Surgical Risk Surgical Risk

Dr Chris Snowden MD FRCADr Chris Snowden MD FRCAConsultant Anaesthetist Consultant Anaesthetist

Freeman HospitalFreeman HospitalNewcastle upon Tyne Newcastle upon Tyne

Population Studies: Population Studies: Safety in NumbersSafety in Numbers

MetanalysesMetanalyses– Multiple RCTsMultiple RCTs– Trial OmissionsTrial Omissions

Large Cohort Large Cohort e.g. NSQUIP e.g. NSQUIP – clinically meaningful data clinically meaningful data – standardized outcome definition standardized outcome definition – validated risk-adjustmentvalidated risk-adjustment

Decreased unadjusted Decreased unadjusted – 30-day mortality (3.2% to 2.3%)30-day mortality (3.2% to 2.3%)– 30-day morbidity (17.4% to 9.9%) 30-day morbidity (17.4% to 9.9%)

Procedural RiskProcedural Risk

Netherlands Population study3.5 M Operations1991-2005Evaluated trends Elective, open, non-laparoscopic

ResultsAll cause 30 d mortality – 1.85%Hugely Variable High/Low stratification unacceptable

Anesthesiology 2010; 112:1105

Mortality Mortality

Ghaferi et al. Annals of Surgery 2009: 250;6,

N= 110,000 pts

Across ProceduresAcross Procedures

Ghaferi et al NEJM 2009: 361:1638

Khuri SF et al; Ann Surg 2005

Population105,952 pts

Complications and Outcome Complications and Outcome

Khuri et al. Ann Surg 2005

Defining Surgical Risk

Outcome

Abdominal

Ortho

Vascular

Transplant

“FTR”

MortalityComplications

Survival

Surgical Intervention

Complication TypesComplication Types

Prospective data 3970 pts Age >50 yrsNon-cardiac surgeryAdjusted Data

Fleischmann KE et al; Am J Med: 2003

ComplicationComplicationss

Length of Length of Stay (Days)Stay (Days)

NoneNone 4 (3-4)4 (3-4)

Non-cardiacNon-cardiac 11 (10-12)11 (10-12)

Cardiac and Cardiac and non-cardiacnon-cardiac

15 (12-18)15 (12-18)

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7

Postoperative day

Patie

nts

with

Com

plic

atio

ns

(%) Cardiac

Non-Cardiac

Patterns of Complications Patterns of Complications

No GI comps

GI comps

Median: 10 vs 17 daysP=0.0001

Cardiorespiratory Complications Cardiorespiratory Complications

Median: 8 vs 12 vs 23 daysP<0.0001

No Comps

CVS/RS

Non-CVS/RS

Defining Surgical Risk

Abdominal

Ortho

Vascular

Transplant

FTR

Delayed Recovery

GIInf

Ren

Complications

No Complications

ExtendedRecoveryCVS RS

Appropriate Recovery

Survival

Death

Complications

Surgical Risk Surgical Risk

Defining Surgical Risk

Abdominal

Ortho

Vascular

Transplant

FTR

Delayed Recovery

GIInf

Ren

Complications

No Complications

ExtendedRecoveryCVS RS

Appropriate Recovery

Death

Patient

Ischaemia or Heart FailureIschaemia or Heart Failure

Elderly (> 65 yrs)Elderly (> 65 yrs)159,327 procedures 159,327 procedures 18% HF; 34% CAD 18% HF; 34% CAD Mortality/Readmissions Mortality/Readmissions – Hazard RatiosHazard Ratios

HF 1.63HF 1.63CAD 1.08CAD 1.08

Hammill et al. Anesthesiology 2008; 108. 599

Heart Failure PrevalenceHeart Failure Prevalence

“Asymptomatic” Heart failure

Retrospective studyRetrospective studyThree groups; Three groups; – EF > 40 (n=385) EF > 40 (n=385) – EF < 40 (n=192) EF < 40 (n=192) – Controls (n=10,000)Controls (n=10,000)

““Optimised” heart failureOptimised” heart failure

Results: Results: – No Difference in mortality (short term) No Difference in mortality (short term) – Difference ;Difference ;

Longer hospital stays - 2 days Longer hospital stays - 2 days Hospital readmissions - 18% (EF >40% more likely than EF >40)Hospital readmissions - 18% (EF >40% more likely than EF >40)Long term outcomeLong term outcome

Xu-Cai et al. Mayo clinic Proc 2008; 83. 203

1000 patients1000 patients501 (50%) LV dysfunction (EF<50%)501 (50%) LV dysfunction (EF<50%)52% diastolic dysfunction52% diastolic dysfunction

Anesthesiology 2010; 112:1316 –24

Defining Surgical Risk

Abdominal

Ortho

Vascular

Transplant

FTR

Delayed Recovery

GIInf

Ren

Complications

No Complications

ExtendedRecoveryCVS RS

Appropriate Recovery

Death

Patient Cardiorespiratory Dysfunction

Exercise Ability

CPET: Risk Tool ?CPET: Risk Tool ?

CPeTCPeT– Comorbidity summary measure Comorbidity summary measure – Quantitative and Qualitative endpointsQuantitative and Qualitative endpoints– Multiple, simultaneous CVS/RS componentsMultiple, simultaneous CVS/RS components

Structured approach Structured approach – Concept ProofConcept Proof– Incremental valueIncremental value– Clinical UtilityClinical Utility– Predictive validityPredictive validity– Intervention Intervention

EvidenceEvidencenn Patients Patients OutcomeOutcome TrialTrial ConceptConcept IncrementalIncremental Clinical Clinical

Utility Utility

Older Older

19931993

187187 Elderly Elderly MortalityMortality Prospective Cohort (?Blinded)

>11 ; 4%

<11 ; 42%

Older Older

19991999

548548 ElderlyElderly MortalityMortality Prospective Cohort

(No blinding)

CP deaths confined to <11 or ischaemia

Forshaw

2008

7878 OesophagusOesophagus MorbidityMorbidity Prospective Cohort

(No blinding)

13.2 vs 14.4

CP complications

Readmissions

NA

CarlisleCarlisle

20072007

130130 VascularVascular Mid term Mid term mortalitymortality

Retrospective Cohort

(No blinding)

CPeT related to survival

AT

VE/VCO2

RCRI

Hazard Ratio

Hightower Hightower

20102010

3232 Major Major Abdominal Abdominal

MorbidityMorbidity Prospective, Pilot

(Blinded)

PC related to outcome

ASA vs AT,HR

Wilson Wilson 20102010

847847 Major Major SurgerySurgery

MortalityMortality Prospective Cohort

(No Blinding)

<11 Relative risk 7x death

Greater than Clinical factors

Snowden Snowden

20102010

116116 Major Major Abdominal Abdominal

MorbidityMorbidity Prospective

(Blinded)

CPeT variables related to outcome

Improvement on subjective and established factors

Risk increase

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 (0.5-20.6)

Patients with no cardiac risk factors (n=576)

3.2% 0.3% 10.0 (1.7-61.0)

BJA . 2010 105; 297

847 PtsMortality 2.1%

Optimum AT 10.1 ml/min/kgAUC 0.85 ; Sens 88%; Spec 79%

Snowden et al 2010 Ann Surg

Types of ComplicationsTypes of Complications

Modelling Outcome Modelling Outcome

Exercise Ability and Cardiorespiratory Exercise Ability and Cardiorespiratory Complications Complications

P<0.0001

***

*

“High Risk” CCU Groups

ITU 3 ITU 7 n Day 3 Poms

Day 7 Poms

LOS

No No 45 2 0 9

Yes No 45 3 1 12

Yes Yes 20 5 4 19

No Yes 3 4 4 31

0 25 50 75 100

Length of Stay

0.0

0.2

0.4

0.6

0.8

1.0

Pro

port

ion R

em

ain

ing in H

osp

ital

CCU and Exercise Prediction

Low Risk High Risk

High risk ITU

8.0

9.0

10.0

11.0

12.0

ROC Analysis:

Opt AT 10.6 (62%,80%)

AUC 0.873 (0.80-0.95)

P=0.0001

11.4 (2.6)

9.6 (2.3)

CPX Clinic _________No CPX Clinic _________

CPX Clinic No clinic

30 day mortality

3/194 (2%) 8/139 (6%)

Critical Care

22% 10%

The CPeT “Package of Care” The CPeT “Package of Care”

Swart et al. Personal communication

High Risk Surgery:High Risk Surgery:Liver TransplantationLiver Transplantation

Highest Surgical Risk (O.R. 15.8)Highest Surgical Risk (O.R. 15.8)

Early Mortality - 18% Early Mortality - 18%

Ensure appropriate organ allocationEnsure appropriate organ allocation – Limited resourceLimited resource– Marginal OrgansMarginal Organs– High Comorbidity High Comorbidity

Recipient ScoresRecipient 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) NS

Waiting List (Mean;SD) 94 (82) 129 (112) NS

UKELD (Mean;SD) 53 (5.2) 53 (6.7) NS

MELD (Mean;SD) 17 (9) 18 (9) NS

Snowden et al (In Prep)

Transplantation and Exercise Transplantation and Exercise

ROC analysis:Optimum AT 9.6 ml/min/kgAUC 0.97 ; (p=0.001)

p<0.00001

Snowden et al (In Prep)

CCU Stay and Liver Tx CCU Stay and Liver Tx

0 10 20 30 40

0.0

0.2

0.4

0.6

0.8

1.0 Median CCU LOS9 days vs 27 days

P=0.001

Pro

po

rtio

n r

emai

nin

g i

n C

CU

AT< 9.6

AT>= 9.6

Days in CCU

Donor – Recipient MatchingDonor – Recipient Matching

P=0.04

Snowden et al (In Prep)

Selective Training Effect

Summary Summary

Surgical risk - evolving conceptSurgical risk - evolving concept

Insights from large population studiesInsights from large population studies

New concepts for: New concepts for: – Operative risk variability Operative risk variability – Mortality and “Failure to rescue”Mortality and “Failure to rescue”– Importance of complications (esp CVS)Importance of complications (esp CVS)– Cardiac “Dysfunction”Cardiac “Dysfunction”

Summary Summary

Exercise Ability (and assessment):Exercise Ability (and assessment):– Defines important end point for comorbidityDefines important end point for comorbidity– Relates to mortality and morbidityRelates to mortality and morbidity– Varying surgical specialitiesVarying surgical specialities– Pedigree in cardiorespiratory dysfunctionPedigree in cardiorespiratory dysfunction

FutureFuture– Prospective comparative trials Prospective comparative trials – Interventional strategy toolInterventional strategy tool