Surveillance priorities and outcomes for Veterans treated with endovascular abdominal aortic aneurysm repair

点击翻译按钮获取中文摘要

Background: More than 8,000 Veterans undergo abdominal aortic aneurysm (AAA) repair each year. Nearly 70% are treated with endovascular abdominal aortic aneurysm repair (EVAR), where a covered stent is used to reinforce the weakened aorta. Most national guidelines and regulatory directives mandate annual life-long surveillance imaging after EVAR, typically provided via a once-yearly contrast-enhanced CT scan. Surveillance imaging evaluates for blood flowing around the stent into the aorta, called an “endoleak”. While most endoleaks are harmless, 1-3% are high-pressure “Type I” endoleaks, which lead to rupture and require repair. However, a point may be reached where continued annual surveillance imaging may not be the best choice for elderly Veterans after EVAR. Imaging-associated risks include acute kidney injury from contrast dye used during the CT scan (3-10%), the identification of harmless endoleaks which require no treatment (10-20%), and incidental findings such as lung or kidney nodules which trigger further invasive testing or treatment (10-15%). Our scientific rationale in this project centers on better understanding a key gap in knowledge: the tradeoffs between imaging-associated risks and the chance of identifying a dangerous form of endoleak (1-3%) can be difficult, especially for aging Veterans with multiple co-morbidities. Significance: This evidence gap surrounding when to stop surveillance is especially important for Veterans, who are more frail, elderly, and rural than non-Veteran EVAR populations. We estimate that more than 10,000 Veterans are currently alive with an EVAR in place. This suggests that more than 10,000 scans will be performed each year based on our preliminary cohort assembly, and more than 500 Veterans will have complications such as nephrotoxicity. Because it affects a chronic condition among our oldest Veterans, our study is aligned with the HRD&D Topic Category “Management of Chronic Conditions” and the HSR&D Specific Priority Area “Long-term Care and Aging”. Innovation and Impact: There is an absence of guidelines to help Veterans and their clinicians decide when surveillance imaging should occur, and when its utility may be limited. Developing and disseminating this evidence would bring an innovative approach towards limiting unnecessary testing and harms among elderly Veterans. Specific Aims: We propose a mixed-methods study with two Specific Aims. Aim 1 will qualitatively assess Veteran, family, and health care team members’ attitudes and beliefs surrounding surveillance imaging after EVAR. Aim 2 will quantitatively characterize observational data sources to understand surveillance imaging outcomes after EVAR. Our Dissemination Plan will integrate these findings to create evidence for when surveillance imaging should continue, and when it may have limited utility. We hypothesize that imaging associated risks may outweigh the benefits of ongoing surveillance in older Veterans with significant comorbidities. Methodology: Our study design leverages a parallel approach: qualitative assessment of stakeholder beliefs about cessation of imaging surveillance (Aim 1) and quantitative analysis of retrospective clinical data to evaluate the use, outcomes, and risks of imaging surveillance (Aim 2). Next Steps/Implementation: Our project involves leaders from organizations such as the VA’s national VA Surgery Advisory Board, the Society for Vascular Surgery, a nationally recognized web-based forum for geriatric care, and other organizations to ensure effective dissemination of our evidence. The evidence generated in our proposal will be shared using innovative pathways, such as podcasts, to ensure our project’s deliverables and impact are sustained.