Favorable Changes in Cardiac Geometry and Function Following Gastric Bypass Surgery: 2-Year Follow-Up in the Utah Obesity Study
Does gastric bypass surgery (GBS) impact cardiac remodeling and function?
A total of 797 patients with severe obesity who met criteria for GBS and had adequate echocardiographic images were assessed. The GBS cohort included 345 patients and were compared to a nonsurgical group of 240 patients denied surgery for insurance reasons and 271 patients who declined surgery. Multiple clinical and echocardiographic parameters were assessed at baseline and 2-year follow-up.
Baseline characteristics were similar between groups. All patients had increased left ventricular (LV) wall thickness, but normal LV cavity size and volume. LV wall thickness was decreased and the overall proportion of those with LV hypertrophy (LVH) declined in the GBS group (64% with LVH at baseline vs. 56% at 2 years). Left atrial volume decreased nonsignificantly in the GBS group, but was increased in the non-GBS cohort at 2 years. Right ventricular (RV) size decreased significantly in the GBS group at 2 years and correlated with body mass index (BMI) (p = 0.006). RV functional assessments were also improved. LV ejection fraction was normal in the majority of patients and not different between groups at baseline or 2 years. However, mid-wall fractional shortening was decreased at baseline, improved post-GBS, and correlated with exercise capacity (r = 0.12, p = 0.013). Similarly, LV filling pressures assessed by medial annulus E/E’ trended down in the GBS group and had a strong correlation with exercise duration (r = -0.16, p = 0.002). On multivariate analysis, factors independently associated with LV mass were change in BMI, age, and diastolic blood pressure. Findings on multivariate analysis were not different if surgical status was excluded from the model, suggesting that weight loss itself was the driving factor in improvement in chamber size and function.
Obese patients who undergo GBS for weight reduction appear to have improvement in several measures of cardiac size and function.
GBS offers impressive decreases in BMI and the potential for improvement in markers of insulin resistance, blood pressure, and lipids in the severely obese population. At 2 years of follow-up, these nonrandomized data suggest that GBS was associated with improved RV size and functional parameters, decreased LV wall thickness, and modest improvements in LV filling pressures and left atrial size—all of which have been factors that influenced mortality in prior studies. It is interesting that weight loss itself, and not GBS per se, appears to be the driving force behind these changes. However, lifestyle modifications have limited potential to affect change in the severely obese. GBS-induced weight loss may offer objective changes in cardiac chamber size and function, but whether these changes translate into improvement in cardiac morbidity and long-term mortality in this population requires further study.
Keywords: Hypertrophy, Left Ventricular, Utah, Follow-Up Studies, Body Mass Index, Gastric Bypass, Heart, Weight Loss, Obesity, Morbid, Blood Pressure, Obesity
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