A Frailty-Based Risk Score Predicts Morbidity and Mortality After Elective Endovascular Repair of Descending Thoracic Aortic Aneurysms

Abstract

Thoracic endovascular aortic repair (TEVAR) has expanded access to descending thoracic aortic aneurysm (DTAA) repair particularly for elderly and frail patients. This high-risk population has limited long-term overall survival, such that appropriate patient selection is required to optimize patient benefit and resource utilization. Our objective is to develop and validate a frailty-based, procedure-specific risk score for patients undergoing elective TEVAR for DTAA. Patients undergoing nonemergent TEVAR for DTAA during 2005-2016 were identified in the National Surgical Quality Improvement Program database. Those with concurrent cardiac or open aortic surgery, abdominal visceral intervention, or Zone 0 deployment were excluded. Patients were randomly divided between derivation and validation samples. The primary outcome was 30-day major adverse events (MAE), including mortality and major systemic complications. Using the derivation cohort, variables associated with MAE were identified by univariable analyses. Those with P<0.05 were included in multivariable logistic regression analysis. Independent procedure-specific and frailty-related risk factors for MAE were used to develop a pragmatic score to assess risk for TEVAR. Overall, 1,784 patients were included. 14% of the derivation patients had MAE (14% major complications, 4% mortality). Independent risk factors for MAE were primarily associated with markers of frailty and TEVAR extent and complexity and included functional dependence (OR 2.9, 95% CI 1.6-5.4), pulmonary disease (1.6, 1.1-2.4), thoracoabdominal extent (2.2 (1.4-3.4), need for iliac access (2.1, 1.1-3.8), and Zone I or II deployment (OR 1.7, 1.1-2.5). According to their respective beta coefficients, each variable was assigned a single point. Based on total points, patients were stratified as low- (0 points), intermediate- (1 point), or high-risk (≥2 points), with stepwise increases in mortality (0%, 4%, and 9%) and major complications (7%, 11%, and 23%) between strata. Validation patients had similar characteristics, risk strata distribution, and outcomes as the derivation patients, and the risk model had similar performance in both groups. Markers of frailty and procedure complexity strongly predict MAE after TEVAR for DTAA and can improve patient selection by enabling patient and procedure-specific risk stratification. While TEVAR is safe in low-risk patients, intermediate-risk patients warrant careful discussion of the risks and benefits of aortic intervention; under certain circumstances, high-risk patients may not benefit. Further study is required to define the association between frailty and long-term outcomes.