Effect of hemodynamics on clot formation and flow cessation in patient-specific coronary bifurcations

Hemostasis prevents bleeding by forming clots, although disruptions can cause insufficient or excessive clotting. Shear stress is a critical factor influencing the normal function of the blood and can stimulate the formation of unnecessary clots. Stenosed vessels significantly contribute to this phenomenon by increasing shear stress on the vessel walls. This study aims to quantify the effects of shear stress and stenosis severity on thrombus formation in patient-specific left coronary bifurcations. Three-dimensional patient-specific geometries were reconstructed from angiographic data. Blood flow was modeled using the Brinkman equation, while transport and interactions of coagulation factors were simulated through the convection-diffusion-reaction equation. Model predictions were validated using literature data. The findings showed that all patients experienced significant shear stress at the stenosed regions, which are highly susceptible to clot formation. Shear stress was found to be inversely related to vessel diameter and directly related to the stenosis degree. Furthermore, in bifurcated vessels, blood flow may reach zero before complete occlusion by the clot, emphasizing the role of hydrodynamic resistance in redirecting blood flow. Among these factors, the stenosis degree emerges as the most significant predictor of blood flow cessation time. A relationship was developed allowing physicians to accurately and rapidly monitor a patient's condition using angiographic images, providing new insights into the hemodynamic mechanisms of coronary thrombosis and supporting improved diagnosis and treatment of cardiovascular diseases.