RELEVANCE OF THE OBESITY SURGERY MORTALITY RISK SCORE IN PATIENTS UNDERGOING ROUX-EN-Y GASTRIC BYPASS.

A STUDY IN THE UNITED KINGDOM

S Mansour, V Kaur, G Vasilikostas, KM Reddy, A Wan

St George’s Healthcare NHS Trust, London, UK

BARIATRIC SURGERY Obesity is a leading cause of

death worldwideMokdad AH et al, JAMA 2004

Bariatric surgery is currently, the only treatment available for sustained weight loss in the morbidly obese• Reduction in relative risk of death by up to 89%

Colquitt JL et al Cochrane Database Systematic Review 2009Christou NV et al Annals of Surgery 2004

Good safety profile• Overall, 90-day MR* = 0.35% = lap chole 90-day MR*

Pories WJ Journal of Clin Endo & Met 2008*MR – Mortality rate

ROUX-EN-Y GASTRIC BYPASS (RYGB) Overall, reported MR for patients

undergoing primary RYGB 0 – 1.5%

DeMaria EJ et al Ann Surg 2002, Schauer PR et al Ann Surg 2000Wittgrove AC et al Am J Surg 2000, Buchwald H et al JAMA 2004

Published data on MR in ‘high-risk’ patients 0 – 1.0% Usually addressed a single risk factor

Age >60 yrs BMI >50 kg/m2

Wittgrove et al Obes Surg 2009, Adeles D et al J Am

Figure 1: RYGB

RISK STRATIFICATION Important component of surgical

decision – making

Risk stratification tools in surgery APACHE P – POSSUM O – POSSUM NSQIP Surgical APGAR

Does not recognise factors specific to bariatric patients

Surgical scores - not designed as a pre-operative predictive tool

IDENTIFYING RISK FACTORS Recent publications have attempted to identify risk

factors for morbidity and mortality in bariatric surgery

Fernandez AZ et al Ann Surg 2004, Livingston EH et al Ann Surg 2002

Sapala JA et al Obes Surg 2003, Jamal MK et al SOARD 2005

Courcoulas A et al Surgery 2003, Nguyen NT et al Ann Surg 2004Patient factors

Super obeseMale gender

Advanced ageCo-morbidities

Surgical complication

sAnastomotic leak

Pulmonary embolism

Surgeon experience

/ case volume

OBESITY SURGERY MORTALITY RISK SCORE (OS-MRS)

Developed from a single centre's experience with 2075 primary open and laparoscopic RYGB during a 10 year period Analysed multiple pre-op factors of potential significance Determined 5 pre-operative factors correlating with mortality Derived a pre-op scoring system for risk stratification

OS-MRS DeMaria EJ et al SOARD 2007

… Applied to a large (n=4431) multi-centre cohort

accurately predicted mortality risk DeMaria EJ et al Annals Surg 2007

OS-MRS is the first validated stratified scoring system for predicting post-op mortality in bariatric surgery Easy to use Pre-operative

AIM

To assess the utility of OS-MRS in patients undergoing primary laparoscopic RYGB in

a hospital in the United Kingdom

METHODS All patients undergoing elective primary roux-en-Y gastric

bypass surgery from June 2008 – Dec 2009

Planned laparoscopic approach

Exclusion criteria – revision surgery

Prospectively maintained database demographic & pre-op clinical data

90 day procedure-related mortality

Eligibility for surgery – NICE guidelines BMI* >40 kg/m2 or BMI* >35 kg/m2 with obesity-related co-

morbidities

Assessed by a multidisciplinary team

Patients have to display appropriate understanding of procedure

METHODS 5 OS-MRS variables (1 point each)

SBP= systolic blood pressure, DBP = diastolic blood pressure, VTE = venous thromboembolism, IVC = inferior vena cava, HF = heart failure

Variable Definition

Age >45 years

Gender Male

BMI > 50 kg/m2

Hypertension (HT)

• resting SBP >150mmHg or

DBP > 90mmHg at initial visit

• the use of antihypertensive medications

PE risk Previous VTE event

Pre-op IVC filter

Right HF

Pulmonary HT

Venous stasis

Obesity hypoventilatory syndrome

METHODS

OS-MRS points are grouped into 3 categories

Class Points Risk (MR%)

Class A 0-1 Low (0.31)

Class B 2-3 Intermediate (1.9)

Class C 4-5 High (7.56)

RESULTS 18 month period

Total =116 patients

No mortalities

All procedures were completed laparoscopically

F= Female, M= Male, ASA = American Society of Anesthesiologists

Parameter Value

Mean age (years) 43.15 +/- 9.47

Gender F:M (%) 93:23 (80:20)

Mean BMI (kg/m2) 49.45 +/- 7.76

Mode ASA grade 2

RESULTS

OS-MRS variables

Variable n (%)

Age >45 yrs 32 (28%)

Male 23 (20%)

BMI> 50 kg/m 23 (20%)

HT 41 (35%)

PE risk 0 (0%)

RESULTS

OS-MRS points

Points n (%)

0 28 (24.1)

1 41 (35.3)

2 25 (21.6)

3 18 (15.6)

4 4 (3.4)

5 0 (0)

RESULTS

OS-MRS classes (96.6%)

Class n (%)

A 69 (59.5)

B 43 (37.1)

C 4 (3.4)

RESULTS

OS-MRS mortalities

No significant difference seen between the observed and expected mortality OS-MRS was a valid tool for predicting mortality

risk in our cohort

Class Observed MR (%)

Expected MR (%)

A 0 (0) 0.2 (0.31)

B 0 (0) 0.8 (1.90)

C 0 (0) 0.3 (7.56)

OS-MRS RISK FACTORS

0

10

20

30

40

50

60

Our cohort

DeMariaDeMaria EJ et al SOARD 2007

UTILITY OF OS-MRS Provide objectivity

Aid informed consent Risk prediction Understanding prognosis / severity

Pre-op optimisation especially in high risk patients Risk reduction strategies – decreasing BMI, optimise BP

Aid surgical decision making in high-risk patients use alternative lower risk or staged procedures

Planned critical care admission post-operatively

Allow standardisation of outcome comparisons between different units

Instigate ‘new and improved’ risk-stratification scores in bariatric surgery

CONCLUSION

Mortality risk in RYGB can be stratified based on independent variables that can be identified pre-operatively

OS-MRS is a clinically relevant and valid scoring system for predicting mortality risk in our medium volume cohort

OS-MRS may help contribute in surgical decision making in bariatric surgery

THANK YOU FOR LISTENING

QUESTIONS & ANSWERS

RELEVANCE OF THE OBESITY SURGERY MORTALITY RISK SCORE IN PATIENTS UNDERGOING ROUX-EN-Y GASTRIC BYPASS.

Presenter’s name: Ms Vasha Kaur

As previously disclosed I do not have a financial or other relationship with any company.