ASA Score 4 is Not an Indication for Morbid Obesity Surgery
An American Society of Anesthesiologists (ASA) Score of 4 is not an indication for morbid obesity surgery, as it actually represents a significant contraindication due to the high perioperative risk. 1
Established Indications for Bariatric Surgery
The established indications for bariatric surgery include:
- BMI ≥40 kg/m² regardless of comorbidities 1, 2
- BMI ≥35 kg/m² with at least one obesity-related comorbidity (such as type 2 diabetes, hypertension, hyperlipidemia, obstructive sleep apnea) 1, 3
- BMI ≥30 kg/m² with type 2 diabetes that could potentially go into remission (lower threshold indication) 1
Understanding ASA Score 4
An ASA Score of 4 indicates a patient with:
- Severe systemic disease that is a constant threat to life 4
- Significant cardiac, pulmonary, hepatic, renal, or endocrine dysfunction that severely limits daily activities 4
- High risk for perioperative complications and mortality 4
Why ASA Score 4 Contraindicates Bariatric Surgery
- Bariatric surgery requires patients to have acceptable operative risks, which ASA 4 patients do not have 3
- The American College of Cardiology recommends comprehensive medical evaluation to assess obesity-related comorbidities and surgical risk before bariatric surgery 1
- Patients with severe systemic disease (ASA 4) have significantly increased perioperative mortality risk that may outweigh potential benefits of bariatric surgery 4
Other Considerations in Bariatric Surgery Candidacy
Beyond BMI criteria, other important considerations include:
- Failure of non-surgical weight loss methods (structured diet, physical activity, behavioral therapy, pharmacotherapy) 1
- Patient motivation and ability to comply with long-term treatment and follow-up 1
- Comprehensive pre-surgical medical, nutritional, and psychological evaluation 1
Special Populations and Considerations
- For patients with obesity and decompensated cirrhosis, bariatric surgery should only be considered at the time of liver transplantation or thereafter 2
- Sleeve gastrectomy is the preferred technique for selected patients with obesity and well-compensated cirrhosis 2
- Lower BMI thresholds should be applied for Asian populations due to different body composition and risk profiles 1
Potential Benefits of Bariatric Surgery
When performed in appropriate candidates, bariatric surgery can result in:
- Significant and sustained weight loss 2
- Improvement or resolution of obesity-related comorbidities 2, 1
- Reduced risk of some malignancies 1
- Potential improvements in quality of life 2
Potential Risks and Complications
- Surgical complications (infection, bleeding, anastomotic leaks) 1
- Nutritional deficiencies requiring lifelong supplementation 1
- Suboptimal clinical response or weight regain 1
- Increased perioperative mortality in high-risk patients (such as those with ASA 4) 4
In conclusion, while BMI ≥40, BMI ≥35 with comorbidities, and BMI ≥30 with diabetes are established indications for bariatric surgery, an ASA Score of 4 represents a significant contraindication rather than an indication due to unacceptably high surgical risk.