2073-P: Are Early Dumping and Postprandial Hypoglycemia after Roux-en-Y Gastric Bypass Related Events?

Introduction: Early dumping (ED) and postprandial hypoglycemia (PH) are often addressed as two separate complications after Roux-en-Y gastric bypass (RYGB) although symptoms overlap. We investigated the occurrence of ED in RYGB-patients with PH and potential mechanisms.

Methods: In a randomized cross-over study, 11 RYGB-patients with confirmed PH (blood glucose <3.9 mmol/L) underwent 6 separate 4-hour liquid mixed meal tests (MMT) in which continuous heart rate (HR) was recorded by Holter monitoring. The MMTs were preceded by the following: acarbose 50 mg (A), sitagliptin 100 mg (S), verapamil 120 mg (V), liraglutide 1.2 mg s (L), pasireotide 300 µg (P) and no treatment (NT). HR was averaged over 5 minutes intervals and calculated as peak values and incremental changes from baseline (ΔHR). ED was diagnosed as ΔHR ≥10 bpm during the first 60 minutes of the MMT. Associations between HR values and glucose, insulin, and GLP-1 concentrations were tested with the Spearman rank-order correlation and the effects of drug intervention were tested by use of linear mixed models.

Results: With NT, all patients had ΔHR ≥ 15 bpm within the first 35 minutes of the MMT (27 ± 3 bpm, mean ± SEM) corresponding to a 44 ± 4% increase in HR. Peak HR occurred at the same time as peak levels of glucose and GLP-1 (26 ± 2, 31 ± 2, 30 ± 2 minutes; p>0.23) and HR values were positively correlated with glucose, insulin and GLP-1 concentrations (r=0.44, r=0.41, r=0.56; p<0.0001). Intervention with P reduced both ΔHR, insulin and GLP-1 levels, A reduced ΔHR, hyperglycemia and insulin levels, and V reduced ΔHR and peak GLP-1 values (ΔHR: A 18 ± 3, V 18 ± 2, and P 11 ± 2 vs. NT 27 ± 3 bpm; p<0.001).

Conclusion: RYGB-patients with PH have postprandial HR increments suggestive of ED, indicating that PH and ED constitute a combined post-surgical complication. Insulin and GLP-1 are potential mediators driving the HR increments.