Assessment of Thrombotic Risk in Atrial Fibrillation with Ultrasound Molecular Imaging of P-Selectin

Molecular imaging of inflammatory mediators in atria may contribute to thrombotic risk assessment of atrial fibrillation (AF). We investigated the feasibility of ultrasound molecular imaging (UMI) targeted to P-selectin to assess thrombotic risk in AF. Rat AF models were established with rapid atrial pacing. Microbubbles targeted to P-selectin were injected into the rats, followed by left atrial (LA) UMI examination. Furthermore, P-selectin, platelets (PLTs), fibrin and tissue factor (TF) of LA were detected by histopathology and scanning electron microscopy. Plasma levels of P-selectin, thrombin-antithrombin complex (TAT) and prothrombin fragment 1 + 2 (F1 + 2) were measured by enzyme-linked immunosorbent assay. The data showed that P-selectin in LA was correlated with PLT, fibrin and TF (r = 0.735, p < 0.05; r = 0.827, p < 0.05; r = 0.785, p < 0.05, respectively). The plasma level of P-selectin was correlated with the expression of TAT and F1 + 2 (r = 0.866, p < 0.05; r = 0.916, p < 0.05, respectively). The contrast video intensity of adhered microbubbles targeted to P-selectin was correlated with the levels of P-selectin, PLT and fibrin in LA (r = 0.768, p < 0.05; r = 0.798, p < 0.05; r = 0.745, p < 0.05, respectively). In conclusion, P-selectin may serve as a biomarker for thrombotic risk in AF and can be quantified by UMI to assess thrombotic risk.