Impact of Bariatric Surgery on N-Terminal Fragment of the Prohormone Brain Natriuretic Peptide and Left Ventricular Diastolic Function

Background: Obesity is often associated with left ventricular (LV) diastolic dysfunction (DD). Elevated N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) is considered a biomarker of LV dysfunction. Weight loss induced by bariatric surgery may improve LV DD, but conflicting results regarding NT-proBNP levels have been reported. Our objective was to determine the impact of bariatric surgery-induced weight loss on NT-proBNP levels and LV DD. Methods: Seventy (70) patients were evaluated before and 6 and 12 months following a biliopancreatic diversion with duodenal switch (BPD-DS), and 33 subjects were followed as controls at baseline and 6 and 12 months later. Blood was collected for NT-proBNP measurement, and LV diastolic function was assessed with echocardiography. Results: Among the 103 severely obese patients, 82% presented some degree of LV DD. Systolic function was preserved in all subjects. Along with significant weight loss, LV DD significantly improved (P < 0.001) in the BPD-DS group, whereas there was no change in the control group. NT-proBNP levels decreased over time in the control group (P = 0.016) and increased in subjects following BPD-DS (baseline vs 6-month vs 12-month follow-up: 51.8 +/- 62.8 vs 132.0 +/- 112.9 vs 143.3 +/- 120.4 pg/mL; P < 0.001). The most significant associations with changes in NT-proBNP levels were improvements in the metabolic profile. Conclusions: In severely obese patients, NT-proBNP levels decrease with sustained obesity for 1 year. Despite significant improvements in LV DD following bariatric surgery, NT-proBNP levels increase. These results suggest that monitoring NT-proBNP levels following bariatric surgery may be misleading regarding LV DD and symptoms of dyspnea.