Abstract 3151: Improved LV Systolic Function 2 Years After Gastric Bypass Surgery
Background: Breathlessness and dyspnea are common in severe obesity. Conflicting data exist as to whether LV systolic dysfunction contributes to these symptoms and the effects of surgically-induced weight loss are largely unknown.
Methods: We prospectively studied 602 severely obese patients at baseline and 2 years after randomization to nonsurgical therapy (NonSurg, n = 316) or Roux-en-Y gastric bypass surgery (GBS, n = 285). We measured left ventricular (LV) ejection fraction (EF, to assess chamber function) and midwall fractional shortening (MWFS; to assess myocardial function). Because obesity is associated with concentric LV hypertrophy, we hypothesized that MWFS but not LVEF would detect improvements in myocardial function after weight loss.
Results: At the 2 year follow up visit, GBS patients lost more weight than NonSurg (44 ± 20 vs. 0.6 ± 11kg, p < 0.0001). At baseline, LV EF (63 ± 11 vs. 65 ± 9%) and endocardial fractional shortening (EFS, 35 ± 8 vs. 36 ± 6%) in GBS vs. NonSurg were not different. Both parameters remained unchanged at 2 year follow up. MWFS was similar at baseline in the 2 groups, but higher at 2 years in GBS vs. NonSurg subjects (16.7 ± 2.0% vs. 15.7 ± 3.1%, p < 0.0001). LV wall stress (LVWS) decreased more at 2 years in GBS than NonSurg (−4.7 ± 18 dynes/cm2, p = 0.0002 vs. −1.5 ± 14 dynes/cm2, p = 0.1). LV mass decreased by 30 ± x g in the GBS subjects and was inversely correlated with MWFS (r = −0.24, p < 0.0001). These favorable changes in myocardial function occurred in the setting of lower LV filling pressures in the GBS subjects at 2 years as assessed by tissue Doppler measurements (E/E’ = 7.6 ± 2.9 vs. 8.9 ± 3.4), in GBS vs. NonSurg respectively (p < 0.0001).
Conclusion: In this large, prospective study of severely obese patients we find a significant improvement in myocardial function as assessed by LV midwall fractional shortening 2 years after GBS. This change was not apparent from LV EF and occurred in the setting of reduced LV mass and lower LV filling pressures. These findings support the notion that GBS may lower the long-term risk of heart failure in severe obesity.