Corrective surgery for aortic valve stenosis normalized preoperative impairments in shear-induced platelet aggregation, platelet counts, and von Willebrand factor multimeric distribution.
Observational
Does corrective surgery improve shear-induced platelet aggregation and von Willebrand factor abnormalities in patients with aortic valve stenosis?
Corrective surgery for aortic valve stenosis normalizes shear-induced platelet aggregation and von Willebrand factor abnormalities, suggesting that shear stress across the stenosed valve drives the bleeding diathesis in these patients.
BACKGROUND: Excessive bleeding may complicate congenital cardiac defects. To explain the pathogenesis of this abnormality, we evaluated selected parameters of primary hemostasis in patients with aortic valve stenosis before and after corrective surgery. METHODS AND RESULTS: We examined shear-induced platelet aggregation with the filter aggregometer test and von Willebrand factor (vWF) structure by evaluating the multimeric distribution and extent of subunit proteolysis. The platelet count was reduced before corrective surgery, and shear-induced platelet aggregation was impaired. Moreover, vWF multimers of higher molecular mass were decreased, and proteolytic subunit fragments were increased. After correction of the cardiac defect, all of these parameters returned to normal. CONCLUSIONS: Alterations of vWF and platelet function may contribute to the bleeding diathesis in patients with aortic valve stenosis. Improvement after corrective surgery suggests that the passage of blood through a stenosed aortic valve may result in shear forces that induce vWF interaction with platelets in the circulation and, in turn, trigger platelet clearance, vWF degradation, and the impairment of primary hemostasis.
Pareti et al. (Tue,) conducted a observational in Aortic valve stenosis. Corrective surgery vs. Before corrective surgery was evaluated on Shear-induced platelet aggregation and von Willebrand factor structure. Corrective surgery for aortic valve stenosis normalized preoperative impairments in shear-induced platelet aggregation, platelet counts, and von Willebrand factor multimeric distribution.