Prediction of 3-year clinical course in CADASIL

MRI-Proven Incident Ischemia: A New Marker of Disease Progression in Small Vessel Diseases

BACKGROUND

In ischemic cerebral small vessel diseases (cSVD), recurrent ischemic stroke is rare (2%-3% per year). Because acute ischemia may not always lead to stroke in cSVD due to the small size of lesions, acute stroke may not reliably reflect ischemic activity or the risk of further clinical worsening, as both incident lacunes and incidental diffusion-weighted imaging-positive lesions can occur without stroke symptoms. We aimed to evaluate the total ischemic activity by measuring the incidence of magnetic resonance imaging (MRI)-proven incident ischemia, independent of the presence of stroke symptoms in a large cohort of cSVD.

METHODS

DHU-LAC is an ongoing French multicenter cohort study of MRI-proven ischemic stroke presumably due to cSVD. We report data on patients recruited between June 2018 and October 2023. In DHU-LAC, patients are enrolled within 15 days of stroke onset and are cared for according to current guidelines. During the first 6 months, patients are systematically reassessed clinically and by brain MRI: (1) at any time if stroke symptoms occur and (2) at the end of the period. We defined MRI-proven incident ischemia as either recurrent ischemic stroke or at least 1 incident lacune or incidental diffusion-weighted imaging-positive lesion on brain MRI at 6 months.

RESULTS

Two hundred forty-nine patients were included, of whom 172 had available data at both inclusion and after 6 months. They were aged 63±6 years, 28% were women, and 65% had hypertension. Six (3%) had a recurrent ischemic stroke, but 25 more (15%) had at least 1 incident lacune or incidental diffusion-weighted imaging-positive lesion on brain MRI. MRI-proven ischemia occurs about 5× more frequently than ischemic stroke in cSVD.

CONCLUSIONS

As data confirming the detrimental clinical effect of both incident lacunes and incidental diffusion-weighted imaging-positive lesions accumulate, MRI-proven incident ischemia may become a plausible outcome for future clinical trials in cSVD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03552926.

Disease Severity Staging System for NOTCH3-Associated Small Vessel Disease, Including CADASIL

Importance

Typical cysteine-altering NOTCH3 (NOTCH3cys) variants are highly prevalent (approximately 1 in 300 individuals) and are associated with a broad spectrum of small vessel disease (SVD), ranging from early-onset stroke and dementia (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL]) to nonpenetrance. A staging system that captures the full NOTCH3-SVD severity spectrum is needed and currently lacking.

Objective

To design a simple disease severity staging system that captures the broad clinicoradiological NOTCH3-SVD severity spectrum.

Design, Setting, and Participants

A cohort study was performed in which the NOTCH3-SVD severity staging system was developed using a discovery cohort (2019-2020) and validated in independent international CADASIL cohorts (1999-2023) and the UK Biobank. Clinical and imaging data were collected from participants originating from 23 international CADASIL cohorts and from the UK Biobank. Eligibility criteria were presence of a NOTCH3cys variant, availability of brain magnetic resonance imaging, and modified Rankin Scale score. The discovery cohort consisted of 195 NOTCH3cys-positive cases from families with CADASIL; the validation set included 1713 NOTCH3cys-positive cases from 15 countries. The UK Biobank cohort consisted of 101 NOTCH3cys-positive individuals. Data from 2-year (2019-2023) and 18-year (1999-2017) follow-up studies were also analyzed. Data analysis was performed from July 2023 to August 2024.

Main Outcomes and Measures

Percentage of cases following the sequence of events of the NOTCH3-SVD stages, and the association between the stages and ischemic stroke, intracerebral hemorrhage, global cognition, processing speed, brain volume, brain microstructural damage, and serum neurofilament light chain (NfL) level.

Results

The NOTCH3-SVD staging system encompasses 9 disease stages or substages, ranging from stage 0 (premanifest stage) to stage 4B (end stage). Of all 1908 cases, which included 195 in the discovery cohort (mean [SD] age, 52.4 [12.2] years) and 1713 in the validation cohorts (mean [SD] age, 53.1 [13.0] years), 1789 (94%) followed the sequence of events defined by the NOTCH3-SVD staging system. The NOTCH3-SVD stages were associated with neuroimaging outcomes in the NOTCH3cys-positive cases in the CADASIL cohorts and in the UK Biobank and with cognitive outcomes and serum NfL level in cases from the CADASIL cohorts. The NOTCH3-SVD staging system captured disease progression and was associated with 18-year survival.

Conclusions and Relevance

The NOTCH3-SVD staging system captures the full disease spectrum, from asymptomatic individuals with a NOTCH3cys variant to patients with end-stage disease. The NOTCH3-SVD staging system is a simple but effective tool for uniform disease staging in the clinic and in research.

Association of NOTCH3 Variant Risk Category With 2-Year Clinical and Radiologic Small Vessel Disease Progression in Patients With CADASIL

BACKGROUND AND OBJECTIVES

Pathogenic variants in NOTCH3 are the main cause of hereditary cerebral small vessel disease (SVD). SVD-associated NOTCH3 variants have recently been categorized into high risk (HR), moderate risk (MR), or low risk (LR) for developing early-onset severe SVD. The most severe NOTCH3-associated SVD phenotype is also known as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We aimed to investigate whether NOTCH3 variant risk category is associated with 2-year progression rate of SVD clinical and neuroimaging outcomes in CADASIL.

METHODS

A single-center prospective 2-year follow-up study was performed of patients with CADASIL. Clinical outcomes were incident stroke, disability (modified Rankin Scale), and executive function (Trail Making Test B given A t-scores). Neuroimaging outcomes were mean skeletonized mean diffusivity (MSMD), normalized white matter hyperintensity volume (nWMHv), normalized lacune volume (nLV), and brain parenchymal fraction (BPF). Cox regression and mixed-effect models, adjusted for age, sex, and cardiovascular risk factors, were used to study 2-year changes in outcomes and differences in disease progression between patients with HR-NOTCH3 and MR-NOTCH3 variants.

RESULTS

One hundred sixty-two patients with HR (n = 90), MR (n = 67), and LR (n = 5) NOTCH3 variants were included. For the entire cohort, there was 2-year mean progression for MSMD (β = 0.20, 95% CI 0.17-0.23, p = 7.0 × 10-24), nLV (β = 0.13, 95% CI 0.080-0.19, p = 2.1 × 10-6), nWMHv (β = 0.092, 95% CI 0.075-0.11, p = 8.8 × 10-20), and BPF (β = -0.22, 95% CI -0.26 to -0.19, p = 3.2 × 10-22), as well as an increase in disability (p = 0.002) and decline of executive function (β = -0.15, 95% CI -0.30 to -3.4 × 10-5, p = 0.05). The HR-NOTCH3 group had a higher probability of 2-year incident stroke (hazard ratio 4.3, 95% CI 1.4-13.5, p = 0.011), and a higher increase in MSMD (β = 0.074, 95% CI 0.013-0.14, p = 0.017) and nLV (β = 0.14, 95% CI 0.034-0.24, p = 0.0089) than the MR-NOTCH3 group. Subgroup analyses showed significant 2-year progression of MSMD in young (n = 17, β = 0.014, 95% CI 0.0093-0.019, p = 1.4 × 10-5) and premanifest (n = 24, β = 0.012, 95% CI 0.0082-0.016, p = 1.1 × 10-6) individuals.

DISCUSSION

In a trial-sensitive time span of 2 years, we found that patients with HR-NOTCH3 variants have a significantly faster progression of major clinical and neuroimaging outcomes, compared with patients with MR-NOTCH3 variants. This has important implications for clinical trial design and disease prediction and monitoring in the clinic. Moreover, we show that MSMD is a promising outcome measure for trials enrolling premanifest individuals.

Enlarged perivascular spaces are associated with white matter injury, cognition and inflammation in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Enlarged perivascular spaces have been previously reported in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, but their significance and pathophysiology remains unclear. We investigated associations of white matter enlarged perivascular spaces with classical imaging measures, cognitive measures and plasma proteins to better understand what enlarged perivascular spaces represent in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and whether radiographic measures of enlarged perivascular spaces would be of value in future therapeutic discovery studies for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Twenty-four individuals with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and 24 age- and sex-matched controls were included. Disease status was determined based on the presence of NOTCH3 mutation. Brain imaging measures of white matter hyperintensity, brain parenchymal fraction, white matter enlarged perivascular space volumes, clinical and cognitive measures as well as plasma proteomics were used in models. White matter enlarged perivascular space volumes were calculated via a novel, semiautomated pipeline, and levels of 7363 proteins were quantified in plasma using the SomaScan assay. The relationship of enlarged perivascular spaces with global burden of white matter hyperintensity, brain atrophy, functional status, neurocognitive measures and plasma proteins was modelled with linear regression models. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and control groups did not exhibit differences in mean enlarged perivascular space volumes. However, increased enlarged perivascular space volumes in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy were associated with increased white matter hyperintensity volume (β = 0.57, P = 0.05), Clinical Dementia Rating Sum-of-Boxes score (β = 0.49, P = 0.04) and marginally with decreased brain parenchymal fraction (β = -0.03, P = 0.10). In interaction term models, the interaction term between cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy disease status and enlarged perivascular space volume was associated with increased white matter hyperintensity volume (β = 0.57, P = 0.02), Clinical Dementia Rating Sum-of-Boxes score (β = 0.52, P = 0.02), Mini-Mental State Examination score (β = -1.49, P = 0.03) and marginally with decreased brain parenchymal fraction (β = -0.03, P = 0.07). Proteins positively associated with enlarged perivascular space volumes were found to be related to leukocyte migration and inflammation, while negatively associated proteins were related to lipid metabolism. Two central hub proteins were identified in protein networks associated with enlarged perivascular space volumes: CXC motif chemokine ligand 8/interleukin-8 and C-C motif chemokine ligand 2/monocyte chemoattractant protein 1. The levels of CXC motif chemokine ligand 8/interleukin-8 were also associated with increased white matter hyperintensity volume (β = 42.86, P = 0.03), and levels of C-C motif chemokine ligand 2/monocyte chemoattractant protein 1 were further associated with decreased brain parenchymal fraction (β = -0.0007, P < 0.01) and Mini-Mental State Examination score (β = -0.02, P < 0.01) and increased Trail Making Test B completion time (β = 0.76, P < 0.01). No proteins were associated with all three studied imaging measures of pathology (brain parenchymal fraction, enlarged perivascular spaces, white matter hyperintensity). Based on associations uncovered between enlarged perivascular space volumes and cognitive functions, imaging and plasma proteins, we conclude that white matter enlarged perivascular space volumes may capture pathologies contributing to chronic brain dysfunction and degeneration in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Comparison of models for stroke-free survival prediction in patients with CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, which is caused by mutations of the NOTCH3 gene, has a large heterogeneous progression, presenting with declines of various clinical scores and occurrences of various clinical event. To help assess disease progression, this work focused on predicting the composite endpoint of stroke-free survival time by comparing the performance of Cox proportional hazards regression to that of machine learning models using one of four feature selection approaches applied to demographic, clinical and magnetic resonance imaging observational data collected from a study cohort of 482 patients. The quality of the modeling process and the predictive performance were evaluated in a nested cross-validation procedure using the time-dependent Brier Score and AUC at 5 years from baseline, the former measuring the overall performance including calibration and the latter highlighting the discrimination ability, with both metrics taking into account the presence of right-censoring. The best model for each metric was the componentwise gradient boosting model with a mean Brier score of 0.165 and the random survival forest model with a mean AUC of 0.773, both combined with the LASSO feature selection method.

Improvement of an External Predictive Model Based on New Information Using a Synthetic Data Approach: Application to CADASIL

Background and Objectives

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most frequent hereditary cerebral small vessel disease. It is caused by mutations of the NOTCH3 gene. The disease evolves progressively over decades leading to stroke, disability, cognitive decline, and functional dependency. The course and clinical severity of CADASIL seem heterogeneous. Predictive models are thus needed to improve prognostic evaluation and inform future clinical trials. A predictive model of the 3-year variation in the Mattis Dementia Rating Scale (MDRS), which reflects the global cognitive performance of patients with CADASIL, was previously proposed. This model made predictions based on demographic, clinical, and MRI data. We aimed to improve this existing predictive model by integrating a new potential factor, the location of the genetic mutation in the different epidermal growth factor (EGFr) domains of the NOTCH3 gene, dichotomized into EGFr domains 1 to 6 or 7 to 34.

Methods

We used a new synthetic data approach to improve the initial predictive model by incorporating additional genetic information. This method combined the predicted outcomes from the previous model and 5 "synthetic" data sets with the observed outcome in a new data set. We then applied a multiple imputation method for missing data on the mutation location.

Results

The new data set included 367 patients who were followed up for 30 to 42 months. In the multivariable model with synthetic data, patients with NOTCH3 mutations in EGFr domains 7 to 34 had an additional average decrease of -1.4 points (standard error 0.67, p = 0.035) in their MDRS score variation over 3 years compared with patients with mutations located in EGFr domains 1 to 6. Cross-validation results highlighted the improved predictive performance of the enhanced model. Moreover, the model estimation was found to be more robust than fitting a model without synthetic data.

Discussion

The use of synthetic data improved the predictive model of MDRS change over 3 years in CADASIL. The predictive performance and estimation robustness of the predictive model were enhanced using this approach, whether genetic information was used. A statistically significant association between the location of the mutation in the NOTCH3 gene and the 3-year MDRS score variation was detected.

Update on the Epidemiology, Pathogenesis, and Biomarkers of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disorder of the cerebral small blood vessels. It is caused by mutations in the NOTCH3 gene on chromosome 19, and more than 280 distinct pathogenic mutations have been reported to date. CADASIL was once considered a very rare disease with an estimated prevalence of 1.3-4.1 per 100,000 adults. However, recent large-scale genomic studies have revealed a high prevalence of pathogenic NOTCH3 variants among the general population, with the highest risk being among Asians. The disease severity and age at onset vary significantly even among individuals who carry the same NOTCH3 mutations. It is still unclear whether a significant genotype-phenotype correlation is present in CADASIL. The accumulation of granular osmiophilic material in the vasculature is a characteristic feature of CADASIL. However, the exact pathogenesis of CADASIL remains largely unclear despite various laboratory and clinical observations being made. Major hypotheses proposed so far have included aberrant NOTCH3 signaling, toxic aggregation, and abnormal matrisomes. Several characteristic features have been observed in the brain magnetic resonance images of patients with CADASIL, including subcortical lacunar lesions and white matter hyperintensities in the anterior temporal lobe or external capsule, which were useful in differentiating CADASIL from sporadic stroke in patients. The number of lacunes and the degree of brain atrophy were useful in predicting the clinical outcomes of patients with CADASIL. Several promising blood biomarkers have also recently been discovered for CADASIL, which require further research for validation.

Elderly CADASIL patients with intact neurological status

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is one of the most devastating cerebral small vessel diseases. However, despite its progression with aging, some patients remain neurologically intact (Nint) even when they get older. Their main characteristics are poorly known. We aimed to delineate their clinical, imaging, and molecular features.

METHODS

Individuals aged over 65 years were selected from a cohort of 472 CADASIL patients. Subjects who had no focal deficit, cognitive impairment, or disability were considered Nint. Their demographic, genetic, clinical, and imaging features were compared to those with permanent neurological symptoms (Nps).

RESULTS

Among 129 patients, 23 (17.8%) individuals were considered Nint. The frequency of vascular risk factors and NOTCH3 cysteine mutations in epidermal growth factor-like repeat (EGFr) domains 7-34 did not differ between Nint and Nps patients but Nint patients had less stroke events and were more likely to have migraine with aura. The number of lacunes and microbleeds and degree of brain atrophy were lower in the Nint group, but the volume of white matter hyperintensities did not differ between the two groups.

CONCLUSIONS

Nearly one in five CADASIL patients can remain Nint after the age of 65 years. Their clinical and imaging profile differed from that of other age-matched CADASIL patients. The location of NOTCH3 mutation inside or outside EGFr domains 1-6 cannot fully explain this discrepancy. The factors involved in their relative preservation of brain tissue from severe damage despite aging remain to be determined.

Reduced macular vessel density and inner retinal thickness correlate with the severity of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), caused by mutations in NOTCH3, is the most common cause of hereditary cerebral small vessel disease. Whether it will involve systemic vasculopathy such as retinal vessel remains unknown. Optical coherence tomography angiography (OCT-A) is a noninvasive technique for visualising retinal blood flow. We analysed vessel density and retinal thickness in patients with CADASIL and investigated their correlations with disease severity.

METHODS

This prospective study enrolled 35 patients with CADASIL (59 eyes) and 35 healthy controls (54 eyes). OCT-A was used to measure the vessel density of the macular region and the thickness of retinal layers. Patients with CADASIL were divided into stroke (n = 20) and nonstroke (n = 15) subgroups and underwent cognition and gait speed evaluation. Neuroimaging markers of cortical thickness, white matter hyperintensity, lacunae, and cerebral microbleeds were examined through brain magnetic resonance imaging.

RESULTS

The OCT-A parameters, including vessel density, were comparable between the patients with CADASIL and the controls. In patients with CADASIL, vessel density in the superficial retinal plexus in the macula as was inner retinal thickness was significantly lower in the stroke than the nonstroke subgroup. Macular vessel density and inner retinal thickness were positively correlated with gait speed, while negatively correlated with number of lacunae.

CONCLUSIONS

OCT-A is potentially a useful tool for evaluating disease severity, ischaemic burden, and neurodegeneration in patients with advanced CADASIL.

The Epidermal Growth Factor Domain of the Mutation Does Not Appear to Influence Disease Progression in CADASIL When Brain Volume and Sex Are Taken into Account

BACKGROUND AND PURPOSE

By studying the evolution of brain volume across the life span in male and female patients, we aimed to understand how sex, brain volume, and the epidermal growth factor repeat domain of the mutation, the 3 major determinants of disability in CADASIL, interact in driving disease evolution.

MATERIALS AND METHODS

We used validated methods to model the evolution of normalized brain volume with age in male and female patients using nonparametric regression in a large, monocentric cohort with prospectively collected clinical and high-resolution MR imaging data. We used k-means clustering to test for the presence of different clinical course profiles.

RESULTS

We included 229 patients (mean age, 53 [SD, 12] years; 130 women). Brain volume was larger in women (mean size, 1024 [SD, 62] cm³ versus 979 [SD, 50] cm³; P < .001) and decreased regularly. In men, the relationship between brain volume and age unexpectedly suggested an increase in brain volume around midlife. Cluster analyses showed that this finding was related to the presence of a group of older male patients with milder symptoms and larger brain volumes, similar to findings of age-matched women. This group did not show specific epidermal growth factor repeat domain distribution.

CONCLUSIONS

Our results demonstrate a detrimental effect of male sex on brain volume throughout life in CADASIL. We identified a subgroup of male patients whose brain volume and clinical outcomes were similar to those of age-matched women. They did not have a specific distribution of the epidermal growth factor repeat domain, suggesting that yet-unidentified predictors may interact with sex and brain volume in driving disease evolution.

Brain MRI in Monogenic Cerebral Small Vessel Diseases: A Practical Handbook

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Monogenic cerebral small vessel diseases are a topic of growing interest, as several genes responsible have been recently described and new sequencing techniques such as Next generation sequencing are available. Brain imaging is a key exam in these diseases. First, since it is often the first exam performed, an MRI is key in selecting patients for genetic testing and for interpreting Next generation sequencing reports. In addition, neuroimaging can be helpful in describing the underlying pathological mechanisms involved in cerebral small vessel disease. With this review, we aim to provide Neurologists and Stroke physicians with an up-to date overview of the current neuroimaging knowledge on monogenic small vessel diseases.

Cognitive impairment in patients with cerebrovascular disease: A white paper from the links between stroke ESO Dementia Committee

PURPOSE

Many daily-life clinical decisions in patients with cerebrovascular disease and cognitive impairment are complex. Evidence-based information sustaining these decisions is frequently lacking. The aim of this paper is to propose a practical clinical approach to cognitive impairments in patients with known cerebrovascular disease.

METHODS

The document was produced by the Dementia Committee of the European Stroke Organisation (ESO), based on evidence from the literature where available and on the clinical experience of the Committee members. This paper was endorsed by the ESO.

FINDINGS

Many patients with stroke or other cerebrovascular disease have cognitive impairment, but this is often not recognized. With improvement in acute stroke care, and with the ageing of populations, it is expected that more stroke survivors and more patients with cerebrovascular disease will need adequate management of cognitive impairment of vascular etiology. This document was conceived for the use of strokologists and for those clinicians involved in cerebrovascular disease, with specific and practical hints concerning diagnostic tools, cognitive impairment management and decision on some therapeutic options.Discussion and conclusions: It is essential to consider a possible cognitive deterioration in every patient who experiences a stroke. Neuropsychological evaluation should be adapted to the clinical status. Brain imaging is the most informative biomarker concerning prognosis. Treatment should always include adequate secondary prevention.

Apolipoprotein E ε4 Is Associated With the Development of Incident Dementia in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Patients With p.Arg544Cys Mutation

Background and Purpose

To identify clinical, laboratory, and magnetic resonance imaging (MRI) features in predicting incident stroke and dementia in Korean patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

Materials and Methods

We enrolled 87 Korean CADASIL patients who had undergone baseline clinical, laboratory, and MRI examinations between March 2012 and February 2015. The primary outcome of this study is the occurrence of stroke and dementia during the study period. The occurrence of incident stroke was confirmed by neuroimaging study, and dementia was defined by the diagnostic and statistical manual of mental disorders, fourth edition, criteria.

Results

Of the 87 patients, 57.5% were men, and the mean age was 63 ± 13 years (range 34–90 years), and 82 patients (94.3%) had p.Arg544Cys mutation. During an average follow-up of 67 months (interquartile range: 53–69 months), incident stroke occurred in 14 of 87 patients (16.1%) and incident dementia in 7 of 70 non-demented patients (10.0%). In adjusted analysis, increased systolic blood pressure was associated with increased risk of incident stroke [for every 10-mmHg increase; hazard ratio, 1.44 (1.02–2.03)]. Apolipoprotein E ε4 genotype was associated with an increased risk of incident dementia [hazard ratio, 10.70 (1.27–89.88)].

Conclusion

In this study, apolipoprotein E ε4 genotype was associated with the development of incident dementia, and higher blood pressure was associated with increased risk of incident stroke in CADASIL patients with predominant p.Arg544Cys mutation.

Modeling the Cognitive Trajectory in CADASIL

BACKGROUND

For developing future clinical trials in Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), it seems crucial to study the long-term changes of cognition.

OBJECTIVE

We aimed to study the global trajectory of cognition, measured by the Mini-Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (MDRS), along the course of CADASIL.

METHODS

Follow-up data of 185 CADASIL patients, investigated at the French National Referral center CERVCO from 2003, were considered for analysis based on strict inclusion criteria. Assuming that the MMSE and the MDRS provide imprecise measures of cognition, the trajectory of a common cognitive latent process during follow-up was delineated using a multivariate latent process mixed model. After adjustment of this model for sex and education, the sensitivities of the two scales to cognitive change were compared.

RESULTS

Analysis of the cognitive trajectory over a time frame of 60 years of age showed a decrease of performances with aging, especially after age of 50 years. This decline was not altered by sex or education but patients who graduated from high school had a higher mean cognitive level at baseline. The sensitivities of MMSE and MDRS scales were similar and the two scales suffered from a ceiling effect and curvilinearity.

CONCLUSION

These data support that cognitive decline is not linear and mainly occurs after the age of 50 years during the course of CADASIL. They also showed that MMSE and MDRS scales are hampered by major limitations for longitudinal studies.

Plasma neurofilament light chain and glial fibrillary acidic protein predict stroke in CADASIL

Background

Stroke remains the most cumbersome disease burden in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). This study aimed to investigate whether plasma biomarkers can reflect disease severity and predict stroke recurrence in CADASIL patients.

Methods

Sixty-three CADASIL patients (mean age 58.9 ± 9.3 years old, male 63%) from a multicenter registry and 17 controls were recruited. Plasma biomarkers, namely neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), tau, and ubiquitin carboxy-terminal hydrolase L1 (UCHL1), were measured using an ultra-sensitive single molecule array at baseline. Neuroimaging markers assessed included the Fazekas scale of white matter hyperintensity, numbers of lacunes, and cerebral microbleeds (CMBs). Cox proportional hazards regression models were applied to calculate the hazard ratio (HR) of plasma biomarkers at baseline for predicting incident stroke during follow-up.

Results

Plasma NfL, GFAP, and UCHL1 levels were significantly elevated in the CADASIL patients than in the controls. Among the CADASIL patients, both plasma NfL and GFAP levels positively correlated with the numbers of CMBs (r = 0.32 and r = 0.37, respectively; both p < 0.05). Higher plasma levels of NfL and GFAP were associated with any stroke (odds ratio 2.02, 95% confidence interval [CI] 1.06–3.87) and ICH (odds ratio 2.06, 95% CI 1.26–3.35) at baseline, respectively. Within a mean follow-up period of 3.1 ± 2.1 years, 10 patients (16%) had incident stroke and 6 of them were ICH. Higher baseline NfL (HR 1.93, 95% CI 1.19–3.13) predicted any incident stroke, whereas higher GFAP (HR 2.80, 95% CI 1.21–6.53) predicted incident ICH.

Conclusions

In CADASIL patients, plasma NfL can be a promising biomarker for monitoring incident stroke, whereas GFAP may have a role in cerebral hemorrhage.

Reduced resting-state brain functional network connectivity and poor regional homogeneity in patients with CADASIL

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) manifests principally as a suite of cognitive impairments, particularly in the executive domain. Executive functioning requires the dynamic coordination of neural activity over large-scale networks. It remains unclear whether changes in resting-state brain functional network connectivity and regional homogeneities (ReHos) underly the mechanisms of executive dysfunction evident in CADASIL patients.

METHODS

In this study, 22 CADASIL patients and 44 matched healthy controls underwent resting-state functional magnetic resonance imaging (fMRI). Independent component analysis (ICA) was used to measure functional brain network connectivity, and ReHos were calculated to evaluate local brain activities. We used seed-based functional connectivity (FC) analyses to determine whether dysfunctional areas (as defined by ReHos) exhibited abnormal FC with other brain areas. Relationships among the mean intra-network connectivity z-scores of dysfunctional areas within functional networks, and cognitive scores were evaluated using Pearson correlation analyses.

RESULTS

Compared to the controls, CADASIL patients exhibited decreased intra-network connectivity within the bilateral lingual gyrus (LG) and the right cuneus (CU) (thus within the visual network [VIN)], and within the right precuneus (Pcu), inferior frontal gyrus (IFG), and precentral gyrus (thus within the frontal network [FRN]). Compared to the controls, patients also exhibited significantly lower ReHos in the right precuneus and cuneus (Pcu/CU), visual association cortex, calcarine gyri, posterior cingulate, limbic lobe, and weaker FC between the right Pcu/CU and the bilateral parahippocampal gyrus (PHG), and between the right Pcu/CU and the right postcentral gyrus. Notably, the mean connectivity z-scores of the bilateral LG and the right CU within the VIN were positively associated with compromised attention, calculation and delayed recall as revealed by tests of the various cognitive domains explored by the Mini-Mental State Examination.

CONCLUSIONS

The decreases in intra-network connectivity within the VIN and FRN and reduced local brain activity in the posterior parietal area suggest that patients with CADASIL may exhibit dysfunctional visuomotor behaviors (a hallmark of executive function), and that all visual information processing, visuomotor planning, and movement execution may be affected.

Clinical and research applications of magnetic resonance imaging in the study of CADASIL

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is an inherited small vessel disease that leads to early cerebrovascular events and functional disability. It is the most common single-gene disorder leading to stroke. Magnetic resonance imaging (MRI) is a central component of the diagnosis and monitoring of CADASIL. Here we provide a descriptive review of the literature on three important aspects pertaining to the use of MRI in CADASIL. First, we review past research exploring MRI markers for this disease. Secondly, we describe results from studies investigating associations between neuroimaging abnormalities and neuropathology in CADASIL. Finally, we discuss previous findings relating MRI markers to clinical symptoms. This review thus provides a summary of the current state of knowledge regarding the use of MRI in CADASIL as well as suggestions for future research.

Serum Neurofilament light correlates with CADASIL disease severity and survival

Objective

To validate whether serum Neurofilament Light‐chain (NfL) levels correlate with disease severity in CADASIL, and to determine whether serum NfL predicts disease progression and survival.

Methods

Fourty‐one (pre‐) manifest individuals with CADASIL causing NOTCH3 mutations and 22 healthy controls were recruited from CADASIL families. At baseline, MRI‐lesion load and clinical severity was determined and serum was stored. Disease progression was measured in 30/41 patients at 7‐year follow‐up, and survival of all individuals was determined at 17‐year follow‐up. Serum NfL levels were quantified using an ultra‐sensitive molecule array. Generalized estimated equation regression (GEE) was used to analyze association between serum NfL, MRI‐lesion load, disease severity, and disease progression. With GEE‐based Cox regression, survival was analyzed.

Results

At baseline, serum NfL levels correlated with MRI‐lesion load [lacune count (s = 0.64, P = 0.002), brain atrophy (r = −0.50, P = 0.001), and microbleed count (s = 0.48, P = 0.044)], cognition [CAMCOG (s = −0.45, P = 0.010), MMSE (r = −0.61, P = 0.003), GIT (r = −0.61, P < 0.001), TMT‐A (r = 0.70, P < 0.001)) and disability (mRS (r = 0.70, P = 0.002)]. Baseline serum NfL predicted 7‐year changes in disability (B = 0.34, P < 0.001) and cognition (CAMCOG B = −4.94, P = 0.032), as well as 17‐year survival. Higher NfL levels were associated with increased mortality (HR=1.8 per twofold increase in NfL levels, P = 0.006).

Interpretation

Serum NfL levels correlate with disease severity, disease progression and 17‐year survival in CADASIL patients. Serum NfL is a promising biomarker to monitor and predict disease course in CADASIL, as well as potentially assessing therapeutic response in future clinical trials.

Why Are Only Some Subcortical Ischemic Lesions on Diffusion Magnetic Resonance Imaging Associated With Stroke Symptoms in Small Vessel Disease?

Background and Purpose- In cerebral small vessel diseases, small subcortical ischemic lesions (SSIL) on diffusion imaging are responsible for stroke manifestations but can also be occasionally observed in the absence of overt neurological symptoms. We aimed to determine, in a large cohort of young patients with CADASIL (Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy), a severe monogenic condition leading to SSIL in young patients, the characteristics of SSIL and of surrounding cerebral tissue associated with the presence of stroke symptoms. Methods- Among a cohort of 323 genetically confirmed CADASIL patients who were systematically evaluated every 18 months clinically and with magnetic resonance imaging, we studied all visible SSIL and documented ischemic stroke events with available magnetic resonance imaging data. We used mixed-effect logistic regression models to determine whether the presence of stroke symptoms was associated with age, sex, the volume of SSIL, their location with respect to preexisting white matter hyperintensities and with the load of the different magnetic resonance imaging markers of small vessel disease. Results- We identified 73 SSIL (30 with stroke symptoms and 43 without) in 55 patients. In multivariable models, stroke symptoms were more frequent in male patients (estimate=1.94; SE=0.82; P=0.03) and less frequent when SSIL appeared in contact to preexisting white matter hyperintensities (estimate=-2.12; SE=0.83; P=0.01). Within pyramidal tracts, stroke symptoms were more frequent in patients with extensive white matter hyperintensities (estimate=3.8×10^-5; SE=9.3×10^-6; P<10^-4). Conclusions- Altogether, our results suggest that when SSIL occur, the presence of stroke symptoms may depend on sex and alterations of the surrounding brain tissue rather than on the characteristics of the SSIL itself.

Different Types of White Matter Hyperintensities in CADASIL

Objective: In CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), white matter hyperintensities (WMH) are considered to result from hypoperfusion. We hypothesized that in fact the burden of WMH results from the combination of several regional populations of WMH with different mechanisms and clinical consequences.

Methods: To identify regional WMH populations, we used a 4-step approach. First, we used an unsupervised principal component algorithm to determine, without a priori knowledge, the main sources of variation of the global spatial pattern of WMH. Thereafter, to determine whether these sources are likely to include relevant information regarding regional populations of WMH, we tested their relationships with: (1) MRI markers of the disease; (2) the clinical severity assessed by the Mattis Dementia Rating scale (MDRS) (cognitive outcome) and the modified Rankin's score (disability outcome). Finally, through careful interpretation of all the results, we tried to identify different regional populations of WMH.

Results: The unsupervised principal component algorithm identified 3 main sources of variation of the global spatial pattern of WMH, which showed significant and sometime inverse relationships with MRI markers and clinical scores. The models predicting clinical severity based on these sources outperformed those evaluating WMH by their volume (MDRS, coefficient of determination of 39.0 vs. 35.3%, p = 0.01; modified Rankin's score, 43.7 vs. 38.1%, p = 0.001). By carefully interpreting the visual aspect of these sources as well as their relationships with MRI markers and clinical severity, we found strong arguments supporting the existence of different regional populations of WMH. For instance, in multivariate analyses, larger extents of WMH in anterior temporal poles and superior frontal gyri were associated with better outcomes, while larger extents of WMH in pyramidal tracts were associated with worse outcomes, which could not be explained if WMH in these different areas shared the same mechanisms.

Conclusion: The results of the present study support the hypothesis that the whole extent of WMH results from a combination of different regional populations of WMH, some of which are associated, for yet undetermined reasons, with milder forms of the disease.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) as a model of small vessel disease: update on clinical, diagnostic, and management aspects

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common and best known monogenic small vessel disease. Here, we review the clinical, neuroimaging, neuropathological, genetic, and therapeutic aspects based on the most relevant articles published between 1994 and 2016 and on the personal experience of the authors, all directly involved in CADASIL research and care. We conclude with some suggestions that may help in the clinical practice and management of these patients.

Predictors and Clinical Impact of Incident Lacunes in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Background and Purpose—

Previous studies in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy showed that accumulation of lacunes strongly relate to clinical severity. However, the potential predictors of incident lacunes and their clinical consequences over a short time frame have not been investigated. This study aimed to determine the predictors and clinical impact of such lesions in a large cohort of patients.

Methods—

Two hundred and six NOTCH3 mutation carriers (mean age, 49.5±10.6 years) were followed up over 3 years. Incident lacunes were identified using difference imaging from 3-dimensional T1 images. Clinical events and change in different clinical scores such as the Mattis Dementia Rating Scale, Modified Rankin Scale, Barthel index, and time to complete part A and part B of Trail Making Test were recorded. Associations were analyzed with multivariable logistic regression analysis and ANCOVA.

Results—

Over a mean period of 3.4±0.7 years, incident lacunes occurred in 51 of 206 patients. Both the number of lacunes ( P <0.0001) and systolic blood pressure at baseline ( P <0.01) were independent predictors of incident lacunes during follow-up. The results were still significant after excluding patients with systolic blood pressure >140 mm Hg. Incident lacunes were also associated with incident stroke and with change in time to complete Trail Making Test part B, initiation/perseveration subscale of the Mattis Dementia Rating Scale and Barthel Index over the study period.

Conclusions—

Systolic blood pressure and the number of prevalent lacunes are independent predictors of incident lacunes in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. These lesions mainly impact executive performances and functional independence over 3 years.