Epidemiology of transient ischemic attack in the normandy stroke population-based study

INTRODUCTION

Transient ischemic attack (TIA) is a frequent neurological emergency which management and definition have changed radically over the last 15 years. However, recent epidemiological studies of TIA are scarce. We report here on the impact of the shift from a time-based to a tissue-based definition of TIA on its incidence and risk of recurrence in a new population-based cohort with a high rate of patients investigated by MRI.

MATERIALS AND METHODS

We prospectively included all TIAs that occurred between May 2017 and May 2021 from the Normandy Stroke Study, a population-based registry using multiple overlapping sources for exhaustive case identification in Caen la Mer area. TIAs were classified as either time-based (symptoms <24 h) or tissue-based (<24 h and no lesion on brain imaging). Attack and incidence rates were calculated, as was the 90-day ischemic stroke rate.

RESULTS

Five hundred and sixty-seven TIAs (549 single patients) were included, with 80.6% having a brain MRI. Four hundred and ten (72.3%) met the definition of tissue-based TIA. The age standardized attack (to the 2013 European population) rate was 39.5 (95% CI 35.7-43.5) and the age-standardized incidence rate (first ever cerebrovascular event) was 29.7 (95% CI 27.3-34.2). The overall recurrent stroke rate at 90 days was 2.7%, with no difference between patients with or without ischemic lesions on MRI.

CONCLUSION

We found that the use of the tissue-based definition of TIA resulted in a 27.5% reduction in incidence as compared to the time-based definition, but had no impact on the 90-day stroke rate. The burden of TIA remains high, and is likely to increase as the population ages.

Incidence and outcomes of acute cerebrovascular events: methodology of the population-based Normandy Stroke Study

BACKGROUND

The number of strokes has been steadily increasing due to the ageing of the population and its management has changed dramatically in recent years. Nevertheless, there are few unbiased epidemiological studies to investigate the incidence of strokes and their long-term prognosis.

METHODS

The Normandy Stroke Study (NSS) is a prospective population-based study of all strokes and transient ischemic attacks in a large urban, suburban, and rural area in the Northwest of France. It is designed to meet the current gold standard in stroke epidemiological study by using multiple overlapping sources for case identification. It also aims to assess the impact of socio-economic disparities and long-term prognosis of stroke through an additional follow-up up to three years after the event to better understand the functional and cognitive prognostic of stroke as well as the quality of life in patients after stroke.

CONCLUSION

NSS will provide important data on epidemiology and long-term consequences of stroke at the population level and will help care providers to adapt resource allocation.

Heterozygous HTRA1 nonsense or frameshift mutations are pathogenic

Heterozygous missense HTRA1 mutations have been associated with an autosomal dominant cerebral small vessel disease (CSVD) whereas the pathogenicity of heterozygous HTRA1 stop codon variants is unclear. We performed a targeted high throughput sequencing of all known CSVD genes, including HTRA1, in 3853 unrelated consecutive CSVD patients referred for molecular diagnosis. The frequency of heterozygous HTRA1 mutations leading to a premature stop codon in this patient cohort was compared with their frequency in large control databases. An analysis of HTRA1 mRNA was performed in several stop codon carrier patients. Clinical and neuroimaging features were characterized in all probands. Twenty unrelated patients carrying a heterozygous HTRA1 variant leading to a premature stop codon were identified. A highly significant difference was observed when comparing our patient cohort with control databases: gnomAD v3.1.1 [P = 3.12 × 10-17, odds ratio (OR) = 21.9], TOPMed freeze 5 (P = 7.6 × 10-18, OR = 27.1) and 1000 Genomes (P = 1.5 × 10-5). Messenger RNA analysis performed in eight patients showed a degradation of the mutated allele strongly suggesting a haploinsufficiency. Clinical and neuroimaging features are similar to those previously reported in heterozygous missense mutation carriers, except for penetrance, which seems lower. Altogether, our findings strongly suggest that heterozygous HTRA1 stop codons are pathogenic through a haploinsufficiency mechanism. Future work will help to estimate their penetrance, an important information for genetic counselling.

Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy: international individual patient data pooled analysis

Objective

To investigate the frequency, time-course and predictors of intracerebral haemorrhage (ICH), recurrent convexity subarachnoid haemorrhage (cSAH), and ischemic stroke after cSAH associated with cerebral amyloid angiopathy (CAA).

Methods

We performed a systematic review and international individual patient-data pooled analysis in patients with cSAH associated with probable or possible CAA diagnosed on baseline MRI using the modified Boston criteria. We used Cox proportional hazards models with a frailty term to account for between-cohort differences.

Results

We included 190 patients (mean age 74.5 years; 45.3% female) from 13 centers with 385 patient-years of follow-up (median 1.4 years). The risks of each outcome (per patient-year) were: ICH 13.2% (95% CI 9.9–17.4); recurrent cSAH 11.1% (95% CI 7.9–15.2); combined ICH, cSAH, or both 21.4% (95% CI 16.7–26.9), ischemic stroke 5.1% (95% CI 3.1–8) and death 8.3% (95% CI 5.6–11.8). In multivariable models, there is evidence that patients with probable CAA (compared to possible CAA) had a higher risk of ICH (HR 8.45, 95% CI 1.13–75.5, p = 0.02) and cSAH (HR 3.66, 95% CI 0.84–15.9, p = 0.08) but not ischemic stroke (HR 0.56, 95% CI 0.17–1.82, p = 0.33) or mortality (HR 0.54, 95% CI 0.16–1.78, p = 0.31).

Conclusions

Patients with cSAH associated with probable or possible CAA have high risk of future ICH and recurrent cSAH. Convexity SAH associated with probable (vs possible) CAA is associated with increased risk of ICH, and cSAH but not ischemic stroke. Our data provide precise risk estimates for key vascular events after cSAH associated with CAA which can inform management decisions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10706-3.

Diffusion-Weighted Imaging Hyperintensities in Subtypes of Acute Intracerebral Hemorrhage: Meta-Analysis

Background and Purpose- Diffusion-weighted imaging (DWI) hyperintensities in intracerebral hemorrhage (ICH) are associated with increased risk of recurrent ICH, cognitive impairment, and death, but whether these lesions are specific to a subtype of ICH remains uncertain. We investigated the association between DWI lesions and ICH subtype and explored the risk factors for DWI lesions. Methods- In a systematic review of ICH studies, we identified those reporting prevalence of DWI lesions. Two reviewers independently assessed study eligibility and risk of bias and collected data. We determined the pooled prevalence of DWI lesions within 90 days after ICH onset for cerebral amyloid angiopathy- and hypertensive angiopathy-related ICH using random-effects meta-analysis. We calculated odds ratios to compare prevalence of DWI lesions by ICH subtype and to assess risk factors for DWI lesions. Results- Eleven studies (1910 patients) were included. The pooled prevalence of DWI lesions was 18.9% (95% CI, 11.1-26.7) in cerebral amyloid angiopathy- and 21.0% (95% CI, 15.3-26.6) in hypertensive angiopathy-related ICH. There was no difference in the prevalence of DWI lesions between cerebral amyloid angiopathy- (64/292 [21.9%]) and hypertensive angiopathy-related ICH (79/370 [21.4%]; odds ratio, 1.25; 95% CI, 0.73-2.15) in the 5 studies reporting data on both ICH pathogeneses. In all ICH, presence of DWI lesions was associated with neuroimaging features of microangiopathy (leukoaraiosis extension, previous ICH, and presence, and number of microbleeds) but not with vascular risk factors or the use of antithrombotic therapies. Conclusions- Prevalence of DWI lesions in acute ICH averages 20%, with no difference between cerebral amyloid angiopathy- and hypertensive angiopathy-related ICH. Detection of DWI lesions may add valuable information to assess the progression of the underlying microangiopathy.