DOES INCREASED CAPRINI SCORE PREDICT A HIGHER RATE OF FLAP FAILURE IN FREE TISSUE TRANSFER TO THE LOWER EXTREMITY?
Christopher Parham, M.D., Stacy Henderson, M.D., Michael Pennock, B.S., Audrey Kulaylat, M.D., T. Shane Johnson, M.D.
Penn State Hershey, Hershey, PA, USA.
Free tissue transfer is a commonly utilized tool for reconstruction of lower extremity defects. Risk assessment for deep venous thrombosis (DVT) formation and its relationship to the potential for post-operative free flap venous congestion and overall flap failure has not been adequately evaluated in a U.S. population. We aim to use the Caprini Risk Assessment Model to evaluate the association between DVT risk and post-operative flap venous congestion following lower extremity free tissue transfer.
A retrospective analysis was conducted of all patients who underwent lower extremity free flap reconstruction at a single institution between 2007 and 2016. Patient characteristics, including Caprini score, peri-operative details, and post-operative outcomes were abstracted from the medical record. The primary outcome was the occurrence of flap venous congestion as associated with individual Caprini score. Secondary outcomes included flap failure, number of vascular anastomoses, and venous thromboembolic events. Patient characteristics, peri-operative details, and Caprini scores were compared between patients with and without complications using Student's t-tests and Chi square tests for continuous and categorical variables, respectively. Multivariable logistic regression evaluated each outcome as a function of Caprini scores.
One hundred sixteen patients who underwent lower extremity free flap reconstruction were identified. The mean age was 44.5 years. The majority of patients were male (76.7%) and required reconstruction due to acute trauma (68.1%). The remainder of patients underwent free flap reconstruction for chronic wounds due to osteomyelitis (26.7%) and oncologic defects (5.2%). The mean Caprini score for the entire cohort was 14.9 and tended to be higher among patients with evidence of flap venous congestion (16.8 versus 14.4, p=0.021). Caprini scores were also higher among patients with free flap failure (17 versus 14.6, p=0.044). Each one-point increase in Caprini score was associated with increased odds of flap venous congestion (OR 1.13, p=0.021) and 18% higher odds of flap failure (OR 1.18, p=0.016). The majority of patients received a single arterial anastomosis (93.9%) and a single venous anastomosis (71.5%). Multiple attempts at venous anastomosis were not associated with flap failure (p=0.828). There was no significant difference in Caprini scores between those who developed VTE events and those who did not (16.4 versus 14.8, p=0.377).
In patients with significantly elevated Caprini scores, there was an association between individual risk for DVT potential and flap venous congestion, as well as flap failure following free tissue reconstruction of lower extremities.
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