Prognostic Role of Perihematomal Edema in Intracerebral Hemorrhage: A Systematic Review

Although several studies have suggested perihematomal edema (PHE) is associated with prognosis in intracerebral hemorrhage (ICH), the results are different in other studies. The purpose of this study was to evaluate the prognostic role of PHE in ICH. According to PRISMA guidelines, a systematic literature search of PubMed, EMBASE, SCOPUS, Web of Science and Cochrane Library was performed. Published clinical studies reporting association between PHE and prognosis in ICH were included. Data were extracted including sample size, patient characteristics, PHE measures, outcome measures and follow-up. A total of 21 studies were included with 6 prospective studies and 15 retrospective studies. PHE measures included perihematomal edema absolute volume (PHEAV), relative perihematomal edema volume (rPHE), perihematomal edema absolute volume growth (PHEAV growth), perihematomal edema expansion rate (PHEER), relative perihematomal edema growth (relative PHE growth), cytotoxic edema (CE) and perihematomal edema absolute area (PHEAA). The association of PHEAV/ rPHE /PHEAV growth and outcome are conflicting in different studies. Meta-analysis showed PHEER at 72 hours was significantly associated with poor clinical outcome at 90 days (OR=1.54, 95% CI 1.04-2.22, p<0.001). This study suggests the measures and time points for PHE and outcome are various in previous studies. The prognostic values of PHEAV, rPHE, PHEAV growth and other measures are still controversial. PHEER is likely a prognostic predictor for ICH. Further studies with larger sample size, more accurate measures and more time points are needed to investigate the prognostic role of PHE in ICH and the optimal PHE measure to predict outcome in ICH.