The role of flow stasis in transcatheter aortic valve leaflet thrombosis

With the recent expanded indication for transcatheter aortic valve replacement to low-risk surgical patients, thrombus formation in the neosinus is of particular interest due to concerns of reduced leaflet motion and long-term transcatheter heart valve durability. Although flow stasis likely plays a role, a direct connection between neosinus flow stasis and thrombus severity is yet to be established.

Patients (n = 23) were selected to minimize potential confounding factors related to thrombus formation. Patient-specific 3-dimensional reconstructed in vitro models were created to replicate in vivo anatomy and valve deployment using the patient-specific cardiac output and idealized coronary flows. Dye was injected into each neosinus to quantify washout time as a measure of flow stasis.

Flow stasis (washout time) showed a significant, positive correlation with thrombus volume in the neosinus (rho = 0.621, P < .0001). Neither thrombus volume nor washout time was significantly different in the left, right, and noncoronary neosinuses (P ≥ .54).

This is the first patient-specific study correlating flow stasis with thrombus volume in the neosinus post-transcatheter aortic valve replacement across multiple valve types and sizes. Neosinus-specific factors create hemodynamic and thrombotic variability within individual patients. Measurement of neosinus flow stasis may guide strategies to improve outcomes in transcatheter aortic valve replacement.