Interventional Ischemic Stroke Treatment--A (R)evolution

Dodging blood brain barrier with "nano" warriors: Novel strategy against ischemic stroke

Ischemic stroke (IS) is one of the leading causes of death and disability resulting in inevitable burden globally. Ischemic injury initiates cascade of pathological events comprising energy dwindling, failure of ionic gradients, failure of blood brain barrier (BBB), vasogenic edema, calcium over accumulation, excitotoxicity, increased oxidative stress, mitochondrial dysfunction, inflammation and eventually cell death. In spite of such complexity of the disease, the only treatment approved by US Food and Drug Administration (FDA) is tissue plasminogen activator (t-PA). This therapy overcome blood deficiency in the brain along with side effects of reperfusion which are responsible for considerable tissue injury. Therefore, there is urgent need of novel therapeutic perspectives that can protect the integrity of BBB and salvageable brain tissue. Advancement in nanomedicine is empowering new approaches that are potent to improve the understanding and treatment of the IS. Herein, we focus nanomaterial mediated drug delivery systems (DDSs) and their role to bypass and cross BBB especially via intranasal drug delivery. The various nanocarriers used in DDSs are also discussed. In a nut shell, the objective is to provide an overview of use of nanomedicine in the diagnosis and treatment of IS to facilitate the research from benchtop to bedside.

Experimental Evaluation of the Effectiveness of Aspiration-Based Techniques to Treat Different Types of Acute Thromboembolic Occlusions in the Femoropopliteal Vascular System Using an In Vitro Flow Model

PURPOSE

In this in vitro study, the effectiveness and safety of four aspiration-based techniques for thrombectomy are evaluated for three types of thrombi in a flow model simulating the femoropopliteal segment.

MATERIAL AND METHODS

Red, white, and mixed thrombi were produced in a standardized manner and used to simulate occlusion of a superficial femoral artery using a pulsatile flow model. Four techniques were compared: aspiration alone, aspiration + stent retriever, exposing thrombus to laser by an excimer laser system and a laser catheter + aspiration, and aspiration + mechanical fragmentation by a separator. Rate of first-pass recanalization, embolic events, and number of embolized fragments > 1 mm were compared.

RESULTS

Aspiration alone, stent retriever, laser, and separator differed in rates of first-pass recanalization (53.3%; 86.6%; 20%; and 100%) and embolic events (40%; 93.3%; 73.3%; and 60%). Number of embolized fragments was lowest with aspiration and higher with separator, laser, and stent retriever. Rates of first-pass-recanalization (75%; 75%; and 45%) and embolic events (65%; 60%; and 75%) differed for red, white, and mixed thrombi. The mixed thrombus caused the highest number of embolized fragments, which was particularly high using the stent retriever.

CONCLUSION

Additional use of mechanical techniques significantly enhances the effectiveness of thrombectomy but simultaneously provokes more embolism. Laser seems to negatively alter the structure of a thrombus and thus diminishes the effectiveness, while provoking embolism. All techniques had lowest effectiveness, but highest embolism with the mixed thrombus. This was particularly striking when a stent retriever was used with the mixed thrombus.

Disrupted brain functional network topology in unilateral acute brainstem ischemic stroke

This study aimed to investigate the topological properties of brain functional connectome in unilateral acute brainstem ischemic stroke using graph theory. Fifty-three acute brainstem ischemic stroke patients, consisted of 27 left-sided and 26 right-sided brainstem stroke patients, and 20 age, gender, and education-matched healthy controls (HCs) were recruited to undergo a resting-state functional magnetic resonance imaging (rs-fMRI) scan in this study. Graph theory analyses were then used to examine the group-specific topological properties of the functional connectomes seperately. The unilateral acute brainstem stroke patients and HCs all exhibited "small-world" brain network topology. The functional connectome of the left brainstem stroke patients showed significant differences in all topological properties while the right brainstem stroke patients showed a significant increase in clustering coefficient Cp (p < 0.001) and local efficiency E_local (p < 0.001), and a significantly decrease in normalized clustering coefficient γ (p < 0.001) and global efficiency E_global (p < 0.001), suggesting both a shift toward regular networks. At the nodal level, abnormal nodal centralities were mainly observed in the defaut mode network, subcortical network, frontal and occipital lobe. The findings of disrupted topological properties of functional brain networks may help better understanding the disease characterization and innovation in management for acute brainstem ischemic stroke patients.

Mechanical Thrombectomy for Tandem Occlusions of the Internal Carotid Artery-Results of a Conservative Approach for the Extracranial Lesion

Background: Mechanical thrombectomy (MT) is of clinical benefit for patients with extracranial-intracranial tandem lesions of anterior circulation. However, the optimal approach to the cervical lesion of the internal carotid artery (ICA) during MT has yet to be established. Data on a conservative approach for the proximal lesion during the acute phase are scarce.

Methods: A retrospective study on an institutional, prospective database was conducted. We included patients with anterior circulation stroke presenting with a tandem lesion that was approached conservatively during MT.

Results: Thirty-five 35 patients were included, of whom 25 (71.4%) had an atheromatous ICA lesion and 10 (28.6%) a dissection. Despite implementing a conservative strategy, acute percutaneous transluminal angioplasty (PTA) and/or stenting was necessary in 8 (22.9%) and 3 patients (8.6%), respectively. Of 27 surviving patients, 7 (25.9%) underwent delayed treatment of the ICA lesion. No new embolic events occurred between MT and delayed treatment. A favorable clinical outcome (mRS ≤ 2) was achieved in 15/35 patients (45.7%) and was associated with higher baseline ASPECTS (OR 1.62, 95% CI 1.08–2.45, p = 0.002) and successful recanalization (OR 9.39, 95% CI 1.92–45.80, p = 0.0005). Successful recanalization (TICI ≥ 2B) itself was observed in 54.3% of patients and was more likely with acute treatment of the proximal ICA lesion (OR 6.3, 95% CI 11–35.67, p = 0.03) and, more importantly, by the use of distal access catheters (OR 16.25, 95% CI 3.06–86.41, p = 0.0001).

Conclusion: A conservative approach for ICA lesions during MT is feasible and offers favorable outcomes and successful recanalization for a significant proportion of patients. However, acute treatment of the cervical lesion is often necessary (31.4%) to make the distal occlusion accessible. Clinical outcome is influenced by the size of the baseline ischemic core and by successful recanalization; the latter is strongly favored by the use of distal access catheters to pass the proximal lesion. The fact that acute treatment of the ICA lesion favored intracranial recanalization but had no effect on clinical outcome is probably due to sample size, emphasizing the need for large scale, randomized studies to determine the optimal treatment strategy for this pathology.

A UPLC-MS/MS method for quantification of 5α-androst-3β,5,6β-triol in human plasma: development, validation and its application in clinical pharmacokinetic study

AIM

5α-androst-3β,5,6β-triol is a novel ischemic stroke drug under clinical development. The objective of this study was to develop and validate a simple ultraperformance liquid chromatography tandem mass spectrometry method for 5α-androst-3β,5,6β-triol in human plasma and its application in clinical pharmacokinetic study. Methodology & results: After being pretreated using an automatized solid-phase extraction procedure, plasma sample was separated on a Waters^® Acquity™ BEH C₁₈ column (2.1 × 50 mm id, 1.7 mm) by an Acquity UPLC system and detected by an API 5500 triple quadrupole mass spectrometer, which was validated following international guidelines.

CONCLUSION

A simple method was successfully validated over a concentration range of 2.00-500 ng/ml for 5α-androst-3β,5,6β-triol and applied to investigate its plasma pharmacokinetic profiles in healthy Chinese subjects.