Normobaric Hyperoxia Combined With Endovascular Treatment for Patients With Acute Ischemic Stroke: A Randomized Controlled Clinical Trial

Normobaric Hyperoxia Combined With Endovascular Treatment Based on Temporal Gradient: A Dose-Escalation Study

BACKGROUND

Normobaric hyperoxia (NBO) has neuroprotective effects in acute ischemic stroke. Thus, we aimed to identify the optimal NBO treatment duration combined with endovascular treatment.

METHODS

This is a single-center, randomized controlled, open-label, blinded-end point dose-escalation clinical trial. Patients with acute ischemic stroke who had an indication for endovascular treatment at Tianjin Huanhu Hospital were randomly assigned to 4 groups (1:1 ratio) based on NBO therapy duration: (1) control group (1 L/min oxygen for 4 hours); (2) NBO-2h group (10 L/min for 2 hours); (3) NBO-4h group (10 L/min for 4 hours); and (4) NBO-6h group (10 L/min for 6 hours). The primary outcome was cerebral infarction volume at 72 hours after randomization using an intention-to-treat analysis model. The primary safety outcome was the 90-day mortality rate.

RESULTS

Between June 2022 and September 2023, 100 patients were randomly assigned to the following groups: control group (n=25), NBO-2h group (n=25), NBO-4h group (n=25), and NBO-6h group (n=25). The 72-hour cerebral infarct volumes were 39.4±34.3 mL, 30.6±30.1 mL, 19.7±15.4 mL, and 22.6±22.4 mL, respectively (P=0.013). The NBO-4h and NBO-6h groups both showed statistically significant differences (adjusted P values: 0.011 and 0.027, respectively) compared with the control group. Compared with the control group, both the NBO-4h and NBO-6h groups showed significant differences (P<0.05) in the National Institutes of Health Stroke Scale scores at 24 hours, 72 hours, and 7 days, as well as in the change of the National Institutes of Health Stroke Scale scores from baseline to 24 hours. Additionally, there were no significant differences among the 4 groups in terms of 90-day mortality rate, symptomatic intracranial hemorrhage, early neurological deterioration, or severe adverse events.

CONCLUSIONS

The effectiveness of NBO therapy was associated with oxygen administration duration. Among patients with acute ischemic stroke who underwent endovascular treatment, NBO therapy for 4 and 6 hours was found to be more effective. Larger-scale multicenter studies are needed to validate these findings.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05404373.

The effect of general anesthesia and conscious sedation in endovascular thrombectomy for acute ischemic stroke: an updated meta-analysis of randomized controlled trials and trial sequential analysis

Objectives

General anesthesia (GA) and conscious sedation (CS) are common methods for endovascular thrombectomy (EVT) in acute ischemic stroke (AIS). However, the risks and benefits of each strategy are unclear. This study aimed to summarize the latest RCTs and compare the postoperative effects of the two methods on EVT patients.

Materials and methods

We systematically searched the database for GA and CS in AIS patients during EVT. The retrieval time was from the creation of the database until March 2023. The quality of the studies was evaluated using the Cochrane risk of bias tool. Random-effects or fixed-effects meta-analyses were used to assess all outcomes.

Results

We preliminarily identified 304 studies, of which 8 were included. Based on the pooled estimates, there were no significant differences between the GA group and the CS group in terms of good functional outcomes (mRS0-2) and mortality rate at 3 months (RR = 1.09, 95% CI: 0.95-1.24, p = 0.23) (RR = 0.95, 95% CI: 0.75-1.22, p = 0.70) as well as in NHISS at 24 h after treatment (SMD = -0.01, 95% CI: -0.13 to 0.11, p = 0.89). However, the GA group had better outcomes in terms of achieving successful recanalization of the blood vessel (RR = 1.13, 95% CI: 1.07-1.19, p < 0.0001). The RR value for the risk of hypotension was 1.87 (95% CI: 1.42-2.47, p < 0.00001); for pneumonia, RR was 1.43 (95% CI: 1.07-1.90, p = 0.01); and for symptomatic intracerebral hemorrhage, RR was 0.94 (95% CI: 0.74-1.26, p = 0.68). The pooled RR value for complications after intervention was 1.03 (95% CI, 0.87-1.22, p = 0.76).

Conclusion

In patients undergoing EVT for AIS, GA, and CS are associated with similar rates of functional independence. Further trials of a larger scale are needed to confirm these findings.

The neuroprotective role of prolonged normobaric oxygenation applied during ischemia and in the early stage of reperfusion in cerebral ischemic rats

BACKGROUND

Recanalization is the main treatment option for ischemic stroke. However, prognosis remains poor for about half of patients after recanalization, possibly due to the "no-reflow" phenomenon at the early phase of recanalization. Normobaric oxygenation (NBO) during ischemia can reportedly maintain the partial pressure of oxygen and exert a protective effect in ischemic brain tissue.

OBJECTIVES AND METHODS

This study investigated whether prolonged NBO treatment during ischemia and the early phase of reperfusion (i/rNBO) has neuroprotective effects and to elucidate the underlying mechanisms in rats with middle cerebral artery occlusion plus reperfusion.

RESULTS

NBO treatment significantly elevated the level of O2 in the atmosphere and arterial blood without altering the level of CO2. The infarcted cerebral volume was significantly reduced by application of i/rNBO as compared to iNBO (applied during ischemia) or rNBO (applied at the early phase of reperfusion), indicating better protective effects of i/rNBO. i/rNBO more effectively suppressed s-nitrosylation of MMP-2 (amplifying inflammation) as compared to iNBO and rNBO, dramatically downregulated the cleavage of poly(ADP-ribose)polymerase-1 (PARP-1, acting as the substrate of MMP-2), and suppressed neuronal apoptosis, as determined by the TUNEL assay and staining for NeuN. These results demonstrated that application of i/rNBO in the early stage of reperfusion significantly alleviated neuronal apoptosis via suppression of the MMP-2/PARP-1 pathway.

CONCLUSIONS

The mechanism underlying the neuroprotective role of i/rNBO involved prolonged NBO treatment for cerebral ischemia, suggesting that i/rNBO may allow expansion of the time window for NBO application in stroke patients following vascular recanalization.

A Review on Adjunctive Therapies for Endovascular Treatment in Acute Ischemic Stroke

Endovascular treatment (EVT) has revolutionized the management of acute ischemic stroke (AIS), but almost half of patients undergoing EVT do not achieve a good outcome. Adjunctive therapies have been proposed to improve the outcomes of EVT in AIS. This review aims to summarize the current evidence on the use of adjunctive therapies in EVT for AIS, including antithrombotic agents, intra-arterial thrombolytics, cerebroprotective agents, normobaric oxygen, and hypothermia. Several adjunctive therapies have shown promise in improving the outcomes of EVT in AIS, but phase 3 clinical trials are needed to establish clinical efficacy. We summarize the advantages and disadvantages of adjunctive EVT treatments and outline the challenges that each of these therapies will face before being adopted in clinical practice.

Advances in Acute Ischemic Stroke Treatment: Current Status and Future Directions

The management of acute ischemic stroke has undergone a paradigm shift in the past decade. This has been spearheaded by the emergence of endovascular thrombectomy, along with advances in medical therapy, imaging, and other facets of stroke care. Herein, we present an updated review of the various stroke trials that have impacted and continue to transform stroke management. It is critical for the radiologist to stay abreast of the ongoing developments to provide meaningful input and remain a useful part of the stroke team.

Combined Therapeutics: Future Opportunities for Co-therapy with Thrombectomy

Stroke is an urgent public health issue with millions of patients worldwide living with its devastating effects. The advent of thrombolysis and endovascular thrombectomy has transformed the hyperacute care of these patients. However, a significant proportion of patients receiving these therapies still goes on to have unfavorable outcomes and many more remain ineligible for these therapies based on our current guidelines. The future of stroke care will depend on an expansion of the scope of thrombolysis and endovascular thrombectomy to patients outside traditional time windows, more distal occlusions, and large vessel occlusions with mild clinical deficits, for whom clinical trial results have not proven therapeutic efficacy. Novel cytoprotective therapies targeting the ischemic cascade and reperfusion injury therapy, in combination with our existing treatment modalities, should be explored to further improve outcomes for these patients with acute ischemic stroke. In this review, we will review the current status of thrombolysis and thrombectomy, suggest additional data that is needed to enhance these therapies, and discuss how cytoprotection might be combined with thrombectomy.

Percent Insular Ribbon Infarction for Predicting Infarct Growth Rate and 90-Day Outcomes in Large-Vessel Occlusive Stroke: Secondary Analysis of Prospective Clinical Trial Data

Background: Insight into the natural history of infarct growth could help identify patients with slowly progressing stroke who may benefit from delayed endovascular thrombectomy (EVT). Objective: To evaluate associations of percent insular ribbon infarction (PIRI) with infarct growth rate (IGR) and 90-day outcomes in patients with large-vessel occlusion (LVO) stroke. Methods: This retrospective study was a secondary analysis of a prior clinical trial that enrolled patients with acute stroke not treated with reperfusion therapies from January 2007 to June 2009. The present analysis evaluated 31 trial patients (median age, 71 years; 12 female, 19 male) with anterior-circulation LVO who underwent serial MRI examinations. Two neuroradiologists independently scored PIRI on presentation MRI examinations based on the ratio of the length of the portion of the insula showing restricted diffusion to the insula's total length using a previously described 0-4 scale; scores were categorized [mild (0-1), moderate (2), or severe (3-4)], and discrepancies were resolved by consensus. Ninety-day modified Rankin Scale (mRS) was obtained. As part of earlier clinical trial analysis, collateral pattern on CTA was classified (symmetric, malignant, other), and infarct volumes were measured on DWI during the initial 48 hours after presentation and on FLAIR at 90 days. Results: Inter-rater agreement for PIRI category was strong (K=0.890). PIRI was mild in 10, moderate in 4, and severe in 17 patients. For mild, moderate, and severe PIRI, median onset-to-presentation IGR was 1.6, 8.5, and 17.5 cc/h (p<.001); median presentation-to-48-hour IGR was 0.3, 0.2, and 1.2 cc/h (p=.005); median 90-day infarct volume was 9.4, 39.8, and 108.6 cc (p=0.01); 90-day mRS ≤2 occurred in 78%, 67%, and 6% of patients (p=.001). In multivariable models controlling for age, ICA occlusion, and collateral pattern, PIRI category independently predicted onset-to-presentation IGR (β=1.5), presentation-to-48-hour IGR (β=1.3), and 90-day mRS ≤2 (OR=0.2). For predicting 90-day mRS ≤2, mild-to-moderate PIRI had sensitivity of 90.0% and specificity of 84.2%; symmetric collateral pattern had sensitivity of 70.0% and specificity of 73.7%. Conclusion: PIRI was independently associated with IGR and 90-day outcome. Clinical Impact: PIRI may help identify patients who could benefit from late-window EVT when requiring transfer to EVT-capable centers.

The application and perspective of hyperbaric oxygen therapy in acute ischemic stroke: From the bench to a starter?

Stroke has become a significant cause of death and disability globally. Along with the transition of the world's aging population, the incidence of acute ischemic stroke is increasing year by year. Even with effective treatment modalities, patients are not guaranteed to have a good prognosis. The treatment model combining intravenous thrombolysis/endovascular therapy and neuroprotection is gradually being recognized. After the clinical translation of pharmacological neuroprotective agents failed, non-pharmacological physical neuroprotective agents have rekindled hope. We performed a literature review using the National Center for Biotechnology Information (NCBI) PubMed database for studies that focused on the application of hyperbaric oxygen therapy in acute ischemic stroke. In this review, we present the history and mechanisms of hyperbaric oxygen therapy, focusing on the current status, outcomes, current challenges, perspective, safety, and complications of the application of hyperbaric oxygen in animal experiments and human clinical trials. Hyperbaric oxygen therapy, a non-pharmacological treatment, can improve the oxygenation level at the ischemic lesions in increased dissolved oxygen and oxygen diffusion radius to achieve salvage of neurological function, giving a new meaning to acute ischemic stroke.