Object. Development of edema is known to contribute to poor outcome after spontaneous intracerebral hemorrhage (ICH). Recent research has identified thrombin as a key mediator in the development of edema in animal models; however, little has been published correlating the coagulation cascade and edema in humans.
Methods. In this retrospective clinical study of 80 patients with spontaneous supratentorial ICH, the authors sought to identify factors associated with edema development and outcome, including lesion imaging parameters, anticoagulant use, international normalized ratio and platelet count on hospital admission, and treatment with mannitol and steroid medications. A multivariate model was used to identify edema volume, use of mannitol, elevated blood glucose, and the presence of intraventricular hemorrhage as predictors of poor outcome at the time patients were discharged from the hospital. The authors developed a quadratic model for predicting edema volume against time by using a random coefficients model, and found that edema peaks between Days 5 and 6 after onset of ICH. The volume of the hemorrhage and the platelet count correlated significantly with edema volume within the first 24 hours post-ICH in the multiple regression analysis (p < 0.0001, r2 = 0.75). Edema growth during the first 5 days post-ICH also correlated with the platelet count, with an increasing platelet count associated with an increasing growth of edema (p = 0.0013).
Conclusions. The authors propose that factors released from activated platelets at the site of hemorrhage, for example vascular endothelial growth factor, may interact with thrombin to increase vascular permeability and contribute to the development of edema.