Hospital transfer and associated outcomes in acute limb ischemia

Objective: Timely access to care is critical in time-dependent pathologies such as acute limb ischemia (ALI). Interhospital transfer may increase access to specialist care but at the risk of increasing time to revascularization. The aim of this study is to explore associations between interhospital transfer and outcomes in patients presenting with ALI, with the goal of generating hypotheses for future prospective research. Methods: A retrospective analysis was performed using survey-weighted data from the National Inpatient Sample database (2019-2021). Patients aged ≥18 years who were hospitalized with ALI, based on International Classification of Disease, 10th Revision codes, were analyzed. Outcomes including comorbid conditions, methods of revascularization, limb salvage, organ failure, and mortality. Comparisons were made between patients undergoing transfer or not as part of their care. The χ² test was used for univariate comparison and multivariate modeling used to control for covariates. Comparisons are presented using proportions and odds ratio [95% confidence intervals] (P values). Results: Among 33,434 survey-weighted cases of ALI, 7950 patients (24%) were transferred to another facility. Transfers were significantly more common in micropolitan (3.2 [3.0-3.4]; P < .001) and noncore areas (2.5 [2.3-2.7]; P < .001) when compared with large central and fringe metropolitan areas. Transferred patients exhibited higher rates of primary amputation (4.7% vs 2.7%, P < .0001) and amputation after attempted revascularization (4.6% vs 2.5%, P < .0001). Transferred patients underwent higher rates of surgical thrombectomy (46.5% vs 38.7% P < .001), fasciotomies (3.1% vs 2.1%, P < .001), and hemodialysis (2.4% vs 1.5%, P < .001). Transferred patients had a higher in-hospital mortality (8.6% vs 4.4%, P < .001) than those who were not transferred. Conclusions: Patients presenting with ALI who require hospital transfer have higher mortality and morbidity than patients undergoing definitive care on index admission. The reason for these finding is likely multifactorial and include disease complexity, prolonged warm ischemic times, and vascular surgical workforce distribution. Although expanding the vascular surgery workforce in underserved areas would be ideal, this remains unlikely in the short term. Although our findings are associative, they highlight the need for further research to clarify the drivers of poor outcomes. In the interim, practical strategies such as leveraging technology to reduce ischemic time during transfers and implementing emergency department-based activation protocols for ALI may help address current care delays.