Current status of global research on pericardial diseases: a bibliometric analysis of the top 100 from Web of Science.

Introduction: Bibliometric studies can help guide researchers and funding bodies toward fields where more research activity is warranted. Bibliometric analyses have previously been published in many specialties and sub-specialties. Our literature search did not show a bibliometric analysis on pericardial diseases. We performed a bibliometric analysis of the top 100 cited manuscripts on pericardial diseases to identify knowledge. Material and methods: Bibliometric analysis is a quantitative method to assess research performance and analyze publication trends. Web of Science was searched in April 2020 to identify the top 100 cited manuscripts in pericardial diseases. Results: Twenty-six out of the top 100 cited manuscripts were published between 2000 and 2009. These manuscripts were cited on average189 times (range: 110-743) since publication. Only two manuscripts were cited > 500 times. Among the top-ten cited manuscripts, there were 6 original articles, 1 case series, and 3 review articles. Of the 3 review articles, 2 were society guidelines. 90% of the authors had written just 1 manuscript. There were ten manuscripts with women as first authors with a significant association between gender of the first and corresponding author (odds ratio = 44, p < 0.001). Only 20% of manuscripts were funded. Most publications came from institutions in the United States (n = 40), Italy (n = 10), and Spain (n = 5). Conclusions: Our study provides an insight into the characteristics and quality of the highly cited literature in the field of pericardial diseases. This can be used to guide further research in the field of pericardial diseases.

Coronary flow abnormalities in chronic kidney disease: A systematic review and meta-analysis.

BACKGROUND: Coronary vasomotion abnormalities have been described in small studies but not studied systematically. We aimed to review the present literature and analyze it to improve our understanding of chronic kidney disease (CKD) related-coronary microvascular dysfunction. OBJECTIVE: Coronary flow reserve (CFR) is a well-known measure of coronary vasomotion. We aimed to assess the difference in CFR among participants with and without CKD. METHODS: PubMed, Embase, and Cochrane CENTRAL were systematically reviewed to identify studies that compared CFR in participants with and without CKD. We estimated standardized mean differences in mean CFR reported in these studies. We performed subgroup analyses according to imaging modality, and the presence of significant epicardial coronary artery disease. RESULTS: In 14 observational studies with 5966 and 1410 patients with and without CKD, the mean estimated glomerular filtration rate (eGFR) was 29 ± 04 and 87 ± 25 ml/min/1.73 m2 , respectively. Mean CFR was consistently lower in patients with CKD in all studies and the cumulative mean difference was statistically significant (2.1 ± .3 vs. 2.7 ± .5, standardized mean difference -.8, 95% CI -1.1, -.6, p < .05). The lower mean CFR was driven by both significantly higher mean resting flow velocity (.58 cm/s, 95% CI .17, .98) and lower mean stress flow velocity (-.94 cm/s, 95% CI -1.75, -.13) in studies with CKD. This difference remained significant across diagnostic modalities and even in absence of epicardial coronary artery disease. In meta-regression, there was a significant positive relationship between mean eGFR and mean CFR (p < .05). CONCLUSION: Patients with CKD have a significantly lower CFR versus those without CKD, even in absence of epicardial coronary artery disease. There is a linear association between eGFR and CFR. Future studies are required to understand the mechanisms and therapeutic implications of these findings. KEY POINTS: In this meta-analysis of observational studies, there was a significant reduction in coronary flow reserve in studies with chronic kidney disease versus those without. This difference was seen even in absence of epicardial coronary artery disease. In meta-regression, a lower estimate glomerular filtration rate was a significant predictor of lower coronary flow reserve. Coronary microvascular dysfunction, rather than atherosclerosis-related epicardial disease may underly increase cardiovascular risk in a patient with chronic kidney disease.

Role of Exercise Treadmill Testing in the Assessment of Coronary Microvascular Disease.

OBJECTIVES: The authors aimed to study the sensitivity and specificity of exercise treadmill testing (ETT) in the diagnosis of coronary microvascular disease (CMD), as well as the prognostic implications of ETT results in patients with CMD. BACKGROUND: ETT is validated to evaluate for flow-limiting coronary artery disease (CAD), however, little is known about its use for evaluating CMD. METHODS: We retrospectively studied 249 consecutive patients between 2006 and 2016 who underwent ETT and positron emission tomography within 12 months. Patients with obstructive CAD or left ventricular systolic dysfunction were excluded. CMD was defined as a coronary flow reserve <2. Patients were followed for the occurrence of a first major adverse event (composite of death or hospitalization for myocardial infarction or heart failure). RESULTS: The sensitivity and specificity of a positive ETT to detect CMD were 34.7% (95% CI: 25.4%-45.0%) and 64.9% (95% CI: 56.7%-72.5%), respectively. The specificity of a positive ETT to detect CMD increased to 86.8% (95% CI: 80.3%-91.7%) when only classifying studies with ischemic electrocardiogram changes that lasted at least 1 minute into recovery as positive, although at a cost of lower sensitivity (15.3%; 95% CI: 8.8%-24.0%). Over a median follow-up of 6.9 years (IQR: 5.1-8.2 years), 30 (12.1%) patients met the composite endpoint, including 13 (13.3%) with CMD (n = 98). In patients with CMD, ETT result was not associated with the composite endpoint (P = 0.076). CONCLUSIONS: Our data suggest limited sensitivity of ETT to detect CMD. However, a positive ETT with ischemic changes that persist at least 1 minute into recovery in the absence of obstructive CAD should raise suspicion for the presence of CMD given a high specificity. Further study is needed with larger patient sample sizes to assess the association between ETT results and outcomes in patients with CMD.

Association of Myocardial Blood Flow Reserve With Adverse Left Ventricular Remodeling in Patients With Aortic Stenosis: The Microvascular Disease in Aortic Stenosis (MIDAS) Study.

Importance: Impaired myocardial flow reserve (MFR) and stress myocardial blood flow (MBF) on positron emission tomography (PET) myocardial perfusion imaging may identify adverse myocardial characteristics, including myocardial stress and injury in aortic stenosis (AS). Objective: To investigate whether MFR and stress MBF are associated with LV structure and function derangements, and whether these parameters improve after aortic valve replacement (AVR). Design, Setting, and Participants: In this single-center prospective observational study in Boston, Massachusetts, from 2018 to 2020, patients with predominantly moderate to severe AS underwent ammonia N13 PET myocardial perfusion imaging for myocardial blood flow (MBF) quantification, resting transthoracic echocardiography (TTE) for assessment of myocardial structure and function, and measurement of circulating biomarkers for myocardial injury and wall stress. Evaluation of health status and functional capacity was also performed. A subset of patients underwent repeated assessment 6 months after AVR. A control group included patients without AS matched for age, sex, and summed stress score who underwent symptom-prompted ammonia N13 PET and TTE within 90 days. Exposures: MBF and MFR quantified on ammonia N13 PET myocardial perfusion imaging. Main Outcomes and Measures: LV structure and function parameters, including echocardiographic global longitudinal strain (GLS), circulating high-sensitivity troponin T (hs-cTnT), N-terminal pro-B-type natriuretic peptide (NT-pro BNP), health status, and functional capacity. Results: There were 34 patients with AS (1 mild, 9 moderate, and 24 severe) and 34 matched control individuals. MFR was independently associated with GLS and LV ejection fraction, (ß,-0.31; P = .03; ß, 0.41; P = .002, respectively). Stress MBF was associated with hs-cTnT (unadjusted ß, -0.48; P = .005) and log NT-pro BNP (unadjusted ß, -0.37; P = .045). The combination of low stress MBF and high hs-cTnT was associated with higher interventricular septal thickness in diastole, relative wall thickness, and worse GLS compared with high stress MBF and low hs-cTnT (12.4 mm vs 10.0 mm; P = .008; 0.62 vs 0.46; P = .02; and -13.47 vs -17.11; P = .006, respectively). In 9 patients studied 6 months after AVR, mean (SD) MFR improved from 1.73 (0.57) to 2.11 (0.50) (P = .008). Conclusions and Relevance: In this study, in AS, MFR and stress MBF were associated with adverse myocardial characteristics, including markers of myocardial injury and wall stress, suggesting that MFR may be an early sensitive marker for myocardial decompensation.

Sleep duration, baseline cardiovascular risk, inflammation and incident cardiovascular mortality in ambulatory U.S. Adults: National health and nutrition examination survey.

INTRODUCTION: The interplay between sleep duration and inflammation on the baseline and incident cardiovascular (CV) risk is unknown. We sought to evaluate the association between sleep duration, C-reactive protein (CRP), baseline CV risk, and incident CV mortality. METHODS: We used data from the National Health and Nutrition Examination Survey 2005-2010 linked with the cause of death data from the National Center for Health Statistics for adults aged ≥18 years. The associations between self-reported sleep duration and CRP, 10-year atherosclerotic CV disease risk score (ASCVD) and CV mortality were assessed using Linear, Poisson and Cox proportional hazard modeling as appropriate. RESULTS: There were 17,635 eligible participants with a median age of 46 years (interquartile range [IQR] 31, 63). Among them, 51.3% were women and 46.9% were non-Hispanic Whites. Over a median follow-up of 7.5 years (IQR 6.0, 9.1), 350 CV deaths occurred at an incident rate of 2.7 per 1000-person years (IQR 2.4, 3.0). We observed a U-shaped associations between sleep duration and incident CV mortality rate (P-trend=0.011), sleep duration and 10-year ASCVD risk (P-trend <0.001), as well as sleep duration and CRP (P-trend <0.001). A self-reported sleep duration of 6-7 hours appeared most optimal. We observed that those participants who reported <6 or >7 hours of sleep had higher risk of CV death attributable to inflammation after accounting for confounders. CONCLUSIONS: There was a U-shaped relationship of incident CV mortality, 10-year ASCVD risk, and CRP with sleep duration. These findings suggest an interplay between sleep duration, inflammation, and CV risk.

Regional impact of updated guidelines on prevalence and distribution of blood pressure categories for hypertension in India: Results from the National Family Health Survey 4.

INTRODUCTION: In 2017, the American College of Cardiology/American Heart Association revised guidelines for diagnosis and management of hypertension in adults. The regional impact of the updated guidelines on the prevalence of hypertension in India is unknown. METHODS: Data from nationally representative Indian households were analyzed to estimate the regional prevalence of hypertension according to the old and the new guidelines in men (age 18-54 years) and women (age 18-49 years). The old guidelines defined hypertension as a systolic blood pressure of ≥140 mmHg or diastolic blood pressure of ≥90 mmHg or treatment. The new guidelines define hypertension as a systolic blood pressure of ≥130 mmHg or diastolic blood pressure of ≥80 mmHg or treatment. We calculated the increase in the prevalence of hypertension among the states and union territories of India (hereafter "states"). RESULTS: Among 679,712 participants (85.6% women), the median age was 31 years (interquartile range 24, 40) and was comparable among men and women (33 vs. 31 years, respectively). The overall weighted prevalence according to old and new guidelines was 18.5% (95% CI 18.2, 18.7) and 43.0% (95% CI 42.8, 43.3), respectively. There was a significant increase in hypertension prevalence, both among men and women, and across all regions. The northeast region of the country had the highest prevalence. CONCLUSION: The overall prevalence of hypertension significantly increases with the new compared to the old guidelines, however, the regional heterogeneity of prevalence of hypertension is maintained.

Relative Predictive Value of Circulating Immune Markers in US Adults Without Cardiovascular Disease: Implications for Risk Reclassification.

OBJECTIVE: To investigate the relative predictive value of circulating immune cell markers for cardiovascular mortality in ambulatory adults without cardiovascular disease. METHODS: We analyzed data of participants enrolled in the National Health and Nutrition Examination Survey from January 1, 1999, to December 31, 2010, with the total leukocyte count within a normal range (4000-11,000 cells/µL [to convert to cells ×109/L, multiply by 0.001]) and without cardiovascular disease. The relative predictive value of circulating immune cell markers measured at enrollment-including total leukocyte count, absolute neutrophil count, absolute lymphocyte count, absolute monocyte count, monocyte-lymphocyte ratio (MLR), neutrophil-lymphocyte ratio, and C-reactive protein-for cardiovascular mortality was evaluated. The marker with the best predictive value was added to the 10-year atherosclerotic cardiovascular disease (ASCVD) risk score to estimate net risk reclassification indices for 10-year cardiovascular mortality. RESULTS: Among 21,599 participants eligible for this analysis, the median age was 47 years (interquartile range, 34-63 years); 10,651 (49.2%) participants were women, and 10,713 (49.5%) were self-reported non-Hispanic white. During a median follow-up of 9.6 years (interquartile range, 6.8-13.1 years), there were 627 cardiovascular deaths. MLR had the best predictive value for cardiovascular mortality. The addition of elevated MLR (≥0.3) to the 10-year ASCVD risk score improved the classification by 2.7%±1.4% (P=.04). Elevated MLR had better predictive value than C-reactive protein and several components of the 10-year ASCVD risk score. CONCLUSION: Among ambulatory US adults without preexisting cardiovascular disease, we found that MLR had the best predictive value for cardiovascular mortality among circulating immune markers. The addition of MLR to the 10-year risk score significantly improved the risk classification of participants.

Review of Published Cases of Syncope and Sudden Death in Patients With Severe Aortic Stenosis Documented by Electrocardiography.

The ECG findings during sudden collapse (syncope or sudden death) in severe aortic stenosis (AS) are not well defined. We conducted a comprehensive review of the literature for ECG data during sudden collapse in patients with AS and provided a case report of our own. There were 37 published cases of syncope or sudden death in patients with severe AS which were documented by ECG. Brady- or ventricular arrhythmias were documented in 34 cases (92%). Bradyarrhythmia (n = 24; 71%) was more common at the time of collapse than ventricular tachyarrhythmia (n = 10; 29%). There was slowing of the sinus rate before bradyarrhythmia in the vast majority of patients with bradyarrhythmia but not in those presenting with ventricular tachyarrhythmia (75% vs 0%; p <0.001). ECG evidence of ischemia (ST-segment depression or elevation) was present in most patients with bradyarrhythmia but not in those with ventricular tachyarrhythmia (75% vs 0%; p = 0.011). In conclusion, our findings suggest that left ventricular baroreceptor activation plays a dominant role in the pathophysiology of sudden collapse in patients with severe AS and suggest that ischemia may play a role as well.

Management of reproductive health in patients with pulmonary hypertension.

Pulmonary hypertension is characterized by elevated pulmonary artery pressure caused by several clinical conditions that affect pulmonary vasculature. Morbidity and death in this condition are related to the development of right ventricular failure. Normal physiologic changes that occur in pregnancy to support the growing fetus can pose hemodynamic challenges to the pregnant patient with pulmonary hypertension that results in increased morbidity and mortality rates. Current guidelines recommend that patients with known pulmonary hypertension be counseled against pregnancy. This review aims to provide clinicians with guidelines for preconception counseling, medication management, and delivery planning.

Assessment of Heterogeneity in Heart Failure-Related Meta-Analyses.

BACKGROUND: Assessment of heterogeneity in meta-analyses is critical to ensure the consistency of pooled results. Therefore, we sought to assess the evaluation and reporting of heterogeneity in heart failure (HF) meta-analyses. METHODS: Study level meta-analyses pertaining to HF were selected from January 2009 to July 2019, published in 11 high impact factor journals. We tabulated the overall proportion of the meta-analyses reporting statistical heterogeneity and specific metrics and methods employed to quantify and explore heterogeneity. RESULTS: Of 126 HF meta-analyses (612 outcomes), heterogeneity was reported for 422 outcomes (68.9 %) in 108 meta-analyses. Out of the 422 outcomes reporting statistical heterogeneity, 137 outcomes (32.5%) had no observable heterogeneity: (I2=0%), 40 outcomes (9.5%) had low heterogeneity (I2<25%), 76 outcomes (18%) had moderate heterogeneity (I2=25%-50%), and 169 outcomes (40%) had high heterogeneity (I2>50%). Reporting of statistical heterogeneity was not significantly associated with year of publication, funding source, disclosure information, or the type of studies pooled. Sensitivity analysis (n=68) was the most common statistical technique employed to evaluate the source of heterogeneity followed by subgroup analyses (n=59) and meta-regression (n=40). CONCLUSIONS: Despite being an essential component of meta-analyses, heterogeneity was not reported for nearly 30% of outcomes and variably handled in contemporary HF meta-analyses. As meta-analyses increase across HF science, interpreting and handling of heterogeneity should be standardized.

Cardiac Function and Sudden Cardiac Death in Heart Failure With Preserved Ejection Fraction (from the TOPCAT Trial).

Patients with heart failure with preserved ejection fraction (HFpEF) have a significantly elevated risk of sudden cardiac death (SCD). However, few imaging data have been correlated to this risk. We evaluated the value of multiple echocardiographic markers of left ventricular (LV) function to predict SCD in HFpEF patients. The Treatment of Heart Failure with Preserved Ejection Fraction with Aldosterone Trial (TOPCAT)-Americas cohort was used to evaluate the echocardiographic predictors of SCD and/or aborted cardiac arrest (SCD/ACA). A retrospective cohort design was used. Cox proportional hazards and Poisson regression models were used to determine the associations between the risk of SCD/ACA and echocardiographic parameters: diastolic dysfunction grade, left ventricle ejection fraction, and LV global longitudinal strain (GLS) during follow-up. Impaired left ventricle ejection fraction and GLS were associated with SCD/ACA in univariate models (p = 0.007 and 0.002, respectively), but not diastolic function grade. After multivariate adjustment, only GLS remained a significant predictor of the incidence rate of SCD/ACA (p = 0.006). There was a 58% increase in the hazard of incident SCD/ACA for every 1 unit increase in GLS (1.58, 95%CI: 1.12 to 2.22, p = 0.009). These findings remained robust in the competing risk analyses. In conclusion, amongst the multiple echocardiographic parameters of LV function, GLS may help prognosticate the risk of SCD/ACA in HFpEF patients.

Leucocyte count predicts cardiovascular risk in heart failure with preserved ejection fraction: insights from TOPCAT Americas.

AIMS: Prior evidence has implicated leucocyte expansion in several cardiovascular disorders, including heart failure (HF) with reduced ejection fraction (rEF). However, the prognostic importance of leucocyte count in HF with preserved EF (HFpEF) remains largely unexplored. METHODS AND RESULTS: The Americas cohort of the treatment of preserved cardiac function heart failure with an aldosterone antagonist (TOPCAT-Americas) was used to evaluate the association between total leucocyte count and clinical outcomes in HFpEF. The primary outcome was a composite of aborted cardiac arrest, cardiovascular mortality, or hospitalization for HF. Secondary outcomes were hospitalization for HF, aborted cardiac arrest, stroke, non-fatal myocardial infarction (MI), cardiovascular mortality, non-cardiovascular mortality, and all-cause mortality. Survival models were used to identify the risk of the primary and secondary outcomes in those with leucocyte count above the median (7100 cells/µL), as compared to those with leucocyte count below the median, during the follow-up period. A total of 1746 (out of 1767; 99%) patients from TOPCAT-Americas were available for the analyses with a median follow up of 2.4 (25th to 75th percentile 1.4-3.9) years. Patients with leucocyte count >7100 cells/µL were 36% more likely to experience the primary endpoint compared to those with ≤7100 cells/µL (hazard ratio: 1.36, 95% confidence interval: 1.14-1.61). This association remained significant after extensive adjustment for potential confounders (hazard ratio: 1.27, 95% confidence interval: 1.06-1.52). We also observed a greater incidence of HF hospitalization and non-fatal MI in patients with higher leucocyte count. These associations remained robust on sensitivity analyses, suggesting a low probability of confounding. Exploratory analyses suggested that both higher leucocyte count (integrating the combined influence of both myeloid and lymphoid immune cells) and augmented platelet count (as a surrogate for myeloid immune cell expansion) in the same model were associated with the primary outcome (both P < 0.05). CONCLUSIONS: Leucocyte count >7100 cells/µL was independently associated with adverse clinical outcomes in HFpEF patients from TOPCAT-Americas. These results were primarily driven by the HF hospitalization outcome but were also accompanied by an excess of non-fatal MI. Further research is needed to define the mechanisms underlying our findings and their prognostic implications.

Reduced Left Atrial Emptying Fraction and Chymase Activation in Pathophysiology of Primary Mitral Regurgitation.

Increasing left atrial (LA) size predicts outcomes in patients with isolated mitral regurgitation (MR). Chymase is plentiful in the human heart and affects extracellular matrix remodeling. Chymase activation correlates to LA fibrosis, LA enlargement, and a decreased total LA emptying fraction in addition to having a potential intracellular role in mediating myofibrillar breakdown in LA myocytes. Because of the unreliability of the left ventricular ejection fraction in predicting outcomes in MR, LA size and the total LA emptying fraction may be more suitable indicators for timing of surgical intervention.