Bariatric Surgery Associated with Improved Vascular Outcomes Across Patient Groups

Noyan Gokce, MD

Deaths from the obesity epidemic are largely due to cardiovascular (CV) diseases, with reduced CV mortality associated with bariatric surgical weight loss.

A recent study, led by Noyan Gokce, MD, Boston Medical Center, aimed to identify variables associated with vascular improvement following bariatric surgery, as well as an examination on age, sex and metabolic status in respect to microvascular and macrovascular outcomes.

Investigators found bariatric surgery was associated with reductions in weight, improvement in CV risk factors, as well as improvements in vascular endothelial phenotype.

Study

Data was collected on a population-based longitudinal cohort of patients with obesity (BMI ≥35) enrolled in the bariatric surgery program at the Boston Medical Center from December 2001 - August 2019.

The team noted that bariatric operations consisted of Roux-en-Y gastric bypass (RYGB) surgery, sleeve gastrectomy (SG), or laparoscopic adjustable gastric band (LAGB) surgery.

Exclusions included patients with recent coronary syndromes, congestive heart failure, malignant neoplasm, system infection, acute illness, or pregnancy.

At baseline, individuals were asked to self-identify sex and race. Clinical characteristics including antihypertensive and lipid lowering medication use, blood pressure, height, weight, BMI, hip and waist circumference, were recorded during each study visit.

The team measured flow-mediated dilation (FMD) as a percentage change of the brachial artery, used as a measure of endothelium dependent dilation of the macrovasculature.

In addition, reactive hyperemia (RH) was measured, defined as the percentage change in forearm blood flow and served as the measurement of endothelium-dependent microvascular function.

The two measurements, as well as clinical variables, were measured preoperatively at baseline, with ≥1 measurement postoperatively within 12 months of bariatric intervention.

Results

A total of 307 participants with obesity were enrolled in the study, with a mean age of 42 years and 80% (n = 246) women. The mean BMI was 46.

Data show all participants underwent bariatric surgery for weight loss, with 84% (n = 259) having RYGB and the remaining 16% (n = 48) undergoing SG or LAGB surgery.

Individuals in the study had a mean follow-up of 5.9 months. Data show a loss of 17.5% of initial body weight at post surgical assessment (SD pre-surgery 126 kg versus post-surgery 104 kg, P <.001).

In addition, endothelium-dependent FMD was improved after surgery (SD pre- versus post surgery FMD: 9.1% versus 10.2%; P = .001), as well as RH improvements (mean pre- vs post surgery RH: 764% versus 923%; P < .001).

Further, the team found that factors associated with change in vascular phenotype correlated with adiposity markers and metabolic variables depending on vascular territory.

In reference to this, they noted the association of weight change with change in RH (estimate -3.2; 95% CI, -4.7 to -1.8) and the association of hemoglobin A1c with change in FMD (estimate -0.5; 95% CI, -0.95 to -0.05).

Conclusion

The team concluded both vascular outcomes were significantly improved following bariatric intervention and track changes in anthropometric measures and metabolic risk factors, depending on vascular territory

"Factors associated with vascular change were largely modest using known traditional clinical variables, exposing our limited knowledge of mechanisms that govern vascular physiology in obesity and underscoring the crucial need for further investigative studies in this field," investigators wrote.

The study, “Association of Bariatric Surgery With Vascular Outcomes,” was published online in JAMA Network Open.