DURABILITY OF ESOPHAGEAL ACID EXPOSURE NORMALIZATION AFTER NISSEN FUNDOPLICATION AND ITS ASSOCIATION WITH SYMPTOMS

Introduction: Nissen fundoplication provides durable symptomatic control over time in patients with GERD. Studies have also demonstrated a high rate of distal esophageal acid exposure normalization up to 1-year after surgery. However, data on the durability of acid exposure normalization after surgery is limited. The aim of this study was to assess esophageal acid exposure over time and determine factors associated with its durability in patients with an intact Nissen fundoplication.

Methods: Patients who underwent primary Nissen fundoplication at our institution with an endoscopically intact fundoplication and no herniation were selected. Those who completed esophageal pH monitoring at 1-year and 4-years after surgery were included. One year pH monitoring was performed at a mean (SD) of 17.7 (10) months and the 4-years test at 49.0(26) months after surgery. The degree of esophageal acid exposure was compared before and at 1 and 4-years after surgery. A subgroup of patients with acid normalization at 1-year were divided into durable and waning -normalization groups based on the 4-year pH-monitoring result and compared. Normalization of esophageal acid exposure was defined as a DeMeester score <14.7.

Results: The final study population consisted of 71 patients (78.9% female) with a mean (SD) age of 59.5(14). At one year follow-up after surgery there was improvement in the GERD-HRQL score [28.9(18) to 13.7(9), p<0.0001]. There was improvement in DeMeester score [35.8(27) to 4.3(5.1), p<0.0001] with a 94.4% acid exposure normalization rate.
From 1-year to 4-years, GERD-HRQL score improvement was comparable [13.7(9) to 12.0(12) p=0.889]. Freedom from antisecretory medications was similar (82.6% to 81.8%, p=0.911). DeMeester score was also comparable [4.3(5.1) to7.3 (10.5), p=0.234], with similar normalization rate (94.4% vs 91.5%, p=0.724).
Of the 68 patients with acid exposure-normalization at 1-year, 91% had durable normalization at 4-years. Those with durable pH-normalization were similar in age, sex, BMI and preoperative GERD-HRQL score to those with waning normalization (p>0.05). GERD-HRQL scores and antisecretory medication use were comparable at both 1-year and 4-years between groups (p>0.05).
The remaining 9% with waning pH-normalization had higher preoperative DeMeester scores [65.9(34) vs 32.7(24), p=0.014]. They were also less likely to have > 80% intact peristaltic contractions (30.0% vs. 80%, p=0.047) and had lower % complete bolus clearance on preoperative high-resolution manometry [34(43) vs. 75.5 (29), p=0.021].

Conclusion: Nissen fundoplication provides durable symptomatic and objective reflux control in patients with an intact repair. Only 9% of patients had waning acid exposure normalization over time with no impact on symptoms or medication use. Waning acid exposure-normalization was associated with poor esophageal body function.