Higher BMI means higher risk of endothelial dysfunction

Overweight and obese individuals with suspected coronary artery disease (CAD) could be at increased risk for endothelial dysfunction, according to a study published in the Journal of the American Heart Association.

High body mass index (BMI) is associated with metabolic syndrome and high cardiovascular morbidity and mortality, researcher Niels van Royen and co-authors noted in their study. Obesity also correlates to macrovascular endothelial dysfunction, which can be a determinant in the the outcome of patients with CAD and can be a major indicator of cardiovascular disease. Van Royen and colleagues, all researchers at hospitals in the Netherlands, completed three tests of microvascular vasodilation in more than 100 individuals and found that, more so than any other cardiovascular risk factors, high BMI was directly linked to decreased endothelial function in heart disease patients.

Researchers divided 108 adult patients, all at risk for coronary disease and scheduled for coronary angiographies, into three BMI groups: normal (a BMI of less than 25), overweight (25-30) and obese (greater than 30). Van Royen and his team measured postocclusive reactive hyperemia in each patient using a blood pressure cuff before they completed any other tests.

Other cardiovascular risk factors were considered, including diabetes mellitus, hypercholesterolemia, hypertension, BMI, age, smoking status and sex. Cardiovascular history was also logged.

Endothelial function measurements were all taken at the same time, including EndoPAT measurements used to take arterial pulse wave amplitude, single-point laser doppler flowmetry used to quantify average blood cell velocity and concentration, and digital thermal monitoring used to measure body temperature.

All three tests showed significant connection between BMI and endothelial function, according to van Royen’s study. No other predefined, treated risk factors—especially metabolic risk factors—exhibited the same kind of correlation. Only high BMI numbers were associated with endothelial dysfunction, whether a patient had treated metabolic risk factors or not.

Still, patients without previous CAD or angiographic CAD showed no difference in endothelial function, according to the research. These individuals made up a minority of the total study cohort, while more than half of the population was determined to have stable CAD and saw significant differences in endothelial function. The seven patients who appeared to have acute coronary syndrome also saw reduced endothelial function as measured with EndoPAT, but no other tests, the authors wrote.

Though BMI and symptoms of metabolic syndrome independently affected endothelial function, the study stated, other evidence has suggested impaired microvascular function could be a precursor to metabolic syndrome.

“Not only is increased BMI a plausible cause for endothelial dysfunction, but it has also been posed that endothelial dysfunction itself may initiate other features of metabolic syndrome,” the researchers wrote. “There is evidence that microvascular dysfunction precedes insulin resistance, type 2 diabetes mellitus and high blood pressure.”

The study’s authors suggested further research on the topic to gain more insight into how BMI can affect endothelial function in patients with confirmed or suspected heart disease.