Recent reviews suggest short- and medium-term complication rates may be comparable with sleeve gastrectomy and OAGB in published studies. Limited long-term data mean this should not be interpreted as proof of identical long-term safety.
01 — DAYS TO WEEKS
Early complications
Leak
A leak from the gastric staple line or anastomosis can cause severe infection and may require drainage, endoscopy, or further surgery.
Bleeding
Bleeding into the abdomen or digestive tract may require monitoring, transfusion, endoscopy, or re-operation.
DVT or pulmonary embolism
Obesity and surgery increase clot risk. Early walking, compression, and prescribed anticoagulation may reduce it.
Narrowing or obstruction
Persistent vomiting, difficulty swallowing liquids, or bowel obstruction may require imaging, endoscopy, or surgery.
Dehydration
Poor intake and vomiting can cause kidney injury, dizziness, and readmission.
Infection and anaesthetic risk
Wound or intra-abdominal infection, lung problems, cardiac events, and medicine reactions vary with individual health.
02 — MONTHS TO YEARS
Long-term risks
Nutrient and protein deficiency
Iron, B12, folate, vitamin D, calcium, or other deficiencies may contribute to anaemia, bone loss, nerve injury, or muscle loss.
Diarrhoea, gas, or frequent stool
Earlier delivery of food to the ileum may alter bowel habits. Persistent symptoms require nutrition and medical assessment.
Gallstones and rapid-weight-loss effects
Rapid loss can increase gallstone risk. Hair shedding, fatigue, and muscle loss may relate to nutrition or other conditions.
Ulcer, narrowing, or connection problems
The new connection may ulcerate or narrow. Nicotine and some anti-inflammatory pain medicines can increase risk.
Weight recurrence or insufficient loss
Biology, anatomy, medicines, nutrition, and behaviour all influence long-term weight. Treatment may include support, medication, endoscopy, or revision.
Revision surgery
Complications, reflux, or inadequate outcome may lead to revision. Revisional operations are generally more complex.
03 — GERD AND BILE REFLUX
Acid reflux and bile reflux are not the same.
The sleeve component may worsen gastro-oesophageal reflux in some people. The gastro-ileal connection also raises questions about bile entering the stomach and potentially the oesophagus. Published SASI reflux outcomes are mixed, and improvement in symptoms does not by itself exclude bile exposure.
Search-intent note: “SASI single anastomosis sleeve ileal bypass GERD outcomes” and “reflux outcomes” are recognised long-tail queries. This section answers them without promising a uniform result.
04 — URGENT WARNING SIGNS
Do not wait for these symptoms to pass.
- New or worsening severe abdominal or chest pain
- Persistent fast heart rate, breathlessness, or fainting
- Fever of 38°C / 100.4°F or higher, or shaking chills
- Repeated vomiting or inability to keep fluids down
- Vomiting blood, black stool, or obvious bleeding
- One-sided leg swelling or sudden chest pain
- Very little urine, marked weakness, or confusion
In an emergency: contact the surgical team’s urgent line or local emergency services. Do not use this page to self-diagnose a post-operative complication.
05 — CHOOSING A CENTRE
Look beyond the number of operations performed.
- A bariatric-capable hospital with critical care and 24/7 complication management
- Documented team experience with SASI and its possible revisions
- Routine tracking of leak, bleeding, readmission, re-operation, and long-term outcomes
- Accessible medical, dietetic, and mental health support
- A structured two-year programme and a plan for lifelong annual follow-up
- Pressure-free discussion of benefits, alternatives, uncertainty, and total cost