Assessment of resting myocardial blood flow in regions of known transmural scar to confirm accuracy and precision of 3D cardiac positron emission tomography.

BACKGROUND: Composite invasive and non-invasive data consistently demonstrate that resting myocardial blood flow (rMBF) in regions of known transmural myocardial scar (TMS) converge on a value of ~ 0.30 mL/min/g or lower. This value has been confirmed using the 3 most common myocardial perfusion agents (13N, 15O-H2O and 82Rb) incorporating various kinetic models on older 2D positron emission tomography (PET) systems. Thus, rMBF in regions of TMS can serve as a reference "truth" to evaluate low-end accuracy of various PET systems and software packages (SWPs). Using 82Rb on a contemporary 3D-PET-CT system, we sought to determine whether currently available SWP can accurately and precisely measure rMBF in regions of known TMS. RESULTS: Median rMBF (in mL/min/g) and COV in regions of TMS were 0.71 [IQR 0.52-1.02] and 0.16 with 4DM; 0.41 [0.34-0.54] and 0.10 with 4DM-FVD; 0.66 [0.51-0.85] and 0.11 with Cedars; 0.51 [0.43-0.61] and 0.08 with Emory-Votaw; 0.37 [0.30-0.42], 0.07 with Emory-Ottawa, and 0.26 [0.23-0.32], COV 0.07 with HeartSee. CONCLUSIONS: SWPs varied widely in low end accuracy based on measurement of rMBF in regions of known TMS. 3D PET using 82Rb and HeartSee software accurately (0.26 mL/min/g, consistent with established values) and precisely (COV = 0.07) quantified rMBF in regions of TMS. The Emory-Ottawa software yielded the next-best accuracy (0.37 mL/min/g), though rMBF was higher than established gold-standard values in ~ 5% of the resting scans. 4DM, 4DM-FDV, Cedars and Emory-Votaw SWP consistently resulted values higher than the established gold standard (0.71, 0.41, 0.66, 0.51 mL/min/g, respectively), with higher interscan variability (0.16, 0.11, 0.11, and 0.09, respectively). TRIAL REGISTRATION: clinicaltrial.gov, NCT05286593, Registered December 28, 2021, https://clinicaltrials.gov/ct2/show/NCT05286593 .

Updates on obesity and the obesity paradox in cardiovascular diseases.

The prevalence of obesity has reached pandemic proportions worldwide and certainly in the United States. Obesity is a well-established independent risk factor for development of many cardiovascular diseases (CVD), including heart failure, coronary heart disease, atrial fibrillation, and hypertension. Therefore, it is logical to expect obesity would have a strong correlation with CVD mortality. However, a substantial body of literature demonstrates a paradox with improved prognosis of overweight and obese patients with established CVD compared to lean patients with the identical CVD. Surprisingly, similar data has also shown that cardiovascular fitness, rather than weight loss alone, influences the relationship between obesity and mortality in those with established CVD. The impact of fitness, exercise, physical activity (PA), and weight loss and their relationship to the obesity paradox are all reviewed here.

Peak oxygen consumption achieved at the end of cardiac rehabilitation predicts long-term survival in patients with coronary heart disease.

AIMS: Cardiac rehabilitation (CR) improves survival in patients with coronary heart disease (CHD), which is largely mediated by the improvements in cardiorespiratory fitness (CRF) defined as peak oxygen consumption (VO2). Therefore, measuring CRF is essential to predict long-term outcomes in this population. It is unclear, however, whether peak VO2 achieved at the end of CR (END-peak VO2) predicts survival or whether the changes of CRF achieved during CR provide a greater prognostic value. To determine whether END-peak VO2 independently predicts long-term survival in patients with CHD undergoing CR. We also aimed at identifying cut-offs for END-peak VO2 that could be used in clinical practice. METHODS AND RESULTS: Retrospective analysis of 853 patients with CHD referred to CR who completed a maximal cardiopulmonary exercise test. Survival analysis was performed to examine the risk of all-cause mortality (average follow-up years: 6.65) based on peak VO2. The Contal and O'Quigley's method was used to determine the optimal cut-off of END-peak VO2 based on the log-rank statistic. END-peak VO2 was inversely associated with mortality risk [hazard ratio (HR) = 0.84; 95% confidence interval (CI) = 0.78-0.90], independent of changes in peak VO2 adjusted for the baseline peak VO2. The estimated cut-off of END-peak VO2 at ≥17.6 mL/kg/min best predicted the survival with high predictive accuracy and patients with END-peak VO2 under the cut-off had a greater risk of mortality (HR = 2.93; 95% CI = 1.81-4.74). CONCLUSIONS: In patient with CHD undergoing CR, END-peak VO2 is an independent predictor for long-term survival. Studies utilizing higher intensity CR programmes, with and without pharmacologic strategies, to increase peak VO2 to a greater degree in those achieving a suboptimal END-peak VO2, are urgently needed.

The Effects of Exercise on Lipid Biomarkers.

The World Health Organization has declared obesity to be a global epidemic that increases cardiovascular disease (CVD) mortality risk factors, such as hypertension, diabetes, dyslipidemia, and atherosclerosis. The increasing ratio of time spent in sedentary activities to that spent performing physically demanding tasks increases the trends to obesity and susceptibility to these risk factors. Dyslipidemia is the foundation of atherosclerotic buildup and lipoproteins serve as cofactors to the inflammatory processes that destabilize plaques. Increasing cardiorespiratory fitness and muscular strength helps attenuate concentrations of low-density lipoproteins (LDLs), such as LDL cholesterol, and increase levels of high-density lipoprotein cholesterol, as well as reduce proprotein convertase subtilisin kexin type 9 expression. Effects of physical activity on the inflammatory pathways of atherosclerosis, specifically C-reactive protein, are more closely related to reducing the levels of adiposity in tandem with increasing fitness, than with exercise training alone. The purpose of this review is to describe the physiology of dyslipidemia and relate it to CVD and exercise therapies.

Impact of cardiorespiratory fitness on outcomes in cardiac rehabilitation.

Cardiovascular rehabilitation (CR) significantly improves outcomes in patients with cardiovascular diseases (CVD), especially coronary heart disease and heart failure (HF). Although CR is often considered as an exercise training (ET) program for patients following CVD events, CR is more than just ET as it involves education, dietary and psychological counseling, as well as a multi-factorial risk factor modification. However, a major component of ET involves efforts to measure and improve levels of cardiorespiratory fitness (CRF). In this state-of-the-art review, we analyze the data, including from our John Ochsner Heart and Vascular Institute, evaluating CRF and its impact on psychological improvements and major outcomes with CR, especially long-term survival.

Development and Validation of a Multivariable Risk Prediction Model for COVID-19 Mortality in the Southern United States.

OBJECTIVE: To evaluate clinical characteristics of patients admitted to the hospital with coronavirus disease 2019 (COVID-19) in Southern United States and development as well as validation of a mortality risk prediction model. PATIENTS AND METHODS: Southern Louisiana was an early hotspot during the pandemic, which provided a large collection of clinical data on inpatients with COVID-19. We designed a risk stratification model to assess the mortality risk for patients admitted to the hospital with COVID-19. Data from 1673 consecutive patients diagnosed with COVID-19 infection and hospitalized between March 1, 2020, and April 30, 2020, was used to create an 11-factor mortality risk model based on baseline comorbidity, organ injury, and laboratory results. The risk model was validated using a subsequent cohort of 2067 consecutive hospitalized patients admitted between June 1, 2020, and December 31, 2020. RESULTS: The resultant model has an area under the curve of 0.783 (95% CI, 0.76 to 0.81), with an optimal sensitivity of 0.74 and specificity of 0.69 for predicting mortality. Validation of this model in a subsequent cohort of 2067 consecutively hospitalized patients yielded comparable prognostic performance. CONCLUSION: We have developed an easy-to-use, robust model for systematically evaluating patients presenting to acute care settings with COVID-19 infection.

Tailoring the management of hypertension to comorbidities.

PURPOSE OF REVIEW: In this article, we review the most current evidence for initiation and maintenance of various antihypertension (HTN) drug classes, including other misconceptions with respect to common comorbidities in patients with HTN. RECENT FINDINGS: Although the currently available anti-HTN agents have broad applicability in treating HTN, additional agents, such as angiotensin receptor-neprilysin inhibitors and novel nonsteroidal mineralocorticoid antagonists, have recently gained clinical significance. In addition, there have been some anecdotal concerns regarding the adverse effects, indications, and risks of COVID-19 infection/mortality when using certain anti-HTN agents. SUMMARY: Current guidelines currently address the treatment of primary HTN. However, isolated HTN is uncommon and often involves comorbid diseases that require specific regimentation. Several experimental medications are currently in late-stage trials showing potential superiority over current drugs that are available in the market.

A Review of Obesity, Physical Activity, and Cardiovascular Disease.

PURPOSE OF REVIEW: The focus of this review is to discuss obesity, physical activity (and physical inactivity/sedentary behavior), cardiovascular disease (CVD), and their often interrelated health implications. The authors summarize the pathophysiological changes associated with obesity, which lead to the development of CVD, recommendations for interventions such as diet, increased physical activity, and weight loss according to current literature and guidelines, and the critical importance of cardiorespiratory fitness (CRF). RECENT FINDINGS: Clinical trials continue to demonstrate improved outcomes among overweight or obese individuals who achieve a healthy weight using various methods. Increasing CRF levels appears to demonstrate the largest health improvements, regardless of underlying comorbidities or achieving weight loss. CRF, which is perhaps the single most important predictor of overall health, seems more important than weight loss alone regarding improved CVD outcomes in the obese population. These findings are reproduced in studies involving patients with various forms of CVD and CVD risk factors. The importance of CRF is well established; future endeavors to establish specific CRF targets for various patient cohorts are needed.

Dimensionless index of the mitral valve for evaluation of degenerative mitral stenosis.

PURPOSE: Degenerative mitral stenosis (DMS) is an increasingly recognized cause of mitral stenosis. The goal of this study was to compare echocardiographic differences between DMS and rheumatic mitral stenosis (RMS), identify echocardiographic variables reflective of DMS severity, and propose a dimensionless mitral stenosis index (DMSI) for assessment of DMS severity. METHODS: This is a single-center, retrospective cohort study. We included patients with at least mild MS and a mean transmitral pressure gradient (TMPG) ≥4 mm Hg. Mitral valve area by the continuity equation (MVACEQ ) was used as an independent reference. The DMSI was calculated as follows: DMSI = VTILVOT / VTIMV. All-cause mortality data were collected retrospectively. RESULTS: A total of 64 patients with DMS and 24 patients with RMS were identified. MVACEQ was larger in patients with DMS (1.43 ± 0.4 cm2 ) than RMS (0.9 ± 0.3 cm2 ) by ~0.5 cm2 (P = <.001), and mean TMPG was lower in the DMS group (6.0 ± 2 vs 7.9 ± 3 mm Hg, P = .003). A DMSI of ≤0.50 and ≤0.351 was associated with MVACEQ ≤1.5 and MVACEQ ≤1.0 cm2 (P < .001), respectively. With the progression of DMS from severe to very severe, there was a significant drop in DMSI. There was a nonsignificant trend toward worse survival in patients with MVACEQ ≤1.0 cm2 and DMSI ≤0.35, suggesting severe stenosis severity. CONCLUSION: Our results show that TMPG correlates poorly with MVA in patients with DMS. Proposed DMSI may serve as a simple echocardiographic indicator of hemodynamically significant DMS.

Hypertension in obesity.

PURPOSE OF REVIEW: The obesity epidemic is progressively affecting majority of individuals worldwide leading to many adverse metabolic and cardiovascular outcomes. Increasingly concerning among them is obesity hypertension (HTN). In this review, we delve into the physiology and therapeutic options in obesity HTN as we discuss the implications of obesity HTN on society. RECENT FINDINGS: Obesity is the most common cause of primary HTN and is directly proportional to increases BMI. The significance of adiposity in obesity HTN centers on humoral mechanisms via stimulation of the renal-angiotensin system, leptin activity, sympathetic overdrive, and proinflammatory processes that potentiate vascular remodeling, which results in a higher incidence of the progression of many known serious cardiovascular diseases. Although lifestyle and medical therapies have been recommended for obesity and its sequelae, continued global progression of this disease has driven the development of newer therapies such as carotid baroreflex activation therapy, renal denervation, and selective leptin receptor antagonism. SUMMARY: The pathophysiology of obesity HTN has not yet been fully elucidated despite it being one of the oldest known diseases to mankind. Major efforts to understand obesity HTN endures, paving opportunities for newer and possibly superior therapeutic options.

Impact of fitness and changes in fitness on lipids and survival.

In the past five decades, cardiorespiratory fitness (CRF) has become fairly established as an important risk factor or marker for cardiovascular disease (CVD), as well as CVD - and all-cause mortality. Substantial evidence supports a strong inverse association between baseline levels of CRF and the risk of developing CVD risk factors, including dyslipidemia. Additionally, accumulating evidence also supports that maintaining or improving a certain level of CRF over time leads to a lower rate of developing CVD risk factors, such as dyslipidemia, and also improves survival. Recent evidence also supports the role of resistance exercise and muscular strength to reduce the development of metabolic syndrome and hypercholesterolemia and potentially reduce development of diabetes as well, in addition to improving survival. Therefore, great efforts are needed to increase both CRF and muscle strength with aerobic exercise and resistance exercise in the primary and secondary prevention of CVD.

Who Should Receive a Wearable Defibrillator Vest at Hospital Discharge?

PURPOSE OF REVIEW: To discuss the role of wearable cardioverter defibrillator (WCD) vests in preventing sudden cardiac death (SCD) in at-risk populations. RECENT FINDINGS: The impact of randomized-controlled trials with implantable cardioverter-defibrillators (ICD) therapy is well established in randomized clinical trials in ischemic cardiomyopathy. Although the benefits are not as clear in non-ischemic cardiomyopathy, meta-analyses show significant mortality benefits from immediate electrical cardioversion strategies. The role of WCDs in at-risk populations in whom ICD therapy is temporarily not indicated is not as well-established. Smaller cohort trials have shown efficacy in patients with newly-diagnosed cardiomyopathy, requiring temporary ICD explantation, and others with less common indications for WCD therapy. The Vest Prevention of Early Sudden Death Trial was a landmark randomized control study seeking to examine the benefits of WCD therapy in at-risk population, and although the primary endpoint of reducing arrhythmic death was not reached, the structure of the trial and significant differences in total mortality make a compelling case for continued use of WCD therapies in our healthcare systems.

Exercise training and cardiac rehabilitation in cardiovascular disease.

Introduction: The aim of this review is to introduce the audience to exercise training (ET) as a therapeutic tool in coronary heart disease (CHD) and to discuss the role of and advances in cardiac rehabilitation (CR) as a means of effectively delivering ET. Areas covered: The physiological mechanisms behind ET effects on the cardiovascular (CV) system as well as the implementation of ET in CR and the effects of CR on CV morbidity, risk factor modification, and mortality will be reviewed. Additionally, the clinical and financial impact of CR in today's healthcare systems will be discussed. Expert opinion: It is well-established that CR continues to be under-utilized despite significant benefits to patients and healthcare systems alike. Innovation in the structure of CR (such as the implementation of high-intensity protocols) and in accessibility (home and tele-health CR programs) is already helping improve efficacy and increase utilization of CR. However, the efficacy of home/remote delivery protocols is not well established and they comprise a minority of available CR services. More data and efforts are needed to improve such protocols and maximize the reach of remote delivery systems in order to effectively deliver CR services to more eligible individuals at lower costs.

Effects of Physical Activity, Exercise, and Fitness on Obesity-Related Morbidity and Mortality.

Obesity is associated with increased prevalence of cardiovascular (CV) disease (CVD) risk factors, which may adversely impact CV structure and function and may increase the prevalence of most CVD, particularly heart failure (HF) and coronary heart disease (CHD). Physical activity (PA), exercise training (ET) and cardiorespiratory fitness (CRF) are all associated with marked reductions in most CVD, including HF and CHD. Additionally, PA/ET and, especially CRF, markedly alter the relationship between adiposity and subsequent major CVD outcomes and dramatically impact the "obesity paradox," which are all reviewed, including attention to the debate regarding "fitness versus fatness" for long-term prognosis, including in patients with established CVD.

Echocardiography in Congenital Heart Disease.

As the prevalence of adult congenital heart disease continues to grow secondary to advances in surgical and diagnostic techniques, it is important for a physician to supplement their examinations with non-invasive imaging techniques to assess their patients. Although a number of these patients have regular cardiology followup, some may be new patients that do not even know their cardiac history. Echocardiography has proven to be a useful tool for this purpose and its utility has expanded drastically with the development of better technology and newer techniques. In this article, we highlight some of these advancements including 2D echocardiography, agitated saline, contrast echocardiography, stress, and 4D, in addition to how each modality can help assess key aspects of the structure and function of a congenital heart defect.