Targeted Temperature Management for Severe Subarachnoid Hemorrhage Using Endovascular and Surface Cooling Systems: A Nonrandomized Interventional Study Using Historical Control

High Plasma D-Dimer Levels Correlate with Ictal Infarction and Poor Outcomes in Spontaneous Subarachnoid Hemorrhage

BACKGROUND

Early brain injury is the leading cause of poor outcomes in spontaneous subarachnoid hemorrhage (sSAH). Plasma D-dimer levels and acute cerebral ischemia have been highlighted as relevant findings in early brain injury; however, their correlation has not been substantially investigated.

METHODS

This retrospective, single-center cohort study was conducted at a tertiary emergency medical center from January 2004 to June 2022. Consecutive patients with sSAH who presented within 12 hours of ictus and underwent magnetic resonance imaging within 3 days were included. We assessed the correlation of plasma D-dimer levels with acute ischemic lesions detected on the diffusion-weighted imageing and the clinical characteristics.

RESULTS

Among 402 eligible patients (mean age, 63.5 years; 62.7% women; median time from onset to arrival, 45.5 minutes), 140 (34.8%) had acute ischemic lesions. Higher plasma D-dimer levels linearly correlated with worse neurological grades, more severe SAH on initial computed tomography, acute ischemic lesions, and poor outcomes, except for patients with neurogenic stunned myocardium. In the multivariate analysis, acute ischemic lesions were significantly associated with worse neurological grades, higher plasma D-dimer levels, bilateral loss of light reaction, and advanced age. The receiver operating characteristic curve analysis showed D-dimer levels as excellent predictors for acute ischemic lesions (area under the curve, 0.897; cut-off value, 5.7 μg/mL; P<0.0001) and unfavorable outcomes (area under the curve, 0.786; cut-off value, 4.0 μg/mL; P<0.0001).

CONCLUSIONS

High plasma D-dimer levels correlated with the appearance of acute ischemic lesions on diffusion-weighted imaging and were dose-dependently associated with worse neurological grades, more severe hemorrhage, and worse outcomes.

Progress of Brain Hypothermia Treatment for Severe Subarachnoid Hemorrhage-177 Cases Experienced and a Narrative Review

The benefits of hypothermia for the treatment of subarachnoid hemorrhage (SAH) remain controversial. In 1999, we initiated brain hypothermia treatment (BHT) in the hyperacute phase to mitigate the evolution of early brain injury in patients with World Federation of Neurological Surgeons (WFNS) grade V SAH. In June 2014, we introduced endovascular cooling to maintain normothermia for seven days following the initial BHT period. Immediately after the decision to treat the sources of bleeding, cooling was initiated, with a target temperature of 33-34°C. Bleeding sources were extirpated primarily by clipping with decompressive craniectomy. Patients were rewarmed at a rate of ≤1°C/day after ≥48 hours of surface cooling. After being rewarmed to 36°C, temperatures were controlled with antipyretic (chronologically divided into groups A-C with 47, 46, and 46 patients, respectively) or endovascular (group D, 38 patients) cooling. Overall, 177 patients (median age, 62 [52-68] years; 94 [53.1%] women; onset-to-arrival time, 36 minutes [28-50]) were included. The median Glasgow Coma Scale (GCS) score upon admission was 4 (3-6). Median core body temperature was 36 (35.3-36.6)°C on arrival, 34.6 (34.0-35.3)°C on entering the operating room, 33.8 (33.4-34.3)°C upon starting the microsurgical or interventional radiology procedure, and 33.7 (33.3-34.2)°C upon admission to the intensive care unit. There were no significant differences in age, sex, GCS score, pupillary findings, location of bleeding sources, or treatment methods. There were 69 (39.0%) overall favorable outcomes (modified Rankin Scale score of 0-3) at 6 months and 11 (23.4%), 18 (39.1%), 17 (37.0%), and 23 (60.5%) in groups A-D, respectively (p = 0.0065). The outcomes of patients with WFNS grade V SAH improved over time. Herein, we report our experience using BHT for severe SAH through a narrative review.

Application of artificial hibernation technology in acute brain injury

Controlling intracranial pressure, nerve cell regeneration, and microenvironment regulation are the key issues in reducing mortality and disability in acute brain injury. There is currently a lack of effective treatment methods. Hibernation has the characteristics of low temperature, low metabolism, and hibernation rhythm, as well as protective effects on the nervous, cardiovascular, and motor systems. Artificial hibernation technology is a new technology that can effectively treat acute brain injury by altering the body's metabolism, lowering the body's core temperature, and allowing the body to enter a state similar to hibernation. This review introduces artificial hibernation technology, including mild hypothermia treatment technology, central nervous system regulation technology, and artificial hibernation-inducer technology. Upon summarizing the relevant research on artificial hibernation technology in acute brain injury, the research results show that artificial hibernation technology has neuroprotective, anti-inflammatory, and oxidative stress-resistance effects, indicating that it has therapeutic significance in acute brain injury. Furthermore, artificial hibernation technology can alleviate the damage of ischemic stroke, traumatic brain injury, cerebral hemorrhage, cerebral infarction, and other diseases, providing new strategies for treating acute brain injury. However, artificial hibernation technology is currently in its infancy and has some complications, such as electrolyte imbalance and coagulation disorders, which limit its use. Further research is needed for its clinical application.

Temperature Control in Acute Brain Injury: An Update

Temperature control in severe acute brain injury (SABI) is a key component of acute management. This manuscript delves into the complex role of temperature management in SABI, encompassing conditions like traumatic brain injury (TBI), acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (aSAH), and hypoxemic/ischemic brain injury following cardiac arrest. Fever is a common complication in SABI and is linked to worse neurological outcomes due to increased inflammatory responses and intracranial pressure (ICP). Temperature management, particularly hypothermic temperature control (HTC), appears to mitigate these adverse effects primarily by reducing cerebral metabolic demand and dampening inflammatory pathways. However, the effectiveness of HTC varies across different SABI conditions. In the context of post-cardiac arrest, the impact of HTC on neurological outcomes has shown inconsistent results. In cases of TBI, HTC seems promising for reducing ICP, but its influence on long-term outcomes remains uncertain. For AIS, clinical trials have yet to conclusively demonstrate the benefits of HTC, despite encouraging preclinical evidence. This variability in efficacy is also observed in ICH, aSAH, bacterial meningitis, and status epilepticus. In pediatric and neonatal populations, while HTC shows significant benefits in hypoxic-ischemic encephalopathy, its effectiveness in other brain injuries is mixed. Although the theoretical basis for employing temperature control, especially HTC, is strong, the clinical outcomes differ among various SABI subtypes. The current consensus indicates that fever prevention is beneficial across the board, but the application and effectiveness of HTC are more nuanced, underscoring the need for further research to establish optimal temperature management strategies. Here we provide an overview of the clinical evidence surrounding the use of temperature control in various types of SABI.

The Effectiveness of Target Temperature Management on Poor-Grade Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

The effectiveness of target temperature management (TTM) in poor-grade aneurysmal subarachnoid hemorrhage (aSAH) remains a topic of debate. In order to assess the clinical efficacy of TTM in patients with poor-grade aSAH, we conducted a systematic review and meta-analysis. This research was registered in PROSPERO (CRD42023445582) and included all relevant publications up until October 2023. We compared the TTM groups with the control groups in terms of unfavorable outcomes (modified Rankin scale [mRS] score > 3), mortality, delayed cerebral ischemia (DCI), cerebral vasospasm (CVS), and specific complications. Subgroup analyses were performed based on country, study type, follow-up time, TTM method, cooling maintenance period, and rewarming rate. Effect sizes were calculated as relative risk (RR) using random-effect or fixed-effect models. The quality of the articles was assessed using the methodological index for non-randomized studies scale. Our analysis included a total of 5 clinical studies (including 1 randomized controlled trial) and 219 patients (85 in the TTM group and 134 in the control group). Most of the studies were of moderate quality. TTM was found to be associated with a statistically significant improvement in mortality (mRS score 6) rates compared with the control group (RR = 0.61, 95% confidence interval [CI]: 0.40-0.94, p = 0.026). However, there was no statistically significant difference in unfavorable outcomes (mRS 4-6) between the TTM and control groups (RR = 0.94, 95% CI: 0.71-1.26, p = 0.702). The incidence of adverse events, including DCI, CVS, pneumonia, cardiac complications, and electrolyte imbalance, did not significantly differ between the two groups. In conclusion, our overall results suggest that TTM does not significantly reduce unfavorable outcomes in poor-grade aSAH patients. However, TTM may decrease mortality rates. Preoperative TTM may cause patients to miss the opportunity for surgery, although it temporarily protects the brain. Furthermore, the incidence of adverse events was similar between the TTM and control groups.

Targeted Temperature Management for Poor Grade Aneurysmal Subarachnoid Hemorrhage: A Pilot Study

OBJECTIVE

We assessed the effectiveness and safety of target temperature management (TTM) in treating patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). The primary objective was to evaluate the neurological outcome at 3 months. Secondary objectives were to assess mortality, delayed cerebral ischemia, cerebral edema, hydrocephalus, midline shift, and laboratory indicators related to TTM.

METHODS

A single-blind, nonrandomized controlled trial was conducted. After admission, patients with poor-grade aSAH (Hunt-Hess scores IV ∼ V) were assigned to a TTM group or a control group in a 1:1 ratio. TTM with core temperatures ranging from 36°C to 37°C was performed immediately and maintained until microclipping or endovascular embolization. Subsequently, rapid induction to 33°C ∼ 35°C was carried out and maintained for 3 to 5 days. Then, the patients underwent slow rewarming to 36°C ∼ 37°C and maintained at that temperature for a minimum of 48 hours.

RESULTS

Sixty patients (30 treated with TTM and 30 with standard treatment) were included in the study. At 3 months, a favorable prognosis (modified Rankin scale score 0 to 3) was significantly higher in the TTM group than in the control group (n = 14, 46.7% vs. n = 6, 20.0%, P = 0.028). Adjusted multivariate logistics regression analysis indicated that TTM (odds ratio = 0.20, 95% confidence interval: 0.05-0.77, P = 0.019) reduced the number of unfavorable prognoses 3 months after admission.

CONCLUSIONS

This study demonstrated the effectiveness and safety of TTM in patients with poor-grade aSAH, and its implementation improved neurological outcomes. Multicenter randomized controlled studies with a large number of patients are needed to confirm these observations.

A nomogram for predicting the risk of poor prognosis in patients with poor-grade aneurysmal subarachnoid hemorrhage following microsurgical clipping

Objective

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and potentially fatal cerebrovascular disease. Poor-grade aSAH (Hunt-Hess grades IV and V) accounts for 20-30% of patients with aSAH, with most patients having a poor prognosis. This study aimed to develop a stable nomogram model for predicting adverse outcomes at 6 months in patients with aSAH, and thus, aid in improving the prognosis.

Method

The clinical data and imaging findings of 150 patients with poor-grade aSAH treated with microsurgical clipping of intracranial aneurysms on admission from December 2015 to October 2021 were retrospectively analyzed. Least absolute shrinkage and selection operator (LASSO), logistic regression analyses, and a nomogram were used to develop the prognostic models. Receiver operating characteristic (ROC) curves and Hosmer-Lemeshow tests were used to assess discrimination and calibration. The bootstrap method (1,000 repetitions) was used for internal validation. Decision curve analysis (DCA) was performed to evaluate the clinical validity of the nomogram model.

Result

LASSO regression analysis showed that age, Hunt-Hess grade, Glasgow Coma Scale (GCS), aneurysm size, and refractory hyperpyrexia were potential predictors for poor-grade aSAH. Logistic regression analyses revealed that age (OR: 1.107, 95% CI: 1.056-1.116, P < 0.001), Hunt-Hess grade (OR: 8.832, 95% CI: 2.312-33.736, P = 0.001), aneurysm size (OR: 6.871, 95% CI: 1.907-24.754, P = 0.003) and refractory fever (OR: 3.610, 95% CI: 1.301-10.018, P < 0.001) were independent predictors of poor outcome. The area under the ROC curve (AUC) was 0.909. The calibration curve and Hosmer-Lemeshow tests showed that the nomogram had good calibration ability. Furthermore, the DCA curve showed better clinical utilization of the nomogram.

Conclusion

This study provides a reliable and valuable nomogram that can accurately predict the risk of poor prognosis in patients with poor-grade aSAH after microsurgical clipping. This tool is easy to use and can help physicians make appropriate clinical decisions to significantly improve patient prognosis.