1. Surgical Risk Dr Chris Snowden MD FRCA Consultant Anaesthetist
Freeman Hospital
Newcastle upon Tyne

3. Population Studies: Safety in Numbers
Metanalyses
Multiple RCTs
Trial Omissions
Large Cohort
e.g. NSQUIP
clinically meaningful data
standardized outcome definition
validated risk-adjustment
Decreased unadjusted
30-day mortality (3.2% to 2.3%)
30-day morbidity (17.4% to 9.9%)

4. Procedural Risk Netherlands Population study 3.5 M Operations
Evaluated trends
Elective, open, non-laparoscopic
Results
All cause 30 d mortality – 1.85%
Hugely Variable
High/Low stratification unacceptable
Anesthesiology 2010; 112:1105

5. Mortality
N= 110,000 pts
Ghaferi et al. Annals of Surgery 2009: 250;6,

6. Across Procedures
Ghaferi et al NEJM 2009: 361:1638

7. Population
105,952 pts
Khuri SF et al; Ann Surg 2005

8. Complications and Outcome
Khuri et al. Ann Surg 2005

9. Defining Surgical Risk
Abdominal
Ortho
Vascular
Transplant
Surgical
Intervention
“FTR”
Outcome
Survival
Mortality
Complications

10. Complication Types Prospective data 3970 pts Age >50 yrs
Non-cardiac surgery
Adjusted Data
Complications
Length of Stay (Days)
None
4 (3-4)
Non-cardiac
11 (10-12)
Cardiac and non-cardiac
15 (12-18)
Fleischmann KE et al; Am J Med: 2003

11. Patterns of Complications
No GI comps
GI comps
Median: 10 vs 17 days
P=0.0001

12. Cardiorespiratory Complications
Median: 8 vs 12 vs 23 days
P<0.0001
CVS/RS
Non-CVS/RS
No Comps

13. Defining Surgical Risk
Death
Abdominal
Ortho
Vascular
Transplant
FTR
Survival
Complications No
Extended
Recovery
CVS RS
Complications
Delayed
Recovery GI
Inf
Ren
Appropriate
Recovery

14. Surgical Risk

15. Defining Surgical Risk
Death
Abdominal
Ortho
Vascular
Transplant
FTR
Complications No
Extended
Recovery
CVS RS
Patient
Delayed
Recovery GI
Inf
Ren
Appropriate
Recovery

16. Ischaemia or Heart Failure
Elderly (> 65 yrs)
159,327 procedures
18% HF; 34% CAD
Mortality/Readmissions
Hazard Ratios
HF 1.63
CAD 1.08
Hammill et al. Anesthesiology 2008;

17. Heart Failure Prevalence

18. “Asymptomatic” Heart failure
Retrospective study
Three groups;
EF > 40 (n=385)
EF < 40 (n=192)
Controls (n=10,000)
“Optimised” heart failure
Results:
No Difference in mortality (short term)
Difference ;
Longer hospital stays - 2 days
Hospital readmissions - 18% (EF >40% more likely than EF >40)
Long term outcome
Xu-Cai et al. Mayo clinic Proc 2008;

19. 501 (50%) LV dysfunction (EF<50%) 52% diastolic dysfunction
1000 patients
501 (50%) LV dysfunction (EF<50%)
52% diastolic dysfunction
Anesthesiology 2010; 112:1316 –24

20. Defining Surgical Risk
Death
Exercise
Ability
Abdominal
Ortho
Vascular
Transplant
FTR
Complications No
Extended
Recovery
CVS RS
Patient
Cardiorespiratory
Dysfunction
Delayed
Recovery GI
Inf
Ren
Appropriate
Recovery

21. CPET: Risk Tool ? CPeT Structured approach Comorbidity summary measure
Quantitative and Qualitative endpoints
Multiple, simultaneous CVS/RS components
Structured approach
Concept Proof
Incremental value
Clinical Utility
Predictive validity
Intervention

22. Evidence n Patients Outcome Trial Concept Incremental Clinical Utility
Older
1993
187
Elderly
Mortality
Prospective Cohort (?Blinded)
>11 ; 4%
<11 ; 42%
1999
548
Prospective Cohort
(No blinding)
CP deaths confined to <11 or ischaemia
Forshaw
2008 78
Oesophagus
Morbidity
13.2 vs 14.4
CP complications
Readmissions NA
Carlisle
2007
130
Vascular
Mid term mortality
Retrospective Cohort
CPeT related to survival AT
VE/VCO2
RCRI
Hazard Ratio
Hightower
2010 32
Major Abdominal
Prospective, Pilot
(Blinded)
PC related to outcome
ASA vs AT,HR
Wilson 2010
847
Major Surgery
(No Blinding)
<11 Relative risk 7x death
Greater than Clinical factors
Snowden
116
Prospective
CPeT variables related to outcome
Improvement on subjective and established factors
Risk increase

23. 847 Pts
Mortality 2.1%
Hospital mortality by AT group - effect of cardiac risk factors:
AT < 11
AT >11
RR (95% CI)
Patients with 1 or more cardiac risk factors (n=271)
3.8%
1.1%
3.3 ( )
Patients with no cardiac risk factors (n=576)
3.2%
0.3%
10.0 ( )
BJA ; 297

24. Optimum AT 10.1 ml/min/kg AUC 0.85 ; Sens 88%; Spec 79%
Snowden et al 2010 Ann Surg

25. Types of Complications

26. Modelling Outcome

27. Exercise Ability and Cardiorespiratory Complications*
***

28. Proportion Remaining in Hospital
“High Risk” CCU Groups
Proportion Remaining in Hospital
ITU 3
ITU 7 n
Day 3 Poms
Day 7 Poms
LOS No 45 2 9
Yes 3 1 12 20 5 4 19 31 28

29. CCU and Exercise Prediction
12.0
11.4 (2.6)
11.0
ROC Analysis:
Opt AT 10.6 (62%,80%)
AUC ( )
P=0.0001
10.0
9.0
9.6 (2.3)
8.0
Low Risk
High Risk
High risk ITU 29

30. The CPeT “Package of Care”
CPX Clinic
No clinic
30 day mortality
3/194 (2%)
8/139 (6%)
Critical Care
22%
10%
CPX Clinic _________
No CPX Clinic _________
Swart et al. Personal communication

31. High Risk Surgery: Liver Transplantation
Highest Surgical Risk (O.R. 15.8)
Early Mortality - 18%
Ensure appropriate organ allocation
Limited resource
Marginal Organs
High Comorbidity

32. Recipient Scores Survivors Non Survivors Signif N= 49 6 AGE (Mean;SD)
53.1 (10.6)
49.2 (12.4) NS
BMI (Mean;SD)
26.3 (5.3)
26.7 (6.9)
Waiting List (Mean;SD)
94 (82)
129 (112)
UKELD (Mean;SD)
53 (5.2)
53 (6.7)
MELD (Mean;SD)
17 (9)
18 (9)
Snowden et al (In Prep) 32

33. Transplantation and Exercise
ROC analysis:
Optimum AT 9.6 ml/min/kg
AUC 0.97 ; (p=0.001)
p<
Snowden et al (In Prep) 33

34. CCU Stay and Liver Tx Median CCU LOS 9 days vs 27 days P=0.001
Proportion remaining in CCU
AT< 9.6
AT>= 9.6
Days in CCU 34

35. Donor – Recipient Matching
Snowden et al (In Prep)

36. Selective Training Effect

37. Summary Surgical risk - evolving concept
Insights from large population studies
New concepts for:
Operative risk variability
Mortality and “Failure to rescue”
Importance of complications (esp CVS)
Cardiac “Dysfunction”

38. Summary Exercise Ability (and assessment): Future
Defines important end point for comorbidity
Relates to mortality and morbidity
Varying surgical specialities
Pedigree in cardiorespiratory dysfunction
Future
Prospective comparative trials
Interventional strategy tool