Venous Thromboembolism in Acute Necrotizing Pancreatitis Is Associated With Worse Outcomes, With Subtype-Specific Patterns: A Nationwide Analysis, 2016-2022

Background Venous thromboembolism (VTE) has been increasingly studied as a common complication of acute necrotizing pancreatitis (ANP) and has led to poorer outcomes in recent cohorts. However, variation in clinical outcomes in significant VTE phenotypes in ANP, especially extra-splanchnic deep vein thrombosis (DVT) versus portal vein thrombosis (PVT) and splenic vein thrombosis (SVT), is still poorly characterized. We thus examined national trends and outcomes regarding ANP with versus without VTE as well as in-hospital outcomes for all VTE subtypes. Methods Data from the National Inpatient Sample (2016–2022) were analyzed to identify patients with a principal diagnosis of ANP. Secondary diagnosis codes were used to identify ANP patients with VTE subtypes such as deep venous thrombosis (DVT), splenic venous thrombosis (SVT), and portal vein thrombosis (PVT). Comparison of in-hospital mortality and major complications between ANP with any VTE versus ANP without VTE was the primary analysis. Secondary analyses were used to compare these outcomes within VTE subtypes. Results The cohort included 110,225 ANP hospitalizations (n = 96,720; 87.75% did not have VTE in total; 12.25% had VTE). ANP with VTE had higher in-hospital mortality [aOR 1.89, p < 0.001], longer length of stay (LOS) [adjusted mean difference 10.7 days, p < 0.001], and higher total adjusted hospitalization charges [adjusted mean difference $151,685, p < 0.001] compared to ANP without VTE. In addition, the VTE group also had a greater overall burden of major complications including mesenteric ischemia, gastric varices, upper GI bleeding, AKI, sepsis, shock, respiratory failure, ARDS, vasopressor use, mechanical ventilation, blood transfusion, and ICU admissions. Among the adjusted subtype analyses with ANP without VTE as the reference, DVT and PVT were associated with more in-hospital mortality (DVT aOR 2.39, p < 0.001; PVT aOR 1.45, p = 0.001); SVT was not (SVT aOR 0.37, p = 0.086). PVT was the most statistically related to mesenteric ischemia (aOR 8.28, p < 0.001), whereas gastric varices had the most significant correlation with SVT (aOR 11.37, p < 0.001) and were also significantly associated with PVT (aOR 3.73, p < 0.001). Conclusion Our results verify the association of VTE presence with higher in-hospital mortality, systemic complications, and higher resource utilization in the setting of ANP. It also contributes to the existing literature that the results were reported to differ considerably by VTE subtype, with the highest-risk profile identified for DVT-associated ANP and divergent vascular-complication patterns in PVT and SVT. Prospective studies should elucidate phenotype-specific strategies for prevention and management, including anticoagulation strategies specific to VTE subtype and bleeding risk.