Shlee Song

Overview of Therapeutic Hypothermia

Opinion statementTherapeutic hypothermia has proven neuroprotective effects in global cerebral ischemia. Indications for hypothermia induction include cardiac arrest and neonatal asphyxia. The two general methods of induced hypothermia are either surface cooling or endovascular cooling. Hypothermia should be induced as early as possible to achieve maximum neuroprotection and edema blocking effect. Endovascular cooling has the benefit of shorter time to reach target temperature but catheter insertion requires expertise and training, which may be a barrier to widespread availability. The optimum method of cooling is yet to be determined but a multimodal approach is necessary to address three phases of cooling: induction, maintentance, and rewarm. Specifying core practitioners who are well-versed in established guidelines can help integrate the multidisciplinary team that is needed to successfully implement cooling protocols. Reducing shivering to make heat exchange more efficient with tighter temperature control enables quicker time to target temperature and avoids rewarming which can lead to inadvertent increase in intracranial pressure and cerebral edema. Promising applications but yet to be determined is whether hypothermia treatment can improve outcomes in acute ischemic stroke or traumatic brain injury.

Whole-brain intracranial vessel wall imaging at 3 Tesla using cerebrospinal fluid–attenuated T1-weighted 3D turbo spin echo

Although three‐dimensional (3D) turbo spin echo (TSE) with variable flip angles has proven to be useful for intracranial vessel wall imaging, it is associated with inadequate suppression of cerebrospinal fluid (CSF) signals and limited spatial coverage at 3 Tesla (T). This work aimed to modify the sequence and develop a protocol to achieve whole‐brain, CSF‐attenuated T1‐weighted vessel wall imaging.

Whole-brain vessel wall MRI: A parameter tune-up solution to improve the scan efficiency of three-dimensional variable flip-angle turbo spin-echo.

To propose and evaluate a parameter tune‐up solution to expedite a three‐dimensional (3D) variable‐flip‐angle turbo spin‐echo (TSE) sequence for whole‐brain intracranial vessel wall (IVW) imaging.

Optimizing Outcomes for Mechanically Ventilated Patients in an Era of Endovascular Acute Ischemic Stroke Therapy

Endovascular mechanical thrombectomy is a new standard of care for acute ischemic stroke (AIS). The majority of these patients receive mechanical ventilation (MV), which has been associated with poor outcomes. The implication of this is significant, as most neurointerventionalists prefer general compared to local anesthesia during the procedure. Consequences of hemodynamic and respiratory perturbations during general anesthesia and MV are thought to contribute significantly to the poor outcomes that are encountered. In this review, we first describe the unique risks associated with MV in the specific context of AIS and then discuss evidence of brain goal-directed approaches that may mitigate these risks. These strategies include an individualized approach to hemodynamic parameters (eg, adherence to a minimum blood pressure goal and adequate volume resuscitation), respiratory parameters (eg, arterial carbon dioxide optimization), and the use of ventilator settings that optimize neurological outcomes (eg, arterial oxygen optimization).

Management of Factor Xa inhibitor-associated life-threatening major hemorrhage: A retrospective multi-center analysis

Background: Factor Xa (FXa) inhibitors, used for stroke prevention in atrial fibrillation and venous thromboembolism treatment and prevention, are the dominant non‐Vitamin K oral anticoagulants on the market. While major bleeding may be less common with these agents compared to warfarin, it is always a risk, and little has been published on the most serious bleeding scenarios. This study describes a cohort of patients with FXa inhibitor‐associated life‐threatening bleeding events, their clinical characteristics, interventions and outcomes. Methods: We performed a retrospective, 5‐center review of FXa inhibitor‐treated major bleeding patients. Investigators identified potential cases by cross‐referencing ICD‐9/10 codes for hemorrhage with medication lists. Investigators selected cases they deemed to require immediate reversal of coagulopathy, and reviewed charts for characteristics, reversal strategies and other interventions, and outcomes. Results: A total of 56 charts met the inclusion criteria for the retrospective cohort, including 29 (52%) gastrointestinal bleeds (GIB), 19 (34%) intracranial hemorrhages (ICH) and 8 (14%) others. Twenty‐four (43%) patients received various factor or plasma products, and the remainder received supportive care. Thirty‐day mortality was 21% (n = 12). Re‐anticoagulation within 30‐days occurred in 23 (41%) patients. Thromboembolic events (TEEs) occurred in 6 (11%) patients. No differences were observed in outcomes by treatment strategy. Conclusions: This cohort of FXa inhibitor‐associated major bleeding scenarios deemed appropriate for acute anticoagulant reversal illustrates the variable approaches in the absence of a specific reversal agent.

Advanced Imaging in Acute Ischemic Stroke

Advances in stroke neuroimaging have evolved from excluding acute intracranial hemorrhage on computed tomography (CT) to now using perfusion studies (PWI) and magnetic resonance imaging (MRI) to possibly expand thrombolytic treatment to patients most likely to benefit from reperfusion therapy. Advanced imaging has also helped identify those at high risk for hemorrhage and poor outcome so appropriate treatment can occur with fewer complications. Identifying those who can benefit from endovascular recanalization using advanced neuroimaging techniques is particularly useful because endovascular treatment is often initiated much later than intravenous thrombolytic treatment due to logistical constraints. Using imaging markers of tissue injury may eventually lead to a paradigm shift from time-based treatment eligibility in acute stroke reperfusion treatment as the sensitivity and specificity to identify ischemic penumbra improves and correlation with clinical outcomes becomes clearer.

Cerebral microemboli detection for monitoring structural cardiac disease

Cardiac structural disorders can be detected noninvasively with echocardiography or cardiac MRI. Neither of these techniques, however, visualizes emboli, although thrombi can often be seen on valves or walls. Transcranial Doppler ultrasound (TCD) has been shown to be exquisitely sensitive at detecting microemboli, which may be a harbinger of impending macroembolization resulting in stroke.1,2 This report demonstrates the presence of a major valvular thrombus not visualized on echocardiography, but detected by TCD microemboli detection.

Development of a clinically practical whole-brain intracranial vessel wall MRI technique at 3 Tesla

Background T1-weighted variable-flip-angle 3D TSE has emerged as a promising intracranial vessel wall imaging technique. To increase spatial coverage and cerebrospinal fluid (CSF) attenuation, a whole-brain 0.5-mm-reoslution protocol based on an inversion-prepared 3D TSE sequence has recently been proposed at 3T. However, its 11-12-min scan time renders it clinically impractical. This work aimed to develop an expedited protocol and validate it on patients.