How important is managing your weight to cardiovascular health? Coronary heart disease, heart failure, arrhythmias all have an impact!

Source of this article: Guo Yuyang, Zeng Qingchun. Active management of obesity and reduction of risk of cardiovascular disease[J]. China General Practice,2022,25(6):643-650.]

Author: Guo Yuyang, Zeng Qingchun

Corresponding author: Zeng Qingchun, professor, doctoral supervisor; unit: Department of Cardiology, Southern Hospital, Southern Medical University

Combined with the statement "Obesity and Cardiovascular Disease" issued by the American Heart Association in 2021, this paper explores the impact of obesity on cardiovascular diseases such as coronary heart disease, heart failure, arrhythmias and the role of obesity management in improving the prognosis of cardiovascular disease.

Think extended

(1) Is the obesity paradox really a paradox? Or is it an inaccurate clinical definition of obesity?

(2) Are the advantages of bariatric surgery the advantages of the treatment method? Or is it a matter of patient group selection? Are the mechanisms underlying the effects of general obesity and super obesity on cardiovascular risk the same?

(3) Is the significance of BMI to cardiovascular disease risk in obese patients who are not accompanied by metabolic abnormalities different?

The next step is the research direction

With the continuous deepening of obesity research, clinical practices may need to consider formulating a more scientific definition or classification of obesity according to cardiovascular prognosis, and further clarify the impact mechanism of different types of obesity on cardiovascular disease, so as to find the optimal obesity management measures.

Image credit: 123RF

01

Various evaluation indicators of obesity and their relationship with cardiovascular disease

1. Waist Circumference (WC)

(1) Some organizations and expert groups have suggested that in the clinic, WC should be evaluated in conjunction with BMI.

(2) The waist-to-hip ratio (WHR) has been shown to predict cardiovascular disease mortality independently of BMI.

2. Ectopic fat storage

(1) Ectopic fat storage refers to fat storage in adipose tissue stored in non-physiological conditions, such as liver, pancreas, heart, skeletal muscle, etc.

(2) Obese patients with high visceral adipose tissue (VAT) are the people with the highest risk of cardiovascular disease.

3. Pericardial fat

(1) In multiracial studies of atherosclerosis, pericardial fat was associated with a high risk of all-cause cardiovascular disease, coronary atherosclerosis and heart failure.

(2) Rancho Bernardo's study also suggests that pericardial fat predicts the onset of cardiovascular disease.

4. Extracardial fat

Extracardial fat-releasing cytokines and chemokines affect the cardiovascular system, and their thickness is associated with WC, blood pressure, insulin resistance, and dyslipidemia, making them a possible predictor of cardiovascular disease.

5. Effects of lifestyle interventions on visceral/pericardial/extracardial fats

(1) Aerobic exercise is more effective than resistance training, and high-intensity exercise has no obvious advantage over medium-intensity exercise.

(2) The exercise time of 150 min/week is enough to significantly reduce VAT, and longer exercise time has no further benefit in reducing VAT.

(3) Exercise interventions can also reduce liver, epicardial and pericardial fat, but there is also a meta-analysis that shows that its effect on reducing epicardial fat is not significant.

(4) Dietary intervention can also effectively reduce VAT, significantly reducing liver, pericardial and epicardial fat, but some clinical studies have shown that its effect is not as good as that of exercise intervention.

02

Obesity and coronary heart disease

1. The relationship between sudden coronary artery events and obesity

In prospective studies, weight loss through bariatric surgery may improve coronary microvascular function. But there are also some studies that suggest that obesity without metabolic syndrome is not associated with the occurrence of myocardial infarction.

2. The effect of obesity on the diagnosis of coronary artery disease

Obesity can affect patient baseline ECG and maximal exercise testing capacity. Therefore, other tests may be useful in assessing coronary heart disease in this population.

3. Clinical management and treatment

(1) The obesity paradox

Obese patients develop cardiovascular disease at a younger age, have a greater proportion of cardiovascular disease, and live on average shorter than people of normal weight. But for symptomatic cardiovascular disease patients, overweight and obesity are not risk factors for a poor prognosis for cardiovascular disease within 10 years.

(2) Weight loss and risk of coronary artery disease

There are currently no studies showing that weight loss through lifestyle changes can significantly reduce cardiovascular mortality. Drug bariatric interventional trials have also not shown a significant reduction in the incidence of coronary heart disease, but the incidence of fatal and non-fatal cardiovascular events in obese patients undergoing bariatric surgery has decreased significantly.

4. Obesity and percutaneous coronary intervention (PCI)

In the short term, obesity is a relevant factor in improved survival rate after PCI. Over time, patients with low BMI had a higher incidence of postoperative cardiovascular events in PCI compared with obese patients.

5. Obesity and antiplatelet therapy

There is currently no recommended dose adjustment for antiplatelet therapy in obese patients.

6. Obesity and CABG

There is currently no consensus on the effect of obesity on postoperative mortality at CBAG. The results of the study on the effects of CABG on long-term survival after CABG are currently inconclusive. However, obesity has been shown to increase the incidence of postoperative complications such as renal failure, respiratory failure, arrhythmias (especially atrial fibrillation), and incisional infection.

03

Obesity and heart failure

1. The effect of obesity on heart function

Obesity is a major risk factor for hypertension, cardiovascular disease, and left ventricular hypertrophy, particularly with potential adverse effects on left ventricular diastolic function. Studies have shown that patients with overweight and grade 1 obesity (BMI 30.0 to 34.9 kg/m2) have a 38% and 56% higher risk of HFpEF, respectively, independent of other cardiovascular risk factors.

2. Clinical management and treatment

(1) There is also an obesity paradox in the treatment of heart failure.

(2) Currently, there is little evidence that weight loss in heart failure leads to better primary clinical outcomes. But losing weight can reduce symptoms, improve quality of life and other disease conditions. In addition, weight loss in obese patients with advanced heart failure increases the likelihood that patients will receive other positive interventions, such as left ventricular assist device implantation and heart transplantation.

(3) Physical activity and physical fitness levels have an important impact in reducing the development of heart failure, regardless of BMI, heart failure patients who maintain a certain physical fitness level have a better prognosis.

(4) Although there are currently many drugs suitable for weight loss, only orlistat has a certain efficacy and safety in the treatment of obesity complicated by heart failure. Several new drugs developed for people with type 2 diabetes also show promise for treating obesity and heart failure.

(5) Although recent heart failure guidelines do not emphasize weight loss, these guidelines also recognize the high risk associated with severe obesity, so weight control, especially to prevent obesity progression to grades 2 and 3, is necessary.

04

Obesity and arrhythmias

1. Sudden cardiac death (SCD)

(1) Obesity has been identified as the most common non-ischemic cause of SCD, of which abdominal obesity is more associated with SCD.

(2) Mild and moderate obesity will increase the incidence of ventricular tachycardia and ventricular fibrillation.

(3) With the increase of the patient's weight, the effect of chest compression and airway protection may be weakened when cardiac arrest occurs.

(4) The increase in BMI is also associated with higher thoracic impedance, which also reduces the success rate of defibrillation.

(5) Severe obesity is associated with increased mortality in hospitalized cardiac arrest patients.

2. Atrial fibrillation

(1) There is a strong correlation between BMI and the occurrence of atrial fibrillation in the elderly.

(2) Obesity not only promotes the onset of atrial fibrillation, but also promotes the progression of atrial fibrillation.

(3) Extracardial adipose tissue has become an important arrhythmia causative factor, which may have potential paracrine signals with the atrial myocardium.

(4) The higher the degree of weight loss, the lower the likelihood that the patient will develop a more permanent arrhythmia.