External Validation of the ELAPSS Score for Prediction of Unruptured Intracranial Aneurysm Growth Risk

: van Kammen MS, Greving JP, Kuroda S, Kashiwazaki D, Morita A, Shiokawa Y, Kimura T, Cognard C, Januel AC, Lindgren A, Koivisto T, Jaaskelainen JE, Ronkainen A, Pyysalo L, Ohman J, Rahi M, Kuhmonen J, Rinne J, Leemans EL, Majoie CB, Vandertop WP, Verbaan D, Roos YBWEM, van den Berg R, Boogaarts HD, Moudrous W, van den Wijngaard IR, ten Hove L, Teo M, St George EJ, Hackenberg KAM, Abdulazim A, Etminan N, Rinkel GJE, Vergouwena MDI, Rinkel GJE, Vergouwena MDI

Publisher: KOREAN STROKE SOC

: SEOUL

: 2019

: Journal of Stroke

: JOURNAL OF STROKE

: J STROKE

: 21

: 3

: 340

: 346

: 9

: 2287-6391

DOI: https://doi.org/10.5853/jos.2019.01277

Background and purpose Prediction of intracranial aneurysm growth risk can assist physicians in planning of follow-up imaging of conservatively managed unruptured intracranial aneurysms. We therefore aimed to externally validate the ELAPSS (Earlier subarachnoid hemorrhage, aneurysm Location, Age, Population, aneurysm Size and Shape) score for prediction of the risk of unruptured intracranial aneurysm growth.Methods From 11 international cohorts of patients >= 18 years with >= 1 unruptured intracranial aneurysm and >= 6 months of radiological follow-up, we collected data on the predictors of the ELAPSS score, and calculated 3- and 5-year absolute growth risks according to the score. Model performance was assessed in terms of calibration (predicted versus observed risk) and discrimination (c-statistic).Results We included 1,072 patients with a total of 1,452 aneurysms. During 4,268 aneurysm-years of follow-up, 199 (14%) aneurysms enlarged. Calibration was comparable to that of the development cohort with the overall observed risks within the range of the expected risks. The c-statistic was 0.69 (95% confidence interval [CI], 0.64 to 0.73) at 3 years, compared to 0.72 (95% CI, 0.68 to 0.76) in the development cohort. At 5 years, the c-statistic was 0.68 (95% CI, 0.64 to 0.72), compared to 0.72 (95% CI, 0.68 to 0.75) in the development cohort.Conclusions The ELAPSS score showed accurate calibration for 3- and 5-year risks of aneurysm growth and modest discrimination in our external validation cohort. This indicates that the score is externally valid and could assist patients and physicians in predicting growth of unruptured intracranial aneurysms and plan follow-up imaging accordingly.