Preoperative Evaluation of the Bariatric Surgery Patient

1. Preoperative Evaluation of the Bariatric Surgery Patient Eric I. Rosenberg, MD, MSPH, FACP

2. Case #1 “. . . evaluate for metabolic disorder”

3. “Super Super” Morbid Obesity • 53 year-old woman • 399 lbs, 4’ 10”, BMI 83.3 • Bariatric surgeon notes central obesity, abdominal bruises, buffalo hump

4. History

5. Exam • BP 147/73, P 83 • Flat affect • Moon facies • Buffalo hump • No muscle wasting, no striae, no bruising

6. Prior Studies – 8 months prior Ca+ 9 141 106 25 84 TSH 3.7 3.8 0.7 28 11.9 Chest X-ray: normal ECG: normal 282 9.3 36

7. Differential Dx for Severe Obesity • Dietary • Social/Behavioral • Inactivity • Iatrogenic • Neuro-endocrine

8. What would you do next?

9. Key Issues for Bariatric Pre-Operative Evaluation • When should you suspect a non-lifestyle associated etiology for morbid obesity? • What is the most efficient diagnostic strategy to evaluate for a neuro-hormonal cause? • What are the most important medical risks to this patient if she undergoes bariatric surgery?

10. Key Issues for Bariatric Pre-Operative Evaluation • When should you suspect a non-lifestyle associated etiology for morbid obesity? • What is the most efficient diagnostic strategy to evaluate for a neuro-hormonal cause? • What are the most important medical risks to this patient if she undergoes bariatric surgery?

11. Severe Obesity = BMI 40 NHLBI 2000

12. Treatment Guidelines for Obesity

13. Prevalence of Severe Obesity is Increasing

14. Pharmacotherapy: only 3 to 5 kg Average Weight Loss

15. Bariatric Surgery Reduces Obesity-Associated Morbidity

16. Surgery May Improve Longevity

17. “Ideal” Bariatric Surgery Candidates Cleve Clin J Med 2006;73(11).

18. HMO/Medicare Payment for Bariatric Surgery • BMI > 40 for 2 to 5 years • BMI > 35 if CAD, DM, HTN, sleep apnea • Repeated failures of supervised weight loss (6 months duration) • Letter of medical necessity • “Treatable metabolic causes ruled out” • “Thyroid panel” • “adrenal disorders”

19. Roux-en-Y Combines Restriction with Malabsorption

20. Acute Complication Rates for Bariatric Surgery

21. Long Term Complications • Anastomotic Stricture • Marginal ulcers • Bowel obstruction • Cholelithiasis • Nutritional Deficiencies

22. Nutritional Deficiencies are Common after Malabsorptive Procedures • Iron • Vitamin B-12 • Calcium • Vitamin D Multitamins will not adequately treat iron and B-12 deficiencies

23. Key Issues for Bariatric Pre-Operative Evaluation • When should you suspect a non-lifestyle associated etiology for morbid obesity? • What is the most efficient diagnostic strategy to evaluate for a neuro-hormonal cause? • What are the most important medical risks to this patient if she undergoes bariatric surgery?

24. Possible Metabolic Causes of Obesity in Our Patient • Hypothyroidism • Hypothalamic condition • Cushing’s Syndrome • Polycystic Ovarian Syndrome • Pseudohypoparathyroidism

25. This was my “non-clearance”… IMPRESSION: A 53-year-old white female without any history of cardiopulmonary disease. Given her lifelong history of morbid obesity in association with and lack of history of diabetes and hypertension, I think it is unlikely that she has Cushing disease or other underlying metabolic disorder…. I think she is at high risk for perioperative delirium given her significant psychiatric history. I think that the surgical team will need to be cautious with administration of narcotics or hypnotics/sedatives.

26. But Could She Have Cushing’s Syndrome? • Physical exam suggestive of hypercortisolism • From severe obesity? • From psychiatric distress? • From alcoholism? • No history of glucocorticoid use

27. Prevalence of Clinical Features of Cushing’s Syndrome • Obesity (90%) • Neuropsychiatric (85%) • Hirsutism (75%) • Bruising (35%) • Hypertension (85%) • Diabetes (20%) Greenspan’s Basic and Clinical Endocrinology, 8th Edition.

28. Validity of Standard Screening Tests for Cushing’s Syndrome • Elevated midnight serum cortisol • 96-100% sensitivity, 100% specificity • Overnight Dexamethasone Suppression • 90-100% sensitivity, 40% specificity • Elevated 24-hour urinary cortisol excretion • 100% sensitivity, 98% specificity

29. Accuracy of Screening Tests for Cushing’s Syndrome J Clin Endocrinol Metab 88:2003.

30. My Clinical Suspicion was High Enough to Screen for Cushing’s RECOMMENDATIONS: • “I ordered a midnight salivary cortisol test which is very sensitive and has high negative predictive value.”

31. Recommended Preoperative Testing for Bariatric Surgery • Hematocrit • Baseline Iron, B-12 levels • TSH • A1c (if diabetic control in doubt) • Creatinine if appropriate • Baseline ECG and other cardiopulmonary testing if suspect undiagnosed disease

32. 8 Months later… • Test #1: 0.155 ug/dL (normal <0.112) • Test #2: quantity not sufficient • Test #3: quantity not sufficient • Test #4: quantity not sufficient • Endocrine referral

33. Dexamethasone Suppression Test Rules-Out Cushing’s • 1mg Dexamethasone at 11PM to 12AM • 8AM Cortisol level • 1mcg/dL • <8% of patients with Cushing’s show suppression to < 2 mcg/dL • 100% sensitivity if suppress to less than 1.2 mcg/dL

34. Take-Home Points • Severe Obesity is increasingly prevalent • Bariatric Surgery will increase in popularity • Prospective Bariatric Surgery Patients need careful risk assessment and long-term follow-up for complications • Consider appropriate screening for secondary causes if patient presents with characteristic history, signs