P1819Screening for abdominal aortic aneurysm in patients with cardiovascular disease: yield of screening and AAA related-mortality during follow-up
Authors: De Boer A R , Bots M L , Vaartjes I , Van Dis I , Van Herwaarden J A , Visseren F L J 
Published: October 2019

Abstract

Background
Abdominal aortic aneurysm (AAA) is a serious and life-threatening disease. Several countries introduced population-based screening programs targeting males ≥65 years old in an attempt to reduce AAA-related deaths. However, declining incidence rates of AAA and doubt about cost-effectiveness of population-based screening raises the question whether targeted screening in patients with already clinical manifest cardiovascular diseases could increase the yield of screening.

Purpose
The aim of this study was to assess prevalence of AAA in patients with clinical manifest cardiovascular disease and to evaluate AAA related mortality rates.

Methods
Data were obtained from 7446 patients (64361 patient-years of follow-up, median follow-up 8.3 years, interquartile ranges 4.6–12.3) with manifest atherosclerotic disease (62% coronary artery disease, 32% cerebrovascular disease, 18% peripheral artery disease) but without a history of AAA enrolled in the UCC-SMART study, an ongoing single-center, prospective cohort study. All patients underwent baseline examination including ultrasonography and presence of AAA was defined as local dilatation of the aorta with an anteroposterior diameter of 3 cm or larger on ultrasonography. Prevalence of AAA and number needed to screen to detect one aortic aneurysm were calculated stratified for sex and age. Finally, AAA related mortality rates were calculated for both the screen positive and negative group stratified for sex.

Results
Prevalence of newly detected AAA was 2.5% in male and 0.6% in female patients with manifest atherosclerotic disease translating to a number needed to screen of respectively 40 and 154 to detect one aortic aneurysm. In men the number needed to screen to detect one aneurysm decreases with age (134 in men between 50–54 years old; 36 in men between 60–64 years old; 22 in men between 70–75 years old), while in women this was less pronounced (124 in women between 50–54 years old; 81 in women between 60–64 years old; 83 in women between 70–75 years old). 80% of newly detected aneurysms in men was of the smallest diameter (3.0–3.9 cm), while 5% was of a diameter ≥5.5cm. All AAA related deaths (n=7) occurred in men. The incidence rate of AAA related mortality was 2.80 per 1000 patient-years in men with AAA after initial screening and 0.09 per 1000 patient-years without AAA after initial screening.

Conclusion
The yield of screening for AAA in male patients with manifest atherosclerotic disease is appreciable and number needed to screen to detect one aneurysm increases with age. If screening for AAA is considered, it should be performed in specific subgroups of older men with cardiovascular disease to improve yield of screening, taken into account other benefits and harms of AAA screening. Our findings, combined with a formal estimation of life years gained and disability adjusted life years gained attributed to screening and subsequent treatment is mandatory before taking definite steps.

Acknowledgement/Funding
University Medical Center Utrecht