Platelet activation and hypercoagulability in patients with early primary biliary cholangitis compared with healthy controls

Patients with primary biliary cholangitis (PBC) who have advanced disease are hypercoagulable, with no thrombophilic factors compared to non-cholestatic cirrhotics. We investigated whether hypercoagulability is present in early-stage PBC. PBC patients with biopsy-documented early disease and healthy controls matched by sex and age were asked to participate in the study. All were evaluated using rotational thromboelastometry (ROTEM), platelet aggregation, and flow cytometry. Four ROTEM parameters were evaluated (clotting time, clotting formation time, α-angle, and maximum clot firmness [MCF]). Platelet aggregation was determined as the maximal change in light transmission after the addition of adenosine diphosphate, collagen and epinephrine. Flow cytometry was used to evaluate the expression of glycoprotein (GP) IIb, GPIIa, and P-selectin on the platelet surface. We enrolled 50 individuals in the study (25 PBC patients, 25 controls). Prothrombin time and activated partial thromboplastin time did not differ significantly between PBC patients and controls (P-value not significant). In ROTEM, aaaaaaaa-angle and MCF parameters were abnormally elevated in 9 (36%) PBC patients compared to 3 (12%) healthy controls and the difference was statistically significant (P=0.026). Platelet aggregation in PBC patients was not significantly different from controls. In flow cytometry, GPIIb and P-selectin expression was greater in PBC patients than in the control group and the difference was statistically significant (P=0.005 and P=0.006 respectively). In this study, we used a combination of sophisticated methods to detect evidence of platelet activation and hypercoagulability in patients with early PBC. Our findings may have important clinical implications and merit further investigation.