Vikas Pandey, MD

Renú A, Amaro S, Laredo C, San Román L, Llull L, Lopez A, et al. Relevance of Blood–Brain Barrier Disruption After Endovascular Treatment ofIschemic Stroke: Dual-Energy Computed Tomographic Study. Stroke. 2015

With the emergence of interventional stroke trials showing some long-term benefit in those undergoing intervention versus simply IV tPA alone, new questions are now arising as a result of these interventional therapies. One of these questions comes with the often ordered follow up CT scan that is done after such intervention showing hyperdense areas that can resemble hemorrhage, however can also reasonably be contrast that has leaked into the parenchyma due to a disrupted blood-brain barrier (BBB), a common after-effect of the interventional procedures. Many times there is very little to rely on to make a diagnosis of contrast staining (CS) or brain hemorrhage (BH) aside from the clinician’s best guess on the initial scan and the pattern of resorption on follow up scans thereafter. The authors hypothesized that using Dual energy CT (DE-CT) would allow for a more accurate differentiation of CS vs BH and that the presence of either of these entities may be a prognostic factor to clinical outcome.

DE-CT is a technique based on identifying different attenuation effects of brain tissue, iodine and blood at different irradiation energy levels. The authors decided to use this technique as it has been shown in previous studies to be able to differentiate between CS and BH, and the presence of either of these after endovascular therapy may suggest different grades of BBB disruption. To evaluate if this had any prognostic significance, the group prospectively collected 132 patients with proximal artery occlusions without a malignant profile, treated at a single Comprehensive Stroke Center in Spain, and who underwent endovascular therapy aiming for a TICI grade of 2b or 3 at the end of the procedure. The patients then underwent DE-CT which showed (see attached figure) using plain CT, virtual non-contrast and iodine overlay modes whether the patient had CS, BH or both (categorized as BH). The numbers in each category were 53 patients (40%) with no highly attenuated areas, 32 patients (24%) with CS alone, and 47 patients (36%) with BH. The clinical outcomes after 90 days showed that 67 patients (51%) had poor outcome and these were linked to higher stroke severity, higher glucose and systolic blood pressure levels at baseline, absence of recanalization and longer length of endovascular procedures. The rate of poor outcome was increased in CS (OR 5.32, 95% CI 2.05 – 13.77) and BH (OR 5.94, 95% CI 2.5 – 14.12) compared to the patients with no high attenuation areas. Even in the 109 patients (83%) with complete recanalization, 46% of those had poor outcome. The increased rate of poor outcome in CS and BH patients persisted even when taking into account only those patients that had complete recanalization.

The authors showed a link between the presence of CS or BH (signifying BBB disruption) and poor clinical outcome and showed that using DE-CT was able to more reliably distinguish between CS and BH. They also found a very clinically relevant link that the subset of patients with CS alone, had an increased risk of delayed hemorrhagic transformation of the stroke. Their research has put added emphasis on work that is being done to protect the BBB during reperfusion therapies as this can lead to better patient outcomes. They also have further strengthened the potential role of DE-CT in every day clinical practice for both ascertainment of diagnosis as well as a predictor of prognosis.