Impaired cerebral autoregulation distal to carotid stenosis/occlusion is associated with increased risk of stroke at cardiac surgery with cardiopulmonary bypass

ObjectivesSevere carotid stenosis and occlusion are associated with an increased risk of stroke during and after cardiac surgery with cardiopulmonary bypass. Relevance of an impaired cerebral autoregulation caused by stenosis/occlusion is unknown.MethodsWe prospectively assessed the incidence of stroke in relation to severity of carotid disease and corresponding autoregulatory reserve in 2797 patients who had coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. Patients underwent preoperative carotid sonography and, in case of severe extracranial disease, transcranial Doppler sonography with carbon dioxide stimulation to assess cerebrovascular reserve capacity.ResultsSixty-seven (2.4%) patients had an ischemic stroke, which was fatal in 5. Anterior hemispheric stroke occurred in 42 (1.9%) patients with no/low-grade stenosis, 6 (1.8%) with medium-grade stenosis, 1 (0.6%) with high-grade stenosis/occlusion and normal autoregulation, and 3 (27.3%) with high-grade stenosis/occlusion and exhausted autoregulatory reserve. Increased risk was observed in patients with high-grade stenosis/occlusion and exhausted autoregulatory reserve also after adjustment for potential confounders (adjusted odds ratio [OR] 28.3, 95% confidence interval [CI] 5.8–139.1). Stroke risk was not increased in patients with stenosis/occlusion and normal autoregulation (1.5%, adjusted OR 0.6, 95% CI 0.2–1.6).ConclusionsCerebrovascular reserve capacity evaluated by preoperative transcranial Doppler carbon dioxide testing is a major determinant of stroke risk in patients with carotid artery stenosis/occlusion undergoing cardiac surgery with cardiopulmonary bypass. Its assessment facilitates identification of patients with an excess perioperative stroke risk

Kidney Pathology Precedes and Predicts the Pathological Cascade of Cerebrovascular Lesions in Stroke Prone Rats

INTRODUCTION: Human cerebral small vessel disease (CSVD) has been hypothesized to be an age-dependent disease accompanied by similar vascular changes in other organs. SHRSP feature numerous vascular risk factors and may be a valid model of some aspects of human CSVD. Here we compare renal histopathological changes with the brain pathology of spontaneously hypertensive stroke-prone rats (SHRSP). MATERIAL AND METHODS: We histologically investigated the brains and kidneys of 61 SHRSP at different stages of age (12 to 44 weeks). The brain pathology (aggregated erythrocytes in capillaries and arterioles, microbleeds, microthromboses) and the kidney pathology (aggregated erythrocytes within peritubular capillaries, tubular protein cylinders, glomerulosclerosis) were quantified separately. The prediction of the brain pathology by the kidney pathology was assessed by creating ROC-curves integrating the degree of kidney pathology and age of SHRSP. RESULTS: Both, brain and kidney pathology, show an age-dependency and proceed in definite stages whereas an aggregation of erythrocytes in capillaries and arterioles, we parsimoniously interpreted as stases, represent the initial finding in both organs. Thus, early renal tubulointerstitial damage characterized by rather few intravasal erythrocyte aggregations and tubular protein cylinders predicts the initial step of SHRSPs' cerebral vascular pathology marked by accumulated erythrocytes. The combined increase of intravasal erythrocyte aggregations and protein cylinders accompanied by glomerulosclerosis and thrombotic renal microangiopathy in kidneys of older SHRSP predicts the final stages of SHRSPs' cerebrovascular lesions marked by microbleeds and thrombotic infarcts. CONCLUSION: Our results illustrate a close association between structural brain and kidney pathology and support the concept of small vessel disease to be an age-dependent systemic pathology. Further, an improved joined nephrologic and neurologic diagnostic may help to identify patients with CSVD at an early stage

Relevance of Primitive Carotidobasilar Anastomosis for Internal Carotid Artery Stenosis

Primitive carotido-basilar anastomoses (PCA) are persistent fetal vessels. The aim of the study was to compare the clinical characteristics of patients operated on for internal carotid artery (ICA) stenosis with or without PCA in order to evaluate the impact of PCA on the treatment. Material and methods. Consecutive patients operated on for ICA stenosis at our university hospital were included. Surgical treatment consisted in carotid endarterectomy (CEA) with patch plastic. Results. Of the 380 CEA performed between 2006 and 2012, PCA were found in six patients (1.6%). All patients with PCA were symptomatic vs. 54% of patients without PCA (p=0.035). Significantly less posterior collateral flow was present in patients with PCA (33%) compared to those without PCA (85%, p=0.01). Only two of the six patients with PCA were diagnosed prior to surgery, none was ligated intraoperatively. PCA was not associated with stroke and restenosis at long-term follow up. Conclusions. PCA are rarely diagnosed prior to surgery in patients with ICA stenosis and need not to be ligated during CE

Predictors for Adherence to Recommended Anticoagulation after Stroke Unit Discharge in Patients with Atrial Fibrillation

Introduction: Non-adherence to recommended secondary preventive anticoagulation in stroke patients with atrial fibrillation (AF) is a common phenomenon, although the introduction of direct oral anticoagulants (DOACs) has simplified anticoagulation management for physicians as well as for patients. Methods: We examined the adherence of secondary preventive anticoagulation in AF patients after re-integration in their social environment 6–12 weeks after stroke unit and rehabilitation clinic treatment and analyzed for predictors for adherence and non-adherence. We conducted a telephone survey in consecutive patients treated between January 2013 and December 2021 at our institutional stroke unit with an acute cerebrovascular ischemic event, and we analyzed discharge letters of rehabilitation clinics of those patients not anticoagulated at follow-up. All patients had known or newly diagnosed AF, and in all, we had recommended secondary preventive anticoagulation. Results: Follow-up information about anticoagulant intake could be obtained in 1,348 of 1,685 patients (80.0%) treated within the study period. Anticoagulation rate was 91.5%, with 83.6% of patients receiving DOACs and 7.9% receiving vitamin K antagonists (VKAs). Adherence to recommended anticoagulation was associated with intake of the recommended anticoagulant already at discharge (adjusted odds ratio [OR], 18.357; confidence interval [CI], 9.637–34.969), recommendation of a specific DOAC and dose (in contrast to “DOAC” as drug category) (adjusted OR, 2.971; CI, 1.173–7.255), a lower modified Rankin Scale at discharge (per point; adjusted OR, 0.813; CI, 0.663–0.996), younger age (per year; OR, 0.951; CI, 0.926–0.976), and the absence of peripheral vascular disease (adjusted OR, 0.359; CI, 0.173–0.746). In patients already anticoagulated at discharge, adherence was 98.5%, irrespective of a patient’s age, functional deficit at discharge, and peripheral vascular disease. Avoidable obstacles for non-adherence in patients not on anticoagulants at stroke unit discharge were (1) non-implementation of recommended anticoagulation by rehabilitation physicians predominantly in patients with moderate-severe or severe stroke disability (2.1%), (2) delegation of anticoagulation start from rehabilitation physicians to general practitioners/resident radiologists (1.3%), and (3) rejection of recommended anticoagulation because of patients’ severe stroke disability (0.5%). Non-avoidable obstacles were contraindications to anticoagulation (2.1%) and patients’ refusal (0.7%). Conclusions: Commencing drug administration already during stroke unit hospitalization and providing an explanation for the selection of the recommended anticoagulant in discharge letters ensures high adherence at patients’ re-integration in their social environment after acute stroke treatment. If drug administration cannot be commenced before discharge, education of rehabilitation physicians by stroke physicians and the involvement of stroke physicians into the post-stroke decision process might hinder avoidable obstacles

Additive Manufactured Polymer-Bonded Isotropic NdFeB Magnets by Stereolithography and Their Comparison to Fused Filament Fabricated and Selective Laser Sintered Magnets

Magnetic isotropic NdFeB powder with a spherical morphology is used to 3D print magnets by stereolithography (SLA). Complex magnets with small feature sizes in a superior surface quality can be printed with SLA. The magnetic properties of the 3D printed bonded magnets are investigated and compared with magnets manufactured by fused filament fabrication (FFF), and selective laser sintering (SLS). All methods use the same hard magnetic isotropic NdFeB powder material. FFF and SLA use a polymer matrix material as binder, SLS sinters the powder directly. SLA can print magnets with a remanence of 388 mT and a coercivity of 0.923 T. A complex magnetic design for speed wheel sensing applications is presented and printed with all methods

Leveraging Delta Smelt Monitoring for Detecting Juvenile Chinook Salmon in the San Francisco Estuary

Monitoring is an essential component in ecosystem management, and leveraging existing data sources for multiple species of interest can be one effective way to enhance information for management agencies. Here, we analyzed juvenile Chinook Salmon (Oncorhynchus tshawytscha) bycatch data that has been collected by the recently established Enhanced Delta Smelt Monitoring program (EDSM), a survey designed to estimate the abundance and distribution of the San Francisco Estuary’s (estuary) endangered Delta Smelt (Hypomesus transpacificus). Two key aspects of the EDSM program distinguish it from other fish surveys in the estuary: a stratified random sampling design and the spatial scale of its sampling effort. We integrated the EDSM data set with other existing surveys in the estuary, and used an occupancy model to assess differences in the probability of detecting Delta Smelt across gear types. We saw no large-scale differences in size selectivity, and while detection probability varied among gear types, cumulative detection probability for EDSM was comparable to other surveys because of the program’s use of replicate tows. Based on our occupancy model and sampling effort in the estuary during spring of 2017 and 2018, we highlighted under-sampled regions that saw improvements in monitoring coverage from EDSM. Our analysis also revealed that each sampling method has its own benefits and constraints. Although the use of random sites with replicates, as conducted by EDSM, can provide more statistically robust abundance estimates relative to traditional methods, the use of fixed stations and simple methods such as beach seining may provide a more cost-effective way to monitor salmon occurrence in certain regions of the estuary. Leveraging the strengths of each survey’s method can enable stronger inferences on salmon abundance and distribution. Careful consideration of these trade-offs is crucial as the management agencies of the estuary continue to adapt and improve their monitoring programs