Alterations in esophageal acid exposure are an important physiologic consequence of bariatric procedures and are closely linked to gastro-oesophageal reflux disease (GERD) symptoms and mucosal injury. Sleeve gastrectomy (SG) has been associated with new or worsened acid exposure in many series, while Roux-en-Y gastric bypass (RYGB) is generally reported to reduce esophageal acid exposure and improve reflux.  

The aim of the study is to evaluate if any alteration exists in gastric pH before and after bariatric surgery due to anatomical alterations.

A prospective study was designed to determine gastric pH during EGDS before and after bariatric surgery. Gastric pH was mesured by aspiration of gastric pool during endoscopy. Comparison between patients who underwent SG and RYGB was performed to assess differences using chi-squared test. As secondary aim, esophagitis was considered as GERD index in both categories.

Till present date, 36 patients were studied. The complete trial will comprehend 100 patients.

Preliminary analysis shows a general decrease of gastric pH after bariatric surgery (mean preop value= 1.6 vs mean post-op value= 3.9, p value= 0,01) both in SG (mean post-op value= 3.7) and RYGB (mean post-op value= 4.1) without significant difference (p value=0,1). Esophagitis was reported preoperatively in 8 patients (grade A in 4, grade B in 3, grade C in 1) and all these patients underwent gastric bypass. After bariatric surgery, esofagitis was seen in 8/22 patients (36,3%) after SG and 0/14 after RYGB.

Bariatric surgery shows a significant reduction of gastric pH in both SG and RYGB. This datum shows that GERD after SG is mainly related to increased pressure of the gastric remnant and underline the potential role of hypochloridia in post-bariatric malasorbption.