PATIENTS REFERRED FOR BLEEDING SYMPTOMS OF UNKNOWN CAUSE: DOES EVALUATION OF THROMBIN GENERATION CONTRIBUTE TO DIAGNOSIS?

Introduction

Patients with mild to moderate bleeding symptoms referred for coagulation investigation sometimes never receive a definitive diagnosis. Bleed assessment tools have been developed and validated to assess the severity of symptoms. Global coagulation assays, e.g., the thrombin generation test (thrombogram) have a potential to identify hemostatic defects that are not detected in specific assays.

Material and Methods

One hundred and eighty-five patients referred to our centre because of bleeding symptoms were evaluated using  the bleeding assessment tool (BAT) described by Tosetto and colleagues in 2006.  Blood samples were investigated for thrombin generation (TG) capacity (Technoclone) , in platelet poor (PPP)  plasma , and specific clotting factors, i.e, von Willebrand factor, factor VIII and IX, as well as INR, APTT, platelet count, and platelet adhesion.

Results

Of the 185 patients, five women were diagnosed with mild von Willebrand disease and one male with mild hemophilia A. The remaining 179 subjects (76% females and 24% males with average ages of 33 and 28 years, respectively) were evaluated further. In the total cohort and among women, peak TG, and lag time   correlated with bleeding score (p=0.01 and p=0.04, respectively with correlation coefficients).  No such correlations were found among males.

Discussion and conclusion

Although our study showed some correlation between TG and bleeding score, results are generally consistent with a previous report which failed to demonstrate the value of TG measurement in a similar setting. In conclusion, the complexity of the mechanisms underlying clinical bleeding complicates the ability to use TG tests as reliable predictors of bleeding. Mild congenital bleeding disorders, especially VWD, should be specifically screened for in patients with mild/moderate symtoms.