Ian Smith, MD, FRCA

Editor, Journal of One-day Surgery,Senior Lecturer in Anaesthesia

University Hospital of North Staffordshire

Stoke-on-Trent

Cardiovascular Disease in Ambulatory

Surgery

Cardiovascular Disease in Ambulatory

Surgery

Risk AssessmentRisk Assessment

“Despite sophisticated technologies, history and physical examination

remain the key elements of preoperative risk assessment”

Chassot, et al. — Br J Anaesth 89: 747, 2002

Cardiac Risk IndexCardiac Risk Index

Coronary artery disease: MI within 6 moMI > 6 mo

Angina: on mild exerciseat minimal exertion

Pulmonary oedema: within 1 weekever

Critical aortic stenosis

Arrhythmias: any other than SR or PAC>5 PVCs

Poor general medical status

Age >70 years

Emergency surgery

105

1020

105

20

55

5

5

10

Risk factor Points

Detsky, et al. — J Gen Int Med 1: 211, 1986

Classification of Cardiac RiskClassification of Cardiac Risk

Major risk factors:MI, CABG or stenting <6 weeksangina on minimal exertion or at restresidual ischaemia following MIischaemia with CCF or malignant rhythm

Minor risk factors:MI >3 morevascularisation >3 mo(asymptomatic, no treatment)

Chassot, et al. — Br J Anaesth 89: 747, 2002

Intermediate risk factors:MI >6 weeks, <3 morevascularisation >6 weeks, <3 mo, or >6 yearsangina on moderate or strenuous effortprevious perioperative ischaemiasilent ischaemiaventricular arrhythmiadiabetesage (physiological) >70

family history CADuncontrolled hypertensionhigh cholesterolsmokingabnormal ECG

Minor risk factors predict coronary artery disease but not perioperative risk

TooComplicated?

TooComplicated?

4 Factors4 Factors

•Severe angina

•Previous MI

•Heart failure

•Hypertension

Hypertension: What we KnowHypertension: What we Know

• Most important risk factor for:– cerebrovascular disease

– coronary heart disease– in general population– MacMahon, et al. — Lancet 335: 765, 1990

• Control of elevated BP:– significantly lowers CVS

morbidity and mortality– Collins, et al. — Lancet 335: 827, 1990

Hypertension & Surgery:What we Don’t Know

Hypertension & Surgery:What we Don’t Know

• Is hypertension as an independent risk factor?– “plagued by much uncertainty”

• Does delaying reduce perioperative risk?– “unclear”

• Risk of isolated systolic hypertension?– “uncertain”

• Confirming diagnosis: multiple vs single BP reading?

– “not yet assessed” Casadei & Abuzeid —Journal of Hypertension 23: 19, 2005

Recent PracticeRecent Practice

• Cancellation at preassessment clinic– hypertension: 57% of medical reasons, by doctor

– McIntyre, et al. —Journal of Clinical Governance 9: 59, 2001

• Orthopaedic surgery– hypertension 16.2% of medical cancellations

– Wildner, et al. — Health Trends 23: 115, 1991

Deferring Surgery: EvidenceDeferring Surgery: Evidence

• 3 patient groups– untreated hypertensive

– treated hypertensive

– normotensive

• Labile BP and ischaemia– in un-treated and poorly-treated hypertensives

– “no cause for concern” in others– Prys-Roberts, et al. — Br J Anaesth 43: 122, 1971

Definitions Have ChangedDefinitions Have Changed

• Normal blood pressure now:

– 120–129 / 80–84

– <120 / 80 is optimal

–Joint National Committee on prevention, detection, evaluation and treatment of high blood pressure — Arch Intern Med 157: 2413, 1997

Deferring Surgery: EvidenceDeferring Surgery: Evidence

• Normotensive– 130 ± 11 / 73 ± 7 (high normal)

• Treated hypertensive– 174 ± 21 / 89 ± 12 (stage 2 or worse)

• Untreated hypertensive– 204 ± 25 / 102 ± 5 (severe hypertension)

– Prys-Roberts, et al. — Br J Anaesth 43: 122, 1971

More Recent EvidenceMore Recent Evidence

• Meta-analysis of 30 publications 1978–2001

• 12,995 patients

• Risk of perioperative CVS complications– in hypertensive patients is 1.35 that in normotensives

– “clinically insignificant”

– (unless end-organ damage is clinically-evident)

– Howell, et al. — Br J Anaesth 92: 570, 2004

Ambulatory Surgery Evidence?Ambulatory Surgery Evidence?

• 7.7% hypertensive patients had CVS “event”

• Odds ratio 2.47

Chung, et al. — Br J Anaesth 83: 262, 1999

•BUT• 76% of events “hypertension”

• 9% of events “arrhythmia”

• No major events

RecommendationsRecommendations

• Stage 1 & 2 hypertension (<180 / 110 mmHg)– “not an independent risk factor

for perioperative CVS complications”– American Heart Association / American College of Cardiology

– Howell, et al. — Br J Anaesth 92: 570, 2004

• Stage 3 hypertension (≥180 / 110 mmHg)– “should be controlled before surgery”

– American Heart Association / American College of Cardiology

– limited evidence– Howell, et al. — Br J Anaesth 92: 570, 2004

Managing Severe HypertensionManaging Severe Hypertension

•Control– how?

– how fast?

– how long?

•Deferring– how long?

– outcome?

•Perioperative management?

Treating Severe HypertensionTreating Severe Hypertension

• Sedation will not reduce CVS risk

• Rapid treatment may also increase risk

• If deferred– for how long?

– little evidence that outcome is improved

• Need to consider risks & benefits of surgery– cancer versus non-urgent

RecommendationsRecommendations

• Preassessment– eliminate white coat effect

– confirm diagnosis

– refer for treatment (for long-term benefit)

– if surgery can wait

• Day of surgery– try to avoid this scenario!

– proceed (carefully) if <180 / 110, or surgery urgent– refer later, if needed

4 Factors4 Factors

•Severe angina

•Previous MI

•Heart failure

•Hypertension

Angina GradingAngina Grading

0No angina

1Angina on strenuous exertion

2Angina causing slight limitation

3Angina causing marked limitation

4Angina at rest

New York Heart Association

• Traditionally delayed for 6 months

• <6 weeks: high risk

• 6 weeks–3 months: intermediate risk

• >3 months: no further risk reduction– unless complicated by

– arrhythmias

– ventricular dysfunction

– continued therapy for symptoms

Previous MIPrevious MI

Chassot, et al. — Br J Anaesth 89: 747, 2002

Revascularisation ProceduresRevascularisation Procedures

• CABG, angioplasty & stents

• Reduce risk of CVS events– high-risk for 6 weeks

– delay surgery 3 months

– risk increases after 6 years

• Absence of symptoms

• Good functional activity

Chassot, et al. — Br J Anaesth 89: 747, 2002

Heart FailureHeart Failure

• Dyspnoea at rest or on effort– usually worse lying down

• End stage of– coronary artery disease

– hypertension

– valvular heart disease

– cardiomyopathy

Can We Make It Even Simpler?Can We Make It Even Simpler?

Functional LimitationFunctional Limitation

• Exercise tolerance– “major determinant of perioperative risk”

– Chassot, et al. — Br J Anaesth 89: 747, 2002

• Estimated in “Metabolic Equivalents” (METs)

• Ischaemia <5 METs High risk

• >7 METs without ischaemia Low risk– Weiner, et al. — Am J Coll Cardiol 3: 772, 1984

METs?METs?

• <4 METs– light housework

– walk around house

– walk 1–2 blocks on flat

• 5–9 METs– climb flight of stairs

– play golf or dance

• >10 METs– strenuous sport

Climbing StairsClimbing Stairs

Climbing StairsClimbing Stairs

• Inability to climb 2 flights of stairs– 89% probability of cardiopulmonary complications

– Girish, et al. — Chest 120: 1147, 2001

Cardiovascular Risk AssessmentCardiovascular Risk Assessment

• “Can you climb 2 flights of stairs?”

OptimisationOptimisation

• Confirm diagnosis

• Establish limitation

• Optimal therapy

Cardiovascular MedicationCardiovascular Medication

• Continue -blockers

• Continue antihypertensives– “continuation…throughout the perioperative period is

critical”– Howell, et al. —

Br J Anaesth 92: 570, 2004

ACE Inhibitors?ACE Inhibitors?

• Greater hypotension at induction– recommend stopping

– Bertrand, et al. — Anesth Analg 92: 26, 2001

– Comfere, et al. — Anesth Analg 100: 636, 2005

• Hypotension mild– Comfere, et al. — Anesth Analg 100: 636, 2005

• Benefits: cardioprotection, renal function, sympathetic responses

– recommend continuing– Pigott, et al. — Br J Anaesth 83: 715, 2000

ACE Inhibitors?ACE Inhibitors?

• Insufficient evidence to stop

• Continue like other CVS drugs

• Simplifies instructions

Cardiovascular AssessmentCardiovascular Assessment

• Symptoms: angina, SOB

• Severity and functional limitation

• Stability of control

• Current status– ? optimal

Not For Ambulatory Surgery...Not For Ambulatory Surgery...

• Angina on minimal exertion or at rest

• MI or revascularisation in past 3 months

• Symptoms after MI or revascularisation

• Unable to climb 2 flights of stairs– exclude respiratory of locomotor causes

• Significant cardiovascular limitation of activity