Role of Obesity in Cardiomyopathy and Pulmonary Hypertension

Association between obesity and new-onset heart failure among patients with hypertension in Thailand

BACKGROUND

In Thailand, the epidemiological data on the relationship between obesity and heart failure (HF) among high-risk populations was limited. We assessed the association between body mass index (BMI) and the new-onset HF among people with hypertension (HTN), and also assessed the effect modifier of uncontrolled HTN on this association.

METHODS

We analyzed the data obtained from the 2018 Thailand DM/HT study database. Thai people with HTN aged 20 years and older receiving continuous care at outpatient clinics in hospitals nationwide were included. The new-onset HF was defined regarding the ICD-10 as I50 in the medical records within 12 months. Obesity was defined as BMI ≥ 25 kg/m2. Multivariable log-binomial regression analysis was used to determine the association between BMI and new-onset HF and presented as the adjusted risk ratio (aRR) and 95% confidence interval (CI).

RESULTS

A total of 35,756 participants were included in the analysis. In all, 50.0% of the participants had BP control for the last two consecutive visits. The mean BMI was 25.1 ± 4.7 kg/m2. New-onset HF occurred in 75 participants (0.21%; 95% CI 0.17-0.26). After adjusting for potential confounders, an elevated BMI was associated with new-onset HF (p value for quadratic trend < 0.001). In comparison with participants with normal BMI (18.5-22.9 kg/m2), the aRR for new-onset HF was 1.57 (95% CI 0.80-3.07) and 3.97 (95% CI 1.95-8.10) in those with BMI 25.0-29.9, and ≥ 30.0 kg/m2. For participants with obesity, aRR for new-onset HF was 2.05 (95% CI 1.24-3.39) compared to non-obese participants. The study found that among patients with control BP, obesity was associated with a higher risk of new-onset HF with an adjusted RR of 2.33 (95% CI 1.12-4.83). For those with uncontrolled BP, the adjusted RR was 1.83 (95% CI 0.93-3.58), but there was no heterogeneity with p value = 0.642.

CONCLUSION

An increased BMI had a higher risk for new-onset HF among Thai people with HTN. Obesity was independently associated with new-onset HF among people with HTN, regardless of uncontrolled HTN. Our findings highlight that weight reduction is crucial for mitigating the risk of HF development in HTN patients, regardless of their BP control status.

Perioperative management of a patient with morbid obesity and severe cardiomyopathy: a case report and literature review

As the obesity epidemic continues to escalate, the need for bariatric surgery will increase. Patients with severe cardiomyopathy and heart failure have historically been considered at high risk for perioperative complications and thus excluded from bariatric surgery. We herein describe a patient with morbid obesity, severe cardiomyopathy, and heart failure who successfully and safely underwent bariatric surgery and achieved significant weight loss and overall cardiac function improvement 1 year later. Although data are sparse, there is certainly evidence to suggest that significant weight reduction may confer a mechanism of ventricular reverse remodeling and subsequent clinical improvement.

Non-alcoholic Fatty Liver Disease and Its Association With Left Ventricular Diastolic Dysfunction: A Systematic Review

The commonest cause of hepatic illness globally is non-alcoholic fatty liver disease (NAFLD). This multisystemic disease affects extrahepatic organs, including the heart. It causes cardiac remodeling and a disruption of the systolic and diastolic functioning of the left ventricle. Numerous studies have investigated the connection between NAFLD and left ventricular diastolic dysfunction (LVDD). The results, nevertheless, are often contradictory. This systematic review looked at the relationship between NAFLD and LVDD generally and among different patient groups since it is a topic of interest. A thorough search approach was used to locate relevant publications published between 2003 and 2023 using major medical databases. Studies were chosen based on the pre-established eligibility criteria; the studies selected then underwent a critical evaluation using standardized quality assessment tools. For the systematic review, 13 articles were chosen, comprising nine cross-sectional studies, three narrative reviews, and one meta-analysis. There were a total of 13,341 NAFLD patients in these studies. Data extraction and qualitative synthesis from the selected research articles were conducted to determine the relationship between NAFLD and LVDD in various patient categories. We found a significant association between NAFLD and LVDD. Therefore, patients with NAFLD should be treated early to avoid complications since they are more likely to develop cardiac dysfunction in the future.

Impact of Rapid Weight Loss after Bariatric Surgery in Systemic Inflammatory Response and Pulmonary Hemodynamics in Severely Obese Subjects with Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) can be associated with obesity. The excessive production of proinflammatory mediators by dysfunctional adipocytes may enhance remodeling of the pulmonary vasculature and worsen pulmonary hemodynamics. This study aimed to describe the changes in pulmonary arterial pressures and systemic inflammation in patients with obesity with PH after bariatric surgery (BaS).

STUDY DESIGN

In this retrospective cohort study, we compared patients with PH who underwent BaS from 2008 to 2018 at our institution (group 1) to a group of severely obese patients with PH (group 2). Echocardiographic right ventricular systolic pressure (RVSP) was used as an indirect measurement of pulmonary arterial pressures. Red blood cell distribution width (RDW) was used as a marker of systemic inflammation.

RESULTS

A total of 40 patients were included, 20 per group. In group 1, the RVSP decreased from 44.69 ± 7.12 mmHg to 38.73 ± 12.81 mmHg (p = 0.041), and the RDW decreased from 15.22 ± 1.53 to 14.41 ± 1.31 (p = 0.020). In group 2, the RVSP decreased from 60.14 ± 18.08 to 59.15 ± 19.10 (0.828), and the RDW increased from 15.37 ± 1.99 to 15.38 ± 1.26 (0.983). For both groups, we found a positive correlation between RVSP and RDW changes, although the correlation was not statistically significant.

CONCLUSIONS

Previous studies suggest BaS could be a safe and effective procedure to achieve weight loss in obese patients with PH, with an additional modest improvement in pulmonary hemodynamics. The results of this study reinforce this observation and suggest that such improvement could be related to a decrease in systemic inflammation. Further prospective studies with bigger samples are needed to better understand these findings.

Pre-pregnancy Obesity and the Risk of Peripartum Cardiomyopathy

OBJECTIVE

The aim of this study is to evaluate the contribution of pre-pregnancy obesity and overweight to peripartum cardiomyopathy.

STUDY DESIGN

This population-based study used linked birth record and maternal hospital discharge data from live births in California during 2007 to 2012 (n = 2,548,380). All women who had a diagnosis of peripartum cardiomyopathy during the childbirth hospitalization or who were diagnosed with peripartum cardiomyopathy during a postpartum hospital readmission within 5 months of birth were identified as cases. Pre-pregnancy body mass index (BMI, kg/m²) was classified as normal weight (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (≥40). Because of small numbers, we excluded women with underweight BMI, and in some analyses, we combined obesity classes into one group. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) expressing associations between BMI and peripartum cardiomyopathy, adjusted for maternal age, race/ethnicity, education, health care payer, parity, plurality, and comorbidities.

RESULTS

The overall prevalence of peripartum cardiomyopathy during hospital admissions was 1.3 per 10,000 live births (n = 320). Unadjusted ORs were 1.32 (95% CI: 1.01-1.74) for women with overweight BMI and 2.03 (95% CI: 1.57-2.62) for women with obesity, compared with women with normal pre-pregnancy BMI. Adjusted ORs were 1.26 (95% CI: 0.95-1.66) for overweight women and 1.38 (95% CI: 1.04-1.84) for women with obesity. The ORs suggested a dose-response relationship with increasing levels of obesity, but the 95% CIs for the specific classes of obesity included 1.00.

CONCLUSION

Pre-pregnancy obesity was associated with an increased risk of peripartum cardiomyopathy. These findings underscore the importance of BMI during pregnancy. There is a need to recognize the increased risk of peripartum cardiomyopathy in women with high BMI, especially in the late postpartum period.

KEY POINTS

· Pre-pregnancy obesity affects maternal health.. · Effects may extend to peripartum cardiomyopathy.. · The risk includes peripartum cardiomyopathy that emerges postpartum..

The association of non-alcoholic fatty liver disease and cardiac structure and function-Framingham Heart Study

BACKGROUND & AIMS

Non-alcoholic fatty liver disease confers increased risk for cardiovascular disease, including heart failure (HF), for reasons that remain unclear. Possible pathways could involve an association of liver fat with cardiac structural or functional abnormalities even after accounting for body size.

METHODS

We analysed N = 2356 Framingham Heart Study participants (age 52 ± 12 years, 52% women) who underwent echocardiography and standardized computed tomography measures of liver fat.

RESULTS

In cross-sectional multivariable regression models adjusted for age, gender, cohort and cardiovascular risk factors, liver fat was positively associated with left ventricular (LV) mass (β = 1.45; 95% confidence interval (CI): 0.01, 2.88), LV wall thickness (β = 0.01; 95% CI: 0.00, 0.02), mass volume ratio (β = 0.02; 95% CI 0.01, 0.03), mitral peak velocity (E) (β = 0.83; 95% CI 0.31, 1.36) and LV filling pressure (E/e' ratio) (β = 0.16; 95% CI 0.09, 0.23); and inversely associated with global systolic longitudinal strain (β = 0.20, 95% CI 0.07, 0.33), diastolic annular velocity (e') (β = -0.12; 95% CI - 0.22, -0.03), and E/A ratio (β = -0.01; 95% CI - 0.02, -0.00). After additional adjustment for body mass index (BMI), statistical significance was attenuated for all associations except for that of greater liver fat with increased LV filling pressure, a possible precursor to HF (β = 0.11; 95% CI 0.03, 0.18).

CONCLUSION

Increased liver fat was associated with multiple subclinical cardiac dysfunction measures, with most of associations mediated by obesity. Interestingly, the association of liver fat and LV filling pressure was only partially mediated by BMI, suggesting a possible direct effect of liver fat on LV filling pressure. Further confirmatory studies are needed.

Obesity, Systemic Hypertension, and Pulmonary Hypertension: A Tale of Three Diseases

Cardiovascular disease (CVD), especially ischemic heart disease and stroke, is the major cause of death worldwide, accounting for more than one-third of all deaths annually. Hypertension is the most prevalent and modifiable risk factor of CVD-related deaths. The same is true for obesity, which is currently being recognized as a major global epidemic. The prevalence of obesity in the United States has increased dramatically, from 13.4% in 1960 to 36.5% in 2014, with as much as 70.7% of the American adult population being overweight or obese (CDC). Epidemiological studies have shown that obesity predisposes to hypertension and CVD - with the relationship between markers of obesity and blood pressure being almost linear across different populations. In this review, we discuss systemic and pulmonary hypertension in the context of obesity.

Effect of Obesity on Pulmonary Vascular Hemodynamics

CONTEXT

Obesity-related pulmonary arterial hypertension (PAH) is associated with hypoxia and metabolic abnormalities. Although right heart catheterization is the gold standard method for the diagnosis of PAH, Doppler echocardiography is more common. On the other hand, there is no definite echocardiographic parameter for PAH diagnosis. Novel echocardiographic parameter, pulmonary pulse transit time (pPTT), is assumed to be a surrogate marker for the assessment of PAH.

AIMS

The aim was to evaluate whether pPTT might be valuable for evaluating pulmonary vascular hemodynamics in obese patients.

SETTINGS AND DESIGN

A cross-sectional observational study.

METHODS

A total of 130 consecutive obese patients and 50 controls were included. Obese patients were divided into three groups according to body mass index (BMI): 25 < BMI <30 kg/m2 formed Group 1, 30 < BMI <35 kg/m2 formed Group 2, and 35

STATISTICAL ANALYSIS USED

Intergroup differences were analyzed with analysis of variance or Kruskal-Wallis test. Pearson's or Spearman's correlation analysis was used for correlation, multivariate logistic regression analysis, and regression.

RESULTS

Statistically significant reduction in pPTT was detected as early as in the first group (361.24 ± 25.54 vs. 391.26 ± 15.07; P = 0.015) and continued throughout Groups 2 and 3 (299.92 ± 35.10 vs. 391.26 ± 15.07; P < 0.0001, and 245.46 ± 11.25 vs. 391.26 ± 15.07; P < 0.0001, respectively). There was a strong negative correlation between pPTT and BMI (r = -0.848, P = 0.001). On linear regression analysis, BMI was found to be an independent risk factor for pPTT (confidence interval: -9.164-6.379, β = -0.525, P = 0.0001).

CONCLUSION

The results of this study suggest that obesity leads to an increase in PAH, and pPTT allows noninvasive determination of the pulmonary hemodynamics in obese patients. pPTT might be a useful parameter in terms of predicting pulmonary hemodynamics and vascular alterations in obese patients. Further studies are warranted to evaluate the association between obesity and PAH.

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Key Words

• Obesity
• pulmonary pulse transit time
• pulmonary vascular hemodynamics

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Affiliation(s)

Mustafa Duran Department of Cardiology, Konya Education and Research Hospital, Konya, Turkey
Murat Ziyrek Department of Cardiology, Konya Education and Research Hospital, Konya, Turkey

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Cardiovascular Testing Detects Underlying Dysfunction in Childhood Leukemia Survivors

PURPOSE

Childhood leukemia survivors commonly develop late-onset cardiovascular disease after treatment with anthracyclines. Resting echocardiogram is the standard procedure for monitoring cardiac health but this method may not be sensitive enough to detect subclinical injury. Exercise echocardiography may provide a viable alternative.

METHODS

Nineteen (9 males; age, 19 ± 3 yr) anthracycline-treated survivors of childhood leukemia and 17 (8 males) healthy individuals of similar age (22 ± 2 yr) were recruited. All survivors had normal resting echocardiography upon recruitment. Exercise echocardiography was performed using contemporary imaging techniques. Flow-mediated dilation (FMD), body composition, and cardiorespiratory fitness (V˙O2peak) were assessed to determine predisposition to additional disease.

RESULTS

Mitral valve peak flow velocity in late diastole (interaction, P = 0.007) increased from rest in survivors (P = 0.023) and controls (P = 0.020) immediately postexercise but did not recover again in the survivors (exercise-recovery, P = 0.784) after recuperation. Consequently, E/A ratio (interaction, P < 0.001) was lower in the survivors at recovery (P < 0.001). Survivors had reduced FMD (7.88 ± 1.70 vs 9.65 ± 2.83; P = 0.030), maximal and recovery HR (P = 0.001; P < 0.001), minute ventilation (P < 0.001), and V˙O2peak (absolute, 2.64 ± 0.62 vs 3.14 ± 0.74 L·min, P = 0.034; relative, 36.78 ± 11.49 vs 45.14 ± 6.80 mL·kg·min; P = 0.013) compared with controls. They also had higher total body fat (percentage, P = 0.034; mass, P = 0.024) and fat mass in the central (P = 0.050), peripheral (P = 0.039) and visceral (P < 0.001) regions. Survivors matched controls with regard to height (173.0 ± 7.8 cm vs 173.8 ± 9.1 cm; P = 0.796), body mass (76.16 ± 19.05 kg vs 70.07 ± 13.96 kg; P = 0.287) and body mass index (25.2 ± 5.1 vs 22.9 ± 2.7; P = 0.109).

CONCLUSIONS

Exercise echocardiography unmasked subclinical diastolic dysfunction that may indicate late anthracycline toxicity in apparently healthy survivors of childhood leukemia. Presence of secondary risk factors indicates increased predisposition to comorbidities and highlights the importance of assessing cardiovascular health during follow-up.

Integrative Personal Omics Profiles during Periods of Weight Gain and Loss

Advances in omics technologies now allow an unprecedented level of phenotyping for human diseases, including obesity, in which individual responses to excess weight are heterogeneous and unpredictable. To aid the development of better understanding of these phenotypes, we performed a controlled longitudinal weight perturbation study combining multiple omics strategies (genomics, transcriptomics, multiple proteomics assays, metabolomics, and microbiomics) during periods of weight gain and loss in humans. Results demonstrated that: (1) weight gain is associated with the activation of strong inflammatory and hypertrophic cardiomyopathy signatures in blood; (2) although weight loss reverses some changes, a number of signatures persist, indicative of long-term physiologic changes; (3) we observed omics signatures associated with insulin resistance that may serve as novel diagnostics; (4) specific biomolecules were highly individualized and stable in response to perturbations, potentially representing stable personalized markers. Most data are available open access and serve as a valuable resource for the community.

Neural respiratory drive and cardiac function in patients with obesity hypoventilation syndrome following initiation of non-invasive ventilation

Background

Chronic hypercapnic respiratory failure (HRF) in obesity hypoventilation syndrome (OHS) is commonly treated using non-invasive ventilation (NIV). We hypothesised that treatment of OHS would improve neural respiratory drive index (NRDI) and cardiac function.

Methods

Fourteen patients (8 females) with OHS, who were admitted for initiation of domiciliary NIV, were prospectively studied. Patients had (mean ± SD): age (53±10 years), body mass index (BMI) (50.1±10.8 kg/m²), and pCO₂ (7.3±0.9 kPa). NRDI was assessed by surface electromyogram of the parasternal intercostals. Cardiac function was assessed by transthoracic echocardiography (TTE). All measurements were performed at baseline, 6 weeks, and 3 months.

Results

NRDI improved on day one following NIV set-up comparing to baseline (484.2±214.8 vs. 316.5±106.5 AU) and this improvement was maintained at 6 weeks (369.1±173.2 AU) and at 3 months (351.2±167.1 AU) (P=0.004). No significant differences were identified in terms of cardiac function between baseline and 3 months [tricuspid annular plane systolic excursion (TAPSE) (24.6±5.8 vs. 23.0±4.0 mm, P=0.317); systolic pulmonary artery (PA) pressures (36.7±15.2 vs. 44.5±23.9 mmHg, P=0.163].

Conclusions

NIV improves NRDI in patients with OHS, while the cardiac function over a three-month period remains unchanged.

Fruit vinegars attenuate cardiac injury via anti-inflammatory and anti-adiposity actions in high-fat diet-induced obese rats

CONTEXT

Fruit vinegars (FVs) are used in Mediterranean folk medicine for their hypolipidemic and weight-reducing properties.

OBJECTIVE

To investigate the preventive effects of three types of FV, commonly available in Algeria, namely prickly pear [Opuntia ficus-indica (L.) Mill (Cectaceae)], pomegranate [Punica granatum L. (Punicaceae)], and apple [Malus domestica Borkh. (Rosaceae)], against obesity-induced cardiomyopathy and its underlying mechanisms.

MATERIALS AND METHODS

Seventy-two male Wistar rats were equally divided into 12 groups. The first group served as normal control (distilled water, 7 mL/kg bw), and the remaining groups were respectively treated with distilled water (7 mL/kg bw), acetic acid (0.5% w/v, 7 mL/kg bw) and vinegars of pomegranate, apple or prickly pear (at doses of 3.5, 7 and 14 mL/kg bw, acetic acid content as mentioned above) along with a high-fat diet (HFD). The effects of the oral administration of FV for 18 weeks on the body and visceral adipose tissue (VAT) weights, plasma inflammatory and cardiac enzymes biomarkers, and in heart tissue were evaluated.

RESULTS

Vinegars treatments significantly (p < .05) attenuated the HFD-induced increase in bw (0.2-0.5-fold) and VAT mass (0.7-1.8-fold), as well as increase in plasma levels of CRP (0.1-0.3-fold), fibrinogen (0.2-0.3-fold), leptin (1.7-3.7-fold), TNF-α (0.1-0.6-fold), AST (0.9-1.4-fold), CK-MB (0.3-1.4-fold) and LDH (2.7-6.7-fold). Moreover, vinegar treatments preserved myocardial architecture and attenuated cardiac fibrosis.

DISCUSSION AND CONCLUSION

These findings suggest that pomegranate, apple and prickly pear vinegars may prevent HFD-induced obesity and obesity-related cardiac complications, and that this prevention may result from the potent anti-inflammatory and anti-adiposity properties of these vinegars.

Early detection of right ventricular dysfunction using transthoracic echocardiography in ARDS: a more objective approach

PURPOSE

Right ventricular (RV) dysfunction is an independent predictor of morbidity and mortality in acute respiratory distress syndrome (ARDS). Our goal was to describe morphologic changes in the RV using objective measures on transthoracic echocardiography (TTE) that occur following ARDS.

METHODS

We retrospectively measured changes in the following RV parameters from a pre-ARDS TTE to an ARDS TTE: tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI), fractional area change (FAC), systolic pulmonary artery pressure (SPAP), peak tricuspid regurgitant (TR) velocity, and septal shift.

RESULTS

Over 24 months, 14 patients met inclusion/exclusion criteria. Mean TAPSE decreased from 22.4 mm pre-ARDS to 16.3 mm during ARDS, P<.001. Mean MPI increased from 0.19 to 0.38, P=.001. Mean FAC decreased from 60.8% to 41.2%, P=.003. Peak TR velocity increased from 2.67 m/s pre-ARDS to 3.31 m/s during ARDS, P=.02. SPAP and septal shift demonstrated trends but not statistically different between pre-ARDS and ARDS states. TAPSE correlated with ARDS severity (PaO₂ /FiO₂ ratios), P=.004, and was lower among 30-day nonsurvivors compared with survivors, P=.002.

CONCLUSIONS

Mild RV dysfunction is common after ARDS onset. RV morphologic changes coupled with dysfunction can be detected noninvasively through TTE changes with TAPSE, MPI, and FAC. Mild RV dysfunction by TAPSE is associated with ARDS severity and mortality.

Normal Organ Weights in Women: Part I-The Heart

Cardiac enlargement is a well-known independent risk factor for sudden cardiac death, though the definition of what constitutes cardiac enlargement is not universally established. A previous study was undertaken to establish a normal range for male hearts to address this issue; the present study was designed to address the issue and to determine normal cardiac weights in adult human females. A prospective study was undertaken of healthy females dying from sudden, traumatic deaths aged 18 to 35 years. Cases were excluded if: there was a history of medical illness, including illicit drug use; prolonged medical treatment was performed; there was a prolonged period between the time of injury and death; body length and weight could not be accurately assessed; if there was significant cardiac injury; or if any illness or intoxication was identified after gross, microscopic, and toxicologic analysis, including evidence of systemic disease. A total of 102 cases met criteria for inclusion in the study during the approximately 10-year period of data collection from 2004 to 2014. The decedents had an average age of 24.4 years and ranged in length from 141 to 182 cm (56.4 to 72.8 in.) with an average length of 160 cm (64 in.). The weight ranged from 35.9 to 152 kg (79 to 334 lbs) with an average weight of 65.3 kg (143 lbs). The majority of the decedents (86%) died from either ballistic or blunt force (including craniocerebral) injuries. Overall, the heart weights ranged from 156 to 422 g with an average of 245 g and a standard deviation of 52 g. Regression analysis was performed to assess the relationship between heart weight and body weight, body length, and body mass index, respectively, and found insufficient associations to enable predictability. The authors, therefore, propose establishing a normal range for heart weight in women of 148 to 296 g.

Sympathetic hyper-excitation in obesity and pulmonary hypertension: physiological relevance to the 'obesity paradox'

BACKGROUND

Within the lung, sympathetic nerve activity (SNA) has an important role in facilitating pulmonary vasodilation. As SNA is elevated in obesity, we aimed to assess the impact of sympathetic hyper-excitation on pulmonary vascular homeostasis in obesity, and its potential role in ameliorating the severity of pulmonary hypertension (PH); the well-documented 'obesity paradox' phenomenon.

METHODS

Zucker obese and lean rats were exposed to normoxia or chronic hypoxia (CH-10% O2) for 2 weeks. Subsequently, pulmonary SNA (pSNA) was recorded (electrophysiology), or the pulmonary microcirculation was visualized using Synchrotron microangiography. Acute hypoxic pulmonary vasoconstriction (HPV) was assessed before and after blockade of β1-adrenergic receptors (ARs) (atenolol, 3 mg kg(-1)) and β1+β2-adrenergic (propranolol, 2 mg kg(-1)).

RESULTS

pSNA of normoxic obese rats was higher than lean counterparts (2.4 and 0.5 μV s, respectively). SNA was enhanced following the development of PH in lean rats, but more so in obese rats (1.7 and 6.8 μV s, respectively). The magnitude of HPV was similar for all groups (for example, ~20% constriction of the 200-300 μm vessels). Although β-blockade did not modify HPV in lean rats, it significantly augmented the HPV in normoxic obese rats (β1 and β2 blockade), and more so in obese rats with PH (β2-blockade alone). Western blots showed, while the expression of pulmonary β1-ARs was similar for all rats, the expression of β2-ARs was downregulated in obesity and PH.

CONCLUSIONS

This study suggests that sympathetic hyper-excitation in obesity may have an important role in constraining the severity of PH and, thus, contribute in part to the 'obesity paradox' in PH.

Cardiospecific CD36 suppression by lentivirus-mediated RNA interference prevents cardiac hypertrophy and systolic dysfunction in high-fat-diet induced obese mice

Background

Fatty acid (FA) catabolism abnormality has been proved to play an important role in obesity-related cardiomyopathy. We hypothesized that cardiospecific suppression of CD36, the predominant membrane FA transporter, would protect against obesity-related cardiomyopathy.

Methods

Four-wk-old male C57BL/6 J mice were fed with either high-fat-diet (HFD) or control-normal-diet for 2 wk. Then they were subjected to intramyocardial injection with recombinant lentiviral vectors containing short hairpin RNAs to selectively downregulate the expression of either cardiac CD36 or irrelevant gene by RNA interference. After a 10-wk continuation of the diet, biochemical, functional, morphological, histological, metabolic and molecular profiles were assessed.

Results

HFD administration elicited obesity, cardiac hypertrophy and systolic dysfunction accompanied with elevated serum levels of blood urea nitrogen (BUN), creatinine, fasting serum glucose (FSG), total cholesterol (TC) and triglyceride. Additionally, HFD consumption promoted lipid accumulation and reactive oxygen species (ROS) generation in the cardiomyocytes. Cardiospecific CD36 inhibition protected against HFD induced cardiac remodeling by decreasing heart/body weight ratio, increasing left ventricular (LV) ejection fraction and fractional shortening as well as normalizing LV diameter, without influencing body weight gain. Inhibition of cardiac CD36 also mitigated obesity induced alteration in BUN, creatinine and triglyceride, but had no effect on FSG or TC. Moreover, cardiospecific CD36 deficiency corrected myocardial lipid overaccumulation and intracellular ROS overproduction that were induced by HFD feeding.

Conclusions

Cardiospecific CD36 inhibition protects against the aggravation of cardiac functional and morphological changes associated with HFD induced obesity. CD36 represents a potential therapeutic target for obesity cardiomyopathy.

Hypoxia-induced glucose-6-phosphate dehydrogenase overexpression and -activation in pulmonary artery smooth muscle cells: implication in pulmonary hypertension

Severe pulmonary hypertension is a debilitating disease with an alarmingly low 5-yr life expectancy. Hypoxia, one of the causes of pulmonary hypertension, elicits constriction and remodeling of the pulmonary arteries. We now know that pulmonary arterial remodeling is a consequence of hyperplasia and hypertrophy of pulmonary artery smooth muscle (PASM), endothelial, myofibroblast, and stem cells. However, our knowledge about the mechanisms that cause these cells to proliferate and hypertrophy in response to hypoxic stimuli is still incomplete, and, hence, the treatment for severe pulmonary arterial hypertension is inadequate. Here we demonstrate that the activity and expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, are increased in hypoxic PASM cells and in lungs of chronic hypoxic rats. G6PD overexpression and -activation is stimulated by H2O2. Increased G6PD activity contributes to PASM cell proliferation by increasing Sp1 and hypoxia-inducible factor 1α (HIF-1α), which directs the cells to synthesize less contractile (myocardin and SM22α) and more proliferative (cyclin A and phospho-histone H3) proteins. G6PD inhibition with dehydroepiandrosterone increased myocardin expression in remodeled pulmonary arteries of moderate and severe pulmonary hypertensive rats. These observations suggest that altered glucose metabolism and G6PD overactivation play a key role in switching the PASM cells from the contractile to synthetic phenotype by increasing Sp1 and HIF-1α, which suppresses myocardin, a key cofactor that maintains smooth muscle cell in contractile state, and increasing hypoxia-induced PASM cell growth, and hence contribute to pulmonary arterial remodeling and pathogenesis of pulmonary hypertension.

Obesity-related pulmonary arterial hypertension in rats correlates with increased circulating inflammatory cytokines and lipids and with oxidant damage in the arterial wall but not with hypoxia

Obesity is causally linked to a number of comorbidities, including cardiovascular disease, diabetes, renal dysfunction, and cancer. Obesity has also been linked to pulmonary disorders, including pulmonary arterial hypertension (PAH). It was long believed that obesity-related PAH was the result of hypoventilation and hypoxia due to the increased mechanical load of excess body fat. However, in recent years it has been proposed that the metabolic and inflammatory disturbances of obesity may also play a role in the development of PAH. To determine whether PAH develops in obese rats in the absence of hypoxia, we assessed pulmonary hemodynamics and pulmonary artery (PA) structure in the diet-resistant/diet-induced obesity (DR/DIO) and Zucker lean/fatty rat models. We found that high-fat feeding (DR/DIO) or overfeeding (Zucker) elicited PA remodeling, neomuscularization of distal arterioles, and elevated PA pressure, accompanied by right ventricular (RV) hypertrophy. PA thickening and distal neomuscularization were also observed in DIO rats on a low-fat diet. No evidence of hypoventilation or chronic hypoxia was detected in either model, nor was there a correlation between blood glucose or insulin levels and PAH. However, circulating inflammatory cytokine levels were increased with high-fat feeding or calorie overload, and hyperlipidemia and oxidant damage in the PA wall correlated with PAH in the DR/DIO model. We conclude that hyperlipidemia and peripheral inflammation correlate with the development of PAH in obese subjects. Obesity-related inflammation may predispose to PAH even in the absence of hypoxia.

Causes and risk factors for mortality within 1 year after obesity surgery in a population-based cohort study

BACKGROUND

The use of obesity surgery has increased during the past decade. There is a need for population-based assessments of causes and risk factors for postoperative mortality. The objective of this study was to assess causes and risk factors for 1-year mortality after obesity surgery.

METHODS

This nationwide retrospective population-based cohort study included essentially all obesity surgery patients in Sweden from 1980-2010. Data were collected from Swedish national registries and medical records. Patient characteristics, co-morbidities, and surgical procedures were assessed in relation to 1-year mortality through multivariable Cox proportional hazards regression, providing hazard ratios (HR), and 95% confidence intervals (CI) adjusted for age, sex, surgical procedure, surgical access, and co-morbidity.

RESULTS

Among 22,487 obesity surgery patients the 1-year cumulative mortality was .38% (n = 85). Follow-up of cohort was complete. Median time of postoperative death was 45 days. Main causes of death included cardiopulmonary complications (myocardial infarction [n = 14; 16%], pulmonary embolism [n = 12; 14%], sudden cardiac arrest [n = 11; 13%]), and anastomotic leak (n = 12; 14%). Male sex (HR = 2.31; 95% CI 1.48-3.60), diabetes (HR = 2.47; 95% CI 1.44-4.23), and congestive heart failure (HR = 4.82; 95% CI 2.25-10.35) were independently associated with increased 1-year mortality, while age, hypertension, cerebrovascular disease, coronary heart disease, chronic obstructive pulmonary disease, asthma, and surgical procedure were not. Open surgery entailed an increased mortality compared to laparoscopic surgery from 2000-2010 (HR = 2.72; 95% CI 1.53-4.83), but not from 1990-1999 (HR = .39; 95% CI .11-1.32).

CONCLUSION

Although the absolute risk of mortality is low, the increased relative risk of mortality associated with male sex, diabetes, congestive heart failure, and open surgical access could influence clinical decision making.

Predictors of clinical outcome after tracheotomy in critically ill obese patients

OBJECTIVES/HYPOTHESIS

To identify patient factors associated with outcomes in critically ill obese patients requiring tracheotomy.

STUDY DESIGN

Single-institution, retrospective cohort study.

METHODS

Charts were reviewed for inpatients admitted to an intensive care unit from 2007 to 2010 with International Classification of Diseases, 9th Revision codes of obesity or morbid obesity and tracheotomy. Variables collected in the dataset include subject age, ethnicity, gender, body mass index, tracheotomy type, patient outcome, chief diagnosis, and medical comorbid conditions. The primary outcomes of interest were tracheotomy type and patient outcome at the time of hospital discharge. Logistic regression models were developed for the probability of each patient outcome using univariate and multivariate models.

RESULTS

One hundred two patients met inclusion criteria. The most common outcome was tracheostomy dependence (49%). Increased mortality was independently significantly associated with pulmonary hypertension (P = .019) and African American ethnicity (P = .045). Increased tracheostomy dependence was significantly associated with obstructive sleep apnea (P = .030). Increased decannulation was significantly associated with percutaneous tracheotomy (P = .016) and Caucasian ethnicity (P < .001).

CONCLUSIONS

Obese patients in the intensive care unit who undergo tracheotomy have a high likelihood of remaining tracheostomy dependent at the time of discharge from the hospital. The factors most commonly found to be significantly associated with poor outcomes were open tracheotomy, African American ethnicity, obstructive sleep apnea, and pulmonary hypertension.

Mechanisms of heart failure in obesity

Heart failure is a leading cause of morbidity and mortality and its prevalence continues to rise. Because obesity has been linked with heart failure, the increasing prevalence of obesity may presage further rise in heart failure in the future. Obesity-related factors are estimated to cause 11% of heart failure cases in men and 14% in women. Obesity may result in heart failure by inducing haemodynamic and myocardial changes that lead to cardiac dysfunction, or due to an increased predisposition to other heart failure risk factors. Direct cardiac lipotoxicity has been described where lipid accumulation in the heart results in cardiac dysfunction inexplicable of other heart failure risk factors. In this overview, we discussed various pathophysiological mechanisms that could lead to heart failure in obesity, including the molecular mechanisms underlying cardiac lipotoxicity. We defined the obesity paradox and enumerated various premises for the paradoxical associations observed in the relationship between obesity and heart failure.

Normal organ weights in men: part I-the heart

It has been shown that cardiac enlargement, whether hypertrophic or dilated, is an independent risk factor for sudden cardiac death, although the definition of what constitutes cardiac enlargement is not universally established. This study was designed to address this issue and to determine normal cardiac weights in adult men. A prospective study was undertaken of healthy men dying from sudden traumatic deaths aged 18 to 35 years. Cases were excluded if there was a history of medical illness including illicit drug use; prolonged medical treatment was performed; there was a prolonged period between the time of injury and death; body length and weight could not be accurately assessed; there was significant cardiac injury; or any illness or intoxication was identified after gross and microscopic analysis, including evidence of systemic disease. A total of 232 cases met the criteria for inclusion in the study during the approximately 6-year period of data collection from 2005 to 2011. The decedents had an average age of 23.9 years and ranged in length from 146 to 193 cm with an average length of 173 cm. Their weights ranged from 48.5 to 153 kg with an average weight of 76.4 kg. Most decedents (87%) died of either ballistic or blunt force (including craniocerebral) injuries. Overall, their heart weights ranged from 188 to 575 g with an average of 331 g and an SD of 56.7 g. Regression analysis was performed to assess the relationship between heart weight and body weight, body length, and body mass index and found insufficient associations to enable predictability. The authors, therefore, propose establishing a reference range for heart weight in men, much like those in use for other laboratory tests including hemoglobin, hematocrit, or glucose. A reference range (95% inclusion) of 233 to 383 g for the adult male human heart is proposed.

Regulation of adipose tissue energy availability through blood flow control in the metabolic syndrome

Maintenance of blood flow rate is a critical factor for tissue oxygen and substrate supply. The potentially large mass of adipose tissue deeply influences the body distribution of blood flow. This is due to increased peripheral resistance in obesity and the role of this tissue as the ultimate destination of unused excess of dietary energy. However, adipose tissue cannot grow indefinitely, and the tissue must defend itself against the avalanche of nutrients provoking inordinate growth and inflammation. In the obese, large adipose tissue masses show lower blood flow, limiting the access of excess circulating substrates. Blood flow restriction is achieved by vasoconstriction, despite increased production of nitric oxide, the vasodilatation effects of which are overridden by catecholamines (and probably also by angiotensin II and endothelin). Decreased blood flow reduces the availability of oxygen, provoking massive glycolysis (hyperglycemic conditions), which results in the production of lactate, exported to the liver for processing. However, this produces local acidosis, which elicits the rapid dissociation of oxyhemoglobin, freeing bursts of oxygen in localized zones of the tissue. The excess of oxygen (and of nitric oxide) induces the production of reactive oxygen species, which deeply affect the endothelial, blood, and adipose cells, inducing oxidative and nitrosative damage and eliciting an increased immune response, which translates into inflammation. The result of the defense mechanism for adipose tissue, localized vasoconstriction, may thus help develop a more generalized pathologic response within the metabolic syndrome parameters, extending its effects to the whole body.

Ventricular fibrillation resulting from diaphragmatic stimulation during gastric bypass surgery

OBJECTIVE

Gastric bypass operations are common and severely obese patients are prone to arrhythmias, particularly atrial fibrillation. Intraoperative ventricular arrhythmias during bariatric surgery have not been reported previously.

CASE REPORT

A 35-year-old, severely obese, diabetic woman with no other prior medical history underwent thorough preoperative cardiovascular evaluation before having laparoscopic Roux-en-Y gastric bypass. Intraoperatively she developed sudden onset ventricular fibrillation during the use of unipolar electrocautery near the Angle of His. The procedure was aborted, and the patient underwent repeat cardiovascular assessment including coronary angiography and serial electrophysiology studies before being unremarkably re-operated 6 months later, at which time a harmonic scalpel was used for dissection. 12 months post operation, the patient remains asymptomatic.

CONCLUSION

Owing to the proximity of the right ventricle overlying the diaphragm, far-field stimulation was likely responsible for inducing VF.

Obesity and pulmonary hypertension: a review of pathophysiologic mechanisms

Pulmonary hypertension (PH) is a potentially life-threatening condition arising from a wide variety of pathophysiologic mechanisms. Effective treatment requires a systematic diagnostic approach to identify all reversible mechanisms. Many of these mechanisms are relevant to those afflicted with obesity. The unique mechanisms of PH in the obese include obstructive sleep apnea, obesity hypoventilation syndrome, anorexigen use, cardiomyopathy of obesity, and pulmonary thromboembolic disease. Novel mechanisms of PH in the obese include endothelial dysfunction and hyperuricemia. A wide range of effective therapies exist to mitigate the disability of PH in the obese.

Short-term effects of a multi-disciplinary cardiac rehabilitation programme on psychological well-being, exercise capacity and weight in a sample of obese in-patients with coronary heart disease: a practice-level study

Given that many patients referred to cardiac rehabilitation (CR) are obese, diet therapy, exercise training, nutritional and psychological counselling for both obesity and psychological distress should be included as important components in all CR programmes. In this practice-level, observational study we evaluated the short-term within-group effects of a four-week multi-factorial inpatient CR programme specifically addressed to weight loss, fitness improvement and psychological health increase on 176 obese in-patients with coronary heart disease (CHD). Outcome measures were exercise capacity measured with estimated metabolic equivalents (METs), body mass index (BMI) and psychological well-being (PGWBI). Results show statistically significant improvements in all the PGWBI sub-scales and total score, except in general health (p = 0.393). No moderation effects were found for BMI class, age, diabetes and ejection fraction (EF). METs significantly increased by 30.3% (p < 0.001) and BMI decreased by 1.37 points (p < 0.001). Significant correlations were found between BMI and weight reductions with PGWBI anxiety and total score improvements. This multi-disciplinary CR programme including diet therapy, exercise training and psychological counselling provides indication for short-term within-group effectiveness on functional exercise capacity, BMI and PGWBI in a sample of obese in-patients with CHD. However, controlled studies are needed to corroborate the results we found.

Novel computed tomographic chest metrics to detect pulmonary hypertension

Background

Early diagnosis of pulmonary hypertension (PH) can potentially improve survival and quality of life. Detecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right heart catheterization (RHC) for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined measurements utilizing computed tomography (CT) of the chest may be an alternative non-invasive method of detecting PH.

Methods

This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses, who consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting of a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT's.

Results

Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic diameter and pulmonary wedge pressure showed that a main pulmonary artery (PA) diameter ≥29 mm (odds ratio (OR) = 4.8), right descending PA diameter ≥19 mm (OR = 7.0), true right descending PA diameter ≥ 16 mm (OR = 4.1), true left descending PA diameter ≥ 21 mm (OR = 15.5), right ventricular (RV) free wall ≥ 6 mm (OR = 30.5), RV wall/left ventricular (LV) wall ratio ≥0.32 (OR = 8.8), RV/LV lumen ratio ≥1.28 (OR = 28.8), main PA/ascending aorta ratio ≥0.84 (OR = 6.0) and main PA/descending aorta ratio ≥ 1.29 (OR = 5.7) were significant predictors of PH in this population of hospitalized patients.

Conclusion

This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the non-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients.