PHIND Seminar Series: Impact of the Veterans Affairs National Abdominal Aortic Screening Program
Manuel Garcia-Toca, M.D.
Clinical Professor of Surgery
Chief, Division of Vascular Surgery
Santa Clara Valley Medical Center (SCVMC)
Oliver O. Aalami, M.D.
Clinical Associate Professor of Surgery, Vascular Surgery
Lucile Packard Children’s Hospital
Webinar URL: https://stanford.zoom.us/s/98417624095
Dial: US: +1 650 724 9799 or +1 833 302 1536 (Toll Free)
Webinar ID: 984 1762 4095
11:00am – 12:00pm Seminar & Discussion
Background: The U.S. Federal Government enacted the Screen for Abdominal Aortic Aneurysms Very Efficiently Act in January 2007. Simultaneously, the Department of Veterans Affairs (VA) implemented a more inclusive AAA screening policy for veteran beneficiaries shortly afterwards.
Our study aimed to evaluate the impact of the VA program on AAA detection rate and all-cause mortality compared to a cohort of patients whose aneurysms were identified by other abdominal imaging.
Methods: We identified veterans with an AAA screening study using the two existing Current Procedural Terminology (CPT) codes (G0389 and 76706). In the comparison group, eligible abdominal imaging studies included ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) queried according to CPT codes between 2001 and 2018.
We used a difference-in-differences regression model to evaluate the change in aneurysm detection rate and all-cause mortality five years before and eleven years after the VA implemented the screening policy in 2007.
We calculated survival estimates after AAA screening or non-screening imaging of patients with or without AAA diagnosis and used multivariate Cox regression model to evaluate mortality in patients with a positive AAA diagnosis adjusting for patient characteristics and comorbidities.
Results: We identified 3.9 million veterans with abdominal imaging, a total of 303,664 of whom were coded has having an AAA US screening between 2007 and 2018. An AAA diagnosis was made in 4.84% of the screening group vs. 1.3% in the non-screening imaging group P<0.001, yet more aneurysms were found with general imaging studies (50,730 vs.15,449) (Fig 1).
On Kaplan-Meier survival analysis, patients with an AAA diagnosis had higher overall mortality than patients who screened normal; patients with aneurysms found with non-screening imaging had the highest mortality, log-rank P<0.001 (Fig 2).
The difference in differences regression analysis, showed that the absolute AAA detection rate was 1.55% higher (95% CI 1.2- 1.8), and the mortality was 13.89 % lower (95% CI 10.18 %-16.66 %) after the introduction of the screening program in 2007.
Multivariate Cox regression analysis in patients with AAA diagnosis (65-74-year-old) demonstrated a significantly lower 5-year mortality [HR 0.45 (95% CI 0.43-0.48)] for patients in the US Screening group P<0.001.
Conclusions: In a nationwide analysis of VA patients, implementation of AAA screening was associated with improved survival and a higher rate of AAA diagnosis. These findings provide further support for this program’s continuation versus defaulting to incidental recognition following other abdominal imaging.
ABOUT MANUEL GARCIA-TOCA
Dr. Garcia-Toca earned his medical degree at the Universidad Anahuac in Mexico 1999. He has a master’s degree in Health Policy from Stanford University.
He received his general surgery training at the Massachusetts General Hospital and Brown University in 2008. He then completed a Vascular Surgery fellowship at Northwestern University in 2010. Dr. Garcia-Toca is board certified in both surgery and vascular surgery.
Dr. Garcia-Toca joined Stanford Vascular Surgery in 2015. He is currently Clinical Professor of Surgery in the Division of Vascular Surgery. Dr. Garcia-Toca had previously served as an Assistant Professor of Surgery at Brown University. Dr. Garcia Toca is a Staff Surgeon at Santa Clara Valley Medical Center in San Jose.
His research interests include new therapeutic strategies and outcomes for the management of vascular trauma, cerebrovascular diseases, dialysis access, aortic dissection and aneurysms.
ABOUT OLIVER O. AALAMI
Dr. Aalami is a Clinical Associate Professor of Vascular & Endovascular Surgery at Stanford University and the Palo Alto VA and serves as the Lead Director of Stanford’s Biodesign for Digital Health. He is the course director for Biodesign for Digital Health, Building for Digital Health and co-founder of the open source project, CardinalKit, developed to support sensor-based mobile research projects. His primary research focuses on clinically validating the sensors in smartphones and smartwatches in patients with cardiovascular disease to further precision health implementation.
Hosted by: Garry Gold, M.D.
Sponsored by the PHIND Center and the Department of Radiology