Primary neurocritical care involving therapeutic hypothermia for acute ischemic stroke patients with malignant infarct cores

Selective Brain Cooling: A New Horizon of Neuroprotection

Therapeutic hypothermia (TH), which prevents irreversible neuronal necrosis and ischemic brain damage, has been proven effective for preventing ischemia-reperfusion injury in post-cardiac arrest syndrome and neonatal encephalopathy in both animal studies and clinical trials. However, lowering the whole-body temperature below 34°C can lead to severe systemic complications such as cardiac, hematologic, immunologic, and metabolic side effects. Although the brain accounts for only 2% of the total body weight, it consumes 20% of the body's total energy at rest and requires a continuous supply of glucose and oxygen to maintain function and structural integrity. As such, theoretically, temperature-controlled selective brain cooling (SBC) may be more beneficial for brain ischemia than systemic pan-ischemia. Various SBC methods have been introduced to selectively cool the brain while minimizing systemic TH-related complications. However, technical setbacks of conventional SBCs, such as insufficient cooling power and relatively expensive coolant and/or irritating effects on skin or mucosal interfaces, limit its application to various clinical settings. This review aimed to integrate current literature on SBC modalities with promising therapeutic potential. Further, future directions were discussed by exploring studies on interesting coping skills in response to environmental or stress-induced hyperthermia among wild animals, including mammals and birds.

Optic nerve sheath diameter change in prediction of malignant cerebral edema in ischemic stroke: an observational study

Background

In acute large anterior circulation infarct patients with large core volume, we evaluated the role of optic nerve sheath diameter (ONSD) change rates in prediction of malignant progression.

Methods

We performed a retrospective observational study including patients with anterior circulation acute ischemic stroke with large ischemic cores from January 2010 to October 2017. Primary outcome was defined as undergoing decompressive surgery or death due to severe cerebral edema, and termed malignant progression. Patients were divided into malignant progressors and nonprogressors. Malignant progression was divided into early progression that occurred before D1 CT, and late progression that occurred afterwards. Retrospective analysis of changes in mean ONSD/eyeball transverse diameter (ETD) ratio, and midline shifting (MLS) were evaluated on serial computed tomography (CT). Through analysis of CT at baseline, postprocedure, and at D1, the predictive ability of time based change in ONSD/ETD ratio in predicting malignant progression was evaluated.

Results

A total of 58 patients were included. Nineteen (32.8%) were classified as malignant; 12 early, and 7 late progressions. In analysis of CT_{postprocedure}, A 1 mm/hr. rate of change in MLS during the CT_baseline-CT_{postprocedure} time phase lead to a 6.7 fold increased odds of early malignant progression (p < 0.05). For ONSD/ETD, 1%/hr. change lead to a 1.6 fold increased odds, but this association was trending (p = 0.249). In the CT_D1, 1%/day change of ONSD/ETD in the CT_baseline-CT_D1 time phase lead to a 1.4 fold increased odds of late malignant progression (p = 0.021) while 1 mm/day rate of change in MLS lead to a 1.5 fold increased odds (p = 0.014).

Conclusions

The rate of ONSD/ETD changes compared to baseline at D1 CT can be a predictor of late malignant progression along with MLS. ONSD/ETD change rates evaluated at postprocedure did not predict early malignant progression.

The Clinical Usefulness of Targeted Temperature Management in Acute Ischemic Stroke with Malignant Trait After Endovascular Thrombectomy

BACKGROUND/OBJECTIVE

Targeted temperature management (TTM) may be more beneficial after endovascular treatment (EVT) in patients with a large ischemic core. Therefore, we assessed the usefulness of TTM for such patients from a multicenter endovascular registry.

METHODS

Anterior circulation stroke patients who underwent endovascular recanalization were included; acute ischemic stroke with malignant traits was designated as (1) baseline Alberta Stroke Program Early CT Score (ASPECTS) below 6 and (2) diffusion-weighted imaging (DWI) lesion volume measurement (> 82 ml) or National Institutes of Health Stroke Scale score > 20 and item Ia > 0. TTM (34.5 °C) was maintained for at least 48 h.

RESULTS

We evaluated baseline demographics, risk factors, EVT parameters, and clinical outcomes between the TTM and non-TTM groups. Among the 548 patients, the TTM group (n = 91) significantly had a lower baseline ASPECTS (p < 0.001) and a higher DWI volume (p < 0.001) than the non-TTM group (n = 457). TTM group had a lower prevalence of favorable outcome (0-2 of modified Rankin Scale at 3 months; p = 0.008) than the non-TTM group. In a subgroup analysis of malignant trait patients (n = 80), TTM patients (n = 28) had more favorable outcome (32.1% vs. 7.7% p = 0.009) and less hemorrhagic transformation (none vs. any hemorrhage, p = 0.007) than non-TTM patients (n = 52). After adjusting for potential outcome predictors, TTM (odds ratio [OR] 4.63; confidence interval [CI] 1.20-17.89; p = 0.026) and hypertension (OR 0.18; CI 0.04-0.74; p = 0.018) were found to be independent determinants.

CONCLUSIONS

Our data suggest that TTM attenuates impending hemorrhagic transformation and leads to favorable clinical outcomes in EVT patients with malignant trait.