Redefining Secondary Injury After Subarachnoid Hemorrhage in Light of Multimodal Advanced Neuroimaging, Intracranial and Transcranial Neuromonitoring: Beyond Vasospasm

Abstract

The classic idea that arterial narrowing, called vasospasm (VSP), represents the hallmark of secondary injury after subarachnoid hemorrhage, has been challenged. The more complex and pleiotropic pathophysiological repercussions from the irruption of arterial blood into the subarachnoid layers go beyond the ascribed VSP. Putting adjectives in front of this term, such as "symptomatic," "microdialytic," or "angiographic" VSP, is misleading. Delayed cerebral ischemia (DCI) is a better term but remains restrictive to severe hypoperfusive injury and neglects oligemia, edema, and metabolic nonischemic injuries. In recognition of these issues, the international conference on VSP integrated "neurovascular events" into its name ( www.vasospasm2013.com ) and a multidisciplinary research group was formed in 2010 to study subgroups of DCI/VSP and their respective significance.In three parts, this tiered article provides a broader definitional envelope for DCI and secondary neurovascular insults after SAH, with a rubric for each subtype of delayed neuronal dysfunction. First, it pinpoints the need for nosologic precision and covers current terminological inconsistency. Then, it highlights the input of neuroimaging and neuromonitoring in defining secondary injurious processes. Finally, a new categorization of deteriorating patients is proposed, going beyond a hierarchical or dichotomized definition of VSP/DCI, and common data elements are suggested for future trials.

Guía clínica para el manejo de la hemorragia subaracnoídea aneurismática - propuesta de actualización al Ministerio de Salud de Chile

“…A la luz de los últimos avances en el estudio de los fenómenos fisiopatológicos desencadenados por la HSA, el concepto de DCI, como entidad nosológica, ha sido bastante cuestionado. Se le critica una definición confusa y el hecho de ser un concepto ambiguo, que incluye mecanismos fisiopatológicos muy distintos 20 . Esto se puede ver reflejado en la heterogeneidad de los criterios utilizados para diagnosticar la DCI en los distintos trabajos de inves-tigación.…”