Chen, Lin Y

Complex bidirectional interactions between the nervous and cardiovascular systems are integrated through the heart–brain axis, a physiological pathway that governs both neural regulation of cardiovascular function and cardiovascular influences on brain health. Emerging evidence indicates that even in the absence of overt disease, subclinical changes in the heart, aortic arch, and extracranial arteries contribute to brain injury and cognitive vulnerability. This review synthesizes current knowledge on how subclinical heart–brain axis dysfunction affects brain structure and function, highlighting the roles of central and autonomic neural pathways as well as hormonal signaling in driving neurological decline. Key biomarkers linked to silent brain injury, cognitive decline, and dementia are discussed, emphasizing their potential for early risk stratification and as targets for preventive interventions. We also outline mechanistic pathways connecting subclinical heart–brain axis dysfunction to adverse brain outcomes, identify major gaps in current evidence, and propose priorities for future research and clinical trials aimed at early detection and risk reduction to preserve brain health.

Background The contribution of atrial cardiopathy to dementia risk is uncharacterized. We aimed to evaluate the association of atrial cardiopathy with incident dementia and potential mediation by atrial fibrillation (AF) and stroke. Methods and Results We conducted a prospective cohort analysis of participants in the ARIC (Atherosclerosis Risk in Communities) study attending visit 5 (2011–2013). We used Cox regression to determine the association between atrial cardiopathy and risk of dementia. Structural equation modeling methods were used to determine potential mediation by AF and/or stroke. Atrial cardiopathy was defined if ≥1 of the following at visit 5: P‐wave terminal force >5000 mV·ms in ECG lead V1, NT‐proBNP (N‐terminal pro–brain natriuretic peptide) >250 pg/mL or left atrial volume index ≥34 mL/m 2 by transthoracic echocardiography. We repeated our analysis necessitating ≥2 markers to define atrial cardiopathy. The prevalence of atrial cardiopathy was 34% in the 5078 participants (mean age 75 years, 59% female, 21% Black adults), with 763 participants developing dementia. Atrial cardiopathy was significantly associated with dementia (adjusted HR, 1.35 [95% CI, 1.16–1.58]), with strengthening of the effect estimate when necessitating ≥2 biomarkers (adjusted HR, 1.54 [95% CI, 1.25–1.89]). There was an increased risk of dementia among those with atrial cardiopathy when excluding those with AF (adjusted HR, 1.31 [95% CI, 1.12–1.55]) or stroke (adjusted HR, 1.28 [95% CI, 1.09–1.52]). The proportion of the effect mediated by AF was 4% ( P =0.005), and 9% was mediated by stroke ( P =0.048). Conclusions Atrial cardiopathy was significantly associated with an increased risk of dementia, with only a small percent mediation of the effect by AF or stroke.

Background Electronic medical records are increasingly used to identify disease cohorts; however, computable phenotypes using electronic medical record data are often unable to distinguish between prevalent and incident cases. Methods and Results We identified all Olmsted County, Minnesota residents aged ≥18 with a first‐ever International Classification of Diseases, Ninth Revision (ICD‐9) diagnostic code for atrial fibrillation or atrial flutter from 2000 to 2014 (N=6177), and a random sample with an International Classification of Diseases, Tenth Revision (ICD‐10) code from 2016 to 2018 (N=200). Trained nurse abstractors reviewed all medical records to validate the events and ascertain the date of onset (incidence date). Various algorithms based on number and types of codes (inpatient/outpatient), medications, and procedures were evaluated. Positive predictive value (PPV) and sensitivity of the algorithms were calculated. The lowest PPV was observed for 1 code (64.4%), and the highest PPV was observed for 2 codes (any type) >7 days apart but within 1 year (71.6%). Requiring either 1 inpatient or 2 outpatient codes separated by >7 days but within 1 year had the best balance between PPV (69.9%) and sensitivity (95.5%). PPVs were slightly higher using ICD‐10 codes. Requiring an anticoagulant or antiarrhythmic prescription or electrical cardioversion in addition to diagnostic code(s) modestly improved the PPVs at the expense of large reductions in sensitivity. Conclusions We developed simple, exportable, computable phenotypes for atrial fibrillation using structured electronic medical record data. However, use of diagnostic codes to identify incident atrial fibrillation is prone to some misclassification. Further study is warranted to determine whether more complex phenotypes, including unstructured data sources or using machine learning techniques, may improve the accuracy of identifying incident atrial fibrillation.

Growing evidence suggests a consistent association between atrial fibrillation (AF) and cognitive impairment and dementia that is independent of clinical stroke. This report from the AF-SCREEN International Collaboration summarizes the evidence linking AF to cognitive impairment and dementia. It provides guidance on the investigation and management of dementia in patients with AF on the basis of best available evidence. The document also addresses suspected pathophysiologic mechanisms and identifies knowledge gaps for future research. Whereas AF and dementia share numerous risk factors, the association appears to be independent of these variables. Nevertheless, the evidence remains inconclusive regarding a direct causal effect. Several pathophysiologic mechanisms have been proposed, some of which are potentially amenable to early intervention, including cerebral microinfarction, AF-related cerebral hypoperfusion, inflammation, microhemorrhage, brain atrophy, and systemic atherosclerotic vascular disease. The mitigating role of oral anticoagulation in specific subgroups (eg, low stroke risk, short duration or silent AF, after successful AF ablation, or atrial cardiopathy) and the effect of rhythm versus rate control strategies remain unknown. Likewise, screening for AF (in cognitively normal or cognitively impaired patients) and screening for cognitive impairment in patients with AF are debated. The pathophysiology of dementia and therapeutic strategies to reduce cognitive impairment warrant further investigation in individuals with AF. Cognition should be evaluated in future AF studies and integrated with patient-specific outcome priorities and patient preferences. Further large-scale prospective studies and randomized trials are needed to establish whether AF is a risk factor for cognitive impairment, to investigate strategies to prevent dementia, and to determine whether screening for unknown AF followed by targeted therapy might prevent or reduce cognitive impairment and dementia.

Shared decision making (SDM) has been advocated to improve patient care, patient decision acceptance, patient-provider communication, patient motivation, adherence, and patient reported outcomes. Documentation of SDM is endorsed in several society guidelines and is a condition of reimbursement for selected cardiovascular and cardiac arrhythmia procedures. However, many clinicians argue that SDM already occurs with clinical encounter discussions or the process of obtaining informed consent and note the additional imposed workload of using and documenting decision aids without validated tools or evidence that they improve clinical outcomes. In reality, SDM is a process and can be done without decision tools, although the process may be variable. Also, SDM advocates counter that the low-risk process of SDM need not be held to the high bar of demonstrating clinical benefit and that increasing the quality of decision making should be sufficient. Our review leverages a multidisciplinary group of experts in cardiology, cardiac electrophysiology, epidemiology, and SDM, as well as a patient advocate. Our goal is to examine and assess SDM methodology, tools, and available evidence on outcomes in patients with heart rhythm disorders to help determine the value of SDM, assess its possible impact on electrophysiological procedures and cardiac arrhythmia management, better inform regulatory requirements, and identify gaps in knowledge and future needs.

Background and Purpose— Evidence suggests that atrial fibrillation (AF) is associated with increased risk of cognitive decline and dementia, even in the absence of stroke. White matter disease (WMD) is a potential mechanism linking AF to cognitive impairment. In this study, we explored the association between prevalent AF and WMD. Methods— We performed a cross-sectional analysis of participants attending the ARIC-NCS (Atherosclerosis Risk in Communities–Neurocognitive Study) in 2011 to 2013 who underwent brain magnetic resonance imaging. AF was ascertained from study visit electrocardiograms or prior hospitalization codes. Extent of WMD was defined by measures of white matter (WM) microstructural integrity and WM hyperintensity volume. Multivariable linear regression models were used to assess the association between AF and WMD. Results— Among 1899 participants (mean age, 76 years; 28% black; 60% women), 133 (7%) had prevalent AF. After multivariable adjustment, differences between participants with and without AF were −0.001 (95% CI, −0.006 to 0.004) for global WM fractional anisotropy, 0.031×10 −4 mm 2 /s (95% CI, −0.075 to 0.137) for global WM mean diffusivity, and 0.08 mm 3 (95% CI, −0.14 to 0.30) for WM hyperintensity volume. Conclusions— The results suggest that there is no association between prevalent AF and WMD.

Background Oral anticoagulants ( OACs ) in patients with atrial fibrillation ( AF ), in addition to reducing stroke risk, could also prevent adverse cognitive outcomes. The purpose of this study was to compare the risk of dementia incidence across patients with AF initiating different OAC s. Methods and Results We identified patients with nonvalvular AF initiating OAC s in 2 US healthcare claim databases, MarketScan (2007–2015) and Optum Clinformatics (2009–2015). Dementia, comorbidities, and use of medications were defined on the basis of inpatient and outpatient claims. We performed head‐to‐head comparisons of warfarin, dabigatran, rivaroxaban, and apixaban in propensity score–matched cohorts. We calculated hazard ratios ( HR s) and 95% confidence intervals ( CI s) of incident dementia for each propensity score–matched cohort and meta‐analyzed database‐specific results. We analyzed 307 099 patients with AF from the MarketScan database and 161 346 from the Optum database, of which 6572 and 4391, respectively, had a diagnosis of incident dementia. The mean follow‐up of each cohort ranged between 0.7 and 2.2 years. Patients initiating direct OACs experienced lower rates of dementia than those initiating warfarin (dabigatran: HR , 0.85; 95% CI , 0.71–1.01; rivaroxaban: HR , 0.85; 95% CI , 0.76–0.94; apixaban: HR , 0.80; 95% CI , 0.65–0.97). There were no differences in rates of dementia comparing direct OAC user groups (dabigatran versus rivaroxaban: HR , 1.02; 95% CI , 0.79–1.32; dabigatran versus apixaban: HR , 0.92; 95% CI , 0.63–1.36; apixaban versus rivaroxaban: HR , 1.01; 95% CI , 0.86–1.19). Conclusions Patients with AF initiating direct OACs experienced lower rates of incident dementia than warfarin users. No obvious benefit was observed for any particular direct OAC in relation to dementia rates.

Background Differences in anticoagulation rates and direct oral anticoagulant use by provider specialty may identify an area of practice improvement to reduce future stroke events in patients with atrial fibrillation ( AF ). Methods and Results We examined anticoagulant prescription fills in 388 045 (mean age, 68±15 years; 59% male) patients with incident AF from the MarketScan databases between 2009 and 2014. Provider specialty and filled anticoagulant prescriptions around the time of AF diagnosis (3 months before through 6 months after) were obtained from outpatient services and pharmacy claims. We estimated the association of provider specialty (cardiology versus primary care) with filling oral anticoagulant prescriptions, adjusting for patient characteristics. The risk of stroke and bleeding events also was explored. A total of 235 739 patients (61%) had a cardiology provider claim, whereas 152 306 (39%) were exclusively managed by primary care. Patients seen by cardiology providers were more likely to fill anticoagulant prescriptions than those seen by primary care (39% versus 27%; relative risk, 1.39; 95% confidence interval [ CI ], 1.37–1.40). Differences were observed for direct oral anticoagulants (relative risk, 1.74; 95% CI , 1.71–1.78) and warfarin (relative risk, 1.24; 95% CI , 1.22–1.26). A reduced risk of stroke events was observed among those seen by cardiology providers (hazard ratio, 0.90; 95% CI , 0.86–0.94) compared with primary care, without an increased bleeding risk (hazard ratio, 1.03; 95% CI , 0.98–1.07). Conclusions Patients seen by an outpatient cardiology provider shortly after AF diagnosis were more likely to initiate oral anticoagulation and were at lower risk of future stroke events without a higher rate of bleeding. Early referral to cardiology specialists may increase initiation of anticoagulant therapies and improve outcomes in AF .

Background Atrial fibrillation ( AF ) has been associated with faster cognitive decline and increased dementia risk. Factors associated with dementia in patients with AF have been seldom studied. Methods and Results We studied 6432 individuals from the ARIC ‐NCS (Atherosclerosis Risk in Communities Neurocognitive Study). In 2011 to 2013, participants underwent a physical exam, echocardiography, detailed cognitive assessments, and a subset, brain magnetic resonance imaging. Dementia and mild cognitive impairment ( MCI ), as well as etiology of MCI /dementia, Alzheimer's disease–related or vascular, were adjudicated by an expert panel. AF was defined by study ECGs and past hospitalizations. We used logistic regression to estimate odds ratios and 95% CI of MCI /dementia by AF status and to assess cross‐sectional correlates of MCI /dementia in patients with AF . Among 6432 participants, 611 (9.5%) had prevalent AF . AF was associated with increased odds of dementia and MCI (odds ratio, 95% CI , 2.25, 1.64–3.10, and 1.28, 1.04–1.56, respectively). Prevalence of Alzheimer's disease–related MCI /dementia and vascular MCI /dementia were higher in participants with AF than without AF (odds ratio, 95% CI , 1.29, 1.04–1.61, and 1.50, 0.99–2.25, respectively). In multivariable analyses, older age, lower body mass index, diabetes mellitus, stroke, and APOE genotype were associated with dementia prevalence in participants with AF . In models evaluating MCI /dementia subtypes, diabetes mellitus was associated with Alzheimer's disease–related MCI /dementia, whereas male sex and stroke were risk factors for vascular MCI /dementia. Conclusions In a large, community‐based study, AF was associated with higher prevalence of MCI and dementia. Controlling cardiometabolic risk factors is a potential target for prevention of adverse cognitive outcomes in AF patients.

Objective To assess the risk of liver injury hospitalisation in patients with atrial fibrillation (AF) after initiation of direct oral anticoagulants (DOACs) or warfarin and to determine predictors of liver injury hospitalisation in this population. Methods We studied 113 717 patients (mean age 70, 39% women) with AF included in the MarketScan Commercial and Medicare Supplemental databases with a first prescription for oral anticoagulation after 4 November 2011, followed through 31 December 2014. Of these, 56 879 initiated warfarin, 17 286 initiated dabigatran, 30 347 initiated rivaroxaban and 9205 initiated apixaban. Liver injury hospitalisation and comorbidities were identified from healthcare claims. Results During a median follow-up of 12 months, 960 hospitalisations with liver injury were identified. Rates of liver injury hospitalisation (per 1000 person-years) by oral anticoagulant were 9.0 (warfarin), 4.0 (dabigatran), 6.6 (rivaroxaban) and 5.6 (apixaban). After multivariable adjustment, liver injury hospitalisation rates were lower in initiators of DOACs compared with warfarin: HR (95% CI) of 0.57 (0.46 to 0.71), 0.88 (0.75 to 1.03) and 0.70 (0.50 to 0.97) for initiators of dabigatran, rivaroxaban, and apixaban, respectively (vs. warfarin). Compared with dabigatran initiators, rivaroxaban initiators had a 56% increased risk of liver injury hospitalisation (HR 1.56, 95% CI 1.22 to 1.99). In addition to type of anticoagulant, prior liver, gallbladder and kidney disease, cancer, anaemia, heart failure and alcoholism significantly predicted liver injury hospitalisation. A predictive model including these variables had adequate discriminative ability (C-statistic 0.67, 95% CI 0.64 to 0.70). Conclusions Among patients with non-valvular AF, DOACs were associated with lower risk of liver injury hospitalisation compared with warfarin, with dabigatran showing the lowest risk.