Abstract 16870: Short-Term Risk Prognostication for All-Cause Mortality After Endovascular Revascularization in the Medicare Claims-Linked VQI Registry

Abstract

Background: Patients with chronic limb-threatening ischemia (CLTI) have high mortality rates after revascularization. Balancing short-term mortality risk against limb salvage gains is important when triaging patients with CLTI to revascularization. Data for risk stratification is limited. We aimed to develop machine learning models to rank predictive variables for 30-day and 90-day all-cause mortality for CLTI after peripheral vascular intervention (PVI). Methods: Patients undergoing PVI for CLTI between 2017 and 2018 in the Medicare-linked Vascular Quality Initiative (VQI) were included. Sixty-six preprocedural variables were included in random survival forest (RSF) models. RSF models were constructed for 30-day and 90-day all-cause mortality in the training sample (80% of data) and evaluated in the validation sample (20% of data). Predictive variables were ranked based on frequency that they caused branch splitting nearest the root node. Goodness of fit was assessed by Harrell’s C-index. Results: A total of 10,114 patients (mean age 72 ± 11, 59% male, 74% white) were included. The mortality rate was 4.4% at 30 days and 10.6% at 90 days. The RSF model for 30-day mortality identified stage 5 chronic kidney disease (CKD), dementia, and urgent procedures as the most predictive variables. For the 90-day mortality prediction model, the most important variables were stage 5 CKD, dementia, and poor functional status (Figure) . For both models, 8 of the top 10 variables were either medical history or functional status variables. The C-index was 0.72 for the 30-day model and 0.73 for the 90-day model. Conclusion Using data from the claims-linked VQI registry, medical comorbidities and functional status variables were identified as the most predictive variables for 30-day and 90-day all-cause mortality using RSF models. Results may help guide individualized risk conversations regarding PVI versus conservative therapy for the highest risk patients.