Long-Term Trajectories of Left Heart Geometry, Mechanics, and Oxygen Demand After Bariatric Surgery

The long-term impact of bariatric surgery on cardiac mechanics and energetics has been scarcely documented. We aimed to assess prospectively the 5-year trajectories of left heart geometry, mechanics, and myocardial oxygen (O₂) demand after bariatric surgery.

In the Bariatric Surgery on the West Coast of Norway study, left ventricular (LV) and atrial remodeling was evaluated preoperatively, 6 months, and 1 and 5 years after Roux-en-Y gastric bypass in 102 patients. LV geometry was assessed by the LV mass/height^2.7 and the relative wall thickness, and mechanics by the global longitudinal strain and the midwall shortening. LV myocardial O₂ demand was estimated from the product LV mass×wall stress×heart rate. The left atrial reservoir function was measured by the emptying fraction.

After 63 (interquartile range, 62-66) months, LV mass index, global longitudinal strain, myocardial oxygen demand, and left atrial emptying fraction were improved (P<0.001) while midwall shortening did not change significantly. Prevalence of normal LV geometry increased from 61% to 82%. In linear mixed-effects models with adjustment for clinical characteristics, improving global longitudinal strain and myocardial O₂ demand over time were associated with female sex and lower body mass index (P<0.05). In logistic regression analysis, 5-year presence of abnormal LV geometry, low LV global longitudinal strain, or high myocardial O₂ demand was related to preoperative diabetes, hypertension, and higher body mass index, as well as higher 5-year systolic blood pressure (P<0.05; Nagelkerke R²=0.40).

Bariatric surgery results in favorable 5-year trajectories of LV geometry, myocardial O₂ demand, and left heart longitudinal mechanics. However, suboptimal postoperative body mass index and blood pressure control promote long-term LV structural disease.

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01533142.