PROJECT SUMMARY/ABSTRACT The 8th International Symposium on Collaterals to the Brain is a multidisciplinary scientific conference focused on collateral circulation in ischemic stroke. This proposal requests partial support for a conference with broad, long-term objectives that will advance current research on collateral blood flow and identify gaps in current treatment strategies around the world. The collaterome, or individual capacity to offset ischemia in the brain, and determination of a favorable collateral profile have become pivotal factors in the consideration of cerebral ischemia and the precision medicine of stroke driving individualized medical decision-making. The conference directly addresses the most pressing issues and gaps in optimally defining collateral status that limits the realization of stroke therapies around the world. Decisive challenges include generalizability of optimal triage and selection paradigms based on collateral status for definitive treatment of ischemic stroke, rapid dissemination of expert methods and transformative advances, and the urgent need to leverage networking opportunities for stroke education and science related to hemodynamics of collaterals to the brain. The aims of this conference will convene faculty from around the world to connect on-site participants at the state-of-the-art facility with remote audiences in more than 75 countries and regions. Detailed presentation topics have been arranged around themes relating to the basic science, translational, clinical research, routine clinical aspects, imaging, endovascular therapy, and systems of care issues of collaterals in the brain. The confirmed program of this 3-day conference is structured into 40-minute sessions devoted to key issues in translating the collaterome in stroke therapy across the globe. Of particular importance is the interval progress on the use of hemodynamics in stroke that will be presented based on the annual country-based surveys. The dedicated sessions for debates, solutions, and the early career and basic science moderated poster session, hands-on neurovascular device workshop and interspersed networking opportunities will enhance collaborative initiatives in this burgeoning field. Rapid dissemination of electronic posters, proceedings, and other publications, as in past meetings, will intensify the impact of this unique and esteemed annual Symposium. Dedicated efforts for appropriate representation have already been delineated to have parity in the numbers of women, recruit underrepresented minorities and persons with disabilities, culminating in an extremely diverse spectrum of participants. Trainee awards for underrepresented minorities from the local region will markedly enhance the educational impact of this meeting. Measurable outcomes will quantify the impact of this symposium on the NINDS mission to enhance knowledge of collaterals and reduce the burden of neurological disease due to stroke. This unique forum of expertise extending from a state-of-the-art venue across the world emphasizes the timely impact of collaterals on a monumental scale, encouraging maximal participation, rapid diffusion, and added value of networking resources.

PROJECT NARRATIVE/ RELEVANCE TO PUBLIC HEALTH STATEMENT The 8th International Symposium on Collaterals to the Brain is a 3-day multidisciplinary scientific conference focused on collateral circulation and hemodynamics in ischemic stroke due to a variety of causes, fueled by the most current perspective from around the world. Leading experts will connect with remote audiences of stroke investigators in more than 75 countries and regions to address current translational research questions and identify gaps in this area, with rapid and widespread dissemination of meeting proceedings, enhancing collaborative network opportunities. Understanding the pivotal role of collaterals in stroke accelerates development of collateral therapeutics to restore blood flow in stroke, the leading cause of adult disability in the US and a key priority for improving public health.