Reporting Terminology for Brain Arteriovenous Malformation Clinical and Radiographic Features for Use in Clinical Trials

The goal of this writing group is to provide guidelines for use in the design of clinical trials, that can aid in providing sufficient uniformity of definitions for appropriate selection and stratification of patients, as well as analysis of data. We emphasize that this document is not to be construed as a standard-of-care or intended for current routine clinical grading or classification, such as the Spetzler-Martin surgical scoring system. 1 The reporting standards presented in this document represent an “ideal” and are intended for use in research protocols rather than in quality assessment of individual practice. The definitions represent one set of possible guidelines for constructing a reportable research data set; they are not intended to represent the only ones of importance or interest to collect in clinical trials, ie, they are not proposed as a minimally acceptable set of data. Rather, our intent is to facilitate the production of scientifically rigorous results that are capable of being reliably compared between related studies. In some cases, the definitions used arearbitrary or operationalbut have been recommended by consensus of the writing group for the sake of consistency in reporting. Evaluation and treatment of brain arteriovenous malformations (BAVMs) is often a multidisciplinary exercise involving neurosurgeons, neurologists, neuroradiologists, radiotherapists, and numerous other medical specialists. A recent review by an AHA writing group2 has surveyed the literature to develop current guidelines for the clinical management of BAVMs. Despite these tremendous efforts to synthesize existing knowledge on this topic, there remain inconsistencies with nomenclature and definitions of terms for research purposes. This lack of consistency in data reporting by investigators is a major challenge for progress in treatment of BAVMs. A set of well-considered definitions can allow different investigators to publish results that are directly comparable. The intent of this writing group is to formulate a set of definitions based on current practice and imaging technology that may serve as a frame of reference for future reports and of future clinical trials. One of the major challenges to research of BAVMs is the lack of widely accepted prognostic systems other than the Spetzler-Martin scale for estimating surgical treatment risk. 1