Morphological parameters as factors of 12-month neurological worsening in surgical treatment of patients with unruptured saccular intracranial aneurysms: importance of size ratio

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OBJECTIVE

It is well known that larger aneurysm size is a risk factor for poor outcome after surgical treatment of unruptured saccular intracranial aneurysms (USIAs). However, the authors have occasionally observed poor outcome in the surgical treatment of small USIAs and hypothesized that size ratio has a negative impact on outcome. The aim of this paper was to investigate the influence of size ratio on outcome in the surgical treatment of USIAs.

METHODS

Prospectively collected clinical and radiological data of 683 consecutive patients harboring 683 surgically treated USIAs were evaluated. Dome-to-neck ratio was defined as the ratio of the maximum width of the aneurysm to the average neck diameter. The aspect ratio was defined as the ratio of the maximum perpendicular height of the aneurysm to the average neck diameter of the aneurysm. The size ratio was calculated by dividing the maximum aneurysm diameter (height or width, mm) by the average parent artery diameter (mm). Neurological worsening was defined as an increase in modified Rankin Scale score of 1 or more points at 12 months. Clinical and radiological variables were compared between patients with and without neurological worsening.

RESULTS

The median patient age was 64 years (IQR 56–71 years), and 528 (77%) patients were female. The median maximum size, dome-to-neck ratio, aspect ratio, and size ratio were 4.7 mm (IQR 3.6–6.7 mm), 1.2 (IQR 1.0–1.4), 1.0 (IQR 0.76–1.3), and 1.9 (IQR 1.4–2.8), respectively. The size ratio was significantly correlated with maximum size (r = 0.83, p < 0.0001), dome-to-neck ratio (r = 0.69, p < 0.0001), and aspect ratio (r = 0.74, p < 0.0001). Multivariate logistic regression analysis showed that the specific USIA location (paraclinoid segment of the internal carotid artery: OR 6.2, 95% CI 2.6–15, p < 0.0001; and basilar artery: OR 8.4, 95% CI 2.8–25, p < 0.0001), size ratio (OR 1.3, 95% CI 1.1–1.6, p = 0.021), and postoperative ischemic lesion (OR 9.4, 95% CI 4.4–19, p < 0.0001) were associated with neurological worsening (n = 52, 7.6%), and other characteristics showed no significant differences.

CONCLUSIONS

The present study showed that size ratio, and not other morphological parameters, was a risk factor for 12-month neurological worsening in surgically treated patients with USIAs. The size ratio should be further studied in a large, prospective observational cohort to predict neurological worsening in the surgical treatment of USIAs.

ABBREVIATIONS mRS = modified Rankin Scale; USIA = unruptured saccular intracranial aneurysm.

Article Information

Correspondence Rokuya Tanikawa: Teishinkai Hospital, Hokkaido, Japan. taniroku@gmail.com.

INCLUDE WHEN CITING Published online September 21, 2018; DOI: 10.3171/2018.4.JNS173221.

Disclosures Dr. Tanikawa: patent holder with Medical U&A and Takayama Instrument.

© AANS, except where prohibited by US copyright law.

Headings

Figures

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    Exclusion criteria. aSAH = aneurysmal subarachnoid hemorrhage; AVM = arteriovenous malformation; IA = intracranial aneurysm; ICA = internal carotid artery.

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    Size ratio and variables with significant differences. Various symbols indicate the following levels of statistical significance and comparisons: *p < 0.05 and **p < 0.0001. † the size ratio of the aneurysms in the distal basilar artery (DBA) is larger than that of aneurysms in the paraclinoid segment of the internal carotid artery. The size ratio is weakly correlated with age (r = 0.11, p = 0.005). + = present; − = absent.

References

  • 1

    Backes DVergouwen MDTiel Groenestege ATBor ASVelthuis BKGreving JP: PHASES score for prediction of intracranial aneurysm growth. Stroke 46:122112262015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Brinjikji WCloft HJKallmes DF: Difficult aneurysms for endovascular treatment: overwide or undertall? AJNR Am J Neuroradiol 30:151315172009

  • 3

    Caranci FBriganti FCirillo LLeonardi MMuto M: Epidemiology and genetics of intracranial aneurysms. Eur J Radiol 82:159816052013

  • 4

    Chalouhi NHoh BLHasan D: Review of cerebral aneurysm formation, growth, and rupture. Stroke 44:361336222013

  • 5

    Choi ISDavid C: Giant intracranial aneurysms: development, clinical presentation and treatment. Eur J Radiol 46:1781942003

  • 6

    Dengler JMaldaner NGläsker SEndres MWagner MMalzahn U: Outcome of surgical or endovascular treatment of giant intracranial aneurysms, with emphasis on age, aneurysm location, and unruptured aneuryms—a systematic review and meta-analysis. Cerebrovasc Dis 41:1871982016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Greving JPWermer MJBrown RD JrMorita AJuvela SYonekura M: Development of the PHASES score for prediction of risk of rupture of intracranial aneurysms: a pooled analysis of six prospective cohort studies. Lancet Neurol 13:59662014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Hauck EFWohlfeld BWelch BGWhite JASamson D: Clipping of very large or giant unruptured intracranial aneurysms in the anterior circulation: an outcome study. J Neurosurg 109:101210182008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Ishibashi TMurayama YUrashima MSaguchi TEbara MArakawa H: Unruptured intracranial aneurysms: incidence of rupture and risk factors. Stroke 40:3133162009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Juvela SPoussa KLehto HPorras M: Natural history of unruptured intracranial aneurysms: a long-term follow-up study. Stroke 44:241424212013

  • 11

    Kashiwazaki DKuroda S: Size ratio can highly predict rupture risk in intracranial small (<5 mm) aneurysms. Stroke 44:216921732013

  • 12

    Kassell NFTorner JCHaley EC JrJane JAAdams HPKongable GL: The International Cooperative Study on the Timing of Aneurysm Surgery. Part 1: Overall management results. J Neurosurg 73:18361990

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13

    Korja MLehto HJuvela S: Lifelong rupture risk of intracranial aneurysms depends on risk factors: a prospective Finnish cohort study. Stroke 45:195819632014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Matsukawa HKamiyama HMiyazaki TKinoshita YNoda KOta N: Impacts of a size ratio on outcome in patients with surgically treated unruptured nondissecting anterior cerebral artery aneurysms. World Neurosurg 111:e250e2602018

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15

    Matsukawa HKamiyama HTsuboi TNoda KOta NMiyata S: Is age a risk factor for poor outcome of surgical treatment of unruptured intracranial aneurysms? World Neurosurg 94:2222282016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Morita AKirino THashi KAoki NFukuhara SHashimoto N: The natural course of unruptured cerebral aneurysms in a Japanese cohort. N Engl J Med 366:247424822012

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 17

    Murayama YTakao HIshibashi TSaguchi TEbara MYuki I: Risk analysis of unruptured intracranial aneurysms: prospective 10-year cohort study. Stroke 47:3653712016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Nakase HShin YKanemoto YOhnishi HMorimoto TSakaki T: Long-term outcome of unruptured giant cerebral aneurysms. Neurol Med Chir (Tokyo) 46:3793862006

  • 19

    Ponce FAAlbuquerque FCMcDougall CGHan PPZabramski JMSpetzler RF: Combined endovascular and microsurgical management of giant and complex unruptured aneurysms. Neurosurg Focus 17(5):E112004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Raaymakers TWRinkel GJLimburg MAlgra A: Mortality and morbidity of surgery for unruptured intracranial aneurysms: a meta-analysis. Stroke 29:153115381998

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Rahman MSmietana JHauck EHoh BHopkins NSiddiqui A: Size ratio correlates with intracranial aneurysm rupture status: a prospective study. Stroke 41:9169202010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Solomon RAFink MEPile-Spellman J: Surgical management of unruptured intracranial aneurysms. J Neurosurg 80:4404461994

  • 23

    Tremmel MDhar SLevy EIMocco JMeng H: Influence of intracranial aneurysm-to-parent vessel size ratio on hemodynamics and implication for rupture: results from a virtual experimental study. Neurosurgery 64:6226312009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Ujiie HTamano YSasaki KHori T: Is the aspect ratio a reliable index for predicting the rupture of a saccular aneurysm? Neurosurgery 48:4955032001

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    van Swieten JCKoudstaal PJVisser MCSchouten HJvan Gijn J: Interobserver agreement for the assessment of handicap in stroke patients. Stroke 19:6046071988

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26

    Vlak MHRinkel GJGreebe PAlgra A: Risk of rupture of an intracranial aneurysm based on patient characteristics: a case-control study. Stroke 44:125612592013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    von Elm EAltman DGEgger MPocock SJGøtzsche PCVandenbroucke JP: The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Lancet 370:145314572007

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28

    Wermer MJvan der Schaaf ICAlgra ARinkel GJ: Risk of rupture of unruptured intracranial aneurysms in relation to patient and aneurysm characteristics: an updated meta-analysis. Stroke 38:140414102007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Wiebers DOWhisnant JPHuston J IIIMeissner IBrown RD JrPiepgras DG: Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet 362:1031102003

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

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