Résumé
With a rate of death and poor functional outcome of nearly 50%, aneurysmal subarachnoid hemorrhage (SAH) represents a significant cause of morbidity and mortality in young adults. Patients are usually hospitalized in intensive care units to manage both early brain injury resulting from the initial bleeding, and delayed cerebral ischemia (DCI) occurring unpredictably in 30% of them 3 to 21 days later. In the last years, the proposed pathophysiological mechanisms of this dramatic complication, an arterial vasospasm, has been questioned by both clinical and preclinical studies pointing towards early microvascular defects. We hypothesize that early brain injuries inflicted to microvascular components lead to long-lasting microcirculatory defects and eventually to delayed cerebral ischemia. In order to evaluate early brain perfusion in SAH patients, we designed a monocentric prospective trial. 35 subjects at high risk for delayed ischemia will be included and undergo (F18)2-fluoro-2-désoxy-D-glucose positron emission tomography. Resulting microparametric maps will be quantitatively compared to early and late magnetic resonance imaging (MRI) scans to evaluate the relationship between early perfusion and DCI.To this day, 144 SAH patients were screened, 86 of them showed high risk for DCI, and 14 were included in the trial. Exclusion were equally due to medical contraindications to the examinations and unavailability of the imaging devices. Preliminary analysis of microparametric maps show that early brain injury identified on the MRI scans indeed presented with altered perfusion parameters. None of the patients were affected with DCI.We currently carry on patients screening to complete inclusions in this clinical trial, which is part of a larger translational research project. Basic research led in an animal model will allow high spatiotemporal resolution measurement of macro and microvascular functions, in order to decipher pathophysiological mechanisms of DCI from molecular and cellular events to clinical manifestations.