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Original research
Venous tortuosity as a novel biomarker of rupture risk in arteriovenous malformations: ARI score
  1. Alejandra Mosteiro1,
  2. Leire Pedrosa1,2,
  3. Ramón Torne1,2,3,
  4. Ana Rodríguez-Hernández4,
  5. Sergi Amaro3,
  6. Luis A Reyes1,
  7. Jhon A Hoyos1,
  8. Luis San Roman5,
  9. Nicolás de Riva6,
  10. Carlos J Domínguez4,
  11. Joaquim Enseñat1,2
  1. 1 Department of Neurosurgery, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain
  2. 2 IDIBAPS Biomedical Research Institute, Barcelona, Spain
  3. 3 Comprehensive Stroke Unit, Neurology, Hospital Clinic de Barcelona, Barcelona, Spain
  4. 4 Department of Neurosurgery, Germans Trias i Pujol University Hospital, Barcelona, Spain
  5. 5 Radiology Department, Angioradiology Section, Hospital Clinic of Barcelona, Barcelona, Spain
  6. 6 Department of Anesthesiology, Hospital Clinic of Barcelona, Barcelona, Spain
  1. Correspondence to Dr Ramón Torne, Department of Neurosurgery, University of Barcelona, Barcelona 08036, Spain; torne{at}


Background Risk of rupture in arteriovenous malformations (AVMs) varies considerably among series. Hemodynamic factors, especially within the venous side of the circuit, seem to be responsible but are not yet well defined. We analyzed tortuosity in the draining vein as a potential new marker of rupture in AVMs, and propose a simple index to predict AVM bleeding.

Methods A retrospective analysis of the venous angioarchitecture of brain AVMs was carried out at our center from 2013 to 2021, with special attention to venous tortuosity. After univariate analysis, the features of interest were combined to construct several predictive models using multivariate logistic regression. The best model proposed was the new AVM rupture index (ARI), which was then validated in an independent cohort.

Results 68 AVMs were included in the first step and 32 in the validation cohort. Venous tortuosity, expressed as at least one curve >180°, was a significant predictor of rupture (p=0.023). The proposed bleeding index consisted of: venous tortuosity (any curve of >180°), single draining vein, and paraventricular/infratentorial location. It seems to be a robust evaluation tool, with an area under the receiver operating characteristic (AUROC) curve of 0.806 (95% CI 0.714 to 0.899), consistently replicated in the independent sample (AUROC 0.759 (95% CI 0.607 to 0.911)), and with an inter-rater kappa coefficient of 0.81 .

Conclusions Venous tortuosity may serve as a predictor of bleeding in AVMs that warrants further investigation. This likely new marker was one of the three elements of the proposed ARI. ARI outperformed the predictive accuracy of previous scores, and remained consistent in an independent cohort.

  • vein
  • arteriovenous malformation
  • hemorrhage
  • angiography

Data availability statement

Data are available upon reasonable request. Further information and clinical data are available for researchers upon reasonable request and under the supervision of the intitution’s ethics committee.

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Data availability statement

Data are available upon reasonable request. Further information and clinical data are available for researchers upon reasonable request and under the supervision of the intitution’s ethics committee.

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  • RT and AR-H are joint senior authors.

  • AM and LP contributed equally.

  • Contributors Substantial contributions to the conception or design of the work: RT, AR-H, SA, and AM. Acquisition, analysis, and interpretation of the data for the work: LSR, RT, AR-H, SA, AM, LAR, and LP. Drafting the work: AM and LP. Critical revision: RT, AR-H, and SA. Final approval of the version to be published: all authors. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: all authors. RT will act as guarantor.

  • Funding This study was funded by Fundació la Marató TV3 (248/C/2020).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.