Ian Smith, MD, FRCA

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Cardiovascular Disease in Ambulatory Surgery

• Ian Smith, MD, FRCA
• Editor, Journal of One-day Surgery,
• Senior Lecturer in Anaesthesia
• University Hospital of North Staffordshire
• Stoke-on-Trent

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Risk 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
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Cardiac Risk Index
Risk factor
Points
Coronary artery disease MI within 6 moMI gt 6
mo Angina on mild exerciseat minimal
exertion Pulmonary oedema within 1
weekever Critical aortic stenosis Arrhythmias an
y other than SR or PACgt5 PVCs Poor general
medical status Age gt70 years Emergency surgery
105 1020 105 20 55 5 5 10
Detsky, et al. J Gen Int Med 1 211, 1986
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Classification of Cardiac Risk
Major risk factorsMI, CABG or stenting lt6
weeksangina on minimal exertion or at
restresidual ischaemia following MIischaemia
with CCF or malignant rhythm
Minor risk factorsMI gt3 morevascularisation gt3
mo(asymptomatic, no treatment)
family history CADuncontrolled
hypertensionhigh cholesterolsmokingabnormal ECG
Intermediate risk factorsMI gt6 weeks, lt3
morevascularisation gt6 weeks, lt3 mo, or gt6
yearsangina on moderate or strenuous
effortprevious perioperative ischaemiasilent
ischaemiaventricular arrhythmiadiabetesage
(physiological) gt70
Minor risk factors predict coronary artery
disease but not perioperative risk
Chassot, et al. Br J Anaesth 89 747, 2002
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TooComplicated?
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4 Factors

• Severe angina
• Previous MI
• Heart failure
• Hypertension

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Hypertension 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 CVSmorbidity and mortality
• Collins, et al. Lancet 335 827, 1990

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Hypertension SurgeryWhat we Dont 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
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Recent 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

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Deferring 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

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Definitions Have Changed

• Normal blood pressure now
• 120129 / 8084
• lt120 / 80 is optimal
• Joint National Committee on prevention,
  detection, evaluation and treatment of high blood
  pressure Arch Intern Med 157 2413, 1997

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Deferring 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

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More Recent Evidence

• Meta-analysis of 30 publications 19782001
• 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

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Ambulatory Surgery Evidence?

• 7.7 hypertensive patients had CVS event
• Odds ratio 2.47

• BUT

• 76 of events hypertension
• 9 of events arrhythmia
• No major events

Chung, et al. Br J Anaesth 83 262, 1999
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Recommendations

• Stage 1 2 hypertension (lt180 / 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

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Managing Severe Hypertension

• Control
• how?
• how fast?
• how long?
• Deferring
• how long?
• outcome?
• Perioperative management?

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Treating 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

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Recommendations

• 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 lt180 / 110, or surgery
  urgent
• refer later, if needed

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4 Factors

• Severe angina
• Previous MI
• Heart failure
• Hypertension

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Angina Grading

• No angina
• Angina on strenuous exertion
• Angina causing slight limitation
• Angina causing marked limitation
• Angina at rest

New York Heart Association
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Previous MI

• Traditionally delayed for 6 months
• lt6 weeks high risk
• 6 weeks3 months intermediate risk
• gt3 months no further risk reduction
• unless complicated by
• arrhythmias
• ventricular dysfunction
• continued therapy for symptoms

Chassot, et al. Br J Anaesth 89 747, 2002
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Revascularisation 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
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Heart Failure

• Dyspnoea at rest or on effort
• usually worse lying down
• End stage of
• coronary artery disease
• hypertension
• valvular heart disease
• cardiomyopathy

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Can We Make It Even Simpler?
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Functional Limitation

• Exercise tolerance
• major determinant of perioperative risk
• Chassot, et al. Br J Anaesth 89 747, 2002
• Estimated in Metabolic Equivalents (METs)
• Ischaemia lt5 METs High risk
• gt7 METs without ischaemia Low risk
• Weiner, et al. Am J Coll Cardiol 3 772, 1984

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METs?

• lt4 METs
• light housework
• walk around house
• walk 12 blocks on flat
• 59 METs
• climb flight of stairs
• play golf or dance
• gt10 METs
• strenuous sport

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Climbing Stairs
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Climbing Stairs

• Inability to climb 2 flights of stairs
• 89 probability of cardiopulmonary complications
• Girish, et al. Chest 120 1147, 2001

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Cardiovascular Risk Assessment

• Can you climb 2 flights of stairs?

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Optimisation

• Confirm diagnosis
• Establish limitation
• Optimal therapy

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Cardiovascular Medication

• Continue ?-blockers
• Continue antihypertensives
• continuationthroughout the perioperative period
  is critical
• Howell, et al. Br J Anaesth 92 570, 2004

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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

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ACE Inhibitors?

• Insufficient evidence to stop
• Continue like other CVS drugs
• Simplifies instructions

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Cardiovascular Assessment

• Symptoms angina, SOB
• Severity and functional limitation
• Stability of control
• Current status
• ? optimal

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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

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