Incidence, Risk Factors, and Outcomes among Patients with Venous Thromboembolic Events in the Early Post-Transplant Period

INTRODUCTION: With the introduction of lung allocation score (LAS), progressively sicker patients are undergoing lung transplantation (LT) which has the potential to increase the risk of venous thromboembolic (VTE) events during the post-transplant period. This study was conducted to determine the incidence and risk factors for early VTE and its association with 2 year survival. METHODS: All adult patients with single, double or heart LT at the UT Southwestern Medical Center between 2012-14 (n=193) were included in the study. Various demographic, clinical and laboratory variables before and after LT were recorded. Development of any VTE events during the first 30 days after LT was the primary outcome variable. Variables were compared among patients with and without VTE to identify risk factors for VTE. Survival at two years was compared among patients with and without VTE. RESULTS: Overall incidence of VTE during the first 30 days after LT was 28.5% (n=55) among which, majority were upper extremity thrombosis (48/55). Pulmonary embolism was uncommon (n=3). Majority events (78%) were diagnosed with in the first 15 days after LT. Pre-transplant history of hyperlipidemia (adjusted OR, 95%CI: 2.8, 1.1-7.2; p=0.03) and use of anticoagulants (AC) for at least 72 hours (4.1, 1.8-9.5; p=0.001) were independently associated with a reduced risk of VTE. On the other hand, development of primary graft dysfunction at 72 hours (1.6, 1.1-2.4; p=0.009) and use of >3 central catheters during the post-transplant period (25.9, 2-342.1; p=0.013) were independently associated with increased risk of VTE. Development of VTE was associated with increased risk of 2 year mortality (log rank p=0.036, see figure). CONCLUSION: A significant proportion of patients develop VTE early after LT and it is associated with worse survival at 2 yr post-LT. Despite majority being catheter related VTE, the use of AC appears to be protective. Protective effect of hyperlipidemia may be linked to statin use among these patients which needs to be investigated further in future studies.