Paradigm Shift of Interventional Strategies and Outcomes for Acute Limb Ischemia Post-Pandemic
Authors: Wainwright Brandon S. , Chihade Deena B. , Costanza Michael J. , Feghali Anthony C. , Shaw Palma M. 
Published: April 2024

Purpose: We performed a large-scale comparison of patients treated for acute limb ischemia (ALI) in the pre-COVID (2017-2019) and COVID (2020-2022) eras to evaluate changes in interventional strategies and compare factors associated with adverse outcomes. We sought to characterize patient outcomes in an evolving ALI treatment algorithm in response to pandemic-associated presentation delays and rapid technological advancements in mechanical thrombectomy (MT). Methods: Using the TriNetX global research network, we conducted a multicenter query across 80 health care organizations (HCOs) spanning 4 countries for patients treated for ALI. Propensity score matching was performed to account for comorbidities. Risk of adverse outcomes within 30 days was calculated for each era, including re-intervention (RI30), major/minor amputation, and death. Patients were then stratified by initial intervention: open revascularization (OR), MT, or catheter-directed thrombolysis and adjunctive endovascular procedures alone (CDT/EP). Risk of adverse outcomes was compared between treatment groups of the same era. Results: After propensity score matching, the pre-COVID era and COVID era cohorts included 7344 patients each. COVID era patients experienced a statistically significant higher risk of 30-day mortality (RR=1.211, p=0.027). Mechanical thrombectomy interventions were performed more frequently in the COVID era (RR=1.314, p<0.0001). Comparing outcomes between treatment groups, MT patients required RI30 more than OR patients (pre-COVID: RR=2.074, p=0.006; COVID: RR=1.600, p=0.025). Open revascularization patients had higher 30-day mortality (pre-COVID: RR=2.368, p<0.0001; COVID: RR=2.013, p<0.0001) and major amputations (pre-COVID: RR=2.432, p<0.0001; COVID: RR=2.176, p<0.0001) than CDT/EP. Pre-COVID CDT/EP patients were at higher risk for RI30 (RR=1.449, p=0.005) and minor amputations (RR=1.500, p=0.010) than OR. The MT group had higher major amputation rates than CDT/EP (pre-COVID: RR=2.043, p=0.019; COVID: RR=1.914, p=0.007). COVID-era MT patients had greater 30-day mortality (RR=1.706, p=0.031) and RI30 (RR=1.544, p=0.029) than CDT/EP. Conclusion: Significant shifts toward an MT-based approach have been observed in the last 3 years. Although MT required more RI30 than OR, there was no associated consequence of mortality and limb salvage. The increased mortality seen among COVID-era patients could be explained by delayed presentation, as well as poorly understood pro-thrombogenic or pro-inflammatory mechanisms related to the first waves of COVID. More research is necessary to determine an optimal treatment algorithm. Clinical Impact Comorbid risk factors and severity of ischemia must be carefully considered before selecting an interventional strategy to prevent adverse outcomes and maximize limb salvage. Open revascularization strategies are associated with increased mortality and limb loss compared to less-invasive thrombolytic therapy alone. Mechanical thrombectomy (MT)-based approaches have been increasingly used in the last 3 years. Patients receiving MT are more likely to require reintervention within 30 days.