November 7, 2019
Analysis From Vascular Quality Initiative Shows Correlation of AAA Size and Outcomes After EVAR
November 6, 2019—The Society for Vascular Surgery announced the publication of findings from a study based on 22,975 patient records in the Vascular Quality Initiative (VQI), showing that abdominal aortic aneurysm (AAA) diameter has important implications for operative and long-term outcomes for patients. The study of differences in patient selection and outcomes based on AAA diameter thresholds in the VQI was published by Douglas W. Jones, MD, et al in Journal of Vascular Surgery (2019;70:1446–1455).
The SVS announcement noted that international societies—using historical data and more recent large randomized controlled trials—recommend elective repair of AAA when the diameter exceeds 5 cm in women and 5.5 cm in men. Repair for small aneurysms may be indicated if there is excessive growth, saccular morphology, or family history of AAA. The authors of the study point out that the relatively high proportion of elective AAA repairs at smaller diameters in the United States is associated with lower population-level AAA-related death and rupture compared with the United Kingdom.
Dr. Jones stated in the SVS announcement, “There are relatively few high-quality data describing national practice patterns and outcomes associated with AAA diameter. Using the VQI database, we sought to describe differences in patient characteristics and selection based on AAA diameter. Secondarily, we examined the effect of AAA diameter on operative and long-term outcomes.”
The multicenter team analyzed 22,975 patients enrolled in the VQI who underwent elective endovascular aneurysm repair (EVAR) from 2003 to 2017. They divided the cohorts studied into small AAA (< 5 cm in women, < 5.5 cm in men; n = 9,353 [41%]), medium AAA (5–6.5 cm in women, 5.5–6.5 cm in men; n = 10,842 [47%]), and large AAA (> 6.5 cm; n = 2,780 [12%]) groups.
The investigators reported that 30-day mortality rates in these three groups were 0.4%, 0.9%, and 1.6%, respectively. Further, patients with small aneurysms had the lowest rates of medical complications, type I endoleak at time of procedure, and the shortest length of stay.
At 5 years, overall survival was predicted by AAA size at the time of EVAR with the following rates: 88% for small, 81% for medium, and 75% for large.
In the SVS announcement, Dr. Jones advised, “The survival rates for patients undergoing EVAR for small AAAs were comparable to those seen in the surveillance arms of recent trials (90% at 4.5 years). As a result, although these data illustrate that long-term survival is associated with AAA diameter at the time of EVAR, they should not be interpreted as supportive of EVAR for small AAAs over surveillance.” He further noted that many factors besides maximum AAA diameter can be factors in recommending repair or surveillance. “These data show that a large proportion of elective EVARs nationwide are being performed for small AAAs and the clinical indications for these repairs merit further study, especially given relative unanimity of guideline recommendations,” concluded Dr. Jones.