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. 2016 Jan;8(1):104-10.
doi: 10.1136/neurintsurg-2014-011477. Epub 2014 Dec 8.

Hemodynamic-morphological discriminant models for intracranial aneurysm rupture remain stable with increasing sample size

Jianping Xiang  1 , Jihnhee Yu  2 , Kenneth V Snyder  3 , Elad I Levy  3 , Adnan H Siddiqui  3 , Hui Meng  1
Affiliations

Hemodynamic-morphological discriminant models for intracranial aneurysm rupture remain stable with increasing sample size

Jianping Xiang et al. J Neurointerv Surg. 2016 Jan.

Abstract

Background: We previously established three logistic regression models for discriminating intracranial aneurysm rupture status based on morphological and hemodynamic analysis of 119 aneurysms. In this study, we tested if these models would remain stable with increasing sample size, and investigated sample sizes required for various confidence levels (CIs).

Methods: We augmented our previous dataset of 119 aneurysms into a new dataset of 204 samples by collecting an additional 85 consecutive aneurysms, on which we performed flow simulation and calculated morphological and hemodynamic parameters, as done previously. We performed univariate significance tests on these parameters, and multivariate logistic regression on significant parameters. The new regression models were compared against the original models. Receiver operating characteristics analysis was applied to compare the performance of regression models. Furthermore, we performed regression analysis based on bootstrapping resampling statistical simulations to explore how many aneurysm cases were required to generate stable models.

Results: Univariate tests of the 204 aneurysms generated an identical list of significant morphological and hemodynamic parameters as previously (from the analysis of 119 cases). Furthermore, multivariate regression analysis produced three parsimonious predictive models that were almost identical to the previous ones, with model coefficients that had narrower CIs than the original ones. Bootstrapping showed that 10%, 5%, 2%, and 1% convergence levels of CI required 120, 200, 500, and 900 aneurysms, respectively.

Conclusions: Our original hemodynamic-morphological rupture prediction models are stable and improve with increasing sample size. Results from resampling statistical simulations provide guidance for designing future large multi-population studies.

Keywords: Aneurysm; Blood Flow; Stroke.

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Conflict of interest statement

Competing Interests Statement

Dr. Xiang: recipient of Dr. Richard J. Schlesinger grant from the American Society for Quality Biomedical Biomedical Division and principal investigator of Dawn Brejcha Chair of Research grant from Brain Aneurysm Foundation.

Dr. Yu: none.

Dr. Snyder: consultant: Toshiba; speakers’ bureau: Toshiba, ev3/Covidien and The Stroke Group; honoraria: Toshiba, ev3/Covidien and The Stroke Group.

Dr. Levy: shareholder/ownership interests: Intratech Medical Ltd., Mynx/Access Closure, Blockade Medical LLC. Principal investigator: Covidien US SWIFT PRIME Trials. Other financial support: Abbott for carotid training for physicians.

Dr. Siddiqui: research grants: co-investigator of NIH grants (R01NS064592 and 5R01EB002873) and Research Development Award from the University at Buffalo; financial interests: Blockade Medical, Hotspur, Intratech Medical, Lazarus Effect, StimSox, Valor Medical; consultant: Blockade Medical, Codman & Shurtleff, Inc., Concentric Medical, ev3/Covidien Vascular Therapies, GuidePoint Global Consulting, Lazarus Effect, MicroVention, Penumbra, Stryker, Pulsar Vascular; National Steering Committee: 3D Separator Trial (Penumbra, Inc.), SWIFT PRIME Trial (Covidien), FRED Trial (MicroVention); speakers’ bureau: Codman & Shurtleff, Inc.; advisory board: Codman & Shurtleff, Inc., Covidien Neurovascular; honoraria: Abbott Vascular and Codman & Shurtleff, Inc. for training other physicians in carotid stenting and endovascular stenting for aneurysms, and Penumbra, Inc.

Dr. Meng: principal investigator of NIH grant (R01NS064592), the grant from Toshiba Medical Systems and The Carol W. Harvey Memorial Chair of Research grant from Brain Aneurysm Foundation.

Figures

Figure 1
Figure 1
Aneurysm geometry, flow streamlines, WSS distribution and OSI distribution of 4 representative ruptured (top) and 4 representative unruptured (bottom) aneurysms from the new cohort. Ruptured aneurysms showed significant higher SR, UI, AR, OSI and lower WSS than unruptured aneurysms.
Figure 2
Figure 2
ROC curves of probabilities from multiple logistic regression models based on SR alone, SR and UI, using size and null predictor as references.
Figure 3
Figure 3
CIs for the coefficients of the three regression models in the previous 119 aneurysms and aggregated 204 aneurysms. M1 = Morphological Model; M2 = Hemodynamic Model; M3 = Combined Model.
Figure 4
Figure 4
A: CI width (each step giving lower and upper limits); B: Relative change of CI in the three regression models from the resampling statistical simulations.
Figure 4
Figure 4
A: CI width (each step giving lower and upper limits); B: Relative change of CI in the three regression models from the resampling statistical simulations.
See this image and copyright information in PMC

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