Abstract
Background:
Vascular diseases, including atherosclerotic cardiovascular disease (ASCVD) and stroke, increase the risk of Alzheimer’s disease and cognitive impairment. Serum biomarkers, such as brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and insulin-like growth factor 1 (IGF-1), may be indicators of cognitive health.
Objective:
We examined whether vascular risk was associated with levels of cognition and serum biomarkers in older women with cardiovascular disease (CVD).
Methods:
Baseline data from a lifestyle trial in older women (n = 253) with CVD (NCT04556305) were analyzed. Vascular risk scores were calculated for ASCVD (ASCVD risk estimator) and stroke (CHA2DS2-VASc) based on published criteria. Cognition-related serum biomarkers included BDNF, VEGF, and IGF-1. Cognition was based on a battery of neuropsychological tests that assessed episodic memory, semantic memory, working memory, and executive function. A series of separate linear regression models were used to evaluate associations of vascular risk scores with outcomes of cognition and serum biomarkers. All models were adjusted for age, education level, and racial and ethnic background.
Results:
In separate linear regression models, both ASCVD and CHA2DS2-VASc scores were inversely associated with semantic memory (β= –0.22, p = 0.007 and β= –0.15, p = 0.022, respectively), with no significant findings for the other cognitive domains. There were no significant associations between vascular risk scores and serum biomarkers.
Conclusions:
Future studies should prospectively examine associations between vascular risk and cognition in other populations and additionally consider other serum biomarkers that may be related to vascular risk and cognition.
INTRODUCTION
Vascular risk factors are associated with lower cognition and faster cognitive decline in older adults, likely due to multifaceted, interrelated mechanisms.1,2, 1,2 Across longitudinal studies in well-defined cohorts, vascular risk factors, including clinical risk of a future atherosclerotic cardiovascular disease (ASCVD) event (defined as coronary death or nonfatal myocardial infarction, or fatal or nonfatal stroke) have been shown to be related to lower levels in specific domains of cognition, including episodic memory, semantic memory, working memory, and executive function.3,4, 3,4 The impact of vascular risk on cognition may be especially important to consider for women, given their overall increased prevalence of cognitive impairment in late life compared to men, even when accounting for their overall longer lifespan. 5 These sex differences in brain health may be due to the more frequent manifestation of microvascular disease in women 6 and potential disparities in vascular disease detection and treatment. 7 The negative effects of vascular risk on cognition in women may be most pronounced in those with overt vascular disease versus those with subclinical disease or healthy individuals. 5
Vascular risk can be estimated using clinical risk scores, which are widely recommended for the prevention and treatment of vascular disease in practice. For instance, the ASCVD risk estimator, developed by the American Heart Association (AHA) and American College of Cardiology (ACC), estimates a patient’s 10-year ASCVD event risk to guide clinical decision-making, patient education, and treatments. 8 The CHA2DS2-VASc score, a guideline-recommended model for estimating thromboembolic risk in atrial fibrillation, is the most widely used stroke risk score. The CHA2DS2-VASc score has also been applied to progression/severity and health outcomes across broader CVD types, including acute coronary syndrome, hypertension, peripheral artery disease, and heart failure. 9 A strength of these clinical vascular risk scores is that they are informed by multiple vascular risk factors, each known to be related to future risk of a vascular event (e.g., demographics, blood pressure [BP], current medications). Moreover, these vascular risk scores can be calculated quickly in busy clinical settings using data collected during routine visits. Both vascular risk scores are frequently used in clinical practice for preventing vascular disease and preventing a future vascular event in patients with preexisting vascular disease.
Earlier studies that have examined the ASCVD risk and CHA2DS2-VASc clinical risk scores have consistently shown that lower vascular risk may be associated with better overall cognition or reduced risk of developing dementia.10–16 In these earliest studies, brief measures of global cognition such as the Mini-Mental State Examination or Montreal Cognitive Assessment were most frequently used.14,15, 14,15 To our knowledge, few studies have related ASCVD risk and CHA2DS2-VASc risk scores to cognitive domain-specific measures, including domains vulnerable to decline in vascular disease, such as episodic memory, semantic memory, working memory, and executive function. 10 Moreover, earlier studies of ASCVD risk and CHA2DS2-VASc risk scores did not examine associations with blood-based biological markers thought to be supportive of overall brain health and potentially early indicators of change in cognition. Such serum biomarkers include brain-derived neurotrophic factor (BDNF), a neurotrophin involved in neuronal survival; 17 vascular endothelial growth factor (VEGF), a protein involved in angiogenesis; 18 and insulin-like growth factor 1 (IGF-1), a growth hormone involved in pleiotropic actions of all neuronal cells that slows neurodegeneration. 19 These three serum biomarkers have been positively associated with higher cognition over time and greater brain volumes, hippocampal perfusion, cerebral blood flow, and synaptic connections.20–23
We aimed to address gaps in the literature by examining if vascular risk (ASCVD and CHA2DS2-VASc clinical risk scores) is associated with specific domains of cognition, including episodic memory, semantic memory, working memory, and executive function, as well as with cognition-related serum biomarkers (i.e., BDNF, VEGF, IGF-1), in older women with CVD.
MATERIALS AND METHODS
Design
This study uses baseline data from a lifestyle trial (MindMoves) for the prevention of cognitive decline in older women with CVD (n = 253; NCT04556305). The trial aims to test the separate and combined effects of two lifestyle interventions, cognitive training (Mind) and physical activity (Move), on primary outcomes of cognition and cognition-related serum biomarkers in older women with CVD over 72 weeks. Baseline data collection occurred following study enrollment but before randomization to intervention conditions. Details of the study design and methods are published elsewhere. 24
Sample
Participants were recruited from two women’s cardiology clinics in a large Midwestern metropolitan area (the Rush Heart Center for Women in two locations). Inclusion and exclusion criteria were previously described. 24 Briefly, inclusion criteria were: age 65 years and older, self-identifying as female, diagnosis of CVD (i.e., coronary artery disease, hypertension, heart failure, valve disease, atrial fibrillation 7 ) and receiving guideline-informed CVD therapies, seen by their cardiologist in the past three months, ability to read/speak English, and access to a Bluetooth-capable device. Exclusion criteria were: regular engagement in moderate-vigorous physical activity (three 30-min sessions per week or more), engagement in a cognitive training program in the month prior to baseline, disabilities, unstable health condition or uncontrolled cardiovascular or respiratory disease preventing regular physical activity, 25 diagnosis of neurological disease or symptoms of significant cognitive impairment,26–28 and self-reported hearing loss that interferes with normal conversation.
Measures
Vascular risk. The ASCVD score determines the 10-year risk for ASCVD. 8 Scores are calculated based on data from study measures and the electronic health record (EHR). Study data included current age, sex, racial and ethnic background, systolic blood pressure, diastolic blood pressure, and self-reported history of smoking. EHR data were the most recent entry less than three months from study enrollment for blood cholesterol (total, high-density lipoprotein [HDL], and low-density lipoprotein [LDL]), history of diabetes, receiving hypertension treatment, and receiving aspirin therapy. Scores were automatically calculated by the ACC ASCVD Risk Estimator Plus Calculator. 29 Scores were categorized as low risk (<5%), borderline risk (5% to 7.4%), intermediate risk (7.5% to 19.9%), and high risk (≥20%). 8
CHA2DS2-VASc scores included data from study measures for self-reported age and sex, as well as EHR data for history of congestive heart failure, hypertension, stroke/transient ischemic attack/thromboembolism, vascular disease, and diabetes. Each item response receives a specific possible number of points (0–2), which informs the overall total score out of 9 possible points. The CHA2DS2-VASc scores measure the annual risk of stroke, and scores correspond to an adjusted stroke risk rate ranging from 1.9% per year for scores of 0 to 18.2% per year for scores of 6 or higher. Scores are also categorized as low risk (scores of 0), moderate risk (score of 1), and high risk (score of 2 for men or 3 for women, or higher). 30
Cognition. Cognitive function was evaluated via telephone administration using seven neurocognitive tests, which were previously validated in epidemiological cohort studies of older adults. 31 Episodic memory was assessed using the East Boston Memory Test, and scores were the sum of the immediate and delayed recall tests. 32 Semantic memory was assessed using the Category Fluency Test, 33 and scores were the sum of the fruits/vegetables and animals tests. Working memory was the sum of the scores of the Digit Span Forwards, Digit Span Backwards, 34 and Digit Ordering Tests. 35 Executive function was assessed using the Oral Trails B tests. 36 For each domain of cognition, scores from the domain-specific tests were averaged to create a domain index score.
Cognition-related serum biomarkers. Blood samples for the serum biomarkers were obtained in the morning (8 am–10 am) after an 8-h fast, following recommendations for validated blood collection procedures for these biomarkers. 37 Blood samples were collected by a trained phlebotomist in the research lab or the participant’s home and were transported to the lab for processing within two hours of collection. After processing, blood samples were stored in a –80°C freezer.
The cognition-related serum biomarkers included BDNF, VEGF, and IGF-1 and were evaluated using assays developed and analytically validated “in house” by the Rush Biomarker Development Core. Assays were prepared upon covalently conjugating 4μg of capture antibodies from validated ELISA pairs obtained from R&D system (Human/Mouse BDNF DuoSet ELISA [cat.# DY248]; Human IGF-I/IGF-1 DuoSet ELISA [cat.# DY291]; and Human VEGF DuoSet ELISA [cat.# DY293]) onto 1.25 million MagPlex-C Microspheres using standard Sulfo-NHS/EDC chemistry, as previously described. 38 Sample preparation for the measurement of IGF-1 uniquely required separation of the IGF-1 target analyte from the IGF Binding Protein/acid-labile subunit (ALS) complex. This was accomplished upon incubation of 25μL serum with 100μL of 0.25 N HCl in 87.5% ethanol for 30 min at RT, followed by centrifugation at 10,000 g for 5 min. Afterward, 75μL of the supernatant was subsequently neutralized for assessment with 45μL of 0.31N NaOH. The final extract was combined with 105μL of a StartingBlock™ Blocking Buffer (Thermo Scientific) diluted 1 : 1 in PBS-T (1X PBS and 0.01% Tween). After processing, the total dilution of sample was 1 : 15 for the IGF-1 assay. For both BDNF and VEGF, the serum was simply diluted 1 : 2 in assay buffer (PBS-T+1% BSA) without further processing. All assays were accomplished with triplicate sampling in a 384-well microtiter plate format, with IGF-1 performed in singleplex and BDNF and VEGF performed in multiplex. Samples (12.5μL) were combined with 1,000 beads per well of the appropriate bead(s) (bead regions: IGF-1 –25; VEGF –78; and BDNF –44) in assay buffer (PBS-T+1% BSA for BDNF and VEGF; 1 : 1 StartingBlock™ Blocking Buffer in PBS-T for IGF-1). Seven-point standard curves of each of the targets were then added to each plate either at a 1 : 4 dilution series for BDNF and VEGF (10,000 and 40,000 pg/mL starting concentrations) or 1 : 3 dilution series for IGF-1 (70,875 pg/mL starting concentration). Plates were then incubated overnight for analyte capture at 4°C with constant agitation, followed by exhaustive washing with PBS-T and the addition of the biotin-conjugated (detection) antibody (all R&D Systems: BDNF [cat.# BAM648]; VEGF165 [cat.# BAF293]; IGF-I [cat.# BAF291]) at a 4μg/mL concentration. Plates were then incubated at RT with continuous agitation for 1 h, followed by exhaustive washing with PBS-T and addition of 12.5μL of a 16μg/mL Streptavidin-R-Phycoerythrin (Thermo Scientific) solution in assay buffer. This mixture was allowed to incubate for 30 min, again exhaustively washed with PBS-T, resuspended in Sheath Fluid Plus (Luminex), and each well read on a Luminex FLEXMAP 3D. Concentrations were calculated based on the 7-point standard curves using a 5-parametric fit algorithm in Belysa v1.2 (EMD Millipore). 39 Values calculated below the lower limit of quantification (39 pg/mL for VEGF, 9.77 pg/mL for BDNF, and 875 pg/mL for IGF-1) were extrapolated based on calculated fit equation. For instances in which a serum biomarker concentration was below the level of detection, the missing value was replaced by the minimum detected value across all assessments.
Covariates. Covariates included in this analysis were selected based on associations with the cognition and serum biomarker variables. These covariates included age, self-reported education level, and self-reported racial and ethnic background.
Data analysis
Baseline characteristics of the study sample are shown as mean and standard deviation (SD), number and percentages of participants, or medians and quartiles. All models were performed using SAS version 9.4. 40 Bivariate correlations (Pearson r, Spearman’s r, point-biserial) were calculated according to the level of measurement for each variable. All three serum biomarkers were positively skewed. Untransformed data are presented in Table 1; however, skewed variables were log-transformed (BDNF, VEGF) or square root transformed (IGF-1) prior to correlation and regression analyses. A series of linear regression models were used to separately evaluate associations of ASCVD and CHA2DS2-VASc scores with cognition and cognition-related serum biomarkers. All models were adjusted for age, education, and racial or ethnic background. Racial and ethnic background was recorded as a categorical variable (White versus other, including Black, Asian, and Hispanic); the proportions of participants of Asian racial background and Hispanic/Latino ethnic background were too low to compare across categories, so they were combined with those self-identifying as Black. The Institutional Review Boards of the Rush University Medical Center and the University of Illinois Chicago approved the study protocols. All participants provided written consent for blood collection, questionnaires, and clinical evaluations. Data for this analysis were collected between September 2020 and November 2021.
Descriptive statistics of older women with cardiovascular disease in a lifestyle trial to prevent cognitive decline (n = 253)
ASCVD, atherosclerotic cardiovascular disease; BDNF, Brain-derived neurotrophic factor; CHA2DS2-VASc, Congestive heart failure or left ventricular dysfunction Hypertension, Age≥75 (doubled), Diabetes, Stroke (doubled)-Vascular disease, Age 65–74, Sex category; IGF-1, Insulin-like growth factor; VEGF, Vascular endothelial growth factor.
RESULTS
These analyses included 253 older women participants (Table 1) who were, on average, 72.4 years (SD = 5.8, range = 65–90), 59.7% received a college degree or greater, 54.2% were of White racial background, 38.3% were of Black racial background, 81.4% were retired, and 43.1% were married or in a committed relationship. ASCVD scores were on average 17.4% (SD = 11.3%, range 3.3% –78.1%), indicating intermediate levels of ASCVD event in the 10 following years, while CHA2DS2-VASc scores were on average 3.5 (SD = 0.9, range 2–7), indicating potentially high annual risk of stroke. BDNF levels ranged from 22.6 to 3888.7 pg/mL (M = 389.2 pg/mL, SD = 480.3); VEGF ranged from 26.4 to 23,311.1 pg/mL (M = 821.7 pg/mL, SD = 2144.7); and IGF-1 ranged from 216.7 to 113,336.9 ng/mL (M = 28,128.3 pg/mL, SD = 19,392.2).
Bivariate correlation findings
Bivariate correlations were conducted among (a) covariate variables (age, education level, racial and ethnic background), (b) vascular risk (ASCVD and CHA2DS2-VASc scores), (c) cognition (episodic memory, semantic memory, working memory, and executive function), and (d) cognition-related serum biomarkers (BDNF, VEGF, and IGF-1; Supplementary Table 1). In bivariate correlations, younger age was related to better semantic memory and working memory; higher levels of education were related to better semantic memory and executive function; and being of White racial background was related to better episodic memory and executive function. Lower ASCVD and lower CHA2DS2-VASc scores were related to better semantic memory. For the serum biomarkers, lower ASCVD scores were related to higher levels of IGF-1 only.
Multiple linear regression findings
In adjusted multiple linear regression models that examined vascular risk and the four domains of cognition separately, lower ASCVD and CHA2DS2-VASc scores were associated with better semantic memory in separate models, each explaining 2.5% and 1.8% of the variance, respectively (Table 2). In adjusted multiple linear regression models that examined vascular risk and the three serum biomarkers separately, there were no significant associations between vascular risk and serum biomarkers (Table 3).
Multiple linear regression of cognition domains on vascular risk in older women with cardiovascular disease (n = 253)
ASCVD, atherosclerotic cardiovascular disease; CHA2DS2-VASc, Congestive heart failure or left ventricular dysfunction Hypertension, Age≥75 (doubled), Diabetes, Stroke (doubled)-Vascular disease, Age 65–74, Sex category.
Multiple linear regression of cognition-related serum biomarkers on vascular risk in older women with cardiovascular disease (n = 244)
ASCVD, atherosclerotic cardiovascular disease; BDNF, Brain-derived neurotrophic factor; CHA2DS2-VASc, Congestive heart failure or left ventricular dysfunction Hypertension, Age≥75 (doubled), Diabetes, Stroke (doubled)-Vascular disease, Age 65–74, Sex category; IGF-1, Insulin-like growth factor; VEGF, Vascular endothelial growth factor. aSerum biomarkers are presented as medians and interquartile ranges.
DISCUSSION
We examined separate associations of vascular risk (ASCVD and CHA2DS2-VASc scores) with four domains of cognition (episodic memory, semantic memory, working memory, and executive function) and three cognition-related serum biomarkers (BDNF, VEGF, and IGF-1) in a sample of older women with CVD who participated in an ongoing lifestyle intervention trial. In adjusted models, lower vascular risk scores were related to better semantic memory but were not significant for the other cognitive domains, while there were no significant findings for any of the serum biomarkers. Across these findings with semantic memory, vascular risk scores explained less than 5% of the variance of the overall model, so these findings, while significant, indicate that the risk scores account for only a small variance in semantic memory. Yet, given the high prevalence of elevated vascular risk, even small variances explained may be important at a population level.
Results of prior cross-sectional research and longitudinal studies with older adults showed significant associations between vascular risk and measures of global cognition,10–16 but in our study, significant associations were observed between vascular risk and semantic memory only. Impairment in semantic memory has been a more prominent feature in vascular dementia, as indicated by a greater burden of white matter hyperintensities, versus dementia caused by predominately Alzheimer’s disease neuropathology.41–43 In our earlier study with another cohort of older adults, diabetes was inversely associated with semantic memory but no other cognitive domain. 44 However, another study showed that vascular risk factors (e.g., low physical activity, poor diet, high blood glucose, high cholesterol) were not related with worse semantic memory, despite significant findings in other domains of cognition. 45 Nonetheless, managing vascular risk continues to be a major priority for preventing cognitive decline, dementia, and Alzheimer’s disease in adult populations. In particular, statements from the 2020 Lancet Commission for dementia prevention 46 stress the importance of considering vascular risk and the presence of cardiometabolic disease, especially in midlife, for long-term dementia prevention.
Despite some earlier research linking various measures of vascular risk with the BDNF, VEGF, and IGF-1 biomarkers, our analyses did not yield any significant biomarker findings in this cohort of older women with CVD. Indeed, published data have shown that ASCVD risk scores and IGF-1 have a potential bidirectional association in adults with diabetes and chronic kidney disease, 47 but other studies have not examined specifically the ASCVD and CHA2DS2-VASc scores with BDNF or VEGF.19,48–50, 19,48–50 The limited clarity on the associations between vascular risk and biomarkers may be attributed to varying study methods (e.g., the heterogeneity of patient populations studied, vascular risk measures), which we similarly found in our integrative review of serious cardiovascular conditions and BDNF. 51 Although these biomarkers have been associated with better brain health over time, these biomarkers can also reflect a variety of processes related to vascular risk and progression. As such, higher levels can indicate either beneficial or pathological disease processes.47,50,51, 47,50,51 Taken together, biomarker levels likely vary across different vascular disease processes and severities; thus, additional research in this area is needed to elucidate these associations.
Despite our lack of associations between vascular risk and cognition-related biomarkers, there is emerging and ongoing research reports that serum biomarkers may be responsive to behavioral interventions in aging, including physical activity 52 and other interventions that involve one or more health behaviors.24,53,54, 24,53,54 In normal aging, changes in cognition can occur over long periods of time, spanning years to decades. Behavioral interventions that are tested in trials are usually implemented over several months, 46 with few studies extending follow-up beyond 1– 2 years.55,56, 55,56 Thus, even if the behavioral intervention benefits cognition, it is possible that significant changes are not detected by neurocognitive test measures of cognition in a shorter follow-up period. In behavioral trials, cognition-related serum biomarkers may be utilized to detect early cognitive changes that are not captured by neurocognitive tests. Compared to other more expensive and invasive biomarkers of brain health, such as neuroimaging or biomarkers assessed in cerebral spinal fluid, serum biomarkers are likely more convenient and preferable for broader older adult populations. Additional exploration in this area of work is needed.
This study has limitations. First, our findings may not be generalizable to a broader population. This sample reflected older women with CVD (i.e., coronary artery disease, hypertension, heart failure, valve disease, atrial fibrillation) recruited from an urban Midwest cardiology clinic to participate in an ongoing lifestyle trial. Participants had higher levels of education, and over half were of non-Hispanic White racial background. Also, they were excluded if their CVD was untreated or if they were experiencing symptoms that prevented participation in physical activity. Therefore, our finding may not be generalizable to a broader population, including those with subclinical disease or healthy individuals. Second, we utilized two convenient vascular risk scores commonly used in clinical practice, but we were limited in that we did not have a measure of overall CVD severity of vascular disease burden. In addition, the ASCVD risk estimator can overestimate the future risk of ASCVD events 57 and be limited when used in older adults 80 years or older. 58 Conversely, the CHA2DS2-VASc was found to discriminate risk for stroke accurately and thromboembolic events across population subgroups, particularly for patients at higher levels of risk. 59 Third, out of necessity, we used a telephone administration of neurocognitive tests to avoid in-person contact during the COVID-19 pandemic, which was this patient population’s preference. Although we utilized a validated telephone battery previously used in older adult populations, there are limitations in that telephone tests cannot adequately capture some aspects of cognition and can be less sensitive than in-person administration. Yet, there is support for telephone testing,31,60, 31,60 and such testing allowed for the successful conduct of the study at a time when it would have otherwise not been possible. Fourth, another important limitation is that the data presented in this study were cross-sectional, which precludes our ability to determine the directionality or causality of vascular risk, serum biomarkers, and cognition. However, the parent study, an interventional randomized clinical trial, had a prospective longitudinal design, and we will examine temporal relations of variables in future analyses. Fifth, we examined only three serum biomarkers: BDNF, VEGF, and IGF-1, so other serum biomarkers should be considered for future research.
Despite these limitations, this study contributes important knowledge by being one of the first examinations of clinical vascular risk scores, specific domains of cognition, and serum biomarkers in a single study. The clinical vascular risk scores are quick and easy to calculate in busy settings using clinical data. Another strength is our examination of associations between vascular risk with biomarkers measured in blood, which offer a potentially feasible strategy for clinical and community settings and may provide early prognostic insights into cognitive decline and neurodegeneration. Finally, we focused on older women with CVD, a growing population at increased risk for cognitive impairment.
In summary, among older women with CVD, the ASCVD and CHA2DS2-VASc scores (scores that assess clinical ASCVD and stroke risk, respectively) appeared to be inversely associated with semantic memory, while there were no significant associations with three serum biomarkers. Due to the limitations in cross-sectional studies, future research should explore associations prospectively and in studies designed to better determine directionality, including trials. Moreover, future studies should examine serum biomarkers by specific CVD type and severity of disease to elucidate baseline levels of biomarkers across clinical groups. Additional serum biomarkers should be considered, including biomarkers related to other mechanisms involved in CVD (e.g., biomarkers related to overall aging and inflammatory processes). Finally, future investigations should be conducted in broader, more diverse populations representing both sexes and other groups underrepresented in research.
AUTHOR CONTRIBUTIONS
Shannon Halloway (Conceptualization; Funding acquisition; Investigation; Methodology; Project administration; Supervision; Writing – original draft; Writing – review & editing); Annabelle Volgman (Investigation; Methodology; Resources; Writing – review & editing); Lisa Barnes (Conceptualization; Investigation; Methodology; Resources; Writing – review & editing); Michael Schoeny (Data curation; Formal analysis; Investigation; Methodology; Supervision; Validation; Writing – review & editing); JoEllen Wilbur (Investigation; Methodology; Project administration; Resources; Software; Supervision; Writing – review & editing); Susan J. Pressler (Investigation; Methodology; Writing – review & editing); Deepika Laddue (Writing – review & editing); Shane Phillips (Writing – review & editing); Shamatree Shakya (Writing – original draft; Writing – review & editing); Madison Goodyke (Writing – original draft; Writing – review & editing); Gabriel Hall (Project administration; Writing – original draft; Writing – review & editing); Claire Auger (Formal analysis; Methodology; Writing – review & editing); Kelly Cagin (Project administration; Writing – review & editing); Jeffrey Borgia (Formal analysis; Methodology; Resources; Writing – review & editing); Zoe Arvanitakis (Conceptualization; Investigation; Methodology; Writing – review & editing).
Footnotes
ACKNOWLEDGMENTS
We would like to thank our research participants and patients of the Rush Heart Center for Women. Also, we acknowledge Dr. Martina Williams, Ana Garcia, and Kaitlin Wilhelm for their data collection and data management efforts. We would also like to thank the Rush Heart Center for women cardiology providers and staff. We thank Kevin Grandfield for editorial assistance.
FUNDING
This work was supported by the National Institute of Nursing Research (R01NR018443).
CONFLICT OF INTEREST
The authors have no conflict of interest to report.
DATA AVAILABILITY
The data supporting the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy restrictions.
