International Society on Thrombosis and Hemostasis Bleeding Assessment Tool (ISTH-BAT) and Intrinsic Rotational Thromboelastometry (INTEM-ROTEM) in the Evaluation and Classification of von Willebrand Disease (VWD): An Egyptian Center Cross-Sectional Observational Study.

BACKGROUND

VWD is the most common inherited bleeding disorder, characterized by quantitative or qualitative defects of VWF. Accurate assessment of bleeding severity and disease classification remains clinically challenging. The ISTH-BAT standardizes bleeding history, while viscoelastic assays such as ROTEM may provide additional global hemostatic information.

OBJECTIVE

To evaluate the diagnostic performance of ISTH-BAT in VWD screening and severity assessment, and to investigate the role of INTEM-ROTEM parameters in VWD identification and classification, with correlation to conventional laboratory markers.

METHODS

This cross-sectional observational study included 69 patients diagnosed with VWD and 68 age- and sex-matched healthy controls. All participants underwent ISTH-BAT evaluation and standard VWD laboratory workup, including VWF antigen (VWF:Ag), VWF activity (VWF:GPIbM), and factor VIII (FVIII). INTEM-ROTEM analysis was performed in 44 patients. Correlation, regression, and receiver operating characteristic (ROC) curve analyses were conducted.

RESULTS

Total ISTH-BAT scores differed significantly across VWD types (p=0.047). Clotting time (CT) was the only INTEM-ROTEM parameter showing significant differences between VWD types (p=0.001) and subtypes (p=0.022). CT correlated negatively with VWF:Ag (r=-0.561, p<0.001) and FVIII (r=-0.664, p<0.001), and positively with aPTT (r=0.693, p<0.001). Regression analysis demonstrated that each 1-second increase in CT was associated with a 0.31% decrease in VWF:Ag (p=0.002) and a 0.48% decrease in FVIII (p<0.001). For VWF:Ag <10%, a CT >193 seconds predicted VWD with an AUC of 0.809.

CONCLUSION

ISTH-BAT is a highly sensitive screening tool for VWD and correlates with disease severity. Among INTEM-ROTEM parameters, clotting time shows potential adjunctive value in distinguishing VWD severity, types and subtypes, and correlates significantly with conventional laboratory markers. INTEM-ROTEM CT may provide supportive diagnostic information in clinical settings requiring rapid hemostatic assessment.