Comparative Outcomes of One-Anastomosis Gastric Bypass and Roux-en-Y Gastric Bypass As Revisional Procedures Following Failed Restrictive Bariatric Surgery

Study Description

This prospective, multicenter study aims to compare the outcomes of One-Anastomosis Gastric Bypass (OAGB) and Roux-en-Y Gastric Bypass (RYGB) as revisional procedures for patients experiencing insufficient weight loss or weight regain following restrictive bariatric surgeries, such as laparoscopic sleeve gastrectomy (LSG) or laparoscopic adjustable gastric banding (LAGB). Conducted between January 2019 and December 2021, the study involves a three-year follow-up of 328 patients across high-volume bariatric centers.

The primary objective is to evaluate the effectiveness of these revisional procedures in achieving additional weight loss. Secondary objectives include analyzing differences in operative times, complication rates (short- and long-term), reduction of obesity-related comorbidities, mortality, and overall patient outcomes.

This study uniquely integrates comprehensive pre- and postoperative assessments, including radiological evaluations, to better understand predictors of success and provide evidence for optimal surgical strategies in revisional bariatric care.

Study Objective and Design

The primary objective of this multicenter study was to compare the effectiveness of one-anastomosis gastric bypass and Roux-en-Y gastric bypass as revisional procedures for addressing insufficient weight loss or weight regain following failed primary restrictive bariatric surgery. Effectiveness was measured in terms of additional weight loss. Secondary objectives included comparisons of surgical duration, reduction in obesity-related comorbidities, rates of short- and long-term complications, and mortality between the two revisional approaches. The study was conducted from January 2019 to December 2021, with a three-year follow-up for each participant.

Patient Selection and Data Collection

Participants were recruited from four high-volume bariatric centers in Italy. Inclusion criteria encompassed adults aged 18 to 65 years who exhibited insufficient weight loss, defined as excess weight loss of less than 50%, total weight loss of less than 25%, or a BMI greater than 40 kg/m² at least two years after undergoing laparoscopic sleeve gastrectomy or laparoscopic adjustable gastric banding. Eligible patients were those requiring revisional surgery exclusively for inadequate weight loss or regain. Exclusion criteria included revisional surgery for other indications (e.g., complications such as stenosis or severe gastroesophageal reflux), untreated psychiatric illness, active eating disorders, pregnancy, or any previous gastric surgery unrelated to bariatric interventions.

Preoperative assessments involved a multidisciplinary team including an endocrinologist, dietitian, and psychologist. Patients identified with maladaptive eating patterns received treatment before surgery to optimize outcomes. Baseline data on demographics, preoperative BMI, and comorbidities were collected and followed up throughout the study. Ethical approval was obtained from all participating centers' medical ethics committees.

Surgical Technique and Perioperative Management

One-Anastomosis Gastric Bypass

The surgical protocol for one-anastomosis gastric bypass involved removing the gastric band in patients previously treated with laparoscopic adjustable gastric banding, followed by dissection of the angle of His. If present, the fibrous capsule from the band was excised. A gastric pouch was created by horizontally transecting the stomach at the junction of the corpus and antrum, typically at the level of the crow's foot. For patients with a prior sleeve gastrectomy, the residual sleeve was horizontally transected. The length of the biliopancreatic limb was tailored based on the patient's preoperative BMI, ranging from 180 to 200 cm.

Roux-en-Y Gastric Bypass

For Roux-en-Y gastric bypass, the gastric band and fibrous capsule were removed in previously banded patients, followed by adhesiolysis as necessary. A small gastric pouch was created by transecting the stomach. The lengths of the alimentary and biliopancreatic limbs were standardized across centers. Closure of mesenteric defects was performed at the surgeon's discretion.

Data Collection

Type 2 Diabetes Mellitus

Type 2 diabetes mellitus was diagnosed according to established guidelines, based on fasting plasma glucose readings above 126 mg/dL, a two-hour glucose level exceeding 200 mg/dL during an oral glucose tolerance test, or a glycated hemoglobin level above 6.5%. Complete remission was defined as fasting plasma glucose levels below 100 mg/dL and HbA1c less than 6.0% without antidiabetic medications. Follow-ups were conducted at 3, 6, 12, 24, and 36 months post-revision.

Hypertension

Hypertension was defined as systolic blood pressure greater than or equal to 140 mmHg or diastolic pressure greater than or equal to 90 mmHg. Remission was defined as achieving blood pressure below 120/80 mmHg without antihypertensive medications. Blood pressure measurements were taken at 3, 6, 12, 24, and 36 months.

Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea was diagnosed based on prior polysomnography, with an Apnea-Hypopnea Index exceeding 15 events/hour or more than 5 events/hour in the presence of related symptoms such as snoring or daytime sleepiness. Remission was defined by resolution of these symptoms. Follow-up assessments occurred at 3, 6, 12, 24, and 36 months.

Outcome Measures

Baseline characteristics, including demographics, preoperative BMI, and comorbidities, were recorded at study entry.

Primary Outcomes

* Percentage Total Weight Loss: Measured as the proportion of total body weight lost relative to initial weight.
* Percentage Excess BMI Loss: Calculated as the proportion of BMI lost relative to the amount exceeding a BMI of 25.

Secondary Outcomes

* Mortality: Measured throughout the three-year follow-up.
* Complications: Assessed using the Clavien-Dindo classification. Short-term complications included anastomotic leaks, bleeding, infections, perforations, myocardial infarction, and stroke. Long-term complications included nutritional deficiencies, gastric ulcers, strictures, bile reflux, internal herniation, and malnutrition.
* Comorbidity Improvement: Evaluated using standardized criteria for resolution or improvement of type 2 diabetes, cardiovascular disease, obstructive sleep apnea, dyslipidemia, and osteoarthritis.

Quality of Life Outcomes

Quality of life was assessed using validated tools such as the SF-36 at multiple intervals: baseline, and 3, 6, 12, 24, and 36 months post-surgery. Domains evaluated included physical health, mobility, social functioning, emotional well-being, and fatigue. Quality-of-life trends were compared between the two surgical groups to identify differences in patient-reported outcomes.

This structured approach provides a comprehensive evaluation of surgical and patient-centered outcomes in revisional bariatric surgery.Study Objective and Design

The primary objective of this multicenter study was to compare the effectiveness of one-anastomosis gastric bypass and Roux-en-Y gastric bypass as revisional procedures for addressing insufficient weight loss or weight regain following failed primary restrictive bariatric surgery. Effectiveness was measured in terms of additional weight loss. Secondary objectives included comparisons of surgical duration, reduction in obesity-related comorbidities, rates of short- and long-term complications, and mortality between the two revisional approaches. The study was conducted from January 2019 to December 2021, with a three-year follow-up for each participant.

Patient Selection and Data Collection

Participants were recruited from four high-volume bariatric centers in Italy. Inclusion criteria encompassed adults aged 18 to 65 years who exhibited insufficient weight loss, defined as excess weight loss of less than 50%, total weight loss of less than 25%, or a BMI greater than 40 kg/m² at least two years after undergoing laparoscopic sleeve gastrectomy or laparoscopic adjustable gastric banding. Eligible patients were those requiring revisional surgery exclusively for inadequate weight loss or regain. Exclusion criteria included revisional surgery for other indications (e.g., complications such as stenosis or severe gastroesophageal reflux), untreated psychiatric illness, active eating disorders, pregnancy, or any previous gastric surgery unrelated to bariatric interventions.

Preoperative assessments involved a multidisciplinary team including an endocrinologist, dietitian, and psychologist. Patients identified with maladaptive eating patterns received treatment before surgery to optimize outcomes. Baseline data on demographics, preoperative BMI, and comorbidities were collected and followed up throughout the study. Ethical approval was obtained from all participating centers' medical ethics committees.

Surgical Technique and Perioperative Management

One-Anastomosis Gastric Bypass

The surgical protocol for one-anastomosis gastric bypass involved removing the gastric band in patients previously treated with laparoscopic adjustable gastric banding, followed by dissection of the angle of His. If present, the fibrous capsule from the band was excised. A gastric pouch was created by horizontally transecting the stomach at the junction of the corpus and antrum, typically at the level of the crow's foot. For patients with a prior sleeve gastrectomy, the residual sleeve was horizontally transected. The length of the biliopancreatic limb was tailored based on the patient's preoperative BMI, ranging from 180 to 200 cm.

Roux-en-Y Gastric Bypass

For Roux-en-Y gastric bypass, the gastric band and fibrous capsule were removed in previously banded patients, followed by adhesiolysis as necessary. A small gastric pouch was created by transecting the stomach. The lengths of the alimentary and biliopancreatic limbs were standardized across centers. Closure of mesenteric defects was performed at the surgeon's discretion.

Data Collection

Type 2 Diabetes Mellitus

Type 2 diabetes mellitus was diagnosed according to established guidelines, based on fasting plasma glucose readings above 126 mg/dL, a two-hour glucose level exceeding 200 mg/dL during an oral glucose tolerance test, or a glycated hemoglobin level above 6.5%. Complete remission was defined as fasting plasma glucose levels below 100 mg/dL and HbA1c less than 6.0% without antidiabetic medications. Follow-ups were conducted at 3, 6, 12, 24, and 36 months post-revision.

Hypertension

Hypertension was defined as systolic blood pressure greater than or equal to 140 mmHg or diastolic pressure greater than or equal to 90 mmHg. Remission was defined as achieving blood pressure below 120/80 mmHg without antihypertensive medications. Blood pressure measurements were taken at 3, 6, 12, 24, and 36 months.

Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea was diagnosed based on prior polysomnography, with an Apnea-Hypopnea Index exceeding 15 events/hour or more than 5 events/hour in the presence of related symptoms such as snoring or daytime sleepiness. Remission was defined by resolution of these symptoms. Follow-up assessments occurred at 3, 6, 12, 24, and 36 months.

Outcome Measures

Baseline characteristics, including demographics, preoperative BMI, and comorbidities, were recorded at study entry.

Primary Outcomes

* Percentage Total Weight Loss: Measured as the proportion of total body weight lost relative to initial weight.
* Percentage Excess BMI Loss: Calculated as the proportion of BMI lost relative to the amount exceeding a BMI of 25.

Secondary Outcomes

* Mortality: Measured throughout the three-year follow-up.
* Complications: Assessed using the Clavien-Dindo classification. Short-term complications included anastomotic leaks, bleeding, infections, perforations, myocardial infarction, and stroke. Long-term complications included nutritional deficiencies, gastric ulcers, strictures, bile reflux, internal herniation, and malnutrition.
* Comorbidity Improvement: Evaluated using standardized criteria for resolution or improvement of type 2 diabetes, cardiovascular disease, obstructive sleep apnea, dyslipidemia, and osteoarthritis.

Quality of Life Outcomes

Quality of life was assessed using validated tools such as the SF-36 at multiple intervals: baseline, and 3, 6, 12, 24, and 36 months post-surgery. Domains evaluated included physical health, mobility, social functioning, emotional well-being, and fatigue. Quality-of-life trends were compared between the two surgical groups to identify differences in patient-reported outcomes.

Eligibility Criteria:
Eligibility Criteria

Inclusion Criteria:

* Adults aged 18-65 years.
* Experienced insufficient weight loss, defined as:
* Excess weight loss (EWL) \< 50%.
* Total weight loss (TWL) \< 25%.
* BMI \> 40 kg/m² at least two years after primary restrictive surgery.
* Previously underwent laparoscopic sleeve gastrectomy (LSG) or laparoscopic adjustable gastric banding (LAGB).
* Undergoing revisional surgery specifically for inadequate weight loss or weight regain.

Exclusion Criteria:

* Revisional surgery performed for indications other than inadequate weight loss or weight regain (e.g., complications of the primary procedure such as stenosis or refractory gastroesophageal reflux, or for comorbidity management).
* Known psychiatric illness or untreated eating disorders.
* Pregnancy.
* History of prior gastric surgery unrelated to bariatric interventions.