Sergey Kachur

Body Composition and Mortality in a Large Cohort With Preserved Ejection Fraction: Untangling the Obesity Paradox

OBJECTIVE To evaluate the effects of body composition as a function of lean mass index (LMI) and body fat (BF) on the correlation between increasing body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) and decreasing mortality, which is known as the obesity paradox. PATIENTS AND METHODS We retrospectively assessed 47,866 patients with preserved left ventricular ejection fraction (≥50%). We calculated BF by using the Jackson-Pollock equation and LMI using (1 - BF) × BMI. The population was divided according to the sex-adjusted BMI classification, sex-adjusted LMI classification, and sex-adjusted BF tertiles. The population was analyzed by using multivariate analysis for total mortality over a mean follow-up duration of 3.1 years by using the National Death Index, adjusting for left ventricular ejection fraction, left ventricular mass index, age, sex, and relative wall thickness. RESULTS In the entire population, higher BMI was narrowly associated (hazard ratio [HR], 0.99; P<.001) with lower mortality. The higher LMI group was clearly protective (HR, 0.71; P<.001), whereas BF tertile was associated with lower mortality only if no adjustment was made for LMI (HR, 0.87; P<.001 without LMI; HR, 0.97; P=.23 with LMI). In the lean patients, low BMI was clearly associated with higher mortality (HR, 0.92; P<.001) and lower BF tertile was associated with lower mortality only if no adjustment was made for LMI (HR, 0.80; P<.001 without LMI; HR, 1.01; P=.83 with LMI). The underweight patients stratified by BF seemed to have an increased mortality (HR, 1.91; 95% CI, 1.56-2.34) that was independent of LMI. However, in obese patients, both BMI (HR, 1.03; P<.001) and BF (HR, 1.18; P=.003) were associated with higher mortality, even after adjusting for LMI, which remained protective (HR, 0.57; P<.001) independently of BF. CONCLUSION Body composition could explain the inverse J shape of the mortality curve noted with increasing BMI. Body fat seems to be protective in this cohort only if no adjustment was made for LMI, although being underweight stratified by BF seems to be an independent risk factor. Lean mass index seems to remain protective in obese patients even when BMI is not.

Impact of cardiac rehabilitation and exercise training programs in coronary heart disease

Cardiovascular rehabilitation (CR) is the process of developing and maintaining an optimal level of physical, social, and psychological well-being in order to promote recovery from cardiovascular (CV) illness. It is a multi-disciplinary approach encompassing supervised exercise training, patient counseling, education and nutritional guidance that may also enhance quality of life. Beneficial CV effects may include improving coronary heart disease risk factors; particularly exercise capacity, reversing cardiac remodeling, and favorably modifying metabolism and systemic oxygen transport. We review the historical basis for contemporary CR, the indications and critical components of CR, as well as the potential salutary physiological and clinical effects of exercise-based CR.

Obesity and cardiovascular diseases.

Obesity is increasingly more common in postindustrial societies, and the burden of childhood obesity is increasing. The major effects of obesity on cardiovascular (CV) health are mediated through the risk of metabolic syndrome (insulin-resistance, dyslipidemia, and hypertension), such that an absence of these risk factors in obese individuals may not be associated with increased mortality risk. In individuals already diagnosed with chronic CV disease (CVD), the overweight and class I obese have significant associations with improved survival. However, this effect is attenuated by increases in cardiorespiratory fitness. The negative effects of obesity on CV health manifest as accelerated progression of atherosclerosis, higher rates of ventricular remodeling and a higher risk of associated diseases, including stroke, myocardial infarction, and heart failure. The most effective therapies at reversing CVD risk factors associated with obesity have been dietary changes with exercise, especially through structured exercise programs, such as cardiac rehabilitation.

The impact of inflammation on the obesity paradox in coronary heart disease

Background:Despite the well-known adverse effects of obesity on almost all aspects of coronary heart disease, many studies of coronary heart disease cohorts have demonstrated an inverse relationship between obesity, as defined by body mass index (BMI), and subsequent prognosis: the ‘obesity paradox’. The etiology of this and the potential role of inflammation in this process remain unknown.Patients and Methods:We studied 519 patients with coronary heart disease before and after cardiac rehabilitation, dividing them into groups based on C-reactive protein ((CRP)⩾3 mg l−1 and CRP<3 mg l−1 after cardiac rehabilitation). BMI was calculated and body fat was measured using the skin-fold method. Lean mass index (LMI) was calculated as (1−%body fat) × BMI. The population was divided according to age- and gender-adjusted categories based on LMI and body fat and analyzed by total mortality over >3-year follow-up by National Death Index in both CRP groups.Results:During >3-year follow-up, all-cause mortality was higher in the high inflammation and in the low BMI group. In proportional hazard analysis, even after adjusting for ejection fraction and peak O2 consumption, higher BMI was associated with lower mortality in the entire population (hazard ratio (HR) 0.38; confidence interval 0.15–0.97) and a trend to lower mortality in both subgroups (HR 0.45 in low CRP, P=0.24 vs HR 0.32, P=0.06 in high CRP). High body fat, however, was associated with significantly lower mortality in the high CRP group (HR 0.22; P=0.03) but not in the low CRP group (HR 0.73; P=0.64). Conversely, high LMI was associated with markedly lower mortality in the low CRP group (HR 0.04; P=0.04).Conclusions:The obesity paradox has multiple underlying etiologies. Body composition has a different role in different populations with an obesity paradox by BMI. Especially in the subpopulation with persistently high CRP levels, body fat seems protective.

Cardiac Rehabilitation Fitness Changes and Subsequent Survival

Aims Assessments of cardiac rehabilitation (CR) in coronary heart disease (CHD) cohorts usually examine mortality in aggregate. This study examines the prognosis and characteristics of patients who enrolled and completed CR, stratified by their level of improvement in cardiorespiratory fitness (CRF) by examining the characteristics, outcomes and predictors of non-response in CRF (NonRes) compared with low-responders (LowRes) and high-responders (HighRes) after CR. Methods and results A total of 1171 CHD patients were referred for a phase II CR programme after therapy for an acute coronary syndrome, coronary artery bypass graft procedure or a percutaneous coronary intervention between 1 January 2000 and 30 June 2013 underwent cardiopulmonary exercise testing before and after CR. This cohort was divided according to absolute improvements in CRF (i.e. change in peak oxygen consumption expressed in mL⋅kg-1⋅min-1). Mortality was analysed after 0.5-13.4 years of follow-up (mean 6.4 years). A total of 266 (23%) subjects were NonRes. After adjustment for body mass index, age, gender, left ventricular ejection fraction and baseline CRF, NonRes, and LowRes had a statistically significant three-fold and two-fold higher mortality, respectively, when compared with HighRes (HighRes 8% vs. LowRes 17% vs. NonRes 22%; P < 0.001). Age, female gender, baseline CRF, hostility, and presence of diabetes were significant predictors of NonRes and LowRes. In addition, higher waist circumference was a predictor of NonRes. Conclusion Significant proportions of subjects referred to CR have no/low improvement in CRF and higher associated mortality risks. Greater attention is required to increase improvements in CRF following CR and avoid NonRes.

Cardiovascular Risk in Patients with Prehypertension and the Metabolic Syndrome

Prehypertension (pHTN) and metabolic syndrome (MetS) are both lifestyle diseases that are potentiated by increased adiposity, as both disease processes are closely related to weight. In the case of pHTN, increased adiposity causes dysregulation of the renin-angiotensin-aldosterone-system (RAAS) as well as adipokine- and leptin-associated increases in adrenergic tone. In MetS, excess weight potentiates hyperglycemia and insulin resistance which causes positive feedback into the RAAS system, activates an inflammatory cascade that potentiates atherosclerosis, and causes lipid dysregulation which together contribute to cardiovascular disease, especially coronary heart disease (CHD) and heart failure (HF). The relationship with all-cause mortality is not as clear-cut in part because of some protective effects associated with the obesity paradox in chronic diseases such as CHD and HF. However, in healthy populations, the absence of excess weight and its associated effects on prehypertension and MetS are associated with a longer absolute and disease-free lifespan.

Exercise and Cardiovascular Disease: Emphasis on Efficacy, Dosing, and Adverse Effects and Toxicity

Abstract Physical inactivity is one of the greatest threats to health in the United States and throughout most of the world. Many studies have demonstrated a linear relationship between physical activity level and reduction in cardiovascular and all-cause morbidity and mortality. However, there is evolving evidence that high levels of exercise may produce similar or less overall benefit than lower doses of exercise. Very high doses of exercise may be associated with increased risk of coronary heart disease, atrial fibrillation, and sudden cardiac death. The benefits of exercise training, recommendations to optimize the dose of exercise to achieve maximal benefit, and potential cardiotoxicity of excessive exercise are reviewed in this chapter.

FITNESS AND THE OBESITY PARADOX IN CARDIAC REHABILITATION: HOW DOES WEIGHT LOSS FACTOR IN?

Background: Weight loss (WL) confers benefits to insulin resistance and cardiovascular (CV) events, and is a hallmark of most successful exercise programs, but WL in a chronic disease population can also be a sign of progressive frailty. Recent work in the obesity paradox finds that the protective

Cardiac Rehabilitation and Exercise Training in the Elderly

Purpose of ReviewWith recent improvements in cardiovascular care and prevention, the demographic of individuals enrolled into cardiac rehabilitation (CR) is shifting towards an older set of individuals. Management plans for elderly cardiovascular patients must consider processes associated with aging, sarcopenia, cognitive impairment, and inflammation all contributing to declining functional capacity.Recent FindingsIncreased debility at baseline does not translate into a significantly higher risk associated with physical activity but does require better access. High-intensity interval training protocols have shown benefits while preserving safety over the standard of moderate-intensity continuous training.SummaryIn elderly populations, CR needs to include more than just exercise; addressing psychosocial stress burdens as an independent part of CR has the potential to improve adherence and outcomes. Doing this through new programs and at home and through mobile devices has the potential to greatly increase adherence and access, and can help remedy current underutilization of CR in the US medical system.