title: Gastric bypass surgery elevates NT-ProBNP levels.
abstract: BACKGROUND
  Brain natriuretic peptide (BNP) is produced in the heart in response to stretching of the myocardium. BNP levels are negatively correlated to obesity, and in obese subjects, a reduced BNP responsiveness has been described. Diet-induced weight loss has been found to lower or to have no effect on BNP levels, whereas gastric banding and gastric bypass have reported divergent results. We studied obese patients undergoing gastric bypass (GBP) surgery during follow-up of 1 year.
  
  
  METHODS
  Twenty patients, 18 women, mean 41 (SD 9.5) years old, with a mean preoperative BMI of 44.6 (SD 5.5) kg/m(2) were examined. N-terminal pro-brain natriuretic peptide (NT-ProBNP), glucose and insulin were measured preoperatively, at day 6 and months 1, 6 and 12. In 14 of the patients, samples were also taken at days 1, 2 and 4.
  
  
  RESULTS
  The NT-ProBNP levels showed a marked increase during the postoperative week (from 54 pg/mL preop to 359 pg/mL on day 2 and fell to 155 on day 6). At 1 year, NT-ProBNP was 122 pg/mL (125 % increase, p = 0.01). Glucose, insulin and HOMA indices decreased shortly after surgery without correlation to NT-ProBNP change. Mean BMI was reduced from 44.6 to 30.5 kg/m(2) at 1 year and was not related to NT-ProBNP change.
  
  
  CONCLUSIONS
  The data indicate that GBP surgery rapidly alters the tone of BNP release, by a mechanism not related to weight loss or to changes in glucometabolic parameters. The GBP-induced conversion of obese subjects, from low to high NT-ProBNP responders, is likely to influence the evaluation of cardiac function in GBP operated individuals.
authors: Department of Medical Sciences, Uppsala University, Uppsala 751 85, Sweden. niclas.abrahamsson@medsci.uu.se
authors: Niclas
authors: N
authors: Abrahamsson
authors: Britt Edén
authors: BE
authors: Engström
authors: Magnus
authors: M
authors: Sundbom
authors: F Anders
authors: FA
authors: Karlsson
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D005215:Fasting; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects*; D015391:Gastroplasty; D006333:Heart Failure / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000378:metabolism*; D009767:Obesity, Morbid / Q000150:complications / Q000378:metabolism* / Q000601:surgery; D010446:Peptide Fragments / Q000378:metabolism*; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D001786:Blood Glucose; D007328:Insulin; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain