RYGB and SADI-S are effective and safe revisional options after SG

Both Roux-en-Y gastric bypass (RYGB) and single-anastomosis duodeno-ileal bypass (SADI-S) are effective and safe revisional options after sleeve gastrectomy (SG), according to researchers from Hamad Medical Corporation, Doha, Qatar. They noted that SADI-S offers superior long-term weight-loss and metabolic outcomes, whereas RYGB remains preferable for patients with significant or persistent GERD.

“Tailoring revisional procedure selection to patient characteristics and ensuring lifelong nutritional monitoring are essential for optimising long-term outcomes,” they researchers stated.

Among SG has become the predominant primary procedure, the investigators stated that 20–50% of SG patients experience inadequate weight loss, significant weight regain, or complications such as severe gastroesophageal reflux disease (GERD), ultimately necessitating revisional surgery. However, although RYGB and SADI-S, demonstrated effectiveness as revisional procedures, their long-term results regarding weight loss durability, GERD symptom control and comorbidity resolution beyond five years remain less well defined.

By integrating seven-year anthropometric, metabolic and symptom-specific outcomes, the researchers sought to provide important insights into the differential benefits and risks of RYGB and SADI-S. The study included all adult patients who underwent either RYGB or SADI-S between January 2014 and December 2015. A total of 105 patients met the inclusion criteria and were included: 62 RYGB and 43 SADI-S patients.

At one-, five- and seven-year post-revision follow-up, anthropometric measurements were obtained. Variables included body weight, BMI, percentage excess weight loss (percent EWL), percentage total weight loss (percent TWL), and body weight reduction. All complications after the operation, such as bleeding, internal hernia, marginal ulcers, dumping syndrome, severe malnutrition, vitamin deficiencies, and iron deficiency anaemia, were reviewed through electronic records from surgery to the date of data collection.

Outcomes

The age of both groups was similar as the mean age of RYGB was 40.66 years and that of SADI-S was 39.35 years (p=0.48). However, there was significant difference in sex distribution. Females constituted 65.8 percent of the RYGB group and 61.5 percent of the SADI-S group (p=0.01), indicating that there might be gender-related factors that affect the surgical decision-making. SADI-S patients were revised earlier with an average of 3.53 ± 1.29 years after SG as opposed to 4.13 ± 1.31 years in RYGB patients (p=0.02). It could be indicative of a rapid weight recurrence regain after SG in subjects who received SADI-S as a revisional conversion surgery.

Anthropometric measurements indicate that SADI-S patients exhibited higher body weight both before SG and prior to revision. Their pre-SG weight was 141.02/27.14 kg on average in comparison to 128.73/26.95 kg in RYGB patients (p=0.02). Pre-revision weight was also significantly higher in the SADI-S group (119.05 + 23.53 kg) compared with the RYGB group (107.16 + 21.20 kg; p=0.008). Accordingly, the SADI-S group had a significantly higher pre-revision BMI (43.51 ± 7.07 kg/m2) compared with the RYGB group (40.22 ± 6.45 kg/m2; p=0.01).

The prevalence of diabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, and asthma did not differ significantly between groups. Diabetes was present in 11 RYGB and 7 SADI-S patients, and hypertension in 11 and 8 patients, respectively, with non-significant p-values. Although dyslipidaemia appeared more frequently in the RYGB group (71.4 vs. 28.6%).

The only significant difference in preoperative comorbidities was the markedly higher prevalence of GERD among RYGB patients (88.6 vs. 11.4%, p=0.001), indicating that GERD was a major determinant in selecting RYGB. In contrast, the low prevalence of GERD among SADI-S patients suggests that their revisions were primarily driven by weight-related indications.

During the seven-year follow-up, SADI-S consistently achieved superior weight-loss outcomes compared with RYGB. Although absolute weight and BMI were similar between groups at each assessment point, SADI-S produced significantly greater reductions in %EWL (53.75 vs. 43.46%, p=0.05), %TWL (21.63 vs. 15.03%, p=0.001), and BMI (9.54 vs. 6.07, p<0.001) at one year.

At five years, SADI-S maintained higher %EWL (49.67 vs. 34.94%, p=0.03), %TWL (20.52 vs. 12.49%, p=0.001), and BMI reduction (9.27 vs. 5.13, p<0.001). By seven years, absolute weight and BMI were comparable, yet SADI-S continued to show superior %TWL (19.59 vs. 13.23%, p=0.01) and BMI reduction (8.94 vs. 5.44, p=0.002).

“Collectively, these findings indicate that SADI-S provides more durable and clinically meaningful weight-loss outcomes than RYGB as a revisional surgery after inadequate weight loss following sleeve gastrectomy,” the researchers noted.

Lipid profiles showed more pronounced differences with SADI-S patients exhibiting significantly lower total cholesterol at one, five, and seven years (p=0.002, 0.02, and 0.01), and lower triglycerides at five and seven years (p=0.001 and 0.006), alongside reduced HDL and LDL at all assessments, with LDL reaching statistical significance at one year. Micronutrient evaluation revealed higher zinc and folate levels in RYGB patients. In contrast, vitamin B12 concentrations were consistently higher after SADI-S.

Comorbidity outcomes were largely comparable between RYGB and SADI-S, with no statistically significant differences for type 2 diabetes, hypertension, dyslipidaemia, or asthma. Diabetes remission or improvement occurred in 44.4% of RYGB and 55.6% of SADI-S patients (p=0.24). Hypertension outcomes were similar overall, with improvement observed only in the SADI-S group. Dyslipidaemia remission or improvement was 66.7% in RYGB and 33.3% in SADI-S (p=0.99).

GERD outcomes favoured RYGB with complete remission or improvement occurred in 95.0 versus 5.0% with SADI-S (p=0.02), and persistent or progressive GERD was more common after SADI-S.

Postoperative complications were uncommon in both groups and no statistically significant differences were observed between RYGB and SADI-S. Neither group experienced anastomotic leak, bowel obstruction or stricture. Bleeding occurred in one RYGB patient and in none of the SADI-S patients (p=0.99). Marginal ulceration was reported more frequently after RYGB, though not significantly so (p=0.61). Internal hernia occurred only in the RYGB group (two cases), but this difference was also not significant (p=0.64). Dumping syndrome was more frequently reported after RYGB (81.8 vs. 18.2%), although the difference did not reach statistical significance (p=0.19).

Vitamin deficiencies were observed in 62.1% of RYGB and 37.9% of SADI-S patients (p=0.69). Severe malnutrition was rare, occurring in one RYGB and two SADI-S patients (p=0.74). Iron-deficiency anaemia was common in both cohorts - 55.1% in RYGB and 44.9% in SADI-S - with no significant difference (p=0.44).

“Overall, these results support a personalised approach to revisional bariatric surgery, balancing long-term weight-loss goals, symptom control and nutritional risk,” the researchers concluded. “Lifelong follow-up remains essential to optimise outcomes and sustain the benefits of either revisional strategy.”

The findings were reported in the paper, 'Comparative seven year outcomes of RYGB and SADI-S as revisional procedures for weight recurrence regain after sleeve gastrectomy: weight loss trajectory, reflux control, and metabolic safety', published in Surgical Endoscopy. To access this paper, please click here