# One anastomosis gastric bypass as a one-stage bariatric surgical procedure in patients with BMI ≥ 50 kg/m2

This prospective study was conducted on patients with severe obesity and BMI ≥ 50 kg/m2 aged 18 years and above who had undergone primary OAGB from January 2016 to February 2019 with at least 2 years follow-ups at the Rasool-e Akram Hospital, an accredited Center of Excellence of the European Branch of the International Federation for Surgery of Obesity ( IFSO).

Exclusion criteria consisted of revisional/conversion OAGB, lost to follow-up and pregnancy during mid-term follow-ups. According to the time of surgery, only 83 of 196 patients (43.8%) completed their 5-year follow-up.

All the patients were screened before the surgery by a multidisciplinary team consisting of an endocrinologist, a bariatric surgeon, a bariatrician physician, a gastroenterologist, a sports medicine specialist, a nutritionist and a psychiatrist/psychologist.

We routinely performed preoperative esophagogastroduodenoscopy (EGD) and biopsy to evaluate the presence of gastroesophageal reflux disease (GERD), hiatal hernia and Helicobacter pylori (HP). In patients with positive HP, eradication were done before OAGB.

All the patients had follow-ups at 10 days, and 1, 3, 6, 9, 12 and then annually after OAGB.

Weight loss outcomes were defined as percent excess weight loss (%EWL) and percent of total weight loss (TWL %)

$$begin{gathered} % EWL:left[ {left( {text{Initial Weight}} right) , {-} , left( {{text{Post}} – {text{Op Weight}}} right)} right]/ , left[ {left( {text{Initial Weight}} right) , {-} , left( {text{Ideal Weight}} right)} right] times { 1}00 hfill \ % TWL:left[ {left( {text{Initial Weight}} right) , {-} , left( {{text{Post}} – {text{Op Weight}}} right)} right]/ , left[ {left( {text{Initial Weight}} right)} right] , times { 1}00. hfill \ end{gathered}$$

The major complications were defined as any complication that resulted in a prolonged hospital stay (beyond 7 days), re-intervention or reoperation, such as anastomotic leak requiring reoperation, a venous thrombotic event (VTE), and gastrointestinal hemorrhage8

Remission of obesity associated medical problems including type-2 diabetes mellitus (T2DM), arterial hypertension (HTN), dyslipidemia (DLP), obstructive sleep apnea (OSA) and GERD, before and after OAGB at the defined follow-up intervals were according to the ASMBS standardized outcomes reporting8 as following:

### Complete remission of T2DM

HbA1c < 6% or FBG < 100 mg/dl in the absence of antidiabetic medications.

### Improvement of T2DM

Statistically significant reductions in HbA1c and FBG not meeting the criteria for remission or discontinuing insulin or one oral agent or a 50% reduction in dosage.

### Complete remission of HTN

BP < 120/80 with no antihypertensive medications.

### Improvement of HTN

Decrease in dosage or number of antihypertensive medications or a decrease in systolic or diastolic blood pressure with the same medications.

### Remission of DLP

A normal lipid panel off medication.

### Complete remission of OSA

Subjective method based on the patient’s discontinuance of CPAP or sleeping better on lower CPAP settings.

### Complete resolution of GERD

Subjective method according to absence of symptoms and no medication use.

The study protocol was approved by the ethics committee of the Iran University of Medical Sciences under this number: IR.IUMS.REC.1399.1198.

### Surgical procedures

OAGB was performed with five trocars laparoscopic technique in French position. The gastric pouch was constructed on a 36-Fr tube along the lesser curvature with 60 mm length linear staplers (Endo-GIA), beginning from the distal part of the crow’s foot to the His angle. Then, gastro-jejunostomy was performed with a 45 mm length linear stapler (Endo-GIA) at the anastomotic length of 40 mm in the posterior wall of the pouch, side to side with the jejunum, with a biliopancreatic limb (BPL) of 200 cm for all the patients. The enterotomies were closed with one-layer absorbable suture (PDS 2-0). Finally, after obtaining a negative air leak test, a drain was placed. All patents received 5000 IU Heparin/SC before starting the surgery that be continued every 8 h for two-weeks after OAGB.

On the first postoperative day, after the methylene blue leak test and clear liquid tolerance, the drain was removed and the patient was discharged in accordance with the Enhanced Recovery after Bariatric Surgery (ERAS) protocol.

### data collection

Data on the patients’ age, sex, weight, BMI and obesity associated medical problems were assessed preoperatively. All pre-operative, operative and post-operative data including lab data, complications and follow-ups were registered in Iran National Obesity Surgery Database (INOSD)9which is a web-based national registry database.

### Statistical analysis

The mean, percentage and 95% confidence interval (CI) were reported for the description of the data. Repeated measurements were used to assess the trend of changes in weight, BMI and EWL overall. All the analyzes were carried out in SPSS version 25.0 (Chicago, Illinois, USA).

### Ethical approval statement

All procedures performed in the study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

### Informed consent statement

Informed consent was obtained from the participants included in the study.