Author + information
- Homam Ibrahim,
- Timothy DeLao,
- Leticia Nolasco,
- Colin Barker,
- Joel Moake,
- Michael Reardon and
- Neal Kleiman
Introduction: Thrombocytopenia and thrombotic events are common after TAVR. Changes in shear forces during TAVR and the subsequent platelet activation may explain these phenomena
Methods: Flow cytometry with dual staining (PE-anti-CD41 and FITC-anti-vWF) was used to assess vWF binding to platelets in nine patients undergoing TAVR. vWF binding was assessed by mean fluorescence intensity (MFI) of anti-vWF in the platelet aggregate gate. Samples obtained from the left ventricle (LV) and aorta (Ao) before and 10 minutes after valve implantation.
In eight patients (2 with and 6 without clopidogrel pretreatment) vWF multimeric analysis was performed on venous samples before and 48 hours after the procedure
Results: All patients developed thrombocytopenia. After TAVR six of nine patients had increased anti-vWF MFI in the aggregate gate in the Ao compared to the LV (Figure). The average MFI difference between the two sites (LV, AO) after the procedure (2.4 + 1.7) was significantly higher compared to the difference before the procedure (-0.2 + 0.7) p=0.017. Unlike patients who received clopidogrel, those who did not receive it exhibited ultra large vWF (ULvWF) multimers post procedure
Conclusions: Increased anti-vWF MFI that is present on platelet aggregates in the Ao samples post procedure indicates increased vWF-platelet binding caused by shear-induced platelet activation during TAVR. Clopidogrel pretreatment may modulate the detection of highly adhesive ULvWF multimers by inhibiting this platelet activation.
Poster Hall, Hall C
Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Interventional Cardiology: TAVR 2
Abstract Category: 17. Interventional Cardiology: Aortic Valve Disease
Presentation Number: 1195-168
- 2017 American College of Cardiology Foundation