Smith, Eric Edward

Background: Alzheimer’s disease (AD) and cerebrovascular pathology are the two most common causes of dementia, frequently co-occurring in older people. Community-based neuropathology studies indicate that vascular disease accounts for approximately one-third of the population-attributable risk of dementia, controlling for other pathologies (including AD). The proportion with vascular disease as co-pathology is likely to be higher (50–70%). The most common vascular substrate is cerebral small vessel disease, which includes small artery fibrosis (arteriolosclerosis), vascular amyloid deposits (cerebral amyloid angiopathy), and monogenic forms of small vessel disease, the commonest being Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). Post-stroke cognitive impairment following both ischemic stroke and intracerebral hemorrhage also contributes. Aims and Methods: In this World Stroke Organization (WSO) scientific statement, we assembled a multi-disciplinary international group of experts to review the vascular contribution to dementia, encompassing both vascular and neurodegenerative dementia. This statement has been reviewed and approved by the WSO executive. Results: We summarize the epidemiology, neuropathology, cognitive profile, clinical impact and management of vascular disease in dementia and discuss the recent VasCog-2-WSO diagnostic criteria. We consider the substantial overlap with clinical stroke and with AD dementia. We catalog transcriptomic and proteomic studies that have revealed novel candidate molecules ( COL4A1/4A2, HTRA1, TRIM47, FOXF2 ) as possible treatment targets. We appraise imaging-based biomarkers relevant to vascular disease and potential biochemical markers (vascular endothelial growth factor-A, placental growth factor, interleukin-6, matrix metalloproteinase-9, cathepsin-B). We highlight the potential for vascular interventions to treat not only vascular dementia but also the vascular component of neurodegenerative dementia. We review recent clinical trials targeting multiple pathways, including nitric oxide signaling, high blood pressure, the GABAergic system, angiogenic activity, microglial inhibition, PDE3 and PDE5 inhibition, as well as dietary supplementation with omega-3 fatty acids, s-equol and vitamin E. Finally, we consider upcoming opportunities and challenges relevant to vascular disease in dementia. Conclusion: The vascular contribution to dementia is i) substantial, ii) increasingly understood at molecular and mechanistic levels, iii) a source of potential treatment opportunities. Data Access Statement: no original data are presented in this document.

The Canadian Consortium on Neurodegeneration in Aging (CCNA) was created by the Canadian federal government through its health research funding agency, the Canadian Institutes for Health Research (CIHR), in 2014, as a response to the G7 initiative to fight dementia. Two five-year funding cycles (2014–2019; 2019–2024) have occurred following peer review, and a third cycle (Phase 3) has just begun. A unique construct was mandated, consisting of 20 national teams in Phase I and 19 teams in Phase II (with research topics spanning from basic to clinical science to health resource systems) along with cross-cutting programs to support them. Responding to the needs of researchers within the CCNA teams, a unique sample of 1173 deeply phenotyped patients with various forms of dementia was accrued and studied over eight years (COMPASS-ND). In the second phase of funding (2019–2024), a national dementia prevention program (CAN-THUMBS UP) was set up. In a short time, this prevention program became a member of the World Wide FINGERS prevention consortium. In this article, the challenges, successes, and impacts of CCNA in Canada and internationally are discussed. Short-term deliverables have occurred, along with considerable promise of impacts in the longer term. The creation of synergy, networking, capacity building, engagement of people with lived experience, and economies of scale have contributed to the considerable success of CCNA by all measures. CCNA is evidence that an organized “centrally-organized” approach to dementia research can catalyze important progress nationally and yield significant and measurable results.

Abstract Increasing evidence recognizes Alzheimer's disease (AD) as a multifactorial and heterogeneous disease with multiple contributors to its pathophysiology, including vascular dysfunction. The recently updated AD Research Framework put forth by the National Institute on Aging–Alzheimer's Association describes a biomarker‐based pathologic definition of AD focused on amyloid, tau, and neuronal injury. In response to this article, here we first discussed evidence that vascular dysfunction is an important early event in AD pathophysiology. Next, we examined various imaging sequences that could be easily implemented to evaluate different types of vascular dysfunction associated with, and/or contributing to, AD pathophysiology, including changes in blood‐brain barrier integrity and cerebral blood flow. Vascular imaging biomarkers of small vessel disease of the brain, which is responsible for >50% of dementia worldwide, including AD, are already established, well characterized, and easy to recognize. We suggest that these vascular biomarkers should be incorporated into the AD Research Framework to gain a better understanding of AD pathophysiology and aid in treatment efforts.

Background and Purpose— Kidney dysfunction is common among patients hospitalized for ischemic stroke. Understanding the association of kidney disease with poststroke outcomes is important to properly adjust for case mix in outcome studies, payment models and risk-standardized hospital readmission rates. Methods— In this cohort study of fee-for-service Medicare patients admitted with ischemic stroke to 1579 Get With The Guidelines-Stroke participating hospitals between 2009 and 2014, adjusted multivariable Cox proportional hazards models were used to determine the independent associations of estimated glomerular filtration rate (eGFR) and dialysis status with 30-day and 1-year postdischarge mortality and rehospitalizations. Results— Of 204 652 patients discharged alive (median age [25th–75th percentile] 80 years [73.0–86.0], 57.6% women, 79.8% white), 48.8% had an eGFR ≥60, 26.5% an eGFR 45 to 59, 16.3% an eGFR 30 to 44, 5.1% an eGFR 15 to 29, 0.6% an eGFR <15 without dialysis, and 2.8% were receiving dialysis. Compared with eGFR ≥60, and after adjusting for relevant variables, eGFR <45 was associated with increased 30-day mortality with the risk highest among those with eGFR <15 without dialysis (hazard ratio [HR], 2.09; 95% CI, 1.66–2.63). An eGFR <60 was associated with increased 1-year poststroke mortality that was highest among patients on dialysis (HR, 2.65; 95% CI, 2.49–2.81). Dialysis was also associated with the highest 30-day and 1-year rehospitalization rates (HR, 2.10; 95% CI, 1.95–2.26 and HR, 2.55; 95% CI, 2.44–2.66, respectively) and 30-day and 1-year composite of mortality and rehospitalization (HR, 2.04; 95% CI, 1.90–2.18 and HR, 2.46; 95% CI, 2.36–2.56, respectively). Conclusions— Within the first year after index hospitalization for ischemic stroke, eGFR and dialysis status on admission are associated with poststroke mortality and hospital readmissions. Kidney function should be included in risk-stratification models for poststroke outcomes.

Background— We explored regional variation in 30-day ischemic stroke mortality and readmission rates and the extent to which regional differences in patients, hospitals, healthcare resources, and a quality of care composite care measure explain the observed variation. Methods and Results— This ecological analysis aggregated patient and hospital characteristics from the Get With The Guidelines–Stroke registry (2007–2011), healthcare resource data from the Dartmouth Atlas of Health Care (2006), and Medicare fee-for-service data on 30-day mortality and readmissions (2007–2011) to the hospital referral region (HRR) level. We used linear regression to estimate adjusted HRR-level 30-day outcomes, to identify HRR-level characteristics associated with 30-day outcomes, and to describe which characteristics explained variation in 30-day outcomes. The mean adjusted HRR-level 30-day mortality and readmission rates were 10.3% (SD=1.1%) and 13.1% (SD=1.1%), respectively; a modest, negative correlation ( r =−0.17; P =0.003) was found between one another. Demographics explained more variation in readmissions than mortality (25% versus 6%), but after accounting for demographics, comorbidities accounted for more variation in mortality compared with readmission rates (17% versus 7%). The combination of hospital characteristics and healthcare resources explained 11% and 16% of the variance in mortality and readmission rates, beyond patient characteristics. Most of the regional variation in mortality (65%) and readmission (50%) rates remained unexplained. Conclusions— Thirty-day mortality and readmission rates vary substantially across HRRs and exhibit an inverse relationship. While regional variation in 30-day outcomes were explained by patient and hospital factors differently, much of the regional variation in both outcomes remains unexplained.

Background and Purpose— The recommended treatment for ischemic stroke is tPA (tissue-type plasminogen activator). Although sickle cell disease (SCD) represents no known contraindication to tPA, National Heart Lung and Blood Institute of the National Institutes of Health recommended acute exchange transfusion for stroke in SCD, not tPA. Data on safety and outcomes of tPA in patients are needed to guide tPA use in SCD. Methods— We matched patients from the American Heart Association and American Stroke Association Get With The Guidelines-Stroke registry with SCD to patients without SCD and compared usage, complications, and discharge outcomes after tPA. Multivariable logistic regression models using generalized estimating equations were used to assess outcomes. Results— From 2 016 652 stroke patients admitted to Get With The Guidelines-Stroke sites in the United States, 832 SCD and 3328 non-SCD controls with no differences in admission National Institutes of Health Stroke Scale or blood pressure were identified. Neither the fraction receiving thrombolytic therapy (8.2% for SCD versus 9.4% non-SCD) nor symptomatic intracranial hemorrhage (4.9% of SCD versus 3.2% non-SCD; P =0.4502) was different. There was no difference in a prespecified set of outcome measures for those with SCD compared with controls. Conclusions— Coexistent SCD had no significant impact on the safety or outcome of thrombolytic therapy in acute ischemic stroke. Although the sample size is relatively small, these data suggest that adults with SCD and acute ischemic stroke should be treated with thrombolysis, if they otherwise qualify. Addition studies, however, should track the intracranial hemorrhage rate and provide information on other SCD-related care such as transfusion.

Background Healthcare resources vary geographically, but associations between hospital‐based resources and acute stroke quality and outcomes remain unclear. Methods and Results Using Get With The Guidelines‐Stroke and Dartmouth Atlas of Health Care data, we examined associations between healthcare resource availability, stroke care, and outcomes. We categorized hospital referral regions with high‐, medium‐, or low‐resource levels based on the 2006 national per‐capita availability median of 6 relevant acute stroke care resources. Using multivariable logistic regression, we examined healthcare resource level and in‐hospital quality and outcomes. Of 1 480 308 admitted ischemic stroke patients (2006–2013), 28.8% were hospitalized in low‐, 44.4% in medium‐, and 26.9% in high‐resource hospital referral regions. Quality‐of‐care/timeliness metrics, adjusted length of stay, and in‐hospital mortality were similar across all resource levels. Conclusions Significant variation exists in regional availability of healthcare resources for acute ischemic stroke treatment, yet among Get With the Guidelines‐Stroke hospitals, quality of care and in‐hospital outcomes did not differ by regional resource availability.

Abstract Dementia is often characterized as being caused by one of several major diseases, such as Alzheimer's disease (AD), cerebrovascular disease, Lewy body disease, or a frontotemporal degeneration. Failure to acknowledge that more than one entity may be present precludes attempts to understand interactive relationships. The clinicopathological studies of dementia demonstrate that multiple pathologic processes often coexist. How overlapping pathologic findings affect the diagnosis and treatment of clinical AD and other dementia phenotypes was the topic taken up by the Alzheimer's Association's Research Roundtable in October 2014. This review will cover the neuropathologic basis of dementia, provide clinical perspectives on multiple pathologies, and discuss therapeutics and biomarkers targeting overlapping pathologies and how these issues impact clinical trials.High prevalence of multiple pathologic findings among individuals with clinical diagnosis of AD suggests that new treatment strategies may be needed to effectively treat AD and other dementing illnesses.