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. 2018 Sep;49(9):2046-2052.
doi: 10.1161/STROKEAHA.118.022412.

Elevated International Normalized Ratio Is Associated With Ruptured Aneurysms

Anil Can  1 , Victor M Castro  2 , Dmitriy Dligach  3 , Sean Finan  4 , Sheng Yu  5 , Vivian Gainer  2 , Nancy A Shadick  6 , Guergana Savova  4 , Shawn Murphy  2   7 , Tianxi Cai  8 , Scott T Weiss  9 , Rose Du  1   9
Affiliations

Elevated International Normalized Ratio Is Associated With Ruptured Aneurysms

Anil Can et al. Stroke. 2018 Sep.

Abstract

Background and Purpose- The effects of anticoagulation therapy and elevated international normalized ratio (INR) values on the risk of aneurysmal subarachnoid hemorrhage are unknown. We aimed to investigate the association between anticoagulation therapy, elevated INR values, and rupture of intracranial aneurysms. Methods- We conducted a case-control study of 4696 patients with 6403 intracranial aneurysms, including 1198 prospective patients, diagnosed at the Massachusetts General Hospital and the Brigham and Women's Hospital between 1990 and 2016 who were on no anticoagulant therapy or on warfarin for anticoagulation. Patients were divided into ruptured and nonruptured groups. Univariable and multivariable logistic regression analyses were performed to evaluate the association of anticoagulation therapy, INR values, and presentation with a ruptured intracranial aneurysm, taking into account the interaction between anticoagulant use and INR. Inverse probability weighting using propensity scores was used to minimize differences in baseline demographics characteristics. The marginal effects of anticoagulant use on rupture risk stratified by INR values were calculated. Results- In unweighted and weighted multivariable analyses, elevated INR values were significantly associated with rupture status among patients who were not anticoagulated (unweighted odds ratio, 22.78; 95% CI, 10.85-47.81 and weighted odds ratio, 28.16; 95% CI, 12.44-63.77). In anticoagulated patients, warfarin use interacts significantly with INR when INR ≥1.2 by decreasing the effects of INR on rupture risk. Conclusions- INR elevation is associated with intracranial aneurysm rupture, but the effects may be moderated by warfarin. INR values should, therefore, be taken into consideration when counseling patients with intracranial aneurysms.

Keywords: aneurysm; anticoagulants; international normalized ratio; subarachnoid hemorrhage; warfarin.

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Figures

Figure 1:
Figure 1:
The marginal effects of anticoagulant use on rupture risk stratified by INR levels. * = significant. Error bars represent 95% confidence intervals.
Figure 2:
Figure 2:
Proportion of ruptured aneurysms stratified by INR-values among A) anticoagulant users and B) non-anticoagulant users.
See this image and copyright information in PMC

References

    1. van Gijn J, Rinkel GJ. Subarachnoid haemorrhage: Diagnosis, causes and management. Brain. 2001;124:249–278 - PubMed
    1. Hop JW, Rinkel GJ, Algra A, van Gijn J. Changes in functional outcome and quality of life in patients and caregivers after aneurysmal subarachnoid hemorrhage. J Neurosurg. 2001;95:957–963 - PubMed
    1. Hijdra A, Braakman R, van Gijn J, Vermeulen M, van Crevel H. Aneurysmal subarachnoid hemorrhage. Complications and outcome in a hospital population. Stroke. 1987;18:1061–1067 - PubMed
    1. Hijdra A, van Gijn J, Nage lkerke NJ, Vermeulen M, van Crevel H. Prediction of delayed cerebral ischemia, rebleeding, and outcome after aneurysmal subarachnoid hemorrhage. Stroke. 1988;19:1250–1256 - PubMed
    1. Taylor CL, Yuan Z, Selman WR, Ratcheson RA, Rimm AA. Cerebral arterial aneurysm formation and rupture in 20,767 elderly patients: Hypertension and other risk factors. J Neurosurg. 1995;83:812–819 - PubMed

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