Thromboelastometry for Microvascular Flap Thrombosis Risk Assessment in Trauma Patients Undergoing Reconstructive Surgery

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.
Keywords: microvascular reconstructive surgery, free flap, thrombosis, risk estimation,
rotational thromboelastometry, posttraumatic hypercoagulability.