Microstructural white matter integrity in relation to vascular reactivity in Dutch-type hereditary cerebral amyloid angiopathy

One-Year Radiologic Progression in Sporadic and Hereditary Cerebral Amyloid Angiopathy

BACKGROUND AND OBJECTIVES

Knowledge on the short-term progression of cerebral amyloid angiopathy (CAA) is important for clinical practice and the design of clinical treatment trials. We investigated the 1-year progression of CAA-related MRI markers in sporadic (sCAA) and Dutch-type hereditary (D-CAA).

METHODS

Participants were included from 2 prospective cohort studies. 3T-MRI was performed at baseline and after 1 year. We assessed macrobleeds, cerebral microbleeds (CMBs), cortical superficial siderosis (cSS), convexity subarachnoid hemorrhages (cSAHs), white matter hyperintensities (WMH), enlarged centrum semiovale perivascular spaces (CSO-EPVS), and visually stimulated blood oxygenation level-dependent (BOLD) fMRI parameters. Progression was defined as increase in number of macrobleeds or CMBs, new focus or extension of cSS, increase in CSO-EPVS category, or volume increase of >10% of WMH. Multivariable regression analyses were performed to determine factors associated with progression and the association between events related to parenchymal injury (cSAH, macrobleeds) and radiologic progression.

RESULTS

We included 98 participants (47% women): 55 with sCAA (mean age 70 years), 28 with symptomatic D-CAA (mean age 59 years), and 15 with presymptomatic D-CAA (mean age 45 years). Progression of >1 MRI markers was seen in all 83 (100%) participants with sCAA and symptomatic D-CAA and in 9 (60%) with presymptomatic D-CAA. The number of CMBs showed the largest progression in sCAA (98%; median increase 24) and symptomatic D-CAA (100%; median increase 58). WMH volume (>10% increase in 70%; mean increase 1.2 mL) was most progressive in presymptomatic D-CAA. A decrease in the upslope of the visually evoked BOLD response was observed for most patients. Symptomatic D-CAA status was associated with more overall progression (adjusted odds ratio [aOR] 9.7; 95% CI 1.7-54.2), CMB (adjusted relative risk [aRR] 2.47; 95% CI 1.5-4.1), and WMH volume progression (β 2.52; 95% CI 0.3-4.8). Baseline CMB count (aRR 1.002; 95% CI 1.001-1.002) was associated with CMB progression and cSS presence at baseline (aOR 8.16; 95% CI 2.6-25.4) with cSS progression. cSS progression was also associated with cSAH and macrobleeds (aOR 21,029; 95% CI 2.042-216.537).

DISCUSSION

CAA is a radiologically progressive disease even in the short-term. After 1 year, all symptomatic and most of the presymptomatic participants showed progression of at least 1 MRI-marker. CMBs and WMH volume (in symptomatic CAA) and WMH volume (in presymptomatic CAA) are the most promising markers to track short-term progression in future trials.

Cerebral Amyloid Angiopathy: Clinical Presentation, Sequelae and Neuroimaging Features-An Update

The prevalence of cerebral amyloid angiopathy (CAA) has been shown to increase with age, with rates reported to be around 50-60% in individuals over 80 years old who have cognitive impairment. The disease often presents as spontaneous lobar intracerebral hemorrhage (ICH), which carries a high risk of recurrence, along with transient focal neurologic episodes (TFNE) and progressive cognitive decline, potentially leading to Alzheimer's disease (AD). In addition to ICH, neuroradiologic findings of CAA include cortical and subcortical microbleeds (MB), cortical subarachnoid hemorrhage (cSAH) and cortical superficial siderosis (cSS). Non-hemorrhagic pathologies include dilated perivascular spaces in the centrum semiovale and multiple hyperintense lesions on T2-weighted magnetic resonance imaging (MRI). A definitive diagnosis of CAA still requires histological confirmation. The Boston criteria allow for the diagnosis of a probable or possible CAA by considering specific neurological and MRI findings. The recent version, 2.0, which includes additional non-hemorrhagic MRI findings, increases sensitivity while maintaining the same specificity. The characteristic MRI findings of autoantibody-related CAA-related inflammation (CAA-ri) are similar to the so-called "amyloid related imaging abnormalities" (ARIA) observed with amyloid antibody therapies, presenting in two variants: (a) vasogenic edema and leptomeningeal effusions (ARIA-E) and (b) hemorrhagic lesions (ARIA-H). Clinical and MRI findings enable the diagnosis of a probable or possible CAA-ri, with biopsy remaining the gold standard for confirmation. In contrast to spontaneous CAA-ri, only about 20% of patients treated with monoclonal antibodies who show proven ARIA on MRI also experience clinical symptoms, including headache, confusion, other psychopathological abnormalities, visual disturbances, nausea and vomiting. Recent findings indicate that treatment should be continued in cases of mild ARIA, with ongoing MRI and clinical monitoring. This review offers a concise update on CAA and its associated consequences.

Temporal Ordering of Biomarkers in Dutch-Type Hereditary Cerebral Amyloid Angiopathy

BACKGROUND

The temporal ordering of biomarkers for cerebral amyloid angiopathy (CAA) is important for their use in trials and for the understanding of the pathological cascade of CAA. We investigated the presence and abnormality of the most common biomarkers in the largest (pre)symptomatic Dutch-type hereditary CAA (D-CAA) cohort to date.

METHODS

We included cross-sectional data from participants with (pre)symptomatic D-CAA and controls without CAA. We investigated CAA-related cerebral small vessel disease markers on 3T-MRI, cerebrovascular reactivity with functional 7T-MRI (fMRI) and amyloid-β40 and amyloid-β42 levels in cerebrospinal fluid. We calculated frequencies and plotted biomarker abnormality according to age to form scatterplots.

RESULTS

We included 68 participants with D-CAA (59% presymptomatic, mean age, 50 [range, 26-75] years; 53% women), 53 controls (mean age, 51 years; 42% women) for cerebrospinal fluid analysis and 36 controls (mean age, 53 years; 100% women) for fMRI analysis. Decreased cerebrospinal fluid amyloid-β40 and amyloid-β42 levels were the earliest biomarkers present: all D-CAA participants had lower levels of amyloid-β40 and amyloid-β42 compared with controls (youngest participant 30 years). Markers of nonhemorrhagic injury (>20 enlarged perivascular spaces in the centrum semiovale and white matter hyperintensities Fazekas score, ≥2, present in 83% [n=54]) and markers of impaired cerebrovascular reactivity (abnormal BOLD amplitude, time to peak and time to baseline, present in 56% [n=38]) were present from the age of 30 years. Finally, markers of hemorrhagic injury were present in 64% (n=41) and only appeared after the age of 41 years (first microbleeds and macrobleeds followed by cortical superficial siderosis).

CONCLUSIONS

Our results suggest that amyloid biomarkers in cerebrospinal fluid are the first to become abnormal in CAA, followed by MRI biomarkers for cerebrovascular reactivity and nonhemorrhagic injury and lastly hemorrhagic injury. This temporal ordering probably reflects the pathological stages of CAA and should be taken into account when future therapeutic trials targeting specific stages are designed.