gms | German Medical Science

70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

12.05. - 15.05.2019, Würzburg

The correlation between haemodynamics and collagen turnover measured by radiocarbon birth dating as an in-vivo indicator of instability in intracranial aneurysms

Die Korrelation zwischen Hämodynamik und Kollagenumsatz gemessen mittels Radiokarbondatierung als in vivo Indikator für Instabilität in intrakraniellen Aneurysmen

Meeting Abstract

  • presenting/speaker Katharina Hackenberg - Universitätsmedizin Mannheim, Neurochirurgie, Mannheim, Deutschland
  • Hamidreza Rajabzadeh-Oghaz - University at Buffalo, Buffalo, NY, United States
  • Rita Dreier - Universitätsklinikum Münster, Institut für Physiologische Chemie und Pathobiochemie, Münster, Deutschland
  • Bruce Buchholz - Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States
  • Daniel Hänggi - Universitätsmedizin Mannheim, Neurochirurgie, Mannheim, Deutschland
  • Adnan Siddiqui - University at Buffalo, Buffalo, NY, United States
  • Hui Meng - University at Buffalo, Buffalo, NY, United States
  • Nima Etminan - Universitätsmedizin Mannheim, Neurochirurgie, Mannheim, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie. Würzburg, 12.-15.05.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. DocV290

doi: 10.3205/19dgnc309, urn:nbn:de:0183-19dgnc3096

Published: May 8, 2019

© 2019 Hackenberg et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Objective: Saccular, unruptured intracranial aneurysms (IA) have a prevalence of 3% in the adult population with a mean 5-year risk of rupture of 3.4%, though assessing the rupture risk of an IA of an individual patient remains challenging. Aberrant hemodynamics have been known to play a role in initiation, growth and rupture of IA. However, studies that connect aneurysmal hemodynamics to the biological response from the aneurysmal wall are limited. We previously facilitated radiocarbon (14C) birth dating of the main molecular constituent in walls of IA, i.e. collagen, for assessment of collagen turnover in IA ex-vivo. In this report, we investigated the relation between collagen turnover in IA and aneurysmal hemodynamics to identify hemodynamic parameters indicative of structural instability in patients with IA.

Methods: Aneurysm samples from patients undergoing surgical repair for IA were previously processed and analyzed for collagen age using 14C birth dating. To obtain aneurysmal hemodynamics, 3-dimensional computed tomography angiographic (CTA) data was facilitated for Computational Fluid Dynamics (CFD). Morphologic and hemodynamic parameters were correlated with collagen turnover. Receiver operating characteristic (ROC) analysis was performed for identification of optimal thresholds separating fast from slow/normal collagen turnover for each parameter.

Results: CTA data sufficient in quality for CFD modelling was available in 20 patients (15 female, 5 male) with 6 unruptured and 14 ruptured IA. Collagen turnover was significantly higher in irregular IA compared to regular IA (Mann-Whitney-test, p<0.05) with a significant, negative correlation between collagen turnover and irregularity (r=-0.5, p<0.05). There was a significant, negative correlation between collagen turnover with aneurysmal time-average wall shear stress (WSS) (r=-0.6, p<0.01) and maximum WSS (r=-0.5, p<0.05). ROC analysis demonstrated a good test accuracy (area under the curve of 0.77, 95%CI 0.53–1.0) for average WSS with a threshold of 2.8 dyne/cm2 for fast collagen turnover (sensitivity 92.3%, specificity 57.1%).

Conclusion: Our data constitute the first ever association of actual biological data on chronological tissue turnover in IA with aneurysmal hemodynamics. WSS represents a promising surrogate for rapid collagen turnover indicative of structural instability of IA, possibly serving as a readily available in-vivo surrogate in future. Reconfirming studies are needed for improving the assessment and management of patients with IA.