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Background and Objectives: Cerebral small vessel disease (cSVD) is a major cause of stroke and dementia, but little is known about disease mechanisms at the level of the small vessels. 7T-MRI allows assessing small vessel function in vivo in different vessel populations. We hypothesized that multiple aspects of small vessel function are altered in patients with cSVD and that these abnormalities relate to disease burden., Methods: Patients and controls participated in a prospective observational cohort study, the ZOOM@SVDs study. Small vessel function measures on 7T-MRI included perforating artery blood flow velocity and pulsatility index in the basal ganglia and centrum semiovale, vascular reactivity to visual stimulation in the occipital cortex, and reactivity to hypercapnia in the gray and white matter. Lesion load on 3T-MRI and cognitive function were used to assess disease burden., Results: Forty-six patients with sporadic cSVD (mean age ± SD 65 ± 9 years) and 22 matched controls (64 ± 7 years) participated in the ZOOM@SVDs study. Compared with controls, patients had increased pulsatility index (mean difference 0.09, p = 0.01) but similar blood flow velocity in basal ganglia perforating arteries and similar flow velocity and pulsatility index in centrum semiovale perforating arteries. The duration of the vascular response to brief visual stimulation in the occipital cortex was shorter in patients than in controls (mean difference -0.63 seconds, p = 0.02), whereas reactivity to hypercapnia was not significantly affected in the gray and total white matter. Among patients, reactivity to hypercapnia was lower in white matter hyperintensities compared with normal-appearing white matter (blood-oxygen-level dependent mean difference 0.35%, p = 0.001). Blood flow velocity and pulsatility index in basal ganglia perforating arteries and reactivity to brief visual stimulation correlated with disease burden., Discussion: We observed abnormalities in several aspects of small vessel function in patients with cSVD indicative of regionally increased arteriolar stiffness and decreased reactivity. Worse small vessel function also correlated with increased disease burden. These functional measures provide new mechanistic markers of sporadic cSVD.

Introduction: Cerebral perforating arteries provide blood supply to the deep regions of the brain. Recently, it became possible to measure blood flow velocity and pulsatility in these small arteries. It is unknown if vascular risk factors are related to these measures., Methods: We measured perforating artery flow with 2D phase contrast 7 Tesla MRI at the level of the centrum semiovale (CSO) and the basal ganglia (BG) in seventy participants from the Heart Brain Connection study with carotid occlusive disease (COD), vascular cognitive impairment (VCI), or no actual cerebrovascular disease. Vascular risk factors included hypertension, diabetes, hyperlipidemia and smoking., Results: No consistent relations were found between any of the vascular risk factors and either flow velocity or flow pulsatility, although there was a relation between lower diastolic blood pressure and higher pulse pressure and higher cerebral perforator pulsatility (p=0,045 and p=0,044, respectively) at the BG level. Results were similar in stratified analyses for patients with and without a history of cardiovascular disease, or only COD or VCI., Conclusion: We conclude that, cross-sectionally, cerebral perforating artery flow velocity and pulsatility are largely independent of the presence of common vascular risk factors in a population with a mixed vascular burden., (The Author(s). Published by S. Karger AG, Basel.)

Background: Hypertension is the leading risk factor for cerebral small vessel disease. We aimed to determine whether antihypertensive drug classes differentially affect microvascular function in people with small vessel disease., Methods: We did a multicentre, open-label, randomised crossover trial with blinded endpoint assessment at five specialist centres in Europe. We included participants aged 18 years or older with symptomatic sporadic small vessel disease or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and an indication for antihypertensive treatment. Participants were randomly assigned (1:1:1) to one of three sequences of antihypertensive treatment using a computer-generated multiblock randomisation, stratified by study site and patient group. A 2-week washout period was followed by three 4-week periods of oral monotherapy with amlodipine, losartan, or atenolol at approved doses. The primary endpoint was change in cerebrovascular reactivity (CVR) determined by blood oxygen level-dependent MRI response to hypercapnic challenge in normal-appearing white matter from the end of washout to the end of each treatment period. Efficacy analyses were done by intention-to-treat principles in all randomly assigned participants who had at least one valid assessment for the primary endpoint, and analyses were done separately for participants with sporadic small vessel disease and CADASIL. This trial is registered at ClinicalTrials.gov, NCT03082014, and EudraCT, 2016-002920-10, and is terminated., Findings: Between Feb 22, 2018, and April 28, 2022, 75 participants with sporadic small vessel disease (mean age 64·9 years [SD 9·9]) and 26 with CADASIL (53·1 years [7·0]) were enrolled and randomly assigned to treatment. 79 participants (62 with sporadic small vessel disease and 17 with CADASIL) entered the primary efficacy analysis. Change in CVR did not differ between study drugs in participants with sporadic small vessel disease (mean change in CVR 1·8 × 10 -4 %/mm Hg [SE 20·1; 95% CI -37·6 to 41·2] for amlodipine; 16·7 × 10 -4 %/mm Hg [20·0; -22·3 to 55·8] for losartan; -7·1 × 10 -4 %/mm Hg [19·6; -45·5 to 31·1] for atenolol; p overall =0·39) but did differ in patients with CADASIL (15·7 × 10 -4 %/mm Hg [SE 27·5; 95% CI -38·3 to 69·7] for amlodipine; 19·4 × 10 -4 %/mm Hg [27·9; -35·3 to 74·2] for losartan; -23·9 × 10 -4 %/mm Hg [27·5; -77·7 to 30·0] for atenolol; p overall =0·019). In patients with CADASIL, pairwise comparisons showed that CVR improved with amlodipine compared with atenolol (-39·6 × 10 -4 %/mm Hg [95% CI -72·5 to -6·6; p=0·019) and with losartan compared with atenolol (-43·3 × 10 -4 %/mm Hg [-74·3 to -12·3]; p=0·0061). No deaths occurred. Two serious adverse events were recorded, one while taking amlodipine (diarrhoea with dehydration) and one while taking atenolol (fall with fracture), neither of which was related to study drug intake., Interpretation: 4 weeks of treatment with amlodipine, losartan, or atenolol did not differ in their effects on cerebrovascular reactivity in people with sporadic small vessel disease but did result in differential treatment effects in patients with CADASIL. Whether antihypertensive drug classes differentially affect clinical outcomes in people with small vessel diseases requires further research., Funding: EU Horizon 2020 programme., Competing Interests: Declaration of interests MD has received consultancy and advisory board fees from Bayer Vital, and speaker's fees from Bayer Vital. MDu reports no competing interests directly related to this work, but declares the following interests outside the submitted work: MIAC (employment), Roche (consultant), Biogen (scientific advisory board), Hovid Berhad (adjudication board), Bayer Vital, and Sanofi Genzyme (speaker honoraria). BN has received consultancy fees from Simbec-Orion for data monitoring committee work. KWM has received consultancy fees from Boehringer Ingelheim, Biogen, Abbvie, Lumosa, and Woolsey, advisory board fees from Boehringer Ingelheim, and speaker's fees from Boehringer Ingelheim. PMR has received consultancy and advisory board fees from Bayer, Bristol Myers Squibb, Sanofi, and Abbott, and speaker fees from Sanofi and Abbott. RvO reports financial support by the European Union's Horizon 2020 project ‘CRUCIAL’ (grant number 848109), and the Collaboration for New Treatments of Acute Stroke (CONTRAST) consortium (financed by the Netherlands Cardiovascular Research Initiative, an initiative of the Dutch Heart Foundation, the Netherlands Brain Foundation, Stryker, Medtronic, and Cerenovus). JMW is part funded by the UK Dementia Research Institute (funded by the Medical Research Council, Alzheimer's Society, and Alzheimer's Research UK) but has no competing interests. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Hypertension is the leading modifiable risk factor for cerebral small vessel diseases (SVDs). Yet, it is unknown whether antihypertensive drug classes differentially affect microvascular function in SVDs., Aims: To test whether amlodipine has a beneficial effect on microvascular function when compared to either losartan or atenolol, and whether losartan has a beneficial effect when compared to atenolol in patients with symptomatic SVDs., Design: TREAT-SVDs is an investigator-led, prospective, open-label, randomised crossover trial with blinded endpoint assessment (PROBE design) conducted at five study sites across Europe. Patients aged 18 years or older with symptomatic SVD who have an indication for antihypertensive treatment and are suffering from either sporadic SVD and a history of lacunar stroke or vascular cognitive impairment (group A) or CADASIL (group B) are randomly allocated 1:1:1 to one of three sequences of antihypertensive treatment. Patients stop their regular antihypertensive medication for a 2-week run-in period followed by 4-week periods of monotherapy with amlodipine, losartan and atenolol in random order as open-label medication in standard dose., Outcomes: The primary outcome measure is cerebrovascular reactivity (CVR) as determined by blood oxygen level dependent brain MRI signal response to hypercapnic challenge with change in CVR in normal appearing white matter as primary endpoint. Secondary outcome measures are mean systolic blood pressure (BP) and BP variability (BPv)., Discussion: TREAT-SVDs will provide insights into the effects of different antihypertensive drugs on CVR, BP, and BPv in patients with symptomatic sporadic and hereditary SVDs., Funding: European Union's Horizon 2020 programme., Trial Registration: NCT03082014., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© European Stroke Organisation 2022.)

Objective: Cerebral small vessel diseases (cSVDs) are a major cause of stroke and dementia. We used cutting-edge 7T-MRI techniques in patients with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), to establish which aspects of cerebral small vessel function are affected by this monogenic form of cSVD., Methods: We recruited 23 CADASIL patients (age 51.1 ± 10.1 years, 52% women) and 13 age- and sex-matched controls (46.1 ± 12.6, 46% women). Small vessel function measures included: basal ganglia and centrum semiovale perforating artery blood flow velocity and pulsatility, vascular reactivity to a visual stimulus in the occipital cortex and reactivity to hypercapnia in the cortex, subcortical gray matter, white matter, and white matter hyperintensities., Results: Compared with controls, CADASIL patients showed lower blood flow velocity and higher pulsatility index within perforating arteries of the centrum semiovale (mean difference - 0.09 cm/s, p = 0.03 and 0.20, p = 0.009) and basal ganglia (mean difference - 0.98 cm/s, p = 0.003 and 0.17, p = 0.06). Small vessel reactivity to a short visual stimulus was decreased (blood-oxygen-level dependent [BOLD] mean difference -0.21%, p = 0.04) in patients, while reactivity to hypercapnia was preserved in the cortex, subcortical gray matter, and normal appearing white matter. Among patients, reactivity to hypercapnia was decreased in white matter hyperintensities compared to normal appearing white matter (BOLD mean difference -0.29%, p = 0.02)., Interpretation: Multiple aspects of cerebral small vessel function on 7T-MRI were abnormal in CADASIL patients, indicative of increased arteriolar stiffness and regional abnormalities in reactivity, locally also in relation to white matter injury. These observations provide novel markers of cSVD for mechanistic and intervention studies. ANN NEUROL 2023;93:29-39., (© 2022 The Authors. Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Patients with carotid occlusive disease express altered hemodynamics in the post-occlusive vasculature and lesions commonly attributed to cerebral small vessel disease (SVD). We addressed the question if cerebral perforating artery flow measures, using a novel 7T MRI technique, are altered and related to SVD lesion burden in patients with carotid occlusive disease. 21 patients were included with a uni- (18) or bilateral (3) carotid occlusion (64±7 years) and 19 controls (65±10 years). Mean flow velocity and pulsatility in the perforating arteries in the semi-oval center (CSO) and basal ganglia (BG), measured with a 2D phase contrast 7T MRI sequence, were compared between patients and controls, and between hemispheres in patients with unilateral carotid occlusive disease. In patients, relations were assessed between perforating artery flow measures and SVD burden score and white matter hyperintensity (WMH) volume. CSO perforating artery flow velocity was lower in patients than controls, albeit non-significant (mean difference [95% confidence interval] 0.08 cm/s [0.00-0.16]; p  = 0.053), but pulsatility was similar (0.07  [-0.04-0.18]; p  = 0.23). BG flow velocity and pulsatility did not differ between patients and controls (velocity = 0.28 cm/s [-0.32-0.88]; p  = 0.34; pulsatility = 0.00 [-0.10-0.11]; p  = 0.97). Patients with unilateral carotid occlusive disease showed no significant interhemispheric flow differences. Though non-significant, within patients lower CSO ( p  = 0.06) and BG ( p  = 0.11) flow velocity related to larger WMH volume. Our findings suggest that carotid occlusive disease may be associated with abnormal cerebral perforating artery flow and that this relates to SVD lesion burden in these patients, although our observations need corroboration in larger study populations., Competing Interests: The authors have no conflicts of interest to declare., (© 2022 Published by Elsevier B.V.)

Background: Cerebral small vessel diseases (SVDs) are a major cause of stroke and dementia. Yet, specific treatment strategies are lacking in part because of a limited understanding of the underlying disease processes. There is therefore an urgent need to study SVDs at their core, the small vessels themselves., Objective: This paper presents the rationale and design of the ZOOM@SVDs study, which aims to establish measures of cerebral small vessel dysfunction on 7T MRI as novel disease markers of SVDs., Methods: ZOOM@SVDs is a prospective observational cohort study with two years follow-up. ZOOM@SVDs recruits participants with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL, N  = 20), sporadic SVDs ( N  = 60), and healthy controls ( N  = 40). Participants undergo 7T brain MRI to assess different aspects of small vessel function including small vessel reactivity, cerebral perforating artery flow, and pulsatility. Extensive work-up at baseline and follow-up further includes clinical and neuropsychological assessment as well as 3T brain MRI to assess conventional SVD imaging markers. Measures of small vessel dysfunction are compared between patients and controls, and related to the severity of clinical and conventional MRI manifestations of SVDs., Discussion: ZOOM@SVDs will deliver novel markers of cerebral small vessel function in patients with monogenic and sporadic forms of SVDs, and establish their relation with disease burden and progression. These small vessel markers can support etiological studies in SVDs and may serve as surrogate outcome measures in future clinical trials to show target engagement of drugs directed at the small vessels., (© 2021 The Author(s). Published by Elsevier B.V.)

Background: Cerebral small vessel disease (SVD) lesions on MRI are common in patients with cognitive impairment. It has been suggested that cerebral hypoperfusion is involved in the etiology of these lesions., Objective: The aim of the study was to determine the relationship between cerebral blood flow (CBF) and SVD burden in patients referred to a memory clinic with SVD on MRI., Method: We included 132 memory clinic patients (mean age 73 ± 10, 56% male) with SVD on MRI. We excluded patients with large non-lacunar cortical infarcts. Global CBF (mL/min per 100 mL of brain tissue) was derived from 2-dimensional phase-contrast MRI focused on the internal carotid arteries and the basilar artery. SVD burden was defined as the sum of (each 1 point): white matter hyperintensities (WMHs) Fazekas 1 or more, lacunes, microbleeds (MBs), or enlarged perivascular spaces (PVS) presence, and each SVD feature separately. Linear regression analyses were performed to study the association between CBF and SVD burden, age- and sex-adjusted., Results: Median SVD burden score was 2, 36.4% of patients had MBs, 35.6% lacunar infarcts, 48.4% intermediate to severe enlarged PVS, and 57.6% a WMH Fazekas score 2 or more. Median WMH volume was 21.4 mL (25% quartile: 9.6 mL, 75% quartile: 32.5 mL). Mean CBF ± SD was 44.0 ± 11.9 mL/min per 100 mL brain. There was no relation between CBF and overall SVD burden (CBF difference per burden score point [95% CI]: -0.5 [-2.4; 1.4] mL/min/100 mL brain, p = 0.9). CBF did also not differ according to presence or absence or an high burden of any of the individual SVD features. Moreover, there was no significant relation between WMH volume and CBF (CBF difference per ml increase in WMH [95% CI] -0.6 [-1.5; 0.3] mL/min/100 mL brain p = 0.2)., Conclusion: Global CBF was not related to overall SVD burden or with individual SVD features in this memory clinic cohort, indicating that in this setting these lesions were not primarily due to cerebral hypoperfusion., (© 2020 The Author(s) Published by S. Karger AG, Basel.)