Aristeidis H. Katsanos, MD, PhD
Even though cerebral edema (CED) is one of the most severe complications of acute ischemic stroke (AIS) and the cause of mortality in 5% of all AIS patients, there are scarce data on risk factors predicting the development of CED following AIS — including the subgroup of AIS patients treated with intravenous thrombolysis (IVT).
Thorén and colleagues aimed to determine potential baseline clinical and radiological predictors of CED after IVT by analyzing data from 42,187 AIS patients recorded in the Safe Implementation of Treatments in Stroke International Register (SITS-ISTR) during a 10-year period. After performing an image-based classification on the severity of post-IVT CED, they found that increased baseline stroke severity, high blood glucose, decreased level of consciousness, the presence of hyperdense artery sign and signs of infract on baseline neuroimaging were the most important baseline predictors for early CED. As expected, patients with CED had worse 3-month functional outcomes and increased mortality rates —proportionally to the severity of edema — compared to patients without CED. Moreover, the authors found increased risk of symptomatic intracerebral hemorrhage in patients with severe CED, providing further support to the hypothesis of a blood-brain disruption induced common pathway leading to both cerebral edema and hemorrhage in the acute phase of cerebral ischemia.
One of the most important and merely highlighted findings of the report by Thorén and colleagues is that the vast majority (>99%) of CED is present on 22 to 36 hours after IVT administration. Taking into account the results of a pooled analysis from available randomized clinical trials (RCTs) on the management of space-occupying hemispheric infarctions (DECIMAL, DESTINY, HAMLET), suggesting that surgical decompression reduces mortality and poor outcome in patients who are treated within 48 hours of stroke onset, patients with severe strokes, hyperglycemia, early ischemic changes and/or hyperdense artery sign on baseline imaging receiving IVT treatment should be closely monitored during the first 36 hours for the development of CED and managed appropriately.