Utility of Viscoelastic Tests to Predict Flap Thrombosis: A Systematic Review

Abstract

Background: Flap thrombosis is a rare but devastating complication in microsurgery. Preoperative identification of patients at increased risk for microvascular thrombosis remains challenging. Viscoelastic testing (VET) provides a comprehensive evaluation of the clotting process and can effectively identify hypercoagulability. However, the utility of VET in microvascular reconstruction remains unclear. Methods: A systematic review of the association between VET and pedicle thrombosis and free flap loss was performed in accordance with Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Identified studies were reviewed independently by two authors for pertinent data. Results: Six studies met inclusion criteria. Heterogenous study design and outcome reporting complicated direct comparisons and precluded a formal meta-analysis. Four studies found a statistically significant relationship between VET results and flap thrombosis or flap loss. The maximum clot strength and the fibrinogen-to-platelet ratio (FPR) were key viscoelastic parameters in these studies, both representing a measure of maximal clot strength. Specifically, an elevated FPR (>42%) generated a sensitivity and specificity for flap loss ranging from 57% to 75% and 60% to 82%, respectively. Notably, the negative predictive value for flap failure with a normal preoperative FPR was greater than 90% in all studies reporting a correlation. The remaining two studies reported no predictive value for VET with respect to flap failure or pedicle thrombosis. Conclusion: The results of this review suggest that VET, particularly parameters relating to clot strength, may help clinicians identify patients at risk for flap thrombosis. However, uncontrolled and heterogenous reporting limit definitive conclusions, and high-quality diagnostic studies are needed to better determine the clinical utility of viscoelastic testing for free flap patients.

Pruebas viscoelásticas en el manejo perioperatorio de pacientes oncológicos

“…Existen varias series de casos que han mostrado la capacidad predictiva de las pruebas viscoelásticas de trombosis del colgajo. Sin embargo, aún faltan estudios con mayor número de pacientes, dada la baja incidencia de esta complicación, que actualmente están en torno al 5% [18], [19].…”

Enhancing Anticoagulation Monitoring and Therapy in Patients Undergoing Microvascular Reconstruction in Maxillofacial Surgery: A Prospective Observational Trial

“…Recent studies showed that VET was able to predict flap thrombosis in patients undergoing maxillofacial surgery [ 26 , 27 ]. However, these studies focused only on hypercoagulability assessed with VET.…”

Thromboelastography-Guided Therapy Enhances Patient Blood Management in Cirrhotic Patients: A Meta-analysis Based on Randomized Controlled Trials

“…5,7,8 Thromboelastography provides a rapid assessment of hemostasis of a whole blood sample and can predict risk of thrombosis and bleeding. [9][10][11] The technology may be beneficial for patients with cirrhosis experiencing bleeding, thrombosis, or undergoing invasive procedures or surgery. 1,7,12,13 A recent prospective cohort study found that the thromboelastography marker of clot stability (maximum amplitude) could accurately distinguish between cirrhosis patients with major, life-threatening procedure-related bleeding and those who were not bleeding or had minor bleeding, whereas a low platelet count could not distinguish between any procedure-related bleeding (major or minor) and no bleeding.…”