Extending the window for thrombolysis for treatment of acute ischaemic stroke during pregnancy: a review

Chemogenetic stimulation of intact corticospinal tract during rehabilitative training promotes circuit rewiring and functional recovery after stroke

BACKGROUND

Neuromodulatory techniques have been proven to enhance functional recovery after stroke in patients and animals, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). However, the success and feasibility of these approaches were often variable, largely due to a lack of target specificity.

OBJECTIVE

We explored the effects of specific chemogenetic stimulation of intact corticospinal tract during rehabilitative training on functional recovery after stroke in mice.

METHODS

We developed a viral-based intersectional targeting approach that allows specific chemogentic activation of contralateral hindlimb corticospinal neurons (CSNs) in a photothrombotic stroke model.

RESULTS

We demonstrated that specific chemogenetic activation of CSNs, when combined with daily rehabilitation training, leads to significant skilled motor functional recovery via promoting corticospinal tract (CST) axons midline crossing sprouting from intact to the denervated spinal hemicord, and rewiring new functional circuits by new synapse formation. Mechanistically, we revealed that combined chemogenetic stimulation of CSNs and daily rehabilitation training significantly enhanced the mTOR activity of CSNs.

CONCLUSIONS

Our findings highlight the great potential of specific neural activation protocols in combination with motor training for the recovery of skilled motor functions after stroke.

Pregnancy-Related Stroke: A Review

Importance

The maternal risk of strokes in the United States is approximately 30/100,000 pregnancies, and strokes are the eighth leading cause of maternal death. Because of the relationship between stroke and significant neurological disability/maternal death, obstetrical health care providers must be able to identify, evaluate, diagnosis, and treat these women.

Evidence Acquisition

PubMed was searched using the search terms "stroke" OR "cerebrovascular accident" OR "intracranial hemorrhage" AND "pregnancy complications" OR "risk factors" OR "management" OR "outcome." The search was limited to the English language and was restricted to articles from 2000 to 2020.

Results

There were 319 abstracts identified, and 90 of the articles were ultimately used as the basis of this review. Presenting stroke signs and symptoms include headache, composite neurologic defects, seizures, and/or visual changes. Diagnosis is typically made with computed tomography scan using abdominal shielding or magnetic resonance imaging without contrast. Management options for an ischemic stroke include reperfusion therapy with intravenous recombinant tissue plasminogen activator catheter-based thrombolysis and/or mechanical thrombectomy. Hemorrhagic strokes are treated similarly to strokes outside of pregnancy, and that treatment is based on the severity and location of the hemorrhage.

Conclusions and Relevance

Early recognition and management are integral in decreasing the morbidity and mortality associated with a stroke in pregnancy.

Relevance Statement

This study was an evidence-based review of stroke in pregnancy and how to diagnose and mange a pregnancy complicated by a stroke.

Cerebrovascular disease in pregnancy and postpartum

PURPOSE OF REVIEW

Cerebrovascular disorders during pregnancy and puerperium are uncommon but potentially serious entities. This review aims to provide guidance on the diagnosis and management of these diseases, according to the most recent findings.

RECENT FINDINGS

Proteinuria is no longer a mandatory criterion for the diagnosis of preeclampsia. Favourable long-term foetal and maternal outcomes are achieved in most patients with ruptured cerebral arterial malformations during pregnancy receiving interventional treatment prior to delivery. Despite the recent recommendations, physicians still hesitate to administer thrombolysis in pregnant women. In women with a history of cerebral venous thrombosis, prophylaxis with low molecular weight heparin during pregnancy and puerperium is associated with lower rates of recurrent thrombotic events and miscarriage.

SUMMARY

Hypertensive disorders of pregnancy are a continuum of failure of autoregulation mechanisms that may lead to eclampsia, posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome and stroke. MRI is the preferred imaging modality of choice. In the absence of specific contraindications, treatment of cerebrovascular complications should not be withheld from pregnant women, including reperfusion therapies in acute ischemic stroke and treatment of ruptured cerebral aneurysms. Previous history of stroke alone does not contraindicate future pregnancy, but counselling and implementation of prevention strategies are needed.

Off-label use of intravenous thrombolysis for acute ischemic stroke: a critical appraisal of randomized and real-world evidence

Intravenous thrombolysis (IVT) represents the only systemic reperfusion therapy able to reverse neurological deficit in patients with acute ischemic stroke (AIS). Despite its effectiveness in patients with or without large vessel occlusion, it can be offered only to a minority of them, because of the short therapeutic window and additional contraindications derived from stringent but arbitrary inclusion and exclusion criteria used in landmark randomized controlled clinical trials. Many absolute or relative contraindications lead to disparities between the official drug label and guidelines or expert recommendations. Based on recent advances in neuroimaging and evidence from cohort studies, off-label use of IVT is increasingly incorporated into the daily practice of many stroke centers. They relate to extension of therapeutic time windows, and expansion of indications in co-existing conditions originally listed in exclusion criteria, such as use of alternative thrombolytic agents, pre-treatment with antiplatelets, anticoagulants or low molecular weight heparins. In this narrative review, we summarize recent randomized and real-world data on the safety and efficacy of off-label use of IVT for AIS. We also make some practical recommendations to stroke physicians regarding the off-label use of thrombolytic agents in complex and uncommon presentations of AIS or other conditions mimicking acute cerebral ischemia. Finally, we provide guidance on the risks and benefits of IVT in numerous AIS subgroups, where equipoise exists and guidelines and treatment practices vary.