Investigating the microstructural determinants of clot mechanics and coagulation function in patients on mechanical circulatory support

Patients receiving long-term cardiac pump support are at increased risk of hemorrhage, often due to impaired blood coagulation. While altered clot mechanical and microstructural properties underpin many coagulation abnormalities, the relationship between these is poorly understood. In this study, we employed Spectrally Encoded Confocal Microscopy (SECM) to rapidly quantify microstructural features during fibrin clot polymerization and compare these against mechanical parameters obtained from TEG and iCoagLab coagulation analyzers. Fiber density strongly correlated with clot strength measured by TEG and iCoagLab, as well as with plasma fibrinogen levels. Anticoagulation (anti-Xa, aPTT) created a distinct microstructural signature with straighter fibers and prolonged polymerization times. Multivariate analyses revealed that fiber density and microstructural heterogeneity were most strongly associated with clot mechanical properties. The interplay between clot microstructure and mechanical function may inform bleeding risk in patients on cardiac pumps.