Clinical Update: Analyzing the Incidence of Venous Thromboembolic Disease and Associated Risk Factors following Lung Transplantation

Background: Lung transplant is the fastest growing solid organ transplant procedure and venous thromboembolism has been described to occur in 8-29% of cases. This is much higher than any other solid organ and the exact incidence has yet to be determined. Risk factors for the development of venous thromboembolic disease (VTE) specific to lung transplant are not fully understood. Purpose: The purpose of this research was to describe the incidence and risk factors for VTE disease during the first year following lung transplant at a busy transplant center in the Southwest United States. Methods: A descriptive retrospective study design was used. Virchow's triad was used as a theoretical model to identify selected variables common to lung transplant in an effort to understand possible risk factors for the development of VTE in this patient population. Consecutive lung transplant cases between June 1, 2013 and May 31, 2014 at St. Joseph's Medical Center in Phoenix, Arizona were retrospectively reviewed and followed for exactly one year following the lung transplant date. Demographic variables, Virchow's triad variables, and variables previously identified in the literature as being risk factors for VTE were collected and analyzed using descriptive, frequency, t-test, chi-square, and logistic regression. Results: The incidence of VTE in this patient population was 25.8% and is consistent with findings from previous studies. Using the constructs of Virchow's triad did not yield any statistically significant predictors for VTE in this patient population. However, lung allocation score (LAS) (OR 1.109, CI 1.038-1.185), body mass index (BMI) (OR 1.362, CI 1.034-1.794), and time on the waitlist (OR 1.094, CI 1.023-1.171) did reach statistical significance as possible predictors for VTE following lung transplant in this patient sample. Conclusions: VTE is a common complication of lung transplant that has a high incidence during the first year following lung transplant. This study did identify LAS, BMI, and time on the waitlist as being possible risk factors for the development of VTE following lung transplant. LAS may be a useful surrogate to determine the risk for VTE in this population