Assessment of Flowing Blood Coagulation Under Impact of Fibrinogen Concentration Using Optical Coherence Tomography

Abstract

There were few studies that demonstrate the relationship between flowing blood coagulation and fibrinogen concentration. In this study, we reported a new way of measuring dynamic 1/e light penetration depth ( $d_{1/e}$ ) of flowing blood under impact of fibrinogen concentrate during clotting by an optical coherence tomography (OCT) system. The clotting porcine blood circulated in a mock flow loop with additional fibrinogen concentrations at varying flow velocities was investigated. A significant difference of coagulation process between stationary and flowing blood under the impact of fibrinogen was observed. Parameters describing the changes in optical property at all stages of the developing clot, i.e., the reaction time $(t_{r})$ , clot formation time $(t_{\rm cf})$ , and total clotting time $(t_{c} = t_{r} + t_{\rm cf})$ were newly developed from the trace of $d_{1/e}$ versus time. The $t_{r}$ and $t_{c}$ were inversely proportional to the fibrinogen concentrate in both the stationary and flowing blood of hematocrit in 35%, 45%, and 55%. More importantly, the $t_{r}$ and $t_{c}$ tended to increase with the flow velocity for all the fibrinogen concentrates. Thus, we concluded that $d_{1/e}$ -OCT is a promisingly tool for dynamic coagulation progress and status measurements of both stationary and flowing blood under the impact of fibrinogen.