Thromboelastometry for Microvascular Flap Thrombosis Risk Assessment in Trauma Patients Undergoing Reconstructive Surgery. Doctoral Thesis
Authors:   ,   Rīga Stradiņš University, Stepanovs Jevgeņijs 
Published: February 2025

Despite technical progress, microvascular flap thrombosis remains a concern in reconstructive surgery. Although microvascular thrombosis is most commonly secondary to technical mishaps and/or prolonged surgical time, a number of other preoperatively identifiable factors have a potential impact on anastomotic thrombosis rate and outcome of tissue transfer. In trauma patients, diagnosing a condition of posttraumatic hypercoagulability is complex. In recent years, viscoelastic methods, including rotational thromboelastometry (RTE) have been widely used for monitoring coagulant activity, but there is a scarcity of data on its use for predicting the risks of microvascular flap thrombotic complications. The aim of the present study was to evaluate the predictive capacity of rotational thromboelastometry for early risk assessment of microvascular flap thrombosis in trauma patients undergoing reconstructive surgery with particular interest in the time period passed from trauma to reconstruction, dividing patients into two subgroups – early surgery and late surgery. During the study, demographic data, type of surgery and surgical parameters were recorded for each patient. Preoperatively, a blood sample was taken to perform RTE and standard coagulation tests. We evaluated the major risk factors for microvascular flap thrombosis in the total population studied and compared the major risk factors for microvascular flap thrombosis in subgroups of early versus late surgery. The results showed that thrombogenic co-morbidities, prolonged surgical time, hyperfibrinogenaemia and hypercoagulability in RTE may lead to a higher rate of postoperative microvascular thrombosis, although the risk factors for free flap thrombosis differ between early and late surgery patients. RTE data can be a convenient tool for detecting hypercoagulability, although its prognostic value varies depending on the time elapsed after trauma. Hypercoagulability detected by RTE may increase the probability of microvascular flap thrombosis, especially in patients undergoing elective surgery (late surgery subgroup) – later than 30 days after a traumatic injury. The presence of thrombogenic co-morbidities, often associated with hypercoagulability, also increases the risk of flap thrombosis in the late post-trauma period. In contrast, in the early surgery subgroup, the duration of microvascular surgery seemed to play a more important role in estimating the risk of microvascular flap thrombosis during the first 30 days after a traumatic injury. We recommend that each patient scheduled for microvascular free flap surgery should be evaluated in a timely manner, with special attention to data on the time elapsed after the traumatic event, the patient’s medical history and preoperative coagulation tests, thus providing more careful preoperative assessment and individualised recommendations for anaesthesiologic and surgical management.
The Doctoral Thesis was developed at Riga East Clinical University Hospital, Department of Anaesthesiology and the Latvian Centre for Reconstructive and Microsurgery. Defence: at the public session of the Promotion Council of Clinical Medicine on 25 February 2025 at 14.00 in the Hippocrates Lecture Theatre, 16 Dzirciema Street, Rīga Stradiņš University and remotely via online platform Zoom.
3.2 Clinical Medicine; Sub-Sector – Anaesthesiology and Intensive Care.
Keywords: microvascular reconstructive surgery; free flap; thrombosis; risk estimation; rotational thromboelastometry; posttraumatic hypercoagulability.