Risk Factors, Pathophysiologic Mechanisms, and Potential Treatment Strategies of Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Stroke-heart syndrome: current progress and future outlook

Stroke can lead to cardiac complications such as arrhythmia, myocardial injury, and cardiac dysfunction, collectively termed stroke-heart syndrome (SHS). These cardiac alterations typically peak within 72 h of stroke onset and can have long-term effects on cardiac function. Post-stroke cardiac complications seriously affect prognosis and are the second most frequent cause of death in patients with stroke. Although traditional vascular risk factors contribute to SHS, other potential mechanisms indirectly induced by stroke have also been recognized. Accumulating clinical and experimental evidence has emphasized the role of central autonomic network disorders and inflammation as key pathophysiological mechanisms of SHS. Therefore, an assessment of post-stroke cardiac dysautonomia is necessary. Currently, the development of treatment strategies for SHS is a vital but challenging task. Identifying potential key mediators and signaling pathways of SHS is essential for developing therapeutic targets. Therapies targeting pathophysiological mechanisms may be promising. Remote ischemic conditioning exerts protective effects through humoral, nerve, and immune-inflammatory regulatory mechanisms, potentially preventing the development of SHS. In the future, well-designed trials are required to verify its clinical efficacy. This comprehensive review provides valuable insights for future research.

Futile recanalization is associated with increased risk of post-stroke epilepsy

BACKGROUND

Endovascular treatment (EVT) is the standard of care of ischaemic stroke due to occlusion of large vessels. Although EVT can significantly improve short- and long-term outcomes, functional dependence can persist despite the achievement of a successful recanalization. The evidence about the predictors of post-stroke epilepsy (PSE) in patients with stroke treated by EVT is limited. We aimed to evaluate the relationship between futile recanalization and the risk of PSE.

METHODS

We retrospectively identified consecutive adults with first-ever ischaemic stroke of anterior circulation who were treated with EVT. Futile recanalization was defined as poor 3-month functional status (modified Rankin scale score ≥ 3) despite complete or near-complete recanalization. Study outcome was the occurrence of PSE during the follow-up.

RESULTS

The study included 327 patients with anterior circulation ischaemic stroke treated with EVT. Futile recanalization occurred in 116 (35.5%) patients and 26 (8.0%) developed PSE during a median follow-up of 35 [interquartile range, 22.7-55.2] months. Futile recanalization was more common among patients who developed PSE compared to those who did not (76.9% versus 31.9%; p < 0.001). Futile recanalization [hazard ratio (HR) = 5.63, 95% confidence interval (CI): 1.88-16.84; p = 0.002], large artery atherosclerosis (HR = 3.48, 95% CI: 1.44-8.40; p = 0.006), cortical involvement (HR = 15.51, 95% CI: 2.06-116.98; p = 0.008), and acute symptomatic status epilepticus (HR = 14.40, 95% CI: 2.80-73.98; p = 0.001) increased the risk of PSE.

CONCLUSIONS

Futile recanalization after EVT is associated with increased risk of PSE in patients with ischaemic stroke due to occlusion of large vessel of the anterior circulation.

Paediatric hydrocephalus

Hydrocephalus is classically considered as a failure of cerebrospinal fluid (CSF) homeostasis that results in the active expansion of the cerebral ventricles. Infants with hydrocephalus can present with progressive increases in head circumference whereas older children often present with signs and symptoms of elevated intracranial pressure. Congenital hydrocephalus is present at or near birth and some cases have been linked to gene mutations that disrupt brain morphogenesis and alter the biomechanics of the CSF-brain interface. Acquired hydrocephalus can develop at any time after birth, is often caused by central nervous system infection or haemorrhage and has been associated with blockage of CSF pathways and inflammation-dependent dysregulation of CSF secretion and clearance. Treatments for hydrocephalus mainly include surgical CSF shunting or endoscopic third ventriculostomy with or without choroid plexus cauterization. In utero treatment of fetal hydrocephalus is possible via surgical closure of associated neural tube defects. Long-term outcomes for children with hydrocephalus vary widely and depend on intrinsic (genetic) and extrinsic factors. Advances in genomics, brain imaging and other technologies are beginning to refine the definition of hydrocephalus, increase precision of prognostication and identify nonsurgical treatment strategies.

Rapid Intravenous Glyceryl Trinitrate in Ischemic Damage (RIGID): A potential neuroprotection strategy for acute ischemic stroke (AIS) patients

Despite advances in intravenous thrombolysis and endovascular thrombectomy, numerous acute ischemic stroke survivors continue to experience various disability levels. The nitric oxide (NO) donor, Glyceryl Trinitrate (GTN), has been identified as a potential neuroprotective agent against ischemic damage. We evaluated the safety and feasibility of intravenous GTN in AIS patients. Subsequently, we conducted a secondary analysis to assess for possible efficacy of GTN as a neuroprotectant. We conducted a prospective, double-blind, randomized controlled trial in the Stroke Intervention & Translational Center (SITC) in Beijing Luhe Hospital, Capital Medical University (ChiCTR2100046271). AIS patients within 24 h of stroke onset were evenly divided into GTN or control groups (n = 20 each). The GTN group received intravenous GTN (5 mg in 50 ml saline at a rate of 0.4 mg/h for 12.5 h/day over 2 days), while controls were administered an equivalent volume of 0.9% saline. Both groups followed standard Stroke Guidelines for treatment. Safety measures focused on SBP<110 mmHg and headache occurrence. Efficacy was assessed via the 90-day modified rankin score (mRS) and the national institutes of health stroke score (NIHSS). Of the 40 AIS patients, baseline characteristics such as age, gender, risk factors, and pre-mRS scores showed no significant difference between the groups. Safety measures of SBP<110 mmHg and headache occurrence were comparable. Overall, 90-day mRS (1 vs. 1) and NIHSS (1 vs. 1) did not significantly differ between groups. However, the GTN-treated group had a benefit in enhancing NIHSS recovery (△NIHSS 4.5 vs. 3, p = 0.028), indicating that GTN may augment recovery. Subgroup analyses revealed a benefit in the GTN group at the 90-day NIHSS score and △NIHSS follow up for non-thrombolysis patients (1 vs. 2, p = 0.016; 5 vs. 2, p = 0.001). Moreover, the GTN group may benefit mild stroke patients in NIHSS score at 90 day and △NIHSS observed at 90 days (1 vs. 1, p = 0.025; 3 vs. 2 p = 0.002). Overall, while preliminary data suggest GTN might aid recovery in NIHSS improvement, the evidence is tempered due to sample size limitations. The RIGID study confirms the safety and feasibility of intravenous GTN administration for AIS patients. Preliminary data also suggest that the GTN group may provide improvement in NIHSS recovery compared to the control group. Furthermore, a potential benefit for non-thrombolysis patients and those with mild stroke symptoms was identified, suggesting a possible potential role as a tailored intervention in specific AIS subgroups. Due to the limited sample size, further larger RCT will be necessary to replicate these results. TRIAL REGISTRATION: www.chictr.org.cn, identifier: ChiCTR2100046271.

Prognostic potency of plasma LRG1 measurement at multiple time points in acute ischemic stroke patients

Objective: This study aimed to investigate the prognostic potency of LRG1 in acute ischemic stroke (AIS) patients. Methods: Plasma LRG1 levels were detected at admission and on days 3, 7 and 30 in 150 AIS patients. Results: LRG1 positively correlated with total cholesterol (p = 0.016), triglycerides (p = 0.046), C-reactive protein (p < 0.001), TNF-α (p = 0.001) and IL-6 (p = 0.004). After admission, LRG1 showed a decreasing trend (p < 0.001). Interestingly, LRG1 levels at admission (p = 0.014), day 3 (p = 0.027), day 7 (p = 0.008) and day 30 (p = 0.002) were higher in patients with modified Rankin scale score ≥2 versus those with scores <2. The LRG1 levels at day 7 (p = 0.032) and day 30 (p = 0.023) were higher in patients with recurrence versus no recurrence. Conclusion: LRG1 correlates with blood lipids, inflammation and short-term prognosis of AIS.

Effects of tirofiban on large vessel occlusion stroke are modified by etiology and renal function

OBJECTIVE

Renal function can modify the outcomes of large vessel occlusion (LVO) stroke across stroke etiologies in disparate degrees. The presence of renal function deficit can also impair the pharmacokinetics of tirofiban. Hence, this study aimed to investigate the roles of renal function in determining efficacy and safety of intravenous tirofiban before endovascular treatment (EVT) for acute ischemic stroke patients with large vessel occlusion (LVO).

METHODS

This study was a post hoc exploratory analysis of the RESCUE-BT trial. The primary outcome was the proportion of patients achieving functional independence (modified Rankin scale 0-2) at 90 days, and the primary safety outcome was the rate of symptomatic intracranial hemorrhage (sICH).

RESULTS

Among 908 individuals with available serum creatinine, decreased estimated glomerular filtration rate (eGFR) status was noted more commonly in patients with cardioembolic stroke (CE), while large artery atherosclerosis (LAA) was predominant in patients with normal renal function. In LAA with normal renal function, tirofiban was associated with higher rates of functional independence at 90 days (41.67% vs 59.80%, p = 0.003). However, for LVO patients with renal dysfunction, tirofiban did not improve functional outcomes for any of the etiologies (LAA, p = 0.876; CE, p = 0.662; others, p = 0.894) and significantly increased the risk of sICH among non-LAA patients (p = 0.020). Mediation analysis showed tirofiban reduced thrombectomy passes (12.27%) and drug/placebo to recanalization time (14.25%) mediated its effects on functional independence.

CONCLUSION

This present study demonstrated the importance of evaluating renal function before administering intravenous tirofiban among patients with LVO who are planned to undergo EVT.

No-reflow after stroke reperfusion therapy: An emerging phenomenon to be explored

In the field of stroke thrombectomy, ineffective clinical and angiographic reperfusion after successful recanalization has drawn attention. Partial or complete microcirculatory reperfusion failure after the achievement of full patency of a former obstructed large vessel, known as the "no-reflow phenomenon" or "microvascular obstruction," was first reported in the 1960s and was later detected in both experimental models and patients with stroke. The no-reflow phenomenon (NRP) was reported to result from intraluminal occlusions formed by blood components and extraluminal constriction exerted by the surrounding structures of the vessel wall. More recently, an emerging number of clinical studies have estimated the prevalence of the NRP in stroke patients following reperfusion therapy, ranging from 3.3% to 63% depending on its evaluation methods or study population. Studies also demonstrated its detrimental effects on infarction progress and neurological outcomes. In this review, we discuss the research advances, underlying pathogenesis, diagnostic techniques, and management approaches concerning the no-reflow phenomenon in the stroke population to provide a comprehensive understanding of this phenomenon and offer references for future investigations.

Impacts of futile reperfusion and reperfusion injury in acute ischemic stroke

Acute ischemic stroke (AIS) remains to be a challenging cerebrovascular disease. The mainstay of AIS management is endovascular reperfusion therapy, including thrombectomy and thrombolysis. However, ineffective (futile) reperfusion (FR) or reperfusion injury (RI) can be seen in a significant number of patients undergoing reperfusion strategy. In this article, we discuss two clinically relevant concepts known as "time window" and "tissue window" that can impact the clinical outcome of reperfusion therapy. We also explore patient risk factors, leading to FR and RI as well as an emerging concept of "no-reflow phenomenon" seen in ineffective reperfusion. These fundamental concepts provide insight into the clinical management of AIS patients and provide references for future research.

Quercetin improves cerebral ischemia/reperfusion injury by promoting microglia/macrophages M2 polarization via regulating PI3K/Akt/NF-κB signaling pathway

The modulation of microglial polarization from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype shows promise as a therapeutic strategy for ischemic stroke. Quercetin, a natural flavonoid abundant in various plants, possesses anti-inflammatory, anti-apoptotic, and antioxidant properties. Nevertheless, its effect and underlying mechanism on microglia/macrophages M1/M2 polarization in the treatment of cerebral ischemia/reperfusion injury (CI/RI) remain poorly explored. In the current study, we observed that quercetin ameliorated neurological deficits, reduced infarct volume, decreased the number of M1 microglia/macrophages (CD16/32+/Iba1+), and enhanced the number of M2 microglia/macrophages (CD206+/Iba1+) after establishing the CI/RI model in rats. Subsequent in vivo and in vitro experiments indicated that quercetin downregulated M1 markers (CD86, iNOS, TNF-α, IL-1β, and IL-6) and upregulated M2 markers (CD206, Arg-1, IL-10, and TGF-β). Network pharmacology analysis and molecular docking revealed that the PI3K/Akt/NF-κB signaling pathway emerged as the core pathway. Western blot confirmed that quercetin upregulated the phosphorylation of PI3K and Akt, while alleviating the phosphorylation of IκBα and NF-κB both in vivo and in vitro. However, the PI3K inhibitor LY294002 reversed the effects of quercetin on M2 polarization and the expression of key proteins in the PI3K/Akt/NF-κB pathway in primary microglia after oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Collectively, our findings demonstrate that quercetin facilitates microglia/macrophages M2 polarization by modulating the PI3K/Akt/NF-κB signaling pathway in the treatment of CI/RI. These findings provide novel insights into the therapeutic mechanisms of quercetin in ischemic stroke.

Association of intravascular enhancement sign on 3D-T1W TSE with collateral status in middle cerebral artery occlusion stroke

OBJECTIVE

The significance of the intravascular enhancement sign (IVES) on high-resolution magnetic resonance vascular wall imaging (HR-VWI) remains unclear. This study aimed to investigate the correlation between the IVES and collateral assessment derived from digital subtraction angiography (DSA).

METHOD

A total of 75 patients with occlusion of the first segment of the middle cerebral artery (MCA) who underwent HR-VWI and DSA examinations at our research institution between November 2016 and February 2023 were included. The number of vessels with IVES, IVES-Alberta Stroke Program Early Computed Tomography Score (ASPECTS), American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral grade, and DSA collateral blood flow grade were retrospectively evaluated. Correlations between these indicators were assessed using Spearman's correlation.

RESULTS

Interrater agreement was good for the assessment of HR-VWI and DSA indicators. After adjustments for age, degree of wall enhancement, and hypertension, a multivariable ordinal logistic regression model identified both the number of IVES vessels (OR = 1.37; 95%CI [1.06-1.78]; P = 0.017) and IVES-ASPECTS (OR = 2.00; 95%CI [1.03-3.87]; P = 0.041) as independent predictors of ischemic stroke. In the patient group with acute ischemic stroke, we found weak correlations between the number of IVES vessels and the ASITN/SIR collateral grade (rho = -0.35; P = 0.002) and between the IVES-ASPECTS and ASITN/SIR collateral grade (rho = -0.27; P = 0.02). Moreover, there were strong correlations between the number of IVES vessels and the DSA collateral blood flow grade (rho = -0.74; P < 0.001) and between the IVES-ASPECTS and the DSA collateral blood flow grade (rho = -0.65; P < 0.001). The number of IVES vessels correlated strongly with the IVES-ASPECTS (rho = 0.92, P < 0.001).

CONCLUSION

We find that the IVES is closely associated with sluggish collateral blood flow, which further confirms the hemodynamic mechanism underlying the IVES in MCA occlusion.

The vascular Na,K-ATPase: clinical implications in stroke, migraine, and hypertension

In the vascular wall, the Na,K-ATPase plays an important role in the control of arterial tone. Through cSrc signaling, it contributes to the modulation of Ca2+ sensitivity in vascular smooth muscle cells. This review focuses on the potential implication of Na,K-ATPase-dependent intracellular signaling pathways in severe vascular disorders; ischemic stroke, familial migraine, and arterial hypertension. We propose similarity in the detrimental Na,K-ATPase-dependent signaling seen in these pathological conditions. The review includes a retrospective proteomics analysis investigating temporal changes after ischemic stroke. The analysis revealed that the expression of Na,K-ATPase α isoforms is down-regulated in the days and weeks following reperfusion, while downstream Na,K-ATPase-dependent cSrc kinase is up-regulated. These results are important since previous studies have linked the Na,K-ATPase-dependent cSrc signaling to futile recanalization and vasospasm after stroke. The review also explores a link between the Na,K-ATPase and migraine with aura, as reduced expression or pharmacological inhibition of the Na,K-ATPase leads to cSrc kinase signaling up-regulation and cerebral hypoperfusion. The review discusses the role of an endogenous cardiotonic steroid-like compound, ouabain, which binds to the Na,K-ATPase and initiates the intracellular cSrc signaling, in the pathophysiology of arterial hypertension. Currently, our understanding of the precise control mechanisms governing the Na,K-ATPase/cSrc kinase regulation in the vascular wall is limited. Understanding the role of vascular Na,K-ATPase signaling is essential for developing targeted treatments for cerebrovascular disorders and hypertension, as the Na,K-ATPase is implicated in the pathogenesis of these conditions and may contribute to their comorbidity.

No-reflow phenomenon following stroke recanalization therapy: Clinical assessment advances: A narrative review

The no-reflow phenomenon (NRP) after successful vascular recanalization in acute ischemic stroke (AIS) has become a major cause of poor clinical prognosis and ineffective recanalization. However, there is currently no clear definition or unified clinical assessment method for the NRP. Therefore, it is urgent to clarify the clinical evaluation criteria for the NRP and develop new no-reflow evaluation techniques so that remedial treatment can be applied to AIS patients suffering from the NRP. In this brief review, a variety of NRP assessment methods and defining criteria for clinical practice are presented.

Comprehensive Meta-Analysis of Futile Recanalization in Acute Ischemic Stroke Patients Undergoing Endovascular Thrombectomy: Prevalence, Factors, and Clinical Outcomes

BACKGROUND

Futile recanalization (FR) continues to raise concern despite the success of endovascular thrombectomy (EVT) in acute ischemic stroke (AIS). Understanding the prevalence of FR and identifying associated factors are crucial for refining patient prognoses and optimizing management strategies.

OBJECTIVES

This study aims to comprehensively assess the pooled prevalence of FR, explore the diverse factors connected with FR, and establish the association of FR with long-term clinical outcomes among AIS patients undergoing EVT.

MATERIALS AND METHODS

Incorporating studies focusing on FR following EVT in AIS patients, we conducted a random-effect meta-analysis to assess the pooled prevalence and its association with various clinical and imaging risk factors linked to FR. Summary estimates were compiled and study heterogeneity was explored.

RESULTS

Our comprehensive meta-analysis, involving 11,700 AIS patients undergoing EVT, revealed a significant pooled prevalence of FR at 51%, with a range of 48% to 54% (Effect Size [ES]: 51%; 95% Confidence Interval [CI]: 48-54%; z = 47.66; p < 0.001). Numerous clinical factors demonstrated robust correlations with FR, including atrial fibrillation (Odds Ratio [OR]: 1.39, 95% CI 1.22 1.59; p < 0.001), hypertension (OR 1.65, 95% CI 1.41 1.92; p < 0.001), diabetes mellitus (OR 1.71, 95% CI 1.47 1.99; p < 0.001), previous stroke or transient ischemic attack (OR 1.298, 95% CI 1.06 1.59; p = 0.012), prior anticoagulant usage (OR 1.33, 95% CI 1.08 1.63; p = 0.007), cardioembolic strokes (OR 1.34, 95% CI 1.10 1.63; p = 0.003), and general anesthesia (OR 1.53, 95% CI 1.35 1.74; p < 0.001). Conversely, FR exhibited reduced likelihoods of smoking (OR 0.66, 95% CI 0.57 0.77; p < 0.001), good collaterals (OR 0.33, 95% CI 0.23 0.49; p < 0.001), male sex (OR 0.87, 95% CI 0.77 0.97; p = 0.016), and intravenous thrombolysis (IVT) (OR 0.75, 95% CI 0.66 0.86; p < 0.001). FR was strongly associated with increasing age (standardized mean difference [SMD] 0.49, 95% CI 0.42 0.56; p < 0.0001), baseline systolic blood pressure (SMD 0.20, 95% CI 0.13 0.27; p < 0.001), baseline National Institute of Health Stroke Severity Score (SMD 0.75, 95% CI: 0.65 0.86; p < 0.001), onset-to-treatment time (SMD 0.217, 95% CI 0.13 0.30; p < 0.001), onset-to-recanalization time (SMD 0.38, 95% CI 0.19; 0.57; p < 0.001), and baseline blood glucose (SMD 0.31, 95% CI 0.22 0.41; p < 0.001), while displaying a negative association with reduced baseline Alberta Stroke Program Early CT Score (ASPECTS) (SMD -0.37, 95% CI -0.46 -0.27; p < 0.001). Regarding clinical outcomes, FR was significantly associated with increased odds of symptomatic intracranial hemorrhages (OR 7.37, 95% CI 4.89 11.12; p < 0.001), hemorrhagic transformations (OR 2.98, 95% CI 2.37 3.75; p < 0.001), and 90-day mortality (OR 19.24, 95% CI 1.57 235.18; p = 0.021).

CONCLUSIONS

The substantial prevalence of FR, standing at approximately 51%, warrants clinical consideration. These findings underscore the complexity of FR in AIS patients and highlight the importance of tailoring management strategies based on individual risk factors and clinical profiles.