Transauricular nerve stimulation in acute ischaemic stroke requiring mechanical thrombectomy: Protocol for a phase 2A, proof-of-concept, sham-controlled randomised trial

BACKGROUND

Labile blood pressure after acute ischaemic stroke requiring mechanical thrombectomy is independently associated with poor patient outcomes.

OBJECTIVES

This study protocol describes is designed to determine whether transauricular nerve stimulation, improves baroreflex sensitivity, reduces blood pressure variability in the first 24 hours after acute ischaemic stroke requiring mechanical thrombectomy.

DESIGN: PHASE 2A, PROOF-OF-CONCEPT, SHAM-CONTROLLED RANDOMISED TRIAL

Methods and Analysis: 36 individuals undergoing mechanical thrombectomy for acute ischaemic stroke with established hypertension aged >18 years will be randomly allocated to receive bilateral active or sham transauricular nerve stimulation for the duration of the mechanical thrombectomy procedure (AffeX-CT/001 investigational device). The intervention will be repeated for 1h the morning following the mechanical thrombectomy. Non-invasive blood pressure will be measured ≥2h for 24h after mechanical thrombectomy. Holter electrocardiographic monitoring will be recorded during transauricular nerve stimulation. Participants, clinicians and investigators will be masked to treatment allocations. The primary outcome will be the coefficient of variation of systolic blood pressure. Secondary outcomes include additional estimates of blood pressure variability and time/frequency-domain measures of autonomic cardiac modulation An adjusted sample size of 36 patients is required to have a 90% chance of detecting, as significant at the 5% level, a difference in the coefficient of variation in systolic blood pressure of 5±4mmHg between sham and active stimulation [assuming 5% non-compliance rate in each group]. Ethics: confirmed on 16 March 2023 by HRA and Health and Care Research Wales ethics committee (reference 23/WA/0013).

DISCUSSION

This study will provide proof-of-concept data that examines whether non-invasive autonomic neuromodulation can be used to favourably modify blood pressure and autonomic control after acute ischaemic stroke requiring mechanical thrombectomy.

TRIAL REGISTRATION

Trial registration number: NCT05417009.

Impact of atrial fibrillation on the treatment effect of bridging thrombolysis in ischemic stroke patients undergoing endovascular thrombectomy: a multicenter international cohort study

BACKGROUND

The role of bridging intravenous thrombolysis (IVT) before endovascular thrombectomy (EVT) in the treatment of acute ischemic stroke (AIS) remains debatable. Atrial fibrillation (AF) associated strokes may be associated with reduced treatment effect from IVT. This study compares the effect of bridging IVT in AF and non-AF patients.

METHODS

This retrospective cohort study comprised anterior circulation large vessel occlusion (LVO) AIS patients receiving EVT alone or bridging IVT plus EVT within 6 hours of symptom onset. Primary outcome was good functional outcome defined as modified Rankin Scale (mRS) 0-2 at 90 days. Secondary outcomes were successful reperfusion defined as expanded Thrombolysis In Cerebral Infarction (eTICI) grading ≥2b flow, symptomatic intracerebral hemorrhage (sICH), and in-hospital mortality.

RESULTS

We included 705 patients (314 AF and 391 non-AF patients). The mean age was 68.6 years and 53.9% were male. The odds of good functional outcomes with bridging IVT was higher in the non-AF (adjusted odds ratio (aOR) 2.28, 95% CI 1.06 to 4.91, P=0.035) compared with the AF subgroups (aOR 1.89, 95% CI 0.89 to 4.01, P=0.097). However, this did not constitute a significant effect modification by the presence of AF on bridging IVT (interaction aOR 0.12, 95% CI -1.94 to 2.18, P=0.455). The rate of successful reperfusion, sICH, and mortality were similar between bridging IVT and EVT for both AF and non-AF patients.

CONCLUSION

The presence of AF did not modify the treatment effect of bridging IVT. Further individual patient data meta-analysis of randomized trials may shed light on the comparative efficacy of bridging IVT in AF versus non-AF LVO strokes.

Association between time to treatment and clinical outcomes in endovascular thrombectomy beyond 6 hours without advanced imaging selection

BACKGROUND

The effectiveness and safety of endovascular thrombectomy (EVT) in the late window (6-24 hours) for acute ischemic stroke (AIS) patients selected without advanced imaging is undetermined. We aimed to assess clinical outcomes and the relationship with time-to-EVT treatment beyond 6 hours of stroke onset without advanced neuroimaging.

METHODS

Patients who underwent EVT selected with non-contrast CT/CT angiography (without CT perfusion or MR imaging), between October 2015 and March 2020, were included from a national stroke registry. Functional and safety outcomes were assessed in both early (<6 hours) and late windows with time analyzed as a continuous variable.

RESULTS

Among 3278 patients, 2610 (79.6%) and 668 (20.4%) patients were included in the early and late windows, respectively. In the late window, for every hour delay, there was no significant association with shift towards poorer functional outcome (modified Rankin Scale (mRS)) at discharge (adjusted common OR 0.98, 95% CI 0.94 to 1.01, p=0.27) or change in predicted functional independence (mRS ≤2) (24.5% to 23.3% from 6 to 24 hours; aOR 0.99, 95% CI0.94 to 1.04, p=0.85). In contrast, predicted functional independence was time sensitive in the early window: 5.2% reduction per-hour delay (49.4% to 23.5% from 1 to 6 hours, p=0.0001). There were similar rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 4.6%, p=0.54) and in-hospital mortality (12.9% vs 14.6%, p=0.33) in the early and late windows, respectively, without a significant association with time.

CONCLUSION

In this real-world study, there was minimal change in functional disability, sICH and in-hospital mortality within and across the late window. While confirmatory randomized trials are needed, these findings suggest that EVT remains feasible and safe when performed in AIS patients selected without advanced neuroimaging between 6-24 hours from stroke onset.

Combined balloon guide catheter, aspiration catheter, and stent retriever technique versus balloon guide catheter and stent retriever alone technique: a systematic review and meta-analysis

BACKGROUND

The use of a combination of balloon guide catheter (BGC), aspiration catheter, and stent retriever in acute ischemic stroke thrombectomy has not been shown to be better than a stent retriever and BGC alone, but this may be due to a lack of power in these studies. We therefore performed a meta-analysis on this subject.

METHODS

A systematic literature search was performed on PubMed, Scopus, Embase/Ovid, and the Cochrane Library from inception to October 20, 2021. Our primary outcomes were the rate of successful final reperfusion (Treatment in Cerebral Ischemia (TICI) 2c-3) and first pass effect (FPE, defined as TICI 2c-3 in a single pass). Secondary outcomes were 3 month functional independence (modified Rankin Scale score of 0-2), mortality, procedural complications, embolic complications, and symptomatic intracranial hemorrhage (SICH). A meta-analysis was performed using RevMan 5,4, and heterogeneity was assessed using the I² test.

RESULTS

Of 1629 studies identified, five articles with 2091 patients were included. For the primary outcomes, FPE (44.9% vs 45.4%, OR 1.04 (95% CI 0.90 to 1.22), I²=57%) or final successful reperfusion (64.5% vs 68.6%, OR 0.98 (95% CI 0.81% to 1.20%), I²=85%) was similar between the combination technique and stent retriever only groups. However, the combination technique had significantly less rescue treatment (18.8% vs 26.9%; OR 0.70 (95% CI 0.54 to 0.91), I²=0%). This did not translate into significant differences in secondary outcomes in functional outcomes, mortality, emboli, complications, or SICH.

CONCLUSION

There was no significant difference in successful reperfusion and FPE between the combined techniques and the stent retriever and BGC alone groups. Neither was there any difference in functional outcomes, complications, or mortality.

Prehospital technologies for early stroke detection - A review

The rate of neural circuitry loss in a typical large vessel occlusion well emphasizes that 'Time is Brain'. Every untreated minute in a large vessel ischaemic stroke results in loss of 1.9 million neurons and 13.8 billion synapses. As such, it is essential to optimize the flow-limiting steps in delivering the current standard of care. The current diagnostic model involves recognition of symptoms by patients, followed by access to Emergency Medical Services and subsequent physical examination and neuroimaging in the Emergency Department. With more than 50% of stroke patients using Emergency Medical Services as the first point of care contact, it can be deduced that the outcome of the 'stroke chain of survival' can be improved by addressing the bottleneck of prehospital stroke diagnosis. Here we present a review of the existing technologies.

The initial experience with the Embotrap III stent-retriever in a real world setting

MATERIALS AND METHODS

We performed a retrospective review of our prospectively maintained database to identify all patients treated with the Embotrap 3 stent-retriever between January 2021 and January 2022. We recorded the baseline demographics, NIHSS, ASPECT score and clot characteristics, first pass and final eTICI scores, complications and 90 day mRS.

RESULTS

One hundred and ten patients met the inclusion criteria, average age 69 ± 14 years, 50% were male (n = 55). The median NIHSS at presentation was 18 (range 3-30) and 58.2% received IV tPA prior to MT. The median ASPECT score on plain CT was 8 with average clot length 20.2 ± 14.8 mm (n = 93). The first pass effect (FPE) was seen in 41.8% of cases with modified FPE seen in 59.1%. A 24-hour CT scan (n = 97) showed median ASPECTs of 7. 43.8% of patients achieve mRS ≤ 2 at 90-day mRS (n = 64).

CONCLUSION

The Embotrap 3 stent-retriever has a high rate of FPE and final recanalization in this real world cohort of patients.

Perfusion Imaging for Endovascular Thrombectomy in Acute Ischemic Stroke Is Associated With Improved Functional Outcomes in the Early and Late Time Windows

The impact on clinical outcomes of patient selection using perfusion imaging for endovascular thrombectomy (EVT) in patients with acute ischemic stroke presenting beyond 6 hours from onset remains undetermined in routine clinical practice.

Effect of Sex on Outcomes of Mechanical Thrombectomy in Basilar Artery Occlusion: A Multicentre Cohort Study

INTRODUCTION

Identifying differences in outcome of basilar artery occlusion (BAO) between males and females may be useful in aiding clinical management. Recent studies have demonstrated widespread underrepresentation of women in acute stroke clinical trials. This international multicentre study aimed to determine sex differences in outcome after mechanical thrombectomy (MT) for patients with acute BAO.

METHODS

We performed a retrospective analysis of consecutive patients with BAO who had undergone MT in seven stroke centres across five countries (Singapore, Taiwan, United Kingdom, Sweden, and Germany), between 2015 and 2020. Primary outcome was a favourable functional outcome measured by a modified Ranking Scale (mRS) of 0-3 at 90 days. Secondary outcomes were mRS 0-3 upon discharge, mortality, symptomatic intracranial haemorrhage (sICH) and subarachnoid haemorrhage (SAH).

RESULTS

Among the 322 patients who underwent MT, 206 (64.0%) patients were male and 116 (36.0%) were female. Females were older than males (mean ± SD 70.9 ± 14.3 years vs. 65.6 ± 133.6 years; p = 0.001) and had higher rates of atrial fibrillation (38.9% vs. 24.2%; p = 0.012). Time from groin puncture to reperfusion was shorter in females than males (mean ± SD 57.2 ± 37.2 min vs. 71.1 ± 50.9 min; p = 0.021). Despite these differences, primary and secondary outcome measures were similar in females and males, with comparable rates of favourable 90-day mRS scores (mean ± SD 46 ± 39.7 vs. 71 ± 34.5; OR = 1.20; 95% confidence interval [CI] = 0.59-2.43; p = 0.611), favourable discharge mRS scores (mean ± SD 39 ± 31.6 vs. 43 ± 25.9; OR = 1.38; 95% CI = 0.69-2.78; p = 0.368) and in-hospital mortality (mean ± SD 30 ± 25.9 vs. 47 ± 22.8; OR = 1.15; 95% CI = 0.55-2.43; p = 0.710. Rates of complications such as sICH (mean ± SD 5 ± 4.3 vs. 9 ± 4.4; OR = 0.46; 95% CI = 0.08-2.66; p = 0.385) and SAH (mean ± SD 4 ± 3.4 vs. 5 ± 2.4; OR = 0.29; 95% CI = 0.03-3.09; p = 0.303) comparably low in both groups.

CONCLUSION

Females achieved comparable functional outcomes compared with males after undergoing MT for BAO acute ischemic stroke.

Bridging Thrombolysis versus Direct Mechanical Thrombectomy in Stroke Due to Basilar Artery Occlusion

Background and Purpose

Mechanical thrombectomy (MT) is an effective treatment for patients with basilar artery occlusion (BAO) acute ischemic stroke. It remains unclear whether bridging intravenous thrombolysis (IVT) prior to MT confers any benefit. This study compared the outcomes of acute BAO patients who were treated with direct MT versus combined IVT plus MT.

Methods

This multicenter retrospective cohort study included patients who were treated for acute BAO from eight comprehensive stroke centers between January 2015 and December 2019. Patients received direct MT or combined bridging IVT plus MT. Primary outcome was favorable functional outcome defined as modified Rankin Scale 0–3 measured at 90 days. Secondary outcome measures included mortality and symptomatic intracranial hemorrhage (sICH).

Results

Among 322 patients, 127 (39.4%) patients underwent bridging IVT followed by MT and 195 (60.6%) underwent direct MT. The mean±standard deviation age was 67.5±14.1 years, 64.0% were male and median National Institutes of Health Stroke Scale was 16 (interquartile range, 8 to 25). At 90-day, the rate of favorable functional outcome was similar between the bridging IVT and direct MT groups (39.4% vs. 34.4%, P=0.361). On multivariable analyses, bridging IVT was not as Comorbidisociated with favorable functional outcome, mortality or sICH. In subgroup analyses, patients with underlying atherosclerosis treated with bridging IVT compared to direct MT had a higher rate of favorable functional outcome at 90 days (37.2% vs. 15.5%, P=0.013).

Conclusions

Functional outcomes were similar in BAO patients treated with bridging IVT versus direct MT. In the subgroup of patients with underlying large-artery atherosclerosis stroke mechanism, bridging IVT may potentially confer benefit and this warrants further investigation.

Left ventricular systolic dysfunction is associated with poor functional outcomes after endovascular thrombectomy

BACKGROUND

Endovascular thrombectomy (ET) has transformed acute ischemic stroke (AIS) therapy in patients with large vessel occlusion (LVO). Left ventricular systolic dysfunction (LVSD) decreases global cerebral blood flow and predisposes to hypoperfusion. We evaluated the relationship between LVSD, as measured by LV ejection fraction (LVEF), and clinical outcomes in patients with anterior cerebral circulation LVO who underwent ET.

METHODS

This multicenter retrospective cohort study examined anterior circulation LVO AIS patients from six international stroke centers. LVSD was measured by assessment of the echocardiographic LVEF using Simpson's biplane method of discs according to international guidelines. LVSD was defined as LVEF <50%. The primary outcome was defined as a good functional outcome using a modified Rankin Scale (mRS) of 0-2 at 3 months.

RESULTS

We included 440 AIS patients with LVO who underwent ET. On multivariate analyses, pre-existing diabetes mellitus (OR 2.05, 95% CI 1.24 to 3.39;p=0.005), unsuccessful reperfusion (Treatment in Cerebral Infarction (TICI) grade 0-2a) status (OR 4.21, 95% CI 2.04 to 8.66; p<0.001) and LVSD (OR 2.08, 95% CI 1.18 to 3.68; p=0.011) were independent predictors of poor functional outcomes at 3 months. On ordinal (shift) analyses, LVSD was associated with an unfavorable shift in the mRS outcomes (OR 2.32, 95% CI 1.52 to 3.53; p<0.001) after adjusting for age and ischemic heart disease.

CONCLUSION

Anterior circulation LVO AIS patients with LVSD have poorer outcomes after ET, suggesting the need to consider cardiac factors for ET, the degree of monitoring and prognostication post-procedure.

An avoidable cause of cardioembolic stroke

Left Atrial Ablation for Atrial Fibrillation is safe and effective for most patients. However a rare complication is thermal damage to the integrity of the normal physical barriers between the left atrium and the adjacent oesophagus due to the ablation process. This can lead to formation of an Atrial-Oesophageal fistula with sepsis, haemorrhage and systemic cardioembolism occurring even up to 2 months post procedure. The presentation is similar to endocarditis but localised instrumentation specifically Transoesophageal echocardiography (TOE) can provoke systemic cardioembolism. This is an important differential in those presenting acutely with a Pyrexia of Unknown Origin or endocarditis-like picture within 2 months of ablation therapy.