In acute ischemic stroke, whether FLAIR vascular hyperintensities represent good or poor collaterals remains controversial. We hypothesized that extensive FLAIR vascular hyperintensities correspond ...to good collaterals, as indirectly assessed by the hypoperfusion intensity ratio.
We included 244 consecutive patients eligible for reperfusion therapy with MCA stroke and pretreatment MR imaging with both FLAIR and PWI. The FLAIR vascular hyperintensity score was based on ASPECTS, ranging from 0 (no FLAIR vascular hyperintensity) to 7 (FLAIR vascular hyperintensities abutting all ASPECTS cortical areas). The hypoperfusion intensity ratio was defined as the ratio of the time-to-maximum >10-second over time-to-maximum >6-second lesion volumes. The median hypoperfusion intensity ratio was used to dichotomize good (low hypoperfusion intensity ratio) versus poor (high hypoperfusion intensity ratio) collaterals. We then studied the association between FLAIR vascular hyperintensity extent and hypoperfusion intensity ratio.
Hypoperfusion was present in all patients, with a median hypoperfusion intensity ratio of 0.35 (interquartile range, 0.19-0.48). The median FLAIR vascular hyperintensity score was 4 (interquartile range, 3-5). The FLAIR vascular hyperintensities were more extensive in patients with good collaterals (hypoperfusion intensity ratio ≤0.35) than with poor collaterals (hypoperfusion intensity ratio >0.35;
= .016). The FLAIR vascular hyperintensity score was independently associated with good collaterals (
= .002).
In patients eligible for reperfusion therapy, FLAIR vascular hyperintensity extent was associated with good collaterals, as assessed by the pretreatment hypoperfusion intensity ratio. The ASPECTS assessment of FLAIR vascular hyperintensities could be used to rapidly identify patients more likely to benefit from reperfusion therapy.
Stroke risk immediately after TIA defined by time-based criteria is high, and prognostic scores (ABCD2 and ABCD3-I) have been developed to assist management. The American Stroke Association has ...proposed changing the criteria for the distinction between TIA and stroke from time-based to tissue-based. Research using these definitions is lacking. In a multicenter observational cohort study, we have investigated prognosis and performance of the ABCD2 score in TIA, subcategorized as tissue-positive or tissue-negative on diffusion-weighted imaging (DWI) or CT imaging according to the newly proposed criteria.
Twelve centers provided data on ABCD2 scores, DWI or CT brain imaging, and follow-up in cohorts of patients with TIA diagnosed by time-based criteria. Stroke rates at 7 and 90 days were studied in relation to tissue-positive or tissue-negative subcategorization, according to the presence or absence of brain infarction. The predictive power of the ABCD2 score was determined using area under receiver operator characteristic curve (AUC) analyses.
A total of 4,574 patients were included. Among DWI patients (n = 3,206), recurrent stroke rates at 7 days were 7.1%(95% confidence interval 5.5-9.1) after tissue-positive and 0.4% (0.2-0.7) after tissue-negative events (p diff < 0.0001). Corresponding rates in CT-imaged patients were 12.8% (9.3-17.4) and 3.0% (2.0-4.2), respectively (p diff < 0.0001). The ABCD2 score had predictive value in tissue-positive and tissue-negative events (AUC = 0.68 95% confidence interval 0.63-0.73 and 0.73 0.67-0.80, respectively; p sig < 0.0001 for both results, p diff = 0.17). Tissue-positive events with low ABCD2 scores and tissue-negative events with high ABCD2 scores had similar stroke risks, especially after a 90-day follow-up.
Our findings support the concept of a tissue-based definition of TIA and stroke, at least on prognostic grounds.
In acute stroke with proximal artery occlusion, FLAIR vascular hyperintensities observed beyond the boundaries of the cortical lesion on DWI (newly defined "FLAIR vascular hyperintensity-DWI ...mismatch") may be a marker of tissue at risk of infarction. Our aim was to compare the occurrence of FLAIR vascular hyperintensity-DWI mismatch relative to that of perfusion-weighted imaging-DWI mismatch in patients with proximal MCA occlusion before IV thrombolysis.
In 141 consecutive patients with proximal MCA occlusion, 2 independent observers analyzed FLAIR images for the presence of FLAIR vascular hyperintensity-DWI mismatch before IV thrombolysis. PWI-DWI mismatch was defined as Volumehypoperfusion > 1.8 × VolumeDWI, with Volumehypoperfusion > 6 seconds on time to maximum value of the residue function maps in the 94 patients with available PWI. The presence of FLAIR vascular hyperintensity-DWI mismatch, PWI-DWI mismatch, and infarct growth on 24-hour follow-up DWI was compared.
A FLAIR vascular hyperintensity-DWI mismatch was present in 102/141 (72%) patients, with an excellent interobserver reliability (κ = 0.91), and a PWI-DWI mismatch, in 61 of the 94 (65%) patients with available PWI. FLAIR vascular hyperintensity-DWI mismatch predicted PWI-DWI mismatch with a sensitivity of 92% (95% CI, 85%-99%) and a specificity of 64% (95% CI, 47%-80%). Patients with FLAIR vascular hyperintensity-DWI mismatch had smaller initial DWI lesion and larger infarct growth (P < .001) than patients without FLAIR vascular hyperintensity-DWI mismatch, even though their final infarcts remained smaller (P < .001).
Albeit being moderately specific, probably due to inclusion of oligemic tissue, the FLAIR vascular hyperintensity-DWI mismatch identifies large PWI-DWI mismatch with high sensitivity.
Background
The effectiveness of carotid endarterectomy (CEA) for stroke prevention depends on low procedural risks. The aim of this study was to assess the frequency and timing of procedural ...complications after CEA, which may clarify underlying mechanisms and help inform safe discharge policies.
Methods
Individual‐patient data were obtained from four large carotid intervention trials (VACS, ACAS, ACST‐1 and GALA; 1983–2007). Patients undergoing CEA for asymptomatic carotid artery stenosis directly after randomization were used for the present analysis. Timing of procedural death and stroke was divided into intraoperative day 0, postoperative day 0, days 1–3 and days 4–30.
Results
Some 3694 patients were included in the analysis. A total of 103 patients (2·8 per cent) had serious procedural complications (18 fatal strokes, 68 non‐fatal strokes, 11 fatal myocardial infarctions and 6 deaths from other causes) Correction added on 20 April, after first online publication: the percentage value has been corrected to 2·8. Of the 86 strokes, 67 (78 per cent) were ipsilateral, 17 (20 per cent) were contralateral and two (2 per cent) were vertebrobasilar. Forty‐five strokes (52 per cent) were ischaemic, nine (10 per cent) haemorrhagic, and stroke subtype was not determined in 32 patients (37 per cent). Half of the strokes happened on the day of CEA. Of all serious complications recorded, 44 (42·7 per cent) occurred on day 0 (20 intraoperative, 17 postoperative, 7 with unclear timing), 23 (22·3 per cent) on days 1–3 and 36 (35·0 per cent) on days 4–30.
Conclusion
At least half of the procedural strokes in this study were ischaemic and ipsilateral to the treated artery. Half of all procedural complications occurred on the day of surgery, but one‐third after day 3 when many patients had been discharged.
Antecedentes
La efectividad de la endarterectomía carotídea (carotid endarterectomy, CEA) en la prevención de un accidente cerebrovascular depende de que este procedimiento tenga pocos riesgos. El objetivo de este estudio fue evaluar la frecuencia y el momento de aparición de las complicaciones tras una CEA, lo que podría clarificar los mecanismos subyacentes y ayudar a establecer una política de altas hospitalarias segura.
Métodos
Se utilizaron los datos de los pacientes incluidos en cuatro grandes ensayos de intervención carotídea (VACS, ACAS, ACST‐1 y GALA; 1983‐2007). Para el presente análisis se utilizaron los datos de pacientes sometidos a CEA por estenosis de la arteria carótida asintomática recogidos inmediatamente tras la aleatorización. Se consideraron diferentes intervalos entre el procedimiento, la muerte o el accidente cerebrovascular: intraoperatorio día 0, postoperatorio día 0, postoperatorio días 1‐3 y postoperatorio días 4‐30.
Resultados
En el análisis se incluyeron 3.694 pacientes. Se detectaron complicaciones graves relacionadas con el procedimiento en 103 (2,8%) pacientes (18 accidentes cerebrovasculares fatales, 68 accidentes cerebrovasculares no fatales, 11 infartos de miocardio fatales y 6 muertes por otras causas). De los 86 accidentes cerebrovasculares, 67 (78%) fueron ipsilaterales, 17 (20%) contralaterales y dos (2%) vertebrobasilares. Los accidentes cerebrovasculares fueron isquémicos en 45 (52%) casos, hemorrágicos en 9 (10%) y no se pudo determinar el subtipo de ictus en 32 (37%). La mitad de los accidentes cerebrovasculares ocurrieron el día de la CEA. De todas las complicaciones graves registradas, 44 (43%) ocurrieron en el día 0 (20 intraoperatorias, 17 postoperatorias y 7 en períodos poco definidos), 23 (22%) entre los días 1‐3 y 36 (35%) entre los días 4‐30.
Conclusión
En este estudio, al menos la mitad de los accidentes cerebrovasculares relacionados con la CEA fueron isquémicos e ipsilaterales respecto a la arteria tratada. La mitad de todas las complicaciones de la CEA ocurrieron el día de la cirugía, pero un tercio de los casos se presentaron después del día 3, cuando muchos pacientes ya habían sido dados de alta.
At least half of the procedural strokes in this study were ischaemic and ipsilateral to the treated artery. Half of all procedural complications occurred on the day of surgery, but one‐third after day 3 when many patients had been discharged. Reported in‐hospital stroke or death rates might underestimate true risks after carotid endarterectomy.
Half the strokes occurred after the day of surgery
According to the French regulation, stroke units (SU) include both an intensive (I-SU) and a non-intensive (NI-SU) component. Their standard operating procedures have been detailed in governmental ...directives in 2003 and 2007.
To evaluate (i) resources available in French SU, (ii) differences between regions, and between France and the 2 close European countries of similar size, and (iii) to identify avenues for improvement.
We performed a survey of all French SU, with an online questionnaire, to evaluate available resources and activity. We compared the 17 French regions, and France, with Germany and Italy. We used 2019 as year of reference.
The 138 French SU, shared 911 I-SU beds; 123 SU (89.1%) answered the questionnaire. The number of I-SU beds per million inhabitants was 13.6 for the whole country, with important differences between regions, ranging from 7.0 (Reunion Island) to 20.9 (Occitanie region). Per million inhabitants, France had fewer I-SU beds than Germany and Italy (13.5 vs. 29.9 and 23.2 respectively), and fewer thrombectomy centres (0.6 vs. 1.8 and 1.0). Per million inhabitants, France had also lower thrombolysis (203 vs. 402) and thrombectomy (104 vs. 194) rates than Germany, but, compared with Italy, similar thrombolysis rates (203 vs. 202) and higher thrombectomy rates (104 vs. 81).
There are still avenues for improvement in acute stroke care in France, especially concerning the number and regional repartition of I-SU beds, and access to reperfusion therapies.
In many organisms, the circadian clock is composed of functionally coupled morning and evening oscillators. In Arabidopsis, oscillator coupling relies on a core loop in which the evening oscillator ...component TIMING OF CAB EXPRESSION 1 (TOC1) was proposed to activate a subset of morning-expressed oscillator genes. Here, we show that TOC1 does not function as an activator but rather as a general repressor of oscillator gene expression. Repression occurs through TOC1 rhythmic association to the promoters of the oscillator genes. Hormone-dependent induction of TOC1 and analysis of RNA interference plants show that TOC1 prevents the activation of morning-expressed genes at night. Our study overturns the prevailing model of the Arabidopsis circadian clock, showing that the morning and evening oscillator loops are connected through the repressing activity of TOC1.
Background and purpose
The susceptibility vessel sign (SVS) on T2*‐weighted magnetic resonance imaging has been reported in several studies as a negative predictor of early recanalization after ...intravenous thrombolysis. The meaning of SVS regarding the results of mechanical thrombectomy with stent retrievers was investigated.
Methods
Susceptibility vessel sign presence and length were studied in 153 acute ischaemic stroke patients (82 men; mean ± SD age 59 ± 17 years, baseline National Institutes of Health Stroke Scale score 17.2 ± 6.5) from three stroke centres, treated with either mechanical thrombectomy alone (n = 84) or bridging therapy (n = 69). Variables were compared between recanalizers, defined as thrombolysis in cerebral infarction (TICI) scores ≥2b, and non‐recanalizers (TICI<2b).
Results
The SVS was present in 113 (73.8%) patients. There was no association between the presence of SVS and recanalization, obtained in 86 (56.2%) patients, in the whole population odds ratio (OR) 1.24, 95% confidence interval (CI) 0.53–2.92, P = 0.84) and in treatment subgroups (bridging: OR = 0.91, 95% CI 0.29–2.87, P = 1.0; thrombectomy alone: OR = 1.85, 95% CI 0.48–7.16, P = 0.54). However, in SVS+ patients, recanalization decreased with SVS length (OR 0.94 for each additional mm, 95% CI 0.89–0.99; P = 0.02).
Conclusions
The success of recanalization in acute stroke patients treated with stent retrievers was related to thrombus length but not to the presence of SVS.
Despite the advances in immunosuppression, renal allograft attrition over time remains unabated due to chronic allograft dysfunction (CAD) with interstitial fibrosis (IF) and tubular atrophy (TA). We ...aimed to evaluate microRNA (miRNA) signatures in CAD with IF/TA and appraise correlation with paired urine samples and potential utility in prospective evaluation of graft function. MiRNA signatures were established between CAD with IF/TA versus normal allografts by microarray. Validation of the microarray results and prospective evaluation of urine samples was performed using real‐time quantitative‐PCR (RT‐qPCR). Fifty‐six miRNAs were identified in samples with CAD‐IF/TA. Five miRNAs were selected for further validation based on array fold change, p‐value and in silico predicted mRNA targets. We confirmed the differential expression of these five miRNAs by RT‐qPCR using an independent set of samples. Differential expression was detected for miR‐142‐3p, miR‐204, miR‐107 and miR‐211 (p < 0.001) and miR‐32 (p < 0.05). Furthermore, differential expression of miR‐142‐3p (p < 0.01), miR‐204 (p < 0.01) and miR‐211 (p < 0.05) was also observed between patient groups in urine samples. A characteristic miRNA signature for IF/TA that correlates with paired urine samples was identified. These results support the potential use of miRNAs as noninvasive markers of IF/TA and for monitoring graft function.
The authors identify a characteristic microRNA signature for chronic allograft dysfunction with interstitial fibrosis and tubular atrophy that correlates with paired urine samples from kidney transplant recipients.
The optimal imaging method for the diagnosis of VAD remains undefined. Our aim was to evaluate the added value of HR-MR imaging for the diagnosis of VAD.
We retrospectively extracted 35 consecutive ...patients suspected of having acute VAD who had the following: 1) a focal lumen abnormality of the VA on CE-MRA, 2) HR-MR imaging during the initial hospital stay, and 3) clinical and imaging follow-up within 6 months. Two neurologists classified patients as either VAD (group A) or non-VAD (group B) by reviewing all the available data at hospital discharge, except HR-MR imaging data. On HR-MR imaging, 2 radiologists searched for signs of acute VAD. The 2 classifications were compared. In case of discordance, CE-MRA follow-up and axial fat-suppressed T1WI, used to obtain supportive evidence for or against VAD, were considered as the standard of reference.
In 4/18 patients in group A, HR-MR imaging did not demonstrate any signs of acute VAD and perivertebral signal-intensity changes were attributed to venous plexus, with an unchanged lumen on follow-up. In 4/17 patients in group B, HR-MRI demonstrated a mural hematoma, with lumen normalization on follow-up CE-MRA.
Our results encourage the use of HR-MR imaging as a second-line diagnostic tool in the event of suspicion of acute VAD and doubtful findings on standard imaging.
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