Bariatric surgery is associated with reductions in weight, amelioration of cardiovascular risk factors, and improvement in vascular endothelial phenotype, according to a study in JAMA Network Open.
Researchers sought to identify variables associated with vascular improvement after bariatric surgery and determine how sex, race, and metabolic status are associated with microvascular and macrovascular outcomes. They recruited patients with obesity from the bariatric surgery program at an urban hospital from December 11, 2001, to August 27, 2019.
A total of 307 participants (mean age, 42 years; SD, 12 years; 246 [80%] women; 199 [65%] White) with a mean body mass index (BMI) of 46 kg/m2 were included. All patients had bariatric surgery for weight loss — 259 (84%) had Roux-en-Y gastric bypass (RYGB) and 48 (16%) had sleeve gastrectomy or laparoscopic adjustable gastric band surgery.
The mean follow-up was 5.9 (SD, 4.1) months, and patients lost 17.5% of their initial body weight at their postsurgical assessment (mean pre vs postsurgery weight: 126 [SD, 25] kg vs 104 [SD, 25] kg; P <.001). Improvements in metabolic parameters, including glucose, insulin, and lipid levels, were associated with weight loss, in addition to a decreased need for medication use.
Endothelium-dependent flow-mediated dilation (FMD) and reactive hyperemia (RH) improved postsurgery, indicating functional benefits to the macrovasculature and microvasculature (mean pre vs postsurgery FMD: 9.1% [SD, 5.3%] vs 10.2% [SD, 5.1%]; P =.001; mean RH change: 764% [SD, 400%] vs 923% [SD, 412%]; P <.001), noted the study authors. Clinical factors that were associated with improved RH included change in weight, BMI, waist circumference, hip circumference, and high-density lipoprotein level (association of weight change with change in RH: estimate, −3.2; 95% CI, −4.7 to −1.8). Improvement in hemoglobin A1c was linked to change in FMD (estimate, −0.5; 95% CI, −0.95 to −0.05).
Men and women lost a similar percentage of weight at their postoperative assessment. White patients had significant improvement in FMD and RH, and Black patients and those who identified as other also had favorable macrovascular and microvascular outcomes.
The investigators found comparable differences in clinical parameters between patients who were metabolically healthy with obesity (MHO) and had high-sensitivity C-reactive protein levels >2 mg/dL vs those who were metabolically unhealthy with obesity. Among this subgroup of patients with MHO, RH improved significantly (mean RH: presurgery, 885% [SD, 413%] vs postsurgery, 1074% [SD, 391%]; P =.047), and FMD was unchanged at the postoperative assessment (mean follow-up, 5.9 [SD, 4.1] months).
The researchers noted several study limitations, as most participants were women, the study was observational and not randomized, and most surgeries were RYGB operations that were determined clinically. Additionally, racial categories were based on self-identification instead of ancestry informative markers. Finally, the investigators did not correct the significance level to account for the multiple testings performed.
“[B]y incorporating inflammatory biomarker assessment, we found that participants with seemingly MHO and signs of chronic low-grade inflammation experienced vascular benefit after weight loss, touching on a growing area of interest and controversy in the field that warrants further investigation,” the investigators commented.
Disclosure: One of the study authors declared affiliations with pharmaceutical and health care companies. Please see the original reference for a full list of authors’ disclosures.
Gokce N, Karki S, Dobyns A, et al. Association of bariatric surgery with vascular outcomes. JAMA Netw Open. 2021;4(7):e2115267. doi: 10.1001/jamanetworkopen.2021.15267