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ARTICLES: C. Stapf, H. Mast, R. R. Sciacca, J. H. Choi, A. V. Khaw, E. S. Connolly, J. Pile-Spellman, and J. P. Mohr Predictors of hemorrhage in patients with untreated brain arteriovenous malformation Neurology 2006; 66: 1350-1355 [Abstract] [Full text] [PDF]

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Predictors of hemorrhage in patients with untreated brain arteriovenous malformation

John F. Dashe   (12 September 2006)

Reply from the Authors

Christian Stapf, J.P.Mohr   (12 September 2006)

Predictors of hemorrhage in patients with untreated brain arteriovenous malformation 12 September 2006
John F. Dashe, UpToDate, Inc., Waltham, MA; New England Medical Center, Boston 95 Sawyer Road, Waltham, MA 02453-3471 Send Correspondence to journal: Re: Predictors of hemorrhage in patients with untreated brain arteriovenous malformation jdashe{at}uptodate.com John F. Dashe	I read the article by Stapf et al [1] regarding brain AVMs with great interest. The study found that infratentorial AVM location was associated with hemorrhage at presentation in the univariate model but not the multivariate model (odds ratio [OR] 1.53, 95% CI 0.84 to 2.79; p = 0.17), suggesting that infratentorial AVM is not an independent predictor of hemorrhage at presentation. However, in an earlier publication from the same group [2] analyzing essentially the same population (623 patients instead of 622), infratentorial AVM location was associated with hemorrhagic presentation in the univariate model and multivariate model (OR 1.99, 95% CI 1.07 to 3.69; p = 0.03). This finding was the major conclusion. I am curious about the discrepancy between these two reports regarding the association of infratentorial brain arteriovenous malformations with hemorrhage at initial presentation. The authors did not provide an explanation nor cite their previous study. References 1. Stapf, C, Mast, H, Sciacca, RR, et al. Predictors of hemorrhage in patients with untreated brain arteriovenous malformation. Neurology 2006; 66:1350. 2. Khaw, AV, Mohr, JP, Sciacca, RR, et al. Association of infratentorial brain arteriovenous malformations with hemorrhage at initial presentation. Stroke 2004; 35:660. Disclosure: The author reports no conflict of interest.
Reply from the Authors 12 September 2006
Christian Stapf, Stroke Center/The Neurological Institute, Columbia University 710 W 168th Street, New York, NY 10032, J.P.Mohr Send Correspondence to journal: Re: Reply from the Authors cstapf{at}neuro.columbia.edu Christian Stapf, et al.	The authors thank Dr. Dashe for his interest in our work. He refers to one of our prior analyses [2] which was based on initial presentation data only and included a limited number of morphological variables. At the time, we concluded that "no immediate treatment recommendations can be derived from our data", mainly "because our cross- sectional study did not analyze the effect of infratentorial AVM location on the risk of future hemorrhage." Two years later, this careful interpretation has proven accurate in the light of our most recent study. [1] The current analysis was based on a prospective follow-up cohort and included an extended set of clinical and morphological variables such as borderzone and deep AVM location. The latter attenuated the effect of infratentorial AVM location on initial AVM rupture in the multivariate logistic regression model, and no further association was seen between infratentorial AVM location and the risk of hemorrhage on follow-up. This statistical detail appeared less important to us, but the finding lends support to far broader conclusions regarding prior AVM risk models, namely that many factors showing positive (associated arterial aneurysms, infratentorial AVM location) or negative associations (increasing AVM size, borderzone location) with initial AVM rupture do not necessarily predict hemorrhage on follow-up. Based on these results, we advocate a general amnesty for studies evaluating variables associated with hemorrhagic AVM presentation only, as no longitudinal risk predictions can be drawn from post hoc associations with a single event. Based on our prospective follow-up data, the Columbia AVM Risk model only confirmed increasing age, deep AVM location, exclusive deep venous drainage, and initial AVM rupture as being independent risk factors for subsequent hemorrhage events in untreated patients. Disclosure: The authors report no conflicts of interest.