Effects of transcutaneous aortic valve implantation on aortic valve disease-related hemostatic disorders involving von Willebrand factor.

BACKGROUND: Aortic valve stenosis (AVS) can be complicated by bleeding associated with acquired type 2A von Willebrand syndrome. The association of AVS and gastrointestinal bleeding from angiodysplasia is defined as Heyde syndrome. We sought to evaluate the effect of transcutaneous aortic valve implantation (TAVI) on hemostasis disorders and to assess its effectiveness to treat Heyde syndrome.
METHODS: We prospectively enrolled 49 consecutive patients with severe AVS addressed for TAVI at our institution. Biological hemostasis parameters involving von Willebrand factor (vWF) were assessed at baseline and 1 week after the procedure.
RESULTS: At baseline, a significant link between vWF abnormalities and the severity of AVS was evidenced: mean aortic transvalvular gradient was negatively correlated with the levels of vWF antigen (vWF:Ag) (r = -0.29; P < 0.05), vWF ristocetin cofactor activity (r = -0.402; P = 0.006), and vWF collagen-binding activity (vWF:CB; r = -0.441; P = 0.005). One week after the procedure, a significant increase of vWF:Ag, vWF ristocetin cofactor activity, and vWF:CB was evidenced in the whole cohort (respectively, 3.32 vs. 2.29 IU/mL, P < 0.001; 2.98 vs. 1.86 IU/mL, P < 0.001; and 3.16 vs. 2.16 IU/mL, P < 0.001). Patients with pre-TAVI vWF abnormalities consistent with a type 2A vWF syndrome (ratio vWF:CB/vWF:Ag < 0.7) preferentially improved their vWF function with respect to patients with a normal ratio (relative increase of vWF:CB of 63.8% vs. 3.5%).
CONCLUSIONS: Hemostasis parameters involving vWF are improved after TAVI, especially in patients with pre-existing abnormalities consistent with acquired type 2A von Willebrand syndrome.