Systemic Blood Pressure Profile in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

The cysteine-altering p.R544C variant in the NOTCH3 gene is a probable candidate for blood pressure and relevant traits in the Taiwan Biobank

BACKGROUND

The cysteine-altering variants in NOTCH3 have been suggested to be associated with stroke, dementia, and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), where aberrant blood pressure levels represent the characteristics of these diseases. We aimed to assess whether the cysteine-altering p.Arg544Cys (p.R544C; rs201118034) variant and common single nucleotide variants (SNVs) in NOTCH3 could contribute to systolic and diastolic blood pressure and related phenotypes in the Taiwan Biobank.

METHODS

We employed a discovery sample of 68,925 individuals, an independent replication sample of 45,676 individuals, and a combined/total sample of 114,601 individuals; all from the Taiwan Biobank. Blood pressure, such as systolic and diastolic blood pressure, was measured for all participants. Association was evaluated using a general linear model, where results were considered statistically significant if the P value < 0.05 divided by the number of independent tests per model.

RESULTS

From our analysis, we identified and replicated three novel candidates for blood pressure that have not previously been reported: the cysteine-altering p.R544C variant for systolic blood pressure, the common SNV rs11669950 for diastolic blood pressure, and the common SNV rs4808235 for diastolic blood pressure. We also generalized two previously identified SNVs (i.e., rs10418305 and rs7408868) in NOTCH3 for blood pressure in European and non-Taiwanese East Asian populations to the Taiwanese population. Moreover, the participants with NOTCH3 p.R544C had an increased stroke frequency (P < 1.0 × 10-5) and a higher dementia frequency (P = 2.0 × 10-4) compared with the whole Taiwan Biobank population in the combined/total sample.

CONCLUSION

NOTCH3 is a strong candidate for a role in stroke, dementia, and CADASIL, which has previously been linked to blood pressure changes. While our preliminary study suggests that NOTCH3 p.R544C may influence blood pressure, stroke, and dementia in the Taiwan Biobank, replication in a well-powered external sample is required. This study also underlines considerable prospects of detecting novel genetic biomarkers in underrepresented worldwide populations.

Mutation screening and association analysis of NOTCH3 p.R544C in patients with migraine with or without aura

BACKGROUND

The role of the NOTCH3 p.R544C variant, the predominant variant of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy in multiple East Asian regions, in migraine is unknown.

METHODS

Migraine patients (n = 2,884) (2,279F/605M, mean age 38.8 ± 11.7 years), including 324 (11.2%) with migraine with aura, were prospectively enrolled by headache specialists according to the International Classification of Headache Disorders criteria. These patients and 3,502 population controls free of stroke, dementia, and headache were genotyped for NOTCH3 p.R544C by TaqMan genotyping assay or Axiom Genome-Wide TWB 2.0 Array. Clinical manifestations and brain magnetic resonance images were examined and compared between migraine patients with and without NOTCH3 p.R544C.

RESULTS

Thirty-two migraine patients (1.1%) and 36 controls (1.0%) harbored the p.R544C variant, and the percentages were comparable among migraine patients without and with aura, and controls (1.2%, vs. 0.6% vs. 1.0%, p = 0.625). Overall, migraine patients with and without the p.R544C variant had similar percentages of migraine with aura, headache characteristics, frequencies and disabilities. However, those with p.R544C were less likely to have pulsatile headaches (50.0% vs. 68.2%, p = 0.028), and more likely to have moderate to severe white matter hyperintensities in the external capsule (18.8% vs. 1.2%, p = 0.006) and anterior temporal lobe (12.5% vs. 0%, p = 0.008).

CONCLUSIONS

Our findings suggest that NOTCH3 p.R544C does not increase the risk of migraine with aura, or migraine as a whole, and generally does not alter clinical manifestations of migraine. The role of NOTCH3 variants, as well as potential influences from ethnicity or modifier genes, in migraine needs to be further clarified.

ER stress and Rho kinase activation underlie the vasculopathy of CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) leads to premature stroke and vascular dementia. Mechanism-specific therapies for this aggressive cerebral small vessel disease are lacking. CADASIL is caused by NOTCH3 mutations that influence vascular smooth muscle cell (VSMC) function through unknown processes. We investigated molecular mechanisms underlying the vasculopathy in CADASIL focusing on endoplasmic reticulum (ER) stress and RhoA/Rho kinase (ROCK). Peripheral small arteries and VSMCs were isolated from gluteal biopsies of CADASIL patients and mesentery of TgNotch3R169C mice (CADASIL model). CADASIL vessels exhibited impaired vasorelaxation, blunted vasoconstriction, and hypertrophic remodeling. Expression of NOTCH3 and ER stress target genes was amplified and ER stress response, Rho kinase activity, superoxide production, and cytoskeleton-associated protein phosphorylation were increased in CADASIL, processes associated with Nox5 upregulation. Aberrant vascular responses and signaling in CADASIL were ameliorated by inhibitors of Notch3 (γ-secretase inhibitor), Nox5 (mellitin), ER stress (4-phenylbutyric acid), and ROCK (fasudil). Observations in human CADASIL were recapitulated in TgNotch3R169C mice. These findings indicate that vascular dysfunction in CADASIL involves ER stress/ROCK interplay driven by Notch3-induced Nox5 activation and that NOTCH3 mutation-associated vascular pathology, typical in cerebral vessels, also manifests peripherally. We define Notch3-Nox5/ER stress/ROCK signaling as a putative mechanism-specific target and suggest that peripheral artery responses may be an accessible biomarker in CADASIL.

Blood Pressure Gradients in the Brain: Their Importance to Understanding Pathogenesis of Cerebral Small Vessel Disease

The term "lacunar infarction" referred to small infarctions in the basal ganglia, internal capsule, thalamus, and brainstem, due to hypertensive small vessel disease. However, it has become common to refer to all small infarctions as "vascular centrencephalon", where short straight arteries with few branches transmit high blood pressure straight through to end-arterioles. The cortex is supplied by long arteries with many branches, so there is a very large blood pressure gradient in the brain. When blood pressure in the brachial artery is 117/75 mmHg, the pressure in the lenticulostriate artery would be 113/73, and the pressure in small parietal arterioles would be only 59/38 mmHg. Recent studies have reported that patients with a pulse pressure >60 mmHg and diastolic pressure <60 mmHg have a doubling of coronary risk and a 5.85-fold increase in stroke risk. This means that new low systolic targets being proposed will probably decrease the incidence of true lacunes, but increase small subcortical infarctions in the hemispheres. The pathogenesis of small vessel disease should be interpreted in the light of these blood pressure gradients.

Vasoreactivity in CADASIL: Comparison to structural MRI and neuropsychology

Impaired cerebrovascular reactivity precedes histological and clinical evidence of CADASIL in animal models. We aimed to more fully characterise peripheral and cerebral vascular function and reactivity in a cohort of adult CADASIL patients, and explore the associations of these with conventional clinical, imaging and neuropsychological measures. A total of 22 adults with CADASIL gave informed consent to participate in an exploratory study of vascular function in CADASIL. Clinical assessment, comprehensive vascular assessment, MRI and neuropsychological testing were conducted. We measured cerebral vasoreactivity with transcranial Doppler and arterial spin labelling MRI with hypercapnia challenge. Number and volume of lacunes, subcortical hyperintensity volume, microbleeds and normalised brain volume were assessed on MRI. Analysis was exploratory and examined the associations between different markers. Cerebrovascular reactivity measured by ASL correlated with peripheral vasoreactivity measured by flow mediated dilatation. Subjects with ≥5 lacunes were older, with higher carotid intima-media thickness and had impaired cerebral and peripheral vasoreactivity. Subjects with depressive symptoms, disability or delayed processing speed also showed a trend to impaired vasoreactivity. Impaired vasoreactivity and vascular dysfunction may play a significant role in the pathophysiology of CADASIL, and vascular assessments may be useful biomarkers of severity in both longitudinal and clinical trials.

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.

CADASIL accelerated by acute hypotension: Arterial and venous contribution to leukoaraiosis

OBJECTIVE

To underline the importance of blood pressure regulation in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and to describe changes that occur in the veins in this condition, specifically venous collagenosis associated with leukoaraiosis.

METHODS

Case report with neuroimaging and pathologic data.

RESULTS

A 61-year-old man with genetically confirmed CADASIL was initially lucid following a motor vehicle accident but subsequently became hypotensive (60/40 mm Hg) due to an open femur fracture and required intubation. Multiple new white matter infarcts appeared on brain imaging. A second hypotensive episode days later was associated with new coin-sized infarcts in the bilateral corona radiata and cerebellar peduncles, and resulted in quadriplegia. No embolic source was found on cardiac or vascular imaging. He died 5 weeks post trauma. Autopsy revealed extensive subcortical and periventricular leukoencephalopathy and multiple cavitations involving deep subcortical gray and white matter. Small arteries had thickened walls, disruption of the muscularis, and intimal periodic acid-Schiff (PAS)-positive material. Both larger periventricular and small caliber veins had thickened walls that were PAS-negative and trichrome-positive, consistent with venous collagenosis. There was no pathologic evidence of global hypoxia or diffuse axonal injury.

CONCLUSIONS

The findings suggest rapid acceleration of CADASIL pathology from acute hypotension in the setting of impaired vasoreactivity. In addition, collagenosis of veins in the affected white matter regions suggests that the veins may play an important, though largely overlooked, role in maintaining white matter integrity.

Effects of sapropterin on endothelium-dependent vasodilation in patients with CADASIL: a randomized controlled trial

BACKGROUND AND PURPOSE

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a rare autosomal dominant disorder caused by NOTCH3 mutations, is characterized by vascular smooth muscle and endothelial cells abnormalities, altered vasoreactivity, and recurrent lacunar infarcts. Vasomotor function may represent a key factor for disease progression. Tetrahydrobiopterin, essential cofactor for nitric oxide synthesis in endothelial cells, ameliorates endothelial function. We assessed whether supplementation with sapropterin, a synthetic tetrahydrobiopterin analog, improves endothelium-dependent vasodilation in CADASIL patients.

METHODS

In a 24-month, multicenter randomized, double-blind, placebo-controlled trial, CADASIL patients aged 30 to 65 years were randomly assigned to receive placebo or sapropterin 200 to 400 mg BID. The primary end point was change in the reactive hyperemia index by peripheral arterial tonometry at 24 months. We also assessed the safety and tolerability of sapropterin. Analysis was done by intention-to-treat.

RESULTS

The intention-to-treat population included 61 patients. We found no significant difference between sapropterin (n=32) and placebo (n=29) in the primary end point (mean difference in reactive hyperemia index by peripheral arterial tonometry changes 0.19 [95% confidence interval, -0.18, 0.56]). Reactive hyperemia index by peripheral arterial tonometry increased after 24 months in 37% of patients on sapropterin and in 28% on placebo; however, after adjustment for age, sex, and clinical characteristics, improvement was not associated with treatment arm. The proportion of patients with adverse events was similar on sapropterin and on placebo (50% versus 48.3%); serious adverse events occurred in 6.3% versus 13.8%, respectively.

CONCLUSIONS

Sapropterin was safe and well-tolerated at the average dose of 5 mg/kg/day, but did not affect endothelium-dependent vasodilation in CADASIL patients.

CLINICAL TRIAL REGISTRATION URL

https://www.clinicaltrialsregister.eu. Unique identifier: 2007-004370-55.

Is the oxidant/antioxidant status altered in CADASIL patients?

The altered aggregation of proteins in non-native conformation is associated with endoplasmic reticulum derangements, mitochondrial dysfunction and excessive production of reactive oxygen species. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary systemic vasculopathy, caused by NOTCH3 mutations within the receptor extracellular domain, that lead to abnormal accumulation of the mutated protein in the vascular wall. NOTCH3 misfolding could cause free radicals increase also in CADASIL. Aim of the study was to verify whether CADASIL patients have increased oxidative stress compared to unrelated healthy controls. We enrolled 15 CADASIL patients and 16 gender- and age-matched healthy controls with comparable cardiovascular risk factor. Blood and plasma reduced and total aminothiols (homocysteine, cysteine, glutathione, cysteinylglycine) were measured by HPLC and plasma 3-nitrotyrosine by ELISA. Only plasma reduced cysteine (Pr-Cys) and blood reduced glutathione (Br-GSH) concentrations differed between groups: in CADASIL patients Br-GSH levels were higher (p = 0.019) and Pr-Cys lower (p = 0.010) than in controls. No correlation was found between Br-GSH and Pr-Cys either in CADASIL patients (rho 0.25, P = 0.36) or in controls (rho -0.15, P = 0.44). Conversely, 3-nitrotyrosine values were similar in CADASIL and healthy subjects (p = 0.82). The high levels of antioxidant molecules and low levels of oxidant mediators found in our CADASIL population might either be expression of an effective protective action against free radical formation at an early stage of clinical symptoms or they could suggest that oxidative stress is not directly involved in the pathogenesis of CADASIL.

Acute watershed infarcts with global cerebral hypoperfusion in symptomatic CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common form of hereditary cerebral angiopathy. We present a case in which a pattern of diffusion signal change compatible with bihemispheric acute watershed infarcts occurred in a symptomatic patient demonstrating global hypoperfusion. To our knowledge, watershed infarcts in the clinical presentation of CADASIL have not been previously described.

CADASIL and migraine: A narrative review

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in the NOTCH3 gene and is clinically characterized by recurrent stroke, cognitive decline, psychiatric disturbances and migraine. The prevalence of migraine in CADASIL is slightly higher than in the general population, and the proportion of migraine with aura is much higher. The pathophysiological mechanism that leads to increased aura prevalence in CADASIL is unknown. Possible mechanisms of the excess of migraine with aura are an increased susceptibility to cortical spreading depression (CSD) or a different expression of CSD. It is also possible that the brainstem migraine area is involved in CADASIL. Last, it is possible that the NOTCH3 mutation acts as a migraine aura susceptibility gene by itself.

In this narrative review we summarize the literature about migraine in CADASIL, with a special focus on what CADASIL might teach us about the pathophysiology of migraine.

CADASIL: pathogenesis, clinical and radiological findings and treatment

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common genetic cause of ischemic strokes and a most important model for the study of subcortical vascular dementia. This unrelentlessly progressive disease affects many hundreds of families all over the world but is not well studied in Brazil. This manuscript reviews pathogenetic, clinical, radiological and therapeutic features of CADASIL. The causal mutations are now very well known, but the same can not be said about its intimate pathogenetic mechanisms. The variable clinical presentation should lead physicians to actively pursue the diagnosis in many settings and to more thouroughly investigate family history in first degree relatives. A rational approach to genetic testing is however needed. Treatment of CADASIL is still largely empiric. High-quality therapeutic studies involving medications and cognitive interventions are strongly needed in CADASIL.

Twenty-four hour blood pressure pattern in patients with normal tension glaucoma in the habitual position

PURPOSE

To investigate the relationship between blood pressure (BP) parameters in the habitual position and glaucomatous damage at initial presentation in patients with untreated normal tension glaucoma (NTG).

METHODS

Fifty-four eyes from 54 subjects diagnosed with NTG were consecutively enrolled. BP was measured with an automated ambulatory monitoring device in the habitual position during 24-hour in-hospitalization. Patients were classified into three groups: non-dippers, dippers, and over-dippers. corresponded to the degree of reduction in their nocturnal mean arterial pressure (MAP) compared with their diurnal MAP. Regression models were used to evaluate potential risk factors, including: age, pre-admission office intraocular pressure (IOP), central corneal thickness (CCT), and BP parameters. Functional outcome variables for glaucomatous damage included mean deviation (MD) and pattern standard deviation (PSD) on a Humphrey field analyzer (HFA). Anatomic outcome variables were TSNIT score (temporal, superior, nasal, inferior, and temporal) average, superior average, inferior average, and nerve fiber indicator (NFI) score on scanning laser polarimetry with variable corneal compensation (SLP-VCC; GDx-VCC).

RESULTS

Marked systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP fluctuation were noted in the over-dipper group (p<0.05). A linear regression analysis model revealed that nocturnal trough DBP and MAP, average nocturnal SBP, and MAP were all significantly associated with a decreased average TSNIT score and an increased NFI score.

CONCLUSIONS

Nocturnal BP reduction estimated in the habitual position was associated with structural damage in eyes with NTG. This finding may suggest systemic vascular etiology of NTG development associated with nocturnal BP reduction.

Cerebrovascular reactivity is a main determinant of white matter hyperintensity progression in CADASIL

BACKGROUND AND PURPOSE

Basal total cerebral blood flow (TCBF) and cerebrovascular reactivity (CVR) are assumed to play an important role in the pathophysiology of small-vessel disease. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a unique monogenetic model to study the pathophysiology of arterial small-vessel disease. The aim of this study was to investigate the role of TCBF and CVR in the progression of MR imaging abnormalities in CADASIL.

MATERIALS AND METHODS

Basal TCBF was measured in 25 NOTCH3 mutation carriers and 13 control subjects at baseline. CVR after administration of acetazolamide was measured in 14 NOTCH3 mutation carriers and 9 control subjects. Increase in white matter hyperintensities (WMHs), lacunar infarcts, and microbleeds on MR imaging was measured 7 years later.

RESULTS

Lower CVR at baseline was associated with larger increase of WMHs (P = .001) but not with a larger increase of lacunar infarcts or microbleeds. TCBF at baseline was not associated with an increase of MR imaging abnormalities.

CONCLUSIONS

Decreased CVR is a potential predictor of disease progression as indicated by increasing WMHs in CADASIL.

Genetics of ischaemic stroke; single gene disorders

Examples of single gene disorders have been described for all major subtypes of ischaemic stroke: accelerated atherosclerosis and subsequent thrombo-embolism (e.g. homocysteinuria), weakening of connective tissue resulting in arterial dissections (e.g. Ehler-Danlos type IV), disorders of cerebral small vessels (e.g. cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and the collagen COL4A1 mutation), disorders increasing the thrombogenic potential of the heart through affecting the myocardium or the heart valves or through disturbance of the heart rhythm (e.g. hypertrophic cardiomyopathy), mitochondrial cytopathies increasing cerebral tissue susceptibility to insults (e.g. mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes), and finally disorders of coagulation that can either directly cause stroke or act synergistically with the aforementioned abnormalities (e.g. sickle cell disease). Most of these disorders are rare but they are important to consider particularly in young patients with stroke, those with a family history or those who have other characteristics of a particular syndrome.

CSF levels of beta-amyloid 1-42, tau and phosphorylated tau protein in CADASIL

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be considered a useful model of pure subcortical vascular dementia (SVD) because it occurs in young adults, unlikely to have concomitant age- and Alzheimer's disease (AD)-related pathology. In patients with CADASIL we evaluated the cerebrospinal fluid (CSF) levels of beta-amyloid 1-42 (Abeta42), total tau protein (t-tau) and phosphorylated tau protein (p-tau), which are well-accepted biomarkers of AD.

METHODS

The CSF Abeta42, t-tau and p-tau levels were determined with Innotest beta-amyloid 1-42, Innotest hTAU-Ag and Innotest Phospho-tau 181p sandwich enzyme-linked immunoassay, in 10 CADASIL patients and 17 healthy age-matched subjects. A case-control statistical analysis was carried out.

RESULTS

CSF Abeta42 levels were significantly lower in CADASIL patients than in controls, whereas CSF t-tau and p-tau levels did not differ between the two groups.

CONCLUSIONS

The pattern found in CADASIL patients is similar to that reported in those with sporadic SVD, suggesting that decreased CSF Abeta42 might be related to the subcortical vascular lesions in the white matter.

Increased QT variability in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

BACKGROUND AND PURPOSE

Although sudden death (SD) accounts for numerous cases of premature mortality in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the risk factors responsible for this dramatic event remain unclear. We sought possible differences in the QT variability index (QTVI) -- a well-known index of temporal dispersion in myocardial repolarization strongly associated with the risk of SD -- between a group of patients with CADASIL and healthy controls.

METHODS

A total of 13 patients with CADASIL and 13 healthy volunteers underwent a 5-min electrocardiogram recording to calculate the QTVI. All the patients also underwent a clinical assessment, including functional status by Rankin score, and a magnetic resonance imaging (MRI) brain scan for quantitative analysis of T2-weighted (T2-W) and T1-weighted (T1-W) lesion volume (LV).

RESULTS

Short-term QT-interval analysis showed significantly higher QTVI (P = 0.029) in patients than in controls. In patients, notwithstanding the limitations of the small sample size, QTVI also well correlated with T1-W LV (r = 0.747, P = 0.003) and T2-W LV (r = 0.731, P = 0.005).

CONCLUSION

Because patients with CADASIL have increased temporal cardiac repolarization variability as assessed by QTVI, this mechanism could underlie these patients' risk of SD. Whether this easily assessed, non-invasive marker could be used to stratify the risk of malignant ventricular arrhythmias in patients with CADASIL and, possibly, to guide their therapeutic management warrants confirmation from larger prospective studies.

Impaired Endothelial Function of Forearm Resistance Arteries in CADASIL Patients

Background and Purpose— Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary arteriopathy, which mainly involves the brain causing stroke and dementia. Mice expressing the mutated protein display early dysfunction in vasoreactivity in resistance arteries, but studies of patients have been inconclusive so far.

Methods— We examined peripheral endothelium-dependent vasodilatation in 10 CADASIL-patients and 20 controls using 3 methods: venous occlusion plethysmography of forearm blood flow with intraarterial acetylcholine and sodium nitroprusside infusions for evaluation of resistance arteries, ultrasound with flow mediated vasodilatation (FMD) of the brachial artery for evaluation of a conduit artery, and the pulse wave method with measurements before and after terbutaline for evaluation of systemic endothelium-dependent vasodilation.

Results— The CADASIL patients displayed reductions in both basal ( P =0.034) and stimulated blood flow ( P =0.023 for the highest dose of acetylcholine) and an impaired endothelium-dependent vasodilation when investigated in forearm resistance arteries ( P =0.019). The FMD and the pulse wave method did not show any reduction in endothelium-dependent vasodilation in the patients.

Conclusions— Endothelium-dependent vasodilation was impaired in resistance arteries, but not in a conduit artery, in the forearm of CADASIL patients.

Cardiac autonomic nervous system and risk of arrhythmias in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited systemic microangiopathy with prevalently cerebral manifestations. Among the causes of death, sudden unexpected death seems to occur in a significant number of CADASIL patients. Because potential causes of sudden unexpected death may include cardiac arrhythmias and myocardial infarction, we evaluated risk factors for life-threatening arrhythmias, such as reduced heart rate variability, sympathetic overactivity and QT interval (QTc) prolongation, in 23 CADASIL patients. The relationship of these changes with brain MRI pattern was also investigated.

METHODS

Frequency domain measures of heart rate variability (10 minutes recordings) and QTc interval were recorded in 23 CADASIL patients (17 males, 6 females) and 22 healthy age- and sex-matched control subjects. The following heart rate variability spectral parameters were considered at rest during spontaneous and controlled breathing (Cb): total power, very-low-frequency component, low-frequency component, high-frequency component, low-frequency/high-frequency ratio, and Cb-total power, Cb-very-low-frequency component, Cb-low-frequency component, Cb-high-frequency component, Cb-low-frequency/high-frequency ratio. R-to-R wave and QTc interval were also analyzed. All data were statistically compared between CADASIL and control subjects. Conventional brain MRI was performed in patients with CADASIL and T1-weighted and T2-weighted lesion volumes, and were compared with each spectral component of the tachogram.

RESULTS

During spontaneous and controlled breathing, total power spectrum and all spectral components (very low frequency component, high-frequency component, low-frequency component) of heart rate variability were significantly reduced in CADASIL patients with respect to controls (P<0.05). The low-frequency/high-frequency component ratio was significantly higher in CADASIL patients than in controls. No significant correlation between heart rate variability spectral parameters and other variables including total brain T2-weighted and T1-weighted lesion volumes were observed in CADASIL subjects.

CONCLUSIONS

We found a statistically significant reduction in all frequency domain parameters of heart rate variability associated with a higher low frequency/high frequency ratio for CADASIL patients with respect to normal subjects. These data are consistent with autonomic derangement and suggests that CADASIL patients may be at risk for life-threatening arrhythmias. This could at least in part explain their higher recurrence of sudden unexpected death and should be taken into account in planning therapy.