Collateral circulation in acute stroke: assessing methods and impact: a literature review.

Collateral circulation plays an important role in the clinical and radiological outcome after acute ischemic stroke. Several modalities are used to evaluate these alternative pathways with a growing interest in recent years. We conducted a literature review of studies evaluating collaterals at the acute phase of a carotid territory ischemic stroke. Most of them were based on conventional angiography and CT angiography, several on the basis of MRI and transcranial Doppler and, more recently, on the basis of dynamic CT angiography, which seems to be the most appropriate modality. Populations studied in these publications are often heterogeneous (especially concerning the occlusion site and the treatments performed) and many classifications have been proposed.

MRI Outcomes Achieved by Simple Flow Blockage Technique in Symptomatic Carotid Artery Stenosis Stenting.

In this study, we aimed to determine the frequency and clinical impact of new ischemic lesions detected with diffusion-weighted-imaging-MRI (DWI-MRI) as well as the clinical outcomes after carotid artery stenting (CAS) using the simple flow blockage technique (SFB). This is a retrospective study with data extraction from a monocentric prospective clinical registry (from 2017 to 2019) of consecutive patients admitted for symptomatic cervical ICA stenosis or web. Herein, patients benefited from DWI-MRI before and within 48 h of CAS for symptomatic ICA stenosis or web. The primary endpoint was the frequency of new DWI-MRI ischemic lesions and the secondary (composite) endpoint was the rate of mortality, symptomatic stroke or acute coronary syndrome within 30 days of the procedure. All of the 82 CAS procedures were successfully performed. Among the 33 patients (40.2%) with new DWI-MRI ischemic lesions, 30 patients were asymptomatic (90.9%). Irregular carotid plaque surface with (n = 13, 44.8%) or without ulceration (n = 12, 60.0%) was associated with higher rates of new DWI-MRI lesions by comparison to patients with a regular plaque (n = 7, 25%) (p = 0.048) using the univariate analysis. Less than half of this CAS cohort using the SFB technique had new ischemic lesions detected with DWI-MRI. Among these patients, more than 90% were asymptomatic. Irregularity of the plaque seems to increase the risk of peri-procedural DWI-MRI lesions.

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.