Introduction

There is frequent debate regarding the role of preoperative endoscopy (EGD) prior to bariatric surgery. Some centers routinely perform EGD in all patients prior to bariatric surgery, while other centers utilize EGD selectively. The 2008 guidelines of from the American Society of Gastrointestinal Endoscopy (ASGE) recommended that that preoperative EGD should be performed in all patients with upper gastrointestinal symptoms and should be considered in patients without symptoms in order to exclude large hiatal hernias that may alter the surgical approach [1]. More recently, the ASGE in conjunction with the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) recommended that the decision to perform preoperative EGD should be “individualized” in bariatric surgery patients [2]. The American Society of Metabolic and Bariatric Surgery (ASMBS) recommends that all clinically significant gastrointestinal symptoms should be evaluated prior to bariatric surgery with imaging studies, upper gastrointestinal series, or EGD [3]. Alternatively, the European Association for Endoscopic Surgery (EAES) recommends either preoperative evaluation with an upper GI series or endoscopy prior to all bariatric surgeries regardless of symptoms, and the European Society of Gastrointestinal Endoscopy (ESGE) currently has no formal recommendations [4].

Although there is no clear standard for patient symptoms requiring preoperative EGD, surgeons may consider preoperative EGD in patients with symptoms of gastroesophageal reflux disease/esophagitis (including heartburn, regurgitation, dysphagia, or any postprandial symptoms that suggest foregut pathology) and/or patients undergoing gastric bypass with a family history of gastric cancer. The objective of this study was to perform a systematic review and meta-analysis of the existing literature to estimate how frequently preoperative EGD changes management.

Materials and Methods

After institutional review board approval, the study was registered on the PROSPERO international prospective register of systematic reviews (CRD42014009024). To identify relevant articles, a medical librarian trained in systematic review methodology searched the PubMed/MEDLINE (1946–present), Embase (1974–present), Cochrane Library, Web of Science (1900–present), BIOSIS (1926–present), Biological Abstracts (1969–present), and the Clinical Trials registries through April 2014. The NYAM Grey Literature, Open Grey, and OIAster databases were searched for gray literature of reports and additional information. Obesity Surgery, Surgery for Obesity & Related Diseases, Surgical Endoscopy, American Journal of Surgery, Annals of Surgery, and Surgical Endoscopy were hand searched for additional citations.

The primary search strategy included several key terms in order to capture all relevant articles and abstracts (Fig. 1). These search terms were generated in conjunction with the surgeons, gastroenterologists, and the medical librarian. Articles (1731) were identified and 1255 articles remained after duplicates were removed. The titles and abstracts were screened for applicability. The full text of the remaining 89 articles was reviewed for eligibility with 28 articles chosen for analysis (Fig. 2).

Fig. 1
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Terms of primary search strategy.

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Fig. 2
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Flow chart outlining search methods and excluded records

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Several articles in the literature utilize multiple groupings, with many patients duplicated in these groups, making analysis difficult. Furthermore, some studies reported selective preoperative EGD based on patient symptoms and/or surgeon preference, while others reported routine preoperative EGD. For the purposes of this review, it seemed most clinically useful to group negative findings and findings that did not change management together and to also group findings that delayed surgery and those that canceled surgery together. Therefore, patients were classified into two distinct groups based on preoperative EGD findings (Table 1): Group 1 included EGDs with negative findings or findings which did not significantly alter management (small hiatal hernia, mild/moderate gastritis, Los Angeles Grade A/B esophagitis [5]). Group 2 was defined as findings that delayed, altered, or cancelled surgery (large hiatal hernia, Los Angeles Grade C/D esophagitis, esophageal stricture, malignancy, etc.). Since some bariatric surgeons may treat all esophagitis, regardless of severity, a second calculation was performed with all esophagitis categorized in Group 2.

Table 1 Definition of two groups based on preoperative EGD findings
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Given the significant heterogeneity of the existing studies, a general estimating equation (GEE) model was used to calculate a confidence interval, accounting for the correlated data within each study.

Results

A total of 28 studies (18 scientific publications and 10 abstracts) encompassing 6616 patients undergoing EGD prior to bariatric surgery were included in the analysis (Table 2). The vast majority of studies (25/28) performed preoperative EGD routinely. Three studies utilized selective preoperative EGD initially but converted to routine preoperative EGD over the course of the study. The mean age of all the patients was 41.4 (±2.9) years and most of the patients were women, reflecting the typical demographics of bariatric surgery patients. The mean preoperative body mass index (BMI) was 47 (±3.2) kg/m2. Overall, 92.4 % (n = 6,112) of the patients had a normal EGD or findings that did not change clinical management and 7.6 % (n = 504) had findings that delayed or altered surgery.

Table 2 Systematic review of preoperative EGD findings
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The patient-level data (when available) is shown in Table 3. EGD findings included gastritis (35 %), hiatal hernia (20 %), esophagitis (18 %), and Barrett’s esophagus (0.1 %). Four patients (0.08 %) were found to have carcinoma.

Table 3 Endoscopic findings in 4511 patients undergoing bariatric surgery
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There was significant heterogeneity within the studies, likely reflecting variation in deciding when to delay/cancel surgery (Fig. 3). The GEE model, accounting for the correlated data within each study, calculated the 95 % confidence interval of the 7.6 % estimate to be 4.6 to 12.4 %. The GEE model was repeated after categorizing all esophagitis (regardless of grade) into Group 2. The revised estimate was 20.6 %, 95 % CI [14.5 %, 28.2 %].

Fig. 3
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There was significant heterogeneity within studies

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Sensitivity analysis was performed regarding the abstract-only data to assess any potential difference from the published articles. The GEE model found no significant difference in the abstract-only data (p = 0.678).

Discussion

Many bariatric surgery centers routinely perform EGD prior to bariatric surgery to potentially identify and treat lesions that may affect the surgery or even cancel the procedure entirely. The data regarding the benefit of routine preoperative EGD is variable and the surgical and gastrointestinal societies have issued potentially conflicting recommendations. This systematic review and meta-analysis of the existing literature was performed to estimate how frequently preoperative EGD changes management. We found that overall 7.6 %, 95 % CI [4.6 %, 12.4 %] of preoperative EGD had findings that delayed or altered surgery, and up to 20.6 %, 95 % CI [14.5 %, 28.2 %] of all grades of esophagitis were categorized in group 2.

Many centers advocate for routine preoperative EGD prior to bariatric surgery. The justification for this is that the increased prevalence of gastrointestinal diseases in the morbidly obese population may impact the perioperative therapy or even the surgical procedure [6]. Others favor a more “selective” approach, since the majority of abnormal EGD findings (e.g., Helicobacter pylori and hiatal hernia) can be diagnosed with other modalities [7, 8]. However, even in patients with upper gastrointestinal symptoms, it is unclear that preoperative EGD is beneficial, as studies have shown that the presence of symptoms cannot be considered a valuable guide to indicated endoscopy [9]. Furthermore, EGD may also be associated with complications such as bleeding, infection or perforation, or cardiopulmonary events secondary to sedation or anesthesia—which constitute up to 60 % of all adverse events associated with EGD [10].

There is also considerable debate regarding the clinical significance of some preoperative endoscopic findings, including H. pylori infection and esophagitis. Although most surgeons treat H. pylori prior to gastric bypass to mitigate the risk of marginal ulcer postoperatively [11], the evidence is unclear regarding the benefit of H. pylori eradication prior to sleeve gastrectomy [12]. Another clinical issue with routine eradication of H. pylori prior to bariatric surgery is that obese patients have a significantly lower rate of eradication compared to controls, which could ultimately delay access to bariatric surgery [13, 14].

Perhaps more relevant, especially given the recent popularity of laparoscopic sleeve gastrectomy (LSG) [15], is the endoscopic finding of reflux esophagitis. Some surgeons may consider severe esophagitis or Barrett’s esophagus a contraindication to LSG [16]. For these surgeons, preoperative EGD may be warranted, as our estimate of EGD findings that delayed or altered surgery increased to 20.6 % when all grades of esophagitis were grouped together. Nevertheless, objective evaluations of reflux pre- and post-LSG show that the vast majority of reflux improves after LSG [17]. In addition, the number of preoperative EGD required to screen to find Barrett’s esophagus is high, especially given low incidence in this review (0.1 %) and reported in other studies [18].

In the past, surgeons advocated for routine preoperative EGD to rule out malignancy of the stomach prior to gastric bypass, as the remnant stomach would no longer be accessible to endoscopic surveillance [7]. However, the incidence of gastric malignancy in the US is very rare and preoperative EGD may miss cancerous lesions [6]. In this review, cancer was found in 0.08 % of patients.

This meta-analysis is limited by the source data that is not a randomized group of patients, but rather a collection of mainly retrospective reports in the literature. The analysis is also limited by the fact that the vast majority of studies utilized routine preoperative EGD, precluding a comparison between studies that report routine EGD vs. selective EGD. We manually reviewed all studies in the analysis to identify any additional patient-level factors.

There is also significant heterogeneity in the existing literature due to the varying protocols across institutions regarding the relevance of various preoperative EGD findings. Due to the heterogeneity, the GEE model was created to estimate confidence intervals, accounting for the correlated data within each study. Sensitivity analysis was also performed to determine whether the data from the abstracts affected our findings and we found no difference (p = 0.678).

How should a practicing bariatric surgeon interpret this data, especially given the shortcomings of the source data? Surgeons will need to balance the risks of a potentially unnecessary invasive procedure that may increase “dropout” prior to bariatric surgery with the possibility of missing an important asymptomatic endoscopic finding that may ultimately require revision surgery (e.g., severe esophagitis in patients undergoing LSG). From our perspective, routine preoperative EGD is not warranted based on the current evidence. Although a significant percentage of LSG revisions are due to intractable reflux, it is unclear that preoperative EGD would make a difference, as “de novo” reflux may develop after LSG [17].

Conclusion

This systematic review and meta-analysis of the existing literature found that overall 7.6 %, 95 % CI [4.6 %, 12.4 %] of preoperative EGD had findings that delayed or altered surgery. If all esophagitis (regardless of grade) were categorized into Group 2, this increases to 20.6 %, 95%CI [14.5 %, 28.2 %]. A selective approach to EGD may be considered, based on the patients’ symptoms, risk factors, and type of procedure planned.