Obesity, severe overweight, is a growing problem worldwide and increases the risk of heart failure, especially a type called heart failure with preserved ejection fraction (HFpEF).

In HFpEF, the heart becomes stiffer. This makes it harder for the heart to fill with blood, which can lead to shortness of breath during physical activity.

In the Netherlands, 15% of the population has obesity. In South Limburg, this is even higher at 19%. Among people with HFpEF, obesity is much more common: about 50% of these patients have obesity.

Life expectancy in people with HFpEF is poor, and current treatment mainly focuses on reducing symptoms. Early recognition and treatment of risk factors, such as obesity, are therefore very important.

This study includes about 250 people with obesity. Using a heart ultrasound and tests of blood and fat tissue, we will look for early signs of HFpEF and study the effects of weight loss. The measurements will be repeated after 1 and 2 years.

The goal of this study is to better understand how obesity contributes to HFpEF and how weight loss affects the heart. This research may help improve future treatments for patients with HFpEF.

The study is an observational, longitudinal cohort study, with extensive phenotyping at baseline and at 1- and 2 years follow-up after Metabolic bariatric surgery. The baseline assessment corresponds to the intake phase at the obesity clinic. All patients will undergo Metabolic Bariatric Surgery and multi-disciplinary treatment focused on life style change. All patients will then be followed longitudinally with repeated assessments after 1- and 2 years follow-up.

The primary objective of this study is:

I) To determine the prevalence of HFpEF and (pre)-HFpEF in patients with obesity requesting MBS.

Secondary objective(s):

I) Evaluate the differences between the three study groups (HFpEF vs preHFpEF vs patients without HF) concerning pathophysiologic mediators, functional status, QoL and medical history/demographics at baseline.

II) Evaluate the prevalence of (pre-)HFpEF at 1- and 2 years after MBS, i.e. evaluating the reclassification (transition) in disease groups from baseline.

III) Evaluate changes in cardiac function and pathophysiologic mediators from baseline to 1- and 2 years after MBS.

IV) Evaluate changes in quality of life (QoL) and functional capacity measured as change in 6-minute walking test distance from baseline to 1- and 2 years after MBS.

Inclusion Criteria:

• Age ≥ 35 years
• Eligible for surgical treatment for obesity, according to the Dutch guideline, i.e. a BMI ≥ 40 kg/m2 or a BMI ≥ 35 kg/m2 with one or more comorbidities associated with obesity. (23)

Exclusion Criteria:

• Inability to provide informed consent.
• A BMI >60 kg/m2
• Inability of undergoing metabolic bariatric surgery safely.
• Inability to undergo the study measurement/tests.
• Not proficient in the Dutch language
• A medical history of a reduced LVEF at any time, history of severe cardiac valve defects or severe congenital cardiac defects.
• A medical history of previous metabolic bariatric surgery.

Our study population consists of patients presenting at the DOC South requesting metabolic bariatric surgery. Our predetermined sample size was set at 250 participants.