated; and despite aspirin, thrombotic complications occur following transcatheter ASD closure. We therefore evaluated the presence, degree and timing of the activation of the coagulation and platelet systems following transcatheter closure of ASDs.
Methods and results: Fourteen consecutive patients (9 females, mean age 41+/-22 years) who underwent successful transcatheter closure of an ASD defect with the Amplatzer septal occluder were prospectively studied. Measurements of the prothrombin fragment 1+2 (F1+2) levels and the percentage of activated platelets (determined by P-selectin expression detected by flow cytometry) were taken at baseline just before the procedure, and at 1, 7, 30 and 90 days following device implantation. F1+2 levels increased from 0.85+/-0.29 nmol/l at baseline to a maximal value of 1.20+/-0.52 nmol/l at 7 days, gradually returning to the baseline levels at 90 days (0.79+/-0.54 nmol/l) (p<0.001). F1+2 levels at 7 days were also significantly higher than those obtained in a control group of 20 healthy subjects (p=0.016). A greater increase in coagulation activation was observed in cases of residual shunt following ASD closure (r=0.53, p=0.050). No significant variations in the percentage of platelets expressing P-selectin were detected at any time.
Conclusions: Transcatheter closure of ASDs with the Amplatzer septal occluder was associated with a significant increase in F1+2 levels during the first week after device implantation, but there was no detectable effect on platelet system activation. These findings raise the question whether the optimal prophylactic approach following transcatheter ASD closure should be anticoagulant instead of antiplatelet therapy.