Regulation of Blood Flow in the Cerebral Posterior Circulation by Parasympathetic Nerve Fibers: Physiological Background and Possible Clinical Implications in Patients With Vertebrobasilar Stroke

Intensive Blood Pressure Control After Endovascular Thrombectomy for Acute Ischemic Stroke: a Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Optimal clinical outcome with successful recanalization from endovascular thrombectomy (EVT) requires optimal blood pressure (BP) management. We aimed to evaluate the efficacy and safety of the intensive BP target (< 140 mm Hg) versus the standard BP target (< 180 mm Hg) after EVT for acute ischemic stroke.

METHODS

We conducted a systematic review and meta-analysis synthesizing evidence from randomized controlled trials (RCTs) obtained from PubMed, Embase Cochrane, Scopus, and WOS until September 7th, 2023. We used the fixed-effect model to report dichotomous outcomes using risk ratio (RR) and continuous outcomes using mean difference (MD), with a 95% confidence interval (CI).

PROSPERO ID

CRD42023463206.

RESULTS

We included four RCTs with 1559 patients. There was no difference between intensive BP and standard BP targets regarding the National Institutes of Health Stroke Scale (NIHSS) change after 24 h [MD: 0.44 with 95% CI (0.0, 0.87), P = 0.05]. However, the intensive BP target was significantly associated with a decreased risk of excellent neurological recovery (mRS ≤ 1) [RR: 0.87 with 95% CI (0.76, 0.99), P = 0.03], functional independence (mRS ≤ 2) [RR: 0.81 with 95% CI (0.73, 0.90), P = 0.0001] and independent ambulation (mRS ≤ 3) [RR: 0.85 with 95% CI (0.79, 0.92), P < 0.0001].

CONCLUSIONS

An intensive BP target after EVT is associated with worse neurological recovery and significantly decreased rates of functional independence and independent ambulation compared to the standard BP target. Therefore, the intensive BP target should be avoided after EVT for acute ischemic stroke.

Frequency, characteristics, and predictors of headache attributed to acute ischemic stroke

OBJECTIVES

Although headache is a common symptom in acute ischemic stroke, the clinical and radiological factors associated with its occurrence are controversial. This work aimed to determine the frequency, characteristics, and predictors of headache occurrence among patients with acute ischemic stroke.

METHODS

This cross-sectional study was conducted on 303 patients with acute ischemic stroke. The patients were submitted to detailed history taking, clinical and radiological assessment. A detailed analysis of headache was performed for the patients who experienced headache temporally related to stroke onset.

RESULTS

Diagnosis of headache attributed to the ischemic stroke was established in 129 (42.6%) patients; sentinel headache in 17.2% of patients, and headache at stroke onset in 25.4% of patients. The headache group had a significantly younger age (P=0.017), lower NIHSS score (P=0.042), higher frequency of pre-existing headache disorders (P=0.001), substance use disorder (P=0.021), and fever (P=0.036), and lower frequency of chronic hypertension (P=0.013) and small vessel disease (P=0.004) than non-headache group. Infarction involving posterior circulation was more frequent in headache than in non-headache groups (P=0.003). The presence of migraine, tension-type headache, other types of headache, fever and posterior circulation stroke increased the odds of headache by 27.4 (95%CI=8.0-94.4), 7.6 (95%CI=3.93-14.6), 26.2 (95%CI=8.0-85.8), 3.75 (95%CI=1.22-11.6) and 3.15 (95%CI=1.65-6.0) times, respectively, whereas, the presence of small vessel disease decreased the odds of headache by 0.51 (95%CI=0.279-0.95) times.

CONCLUSION

Pre-existing headache disorder, fever, and posterior circulation stroke were associated with headache occurrence in acute ischemic stroke patients.

Supratentorial hemangioblastoma: correlation between phenotype, gender and vascular territory affected

Supratentorial hemangioblastomas are rare, vascular lesions. The presence of peri-tumoral cysts and edema has meaningful clinical, diagnostic and therapeutic implications. Nevertheless, the pathogenesis of both cyst and edema formation is not fully understood. This study sought to determine if the radiologic phenotype of supratentorial hemangioblastoma is affected by the different cerebral arterial circulations. Review of the English-language literature from 1973 to 2023 yielded 53 cases of parenchymal supratentorial hemangioblastomas eligible for analysis. Patients were divided by the vascular territorial distribution of the lesions: anterior circulation (n = 36) or posterior circulation (n = 17), and the groups were compared for demographic, clinical, radiologic and molecular variables. Univariate analyses yielded a significant difference between the groups in five variables. Cystic changes and "classic" radiological phenotype were associated with hemangioblastomas of the posterior circulation (OR = 0.19, p = 0.045 and OR = 0.287, p = 0.048, respectively), while female gender, significant peritumoral edema and purely solid phenotype were associated with hemangioblastomas of the anterior circulation (OR = 3.384, p = 0.045 and OR = 5.25, p = 0.05 and OR = 14.0, p = 0.015; respectively). On multivariate analysis, solid phenotype and female gender remained significantly associated with the anterior circulation (OR = 36.04, p = 0.014 and OR = 4.45, p = 0.045). The incidence of von-Hippel Lindau disease was higher in the anterior-circulation group. Cystic tumors were present in all females in the posterior-circulation group compared to 43.4% in the anterior-circulation group (OR = 20.714, 95% CI 1.061 to 404.122; p = 0.045). Based on historical cases of supratentorial hemangioblastoma, this study shows that different tumor phenotypes are associated with the different cerebral circulations. Gender was also associated with differences in tumor distribution and radiologic phenotype. These novel data may improve our understanding of unique vascular diseases of the central nervous system.

Blood pressure management in ischemic stroke patients undergoing mechanical thrombectomy

The relationship between presenting blood pressure in acute ischemic stroke patients and outcome is complex. Several studies have demonstrated a U-shaped curve with worse outcomes when blood pressure is high or low. The American Heart Association/American Stroke Association guidelines recommend values of blood pressure < 185/110 mmHg in patients treated with intravenous t-PA and "permissive hypertension" up to 220/120 mmHg in those not treated with intravenous t-PA. The optimal blood pressure target is less clear in patients undergoing mechanical thrombectomy. Before thrombectomy, the guidelines recommend a blood pressure < 185/110 mmHg though patients with even lower systolic blood pressures may have better outcomes. During and after thrombectomy, the guidelines recommend a blood pressure < 180/105 mmHg. However, several studies have suggested that during thrombectomy the primary goal should be to prevent significant low blood pressure (e.g., target systolic blood pressure > 140 mmHg or MAP > 70 mmHg). After thrombectomy, the primary goal should be to prevent high blood pressure (e.g., target systolic blood pressure < 160 mmHg or MAP < 90 mmHg). To make more specific recommendations, large, randomized-control studies are needed that address factors such as the baseline blood pressure, timing and degree of revascularization, status of collaterals, and estimated risk of reperfusion injury.

The effect of intensive statin therapy in non-symptomatic intracranial arteries: The STAMINA-MRI sub-study

Background and aims

Pleiotropic effects of statins result in the stabilization of symptomatic intracranial arterial plaque. However, little is known about the effect of statins in non-symptomatic cerebral arteries. We hypothesized that intensive statin therapy could produce a change in the non-symptomatic cerebral arteries.

Methods

This is a sub-study of a prospective observational study under the title of "Intensive Statin Treatment in Acute Ischemic Stroke Patients with Intracranial Atherosclerosis: a High-Resolution Magnetic Resonance Imaging (HR-MRI) study." Patients with statin-naive acute ischemic stroke who had symptomatic intracranial artery stenosis (above 50%) were recruited for this study. HR-MRI was performed to assess the patients' cerebral arterial status before and 6 months after the statin therapy. To demonstrate the effect of statins in the non-symptomatic segment of intracranial cerebral arteries, we excluded symptomatic segments from the data to be analyzed. We compared the morphological changes using cerebrovascular morphometry.

Results

A total of 54 patients (mean age: 62.9 ± 14.4 years, 59.3% women) were included in this study. Intensive statin therapy produced significant morphological changes of overall cerebral arteries. Among the morphological features, the arterial luminal area showed the highest number of significant changes with a range from 5.7 and 6.7%. Systolic blood pressure (SBP) was an independent factor associated with relative changes in posterior circulation bed maximal diameter percentage change (beta -0.21, 95% confidence interval -0.36 to -0.07, p = 0.005).

Conclusion

Intensive statin therapy produced a favorable morphological change in cerebral arteries of not only the target arterial segment but also non-symptomatic arterial segments. The change in cerebral arterial luminal diameter was influenced by the baseline SBP and was dependent on the topographic distribution of the cerebral arteries.Clinical Trial Registration: ClinicalTrials.gov, identifier NCT02458755.

Association of Intensive vs Standard Blood Pressure Control With Regional Changes in Cerebral Small Vessel Disease Biomarkers: Post Hoc Secondary Analysis of the SPRINT MIND Randomized Clinical Trial

IMPORTANCE

Little is known about the associations of strict blood pressure (BP) control with microstructural changes in small vessel disease markers.

OBJECTIVE

To investigate the regional associations of intensive vs standard BP control with small vessel disease biomarkers, such as white matter lesions (WMLs), fractional anisotropy (FA), mean diffusivity (MD), and cerebral blood flow (CBF).

DESIGN, SETTING, AND PARTICIPANTS

The Systolic Blood Pressure Intervention Trial (SPRINT) is a multicenter randomized clinical trial that compared intensive systolic BP (SBP) control (SBP target <120 mm Hg) vs standard control (SBP target <140 mm Hg) among participants aged 50 years or older with hypertension and without diabetes or a history of stroke. The study began randomization on November 8, 2010, and stopped July 1, 2016, with a follow-up duration of approximately 4 years. A total of 670 and 458 participants completed brain magnetic resonance imaging at baseline and follow-up, respectively, and comprise the cohort for this post hoc analysis. Statistical analyses for this post hoc analysis were performed between August 2020 and October 2022.

INTERVENTIONS

At baseline, 355 participants received intensive SBP treatment and 315 participants received standard SBP treatment.

MAIN OUTCOMES AND MEASURES

The main outcomes were regional changes in WMLs, FA, MD (in white matter regions of interest), and CBF (in gray matter regions of interest).

RESULTS

At baseline, 355 participants (mean [SD] age, 67.7 [8.0] years; 200 men [56.3%]) received intensive BP treatment and 315 participants (mean [SD] age, 67.0 [8.4] years; 199 men [63.2%]) received standard BP treatment. Intensive treatment was associated with smaller mean increases in WML volume compared with standard treatment (644.5 mm3 vs 1258.1 mm3). The smaller mean increases were observed specifically in the deep white matter regions of the left anterior corona radiata (intensive treatment, 30.3 mm3 [95% CI, 16.0-44.5 mm3]; standard treatment, 80.5 mm3 [95% CI, 53.8-107.2 mm3]), left tapetum (intensive treatment, 11.8 mm3 [95% CI, 4.4-19.2 mm3]; standard treatment, 27.2 mm3 [95% CI, 19.4-35.0 mm3]), left superior fronto-occipital fasciculus (intensive treatment, 3.2 mm3 [95% CI, 0.7-5.8 mm3]; standard treatment, 9.4 mm3 [95% CI, 5.5-13.4 mm3]), left posterior corona radiata (intensive treatment, 26.0 mm3 [95% CI, 12.9-39.1 mm3]; standard treatment, 52.3 mm3 [95% CI, 34.8-69.8 mm3]), left splenium of the corpus callosum (intensive treatment, 45.4 mm3 [95% CI, 25.1-65.7 mm3]; standard treatment, 83.0 mm3 [95% CI, 58.7-107.2 mm3]), left posterior thalamic radiation (intensive treatment, 53.0 mm3 [95% CI, 29.8-76.2 mm3]; standard treatment, 106.9 mm3 [95% CI, 73.4-140.3 mm3]), and right posterior thalamic radiation (intensive treatment, 49.5 mm3 [95% CI, 24.3-74.7 mm3]; standard treatment, 102.6 mm3 [95% CI, 71.0-134.2 mm3]).

CONCLUSIONS AND RELEVANCE

This study suggests that intensive BP treatment, compared with standard treatment, was associated with a slower increase of WMLs, improved diffusion tensor imaging, and FA and CBF changes in several brain regions that represent vulnerable areas that may benefit from more strict BP control.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01206062.

Posterior reversible encephalopathy syndrome presenting with thrombotic microangiopathy triggered by malignant hypertension: a case report and literature review

Background

Posterior reversible encephalopathy syndrome (PRES) is a disease characterised by reversible subcortical vasogenic oedema, neurological symptoms and abnormal findings on head imaging. It is recognised as one of the most prominent organ disorders in hypertensive emergencies but is rarely associated with thrombotic microangiopathy (TMA).

Case presentation

A woman in her 40s with untreated hypertension had occasional headaches in the past 4 months. The headaches worsened during the 3 weeks prior to admission. On the day of admission, the patient presented with severe headache accompanied by frequent vomiting. MRI of the head revealed oedematous changes in the brainstem, including the subcortical, cerebellum and pons. Fundus examination revealed hypertensive retinopathy with papilloedema. Blood tests indicated thrombocytopenia, renal dysfunction and haemolytic anaemia, and a blood smear confirmed fragmented erythrocytes. Coombs’ test, and tests for ADAMTS13 activity and infectious and autoimmune diseases were negative. The patient was diagnosed with PRES, secondary to malignant hypertension (MH) and associated with TMA. Antihypertensive therapy promptly improved the clinical symptoms, blood pressure, and the abnormal MRI and blood test findings. The patient was discharged from the hospital 20 days after admission.

Conclusions

We report a rare case of PRES that was associated with TMA and triggered by MH. Antihypertensive therapy was effective in alleviating the associated adverse clinical symptoms. Differentiation of underlying diseases is essential for early intervention, since treatment depends on factors causing TMA.

“The Wandering Nerve Linking Heart and Mind” – The Complementary Role of Transcutaneous Vagus Nerve Stimulation in Modulating Neuro-Cardiovascular and Cognitive Performance

The vagus nerve is the longest nerve in the human body, providing afferent information about visceral sensation, integrity and somatic sensations to the CNS via brainstem nuclei to subcortical and cortical structures. Its efferent arm influences GI motility and secretion, cardiac ionotropy, chonotropy and heart rate variability, blood pressure responses, bronchoconstriction and modulates gag and cough responses via palatine and pharyngeal innervation. Vagus nerve stimulation has been utilized as a successful treatment for intractable epilepsy and treatment-resistant depression, and new non-invasive transcutaneous (t-VNS) devices offer equivalent therapeutic potential as invasive devices without the surgical risks. t-VNS offers exciting potential as a therapeutic intervention in cognitive decline and aging populations, classically affected by reduced cerebral perfusion by modulating both limbic and frontal cortical structures, regulating cerebral perfusion and improving parasympathetic modulation of the cardiovascular system. In this narrative review we summarize the research to date investigating the cognitive effects of VNS therapy, and its effects on neurocardiovascular stability.