Clot Waveform Analysis: a potential tool in venous thrombosis assessment?

Clot Waveform Analysis (CWA) has been studied in bleeding disorders but remains poorly explored in thrombotic conditions. The aim was to evaluate the performance of CWA parameters for detecting hypercoagulability in venous thrombosis. A study was conducted in 2023 at the hematology laboratory of La Rabta university hospital (Tunis, Tunisia), including patients with a history of venous thrombosis and healthy controls. Analyses were performed on an ACL TOP 350 analyzer (Instrumentation Laboratory (IL)) using two activated partial thromboplastin time (aPTT) reagents from IL: SynthAFax (SFX); activator: ellagic acid and SynthASil (SS); activator: silica and one prothrombin time (PT) reagent: RecombiPlasTin (RPT); IL. The CWA parameters evaluated were Max1, Max2, and Min2 derived from aPTT, and Max1 derived from PT. CWA parameters were higher in patients (N = 50) than in controls (N = 100) with all three reagents. With SFX, patients were 4.1 times more likely to exceed the Max1 threshold (87% specificity, 38% sensitivity; p < 0.001), and 3.9 times for Min2 threshold (91% specificity, 28% sensitivity; p = 0.002). With SS, patients were 3.1 times more likely to exceed Max1 threshold (77% specificity, 48% sensitivity; p = 0.002), 31.3 times for Max2 threshold (99% specificity, 24% sensitivity; p < 0.001), and 2.6 times for Min2 threshold (55% specificity, 68% sensitivity; p = 0.008). The thresholds for RPT:Max1 and SFX:Max2 could not be determined due to non-discriminative ROC curves between patients and controls. CWA parameters reflected hypercoagulability, but their low sensitivity would limit their use as a screening test.