Donor tobacco smoking is associated with postoperative thrombosis after primary liver transplantation

Thrombotic complications post liver transplantation: Etiology and management

Liver transplantation (LT) is the life saving therapeutic option for patients with acute and chronic end stage liver disease. This is a routine procedure with excellent outcomes in terms of patient survival and quality of life post LT. Orthotopic LT (OLT) patients require a critical care as they are prone to variety of post-operative vascular, cardiovascular, biliary, pulmonary and abdominal complications. Thrombotic complications (both arterial and venous) are not uncommon post liver transplant surgery. Such vascular problems lead to increased morbidity and mortality in both donor and graft recipient. Although thromboprophylaxis is recommended in general surgery patients, no such standards exist for liver transplant patients. Drastic advancements of surgical and anesthetic procedures have improvised survival rates of patients post OLT. Despite these, haemostatic imbalance leading to thrombotic events post OLT cause significant graft loss and morbidity and even lead to patient's death. Thus it is extremely important to understand pathophysiology of thrombosis in LT patients and shorten the timing of its diagnosis to avoid morbidity and mortality in both donor and graft recipient. Present review summarizes the current knowledge of vascular complications associated with LT to highlight their impact on short and long-term morbidity and mortality post LT. Also, present report discusses the lacunae existing in the literature regarding the risk factors leading to arterial and venous thrombosis in LT patients.

Outcomes of Portal Vein Thrombosis in Smokers With and Without Cirrhosis and Predictors of Mortality: A Nationwide Assessment

Portal vein thrombosis (PVT) is a rare condition that can lead to numerous complications, like variceal bleeding, hepatic encephalopathy, and chronic liver disease. PVT has various etiologies, including liver disease, infections, and hyper-coagulable disorders. Cirrhosis, a chronic progressive liver condition characterized by liver fibrosis, is one of the risk factors for the development of PVT. Secondly, smoking also increases the risk of PVT. The aim of this study is to identify outcomes in patients with PVT who smoked with and without cirrhosis. This study was performed using the National Inpatient Sample (NIS) database for the years 2016, 2017, and 2018. The study identified 33,314 patients diagnosed with PVT who smoked, of which 14,991 had cirrhosis, and 18,323 did not have cirrhosis. Patients with PVT and cirrhosis had significantly higher in-hospital mortality, upper gastrointestinal bleeds, acute kidney injury, and peritonitis compared to patients without cirrhosis. The results of the study show that patients with PVT and cirrhosis who smoke have a higher risk of unfavorable outcomes.

Donor genetic variants as risk factors for thrombosis after liver transplantation: A genome-wide association study

Thrombosis after liver transplantation substantially impairs graft- and patient survival. Inevitably, heritable disorders of coagulation originating in the donor liver are transmitted by transplantation. We hypothesized that genetic variants in donor thrombophilia genes are associated with increased risk of posttransplant thrombosis. We genotyped 775 donors for adult recipients and 310 donors for pediatric recipients transplanted between 1993 and 2018. We determined the association between known donor thrombophilia gene variants and recipient posttransplant thrombosis. In addition, we performed a genome-wide association study (GWAS) and meta-analyzed 1085 liver transplantations. In our donor cohort, known thrombosis risk loci were not associated with posttransplant thrombosis, suggesting that it is unnecessary to exclude liver donors based on thrombosis-susceptible polymorphisms. By performing a meta-GWAS from children and adults, we identified 280 variants in 55 loci at suggestive genetic significance threshold. Downstream prioritization strategies identified biologically plausible candidate genes, among which were AK4 (rs11208611-T, p = 4.22 × 10^-05 ) which encodes a protein that regulates cellular ATP levels and concurrent activation of AMPK and mTOR, and RGS5 (rs10917696-C, p = 2.62 × 10^-05 ) which is involved in vascular development. We provide evidence that common genetic variants in the donor, but not previously known thrombophilia-related variants, are associated with increased risk of thrombosis after liver transplantation.

Donor tobacco smoking is associated with postoperative thrombosis after primary liver transplantation

BACKGROUND

Thrombosis after liver transplantation is a leading cause of graft loss, morbidity, and mortality. Several known recipient- and surgery-related characteristics have been associated with increased risk of thrombosis after transplantation. Potential donor-related risk factors, however, remain largely undefined.

OBJECTIVES

We aimed to identify risk factors for early post-transplantation thrombosis (<90 days) and to determine the impact of early postoperative thrombosis on long-term graft and patient survival.

PATIENTS/METHODS

A post hoc analysis was performed of an observational cohort study including all primary, adult liver transplantations performed between 1993 and 2018. Donor-, recipient-, and surgery-related characteristics were collected. Competing risk model analyses and multivariable regression analyses were performed to identify risk factors for developing early post-transplant thrombosis and graft failure.

RESULTS

From a total of 748 adult liver transplantations, 58 recipients (7.8%) developed a thrombosis after a median of 7 days. Post-transplantation thrombotic events included 25 hepatic artery thromboses, 13 portal vein thromboses, and 22 other thrombotic complications. Donor history of smoking was independently associated with early postoperative thrombosis (odds ratio [OR] 2.42; 95% confidence interval [CI], 1.29-4.52). Development of early post-transplant thrombosis was independently associated with patient mortality (hazard ratio [HR] 3.61; 95% CI 1.54-8.46) and graft failure (HR 5.80, 95% CI 3.26-10.33), respectively.

CONCLUSION

Donor history of smoking conveys a more than two-fold increased risk of thrombosis after liver transplantation, independent of other factors. Post-transplant thrombosis was independently associated with decreased patient and graft survival.