Effects of bariatric surgery on right ventricular structure and function

Maternal Cardiac Function in Pregnancies with Metabolic Disorders

The obesity epidemic is growing and poses significant risks to pregnancy. Metabolic impairment can be associated with short- and long-term maternal and perinatal morbidity and mortality. The cardiovascular implications are known in those with metabolic disorder outside of pregnancy; however, little is known of the cardiac function in pregnancies complicated by obesity. Maternal cardiac adaptation plays a vital role in normal pregnancy and is known to be involved in the pathophysiology of adverse pregnancy outcomes. Bariatric surgery is the most successful treatment for sustainable weight loss and pre-pregnancy bariatric surgery can drastically change the maternal metabolic profile and pregnancy outcomes. In this review, we discuss the available evidence on maternal cardiac function in pregnancies affected by obesity and its associated consequences of gestational diabetes and hypertension (chronic and hypertensive disorders in pregnancy), as well as pregnancies following bariatric surgery.

The Impact of Bariatric Surgery on Cardiovascular Risk Factors and Outcomes: A Systematic Review

Obesity and its complications are increasing in today's era, with cardiovascular health being one of the most significant obesity-related comorbidities. Hypertension in obesity is considered one of the major causes of death and disability due to their negative repercussions on cardiovascular health. Bariatric surgery is an approved therapeutic modality for obese people in classes II and III who have a body mass index (BMI) of more than 35 kg/m2 and 40 kg/m2, respectively. These weight loss surgeries are procedures that alter metabolism by causing weight reduction and altering gastrointestinal physiology, thereby considerably decreasing cardiometabolic risk factors that have been poorly understood to date. The purpose of this review is to explore the impact of bariatric surgery on reducing cardiac risk factors, in turn protecting the heart from succumbing to premature death. A literature search was done in the following databases: PubMed, Google Scholar, and PubMed Central (PMC). The studies taken into account for this review were observational studies published between 2016 and 2021 in the English language, where the quality was assessed using relevant quality appraisal methodologies. Finally, 10 reports were selected as definitive studies. Upon extensive evaluation of the final studies, it can be concluded that bariatric surgery results in significant weight loss, which lowers metabolic syndrome prevalence, cardiovascular risk factors, and major adverse cardiovascular events, particularly acute coronary events, and a favorable improvement in cardiac structure and function, altogether steering to reduced mortality due to cardiovascular diseases in obese patients. It is also worth noting that, while metabolic surgery can help patients with various metabolic comorbidities, the impact on individuals with hypertension is still debatable. Although the studies show significant effects on the cardiovascular system, these were only observational studies in geographically dispersed locations where each patient's lifestyle patterns and motivational levels could vary. Since real-world data are not fully explored due to the limited randomized controlled trials, it is suggested that further human trials on a larger scale be conducted to provide an even more factual conclusion.

Obesity and heart failure with preserved ejection fraction: a paradox or something else?

Obesity represents one of the most common comorbidities in patients with heart failure and preserved ejection fraction (HFpEF). Studies have shown that obesity is not only a comorbidity, but it could also be an important risk factor for HFpEF development. The mechanisms that connect obesity and HFpEF vary from obesity-induced hemodynamic changes to important biohumoral systems such as adipocitokines, renin-angiotensin-aldosterone and sympathetic nervous systems, natriuretic peptide, and oxidative stress. Studies agree about the negative influence of morbid obesity on cardiac remodeling and HFpEF development. However, there is still no agreement regarding the relationship between body mass index, as the most commonly used parameter of obesity, and HFpEF incidence or outcome in patients who already have HFpEF. The relationship varies from the linear to the U-shaped and, therefore, the "obesity paradox," which refers to the reduced risk in mildly overweight subjects in comparison with normal and underweight individuals, deserves more attention not only in the research but also in the clinical approach to these patients. In the absence of a satisfactory pharmacological approach, which would improve the outcome of this large group of patients, alternative methods such as weight loss and physical activity seem to provide encouraging results. This review article provides a clinical overview of the available data about the mechanisms that connect obesity and HFpEF, the most relevant studies on this topic, clinical relevance of the obesity paradox, and the therapeutic approach including weight loss and physical activity in obese patients with HFpEF.

No more broken hearts: weight loss after bariatric surgery returns patients' postoperative risk to baseline following coronary surgery

BACKGROUND

The obesity epidemic is associated with a rise in coronary surgeries because obesity is a risk factor for coronary artery disease. Bariatric surgery is linked to improvement in cardiovascular co-morbidities and left ventricular function. No studies have investigated survival advantage in postoperative bariatric patients after coronary surgery.

OBJECTIVES

To determine if there is a benefit after coronary surgery in patients who have previously undergone bariatric surgery.

SETTING

National Inpatient Sample.

METHODS

We performed a retrospective, cross-sectional analysis of the National Inpatient Sample database from 2003 to 2010. We selected bariatric surgical patients who later underwent coronary surgery (n = 257). A comparison of postoperative complications and mortality after coronary surgery were compared with controls (n = 1442) using χ² tests, linear regression analysis, and multivariate logistical regression models.

RESULTS

A subset population was identified as having undergone coronary surgery (n = 1699); of this population, 257 patients had previously undergone bariatric surgery. They were compared with 1442 controls. The majority was male (67.2%), white (82.6%), and treated in an urban environment (96.8%). Patients with bariatric surgery assumed the risk of postoperative complications after coronary surgery that was associated with their new body mass index (BMI) (BMI<25 kg/m²: odds ratio (OR) 1.01, 95% CI .76-1.34, P = .94; BMI 25 to<35 kg/m²: OR .20, 95% CI .02-².16, P = .19; BMI≥35 kg/m²: OR>999.9, 95% CI .18 to>999.9, P = .07). Length of stay was significantly longer in postbariatric patients (BMI<25, OR 1.62, 95% CI 1.14-2.30, P = .007).

CONCLUSIONS

Postoperative bariatric patients have a return to baseline risk of morbidity and mortality after coronary surgery.

Effects of Obesity on Cardiovascular Hemodynamics, Cardiac Morphology, and Ventricular Function

Obesity produces a variety of hemodynamic alterations that may cause changes in cardiac morphology which predispose to left and right ventricular dysfunction. Various neurohormonal and metabolic alterations commonly associated with obesity may contribute to these abnormalities of cardiac structure and function. These changes in cardiovascular hemodynamics, cardiac morphology, and ventricular function may, in severely obese patients, predispose to heart failure, even in the absence of other forms of heart disease (obesity cardiomyopathy). In normotensive obese patients, cardiac involvement is commonly characterized by elevated cardiac output, low peripheral vascular resistance, and increased left ventricular (LV) end-diastolic pressure. Sleep-disordered breathing may lead to pulmonary arterial hypertension and, in association with left heart failure, may contribute to elevation of right heart pressures. These alterations, in association with various neurohormonal and metabolic abnormalities, may produce LV hypertrophy; impaired LV diastolic function; and less commonly, LV systolic dysfunction. Many of these alterations are reversible with substantial voluntary weight loss.

Echocardiographic findings and plasma endothelin-1 levels in obese patients with and without obstructive sleep apnea

OBJECTIVE

Obstructive sleep apnea (OSA) and obesity are increasingly prevalent worldwide. Both promote endothelial dysfunction contributing to systemic and pulmonary hypertension over time. Endothelin-1 (ET-1) plays a pivotal role in the development of pulmonary hypertension (PH). The aim of the present study was to assess the association between plasma ET-1 and echocardiographic findings in obese individuals with and without OSA, as well as in non-obese patients with OSA.

METHODS

Ninety-seven subjects (56 males) were enrolled in the study. All subjects underwent the following tests: venous endothelin-1 levels, pulmonary function testing, and arterial blood gas analysis. All patients except controls underwent transthoracic echocardiography and portable testing for sleep-disordered breathing.

RESULTS

Plasma ET-1 levels were significantly higher in obese patients, both with and without OSA (respectively, n = 30 (mean value, 268.06 ± 49.56 pg/ml) and n = 32 (mean value, 263.12 ± 65.26 pg/ml)), compared with non-obese patients with OSA or to healthy controls (respectively, n = 20 (mean value, 149.8 ± 23.09 pg/ml) and n = 15 (mean value, 152.3 ± 27.64 pg/ml); p < 0.0001). Pulmonary artery pressure (PAPs) in obese patients with OSA were significantly higher than in obese patients without OSA (p < 0.0001), while there was no statistical difference between PAPs of obese patients without OSA, compared with the group of non-obese OSA patients. Plasma ET-1 levels significantly correlated with systolic PAPs in obese patients both with and without OSA (respectively, n = 30, r = 0.385, p = 0.03567; n = 32, r = 0.3497, p = 0.0497).

CONCLUSIONS

Our study suggests that endothelin levels are more strongly associated with weight than the presence of sleep-disordered breathing, but pulmonary artery hypertension is associated with both weight and OSA.

Reduced Right Ventricular Function Predicts Long-Term Cardiac Re-Hospitalization after Cardiac Surgery

Background

The significance of right ventricular ejection fraction (RVEF), independent of left ventricular ejection fraction (LVEF), following isolated coronary artery bypass grafting (CABG) and valve procedures remains unknown. The aim of this study is to examine the significance of abnormal RVEF by cardiac magnetic resonance (CMR), independent of LVEF in predicting outcomes of patients undergoing isolated CABG and valve surgery.

Methods

From 2007 to 2009, 109 consecutive patients (mean age, 66 years; 38% female) were referred for pre-operative CMR. Abnormal RVEF and LVEF were considered <35% and <45%, respectively. Elective primary procedures include CABG (56%) and valve (44%). Thirty-day outcomes were perioperative complications, length of stay, cardiac re-hospitalizations and early mortaility; long-term (> 30 days) outcomes included, cardiac re-hospitalization, worsening congestive heart failure and mortality. Mean clinical follow up was 14 months.

Findings

Forty-eight patients had reduced RVEF (mean 25%) and 61 patients had normal RVEF (mean 50%) (p<0.001). Fifty-four patients had reduced LVEF (mean 30%) and 55 patients had normal LVEF (mean 59%) (p<0.001). Patients with reduced RVEF had a higher incidence of long-term cardiac re-hospitalization vs. patients with normal RVEF (31% vs.13%, p<0.05). Abnormal RVEF was a predictor for long-term cardiac re-hospitalization (HR 3.01 [CI 1.5-7.9], p<0.03). Reduced LVEF did not influence long-term cardiac re-hospitalization.

Conclusion

Abnormal RVEF is a stronger predictor for long-term cardiac re-hospitalization than abnormal LVEF in patients undergoing isolated CABG and valve procedures.

Bariatric surgery and prevention of cardiovascular events and mortality in morbid obesity: mechanisms of action and choice of surgery

AIMS

Obesity is associated with increased cardiovascular (CV) morbidity and mortality. Weight loss improves several risk factors for CV diseases, but anti-obesity medications and lifestyle interventions have failed to modify primary CV endpoints. This paper reviews bariatric surgery in prevention of CV diseases and CV mortality, and analyzes the possible mechanisms involved.

DATA SYNTHESIS

In morbidly obese patients bariatric surgery results in stable weight loss and in long-term reduction in the prevalence and incidence of obesity-related comorbidities; controlled trials have shown superiority of bariatric surgery over medical therapy in inducing significant weight loss and improvement of CV risk factors. Bariatric surgery induces several metabolic improvements (resolution of type 2 diabetes mellitus, improvement of lipid metabolism and of insulin resistance, reduction of visceral fat, of subclinical endothelial dysfunction and inflammation), and functional improvements (reduction of hypertension, of sympathetic overactivity, of left and right ventricular hypertrophy), which can explain the protective effect towards CV disease.

CONCLUSIONS

Reduction of CV diseases is mediated by the pleiotropic effects of weight loss through surgery. Available data do not allow conclusions on the comparative efficacy of different surgical techniques; the choice of the surgical technique for a single patient remains an open question, and it is likely that the degree of prevention of CV diseases depends, among other factors, on the baseline conditions of patients. Large prospective studies are needed to address this issue in morbidly obese patients.