Transcript Ian 2 CVS - Smartpublisering

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
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
Cardiac Risk Index
Risk factor
Coronary artery disease:
Angina:
Pulmonary oedema:
Critical aortic stenosis
Arrhythmias:
Poor general medical status
Age >70 years
Emergency surgery
Points
MI within 6 mo
MI > 6 mo
on mild exercise
at minimal exertion
within 1 week
ever
any other than SR or PAC
>5 PVCs
10
5
10
20
10
5
20
5
5
5
5
10
Detsky, et al. — J Gen Int Med 1: 211, 1986
Classification of Cardiac Risk
Major risk factors:
MI, CABG or stenting <6 weeks
angina on minimal exertion or at rest
residual ischaemia following MI
ischaemia with CCF or malignant rhythm
Intermediate risk factors:
MI >6 weeks, <3 mo
revascularisation >6 weeks, <3 mo, or >6 years
angina on moderate or strenuous effort
previous perioperative ischaemia
silent ischaemia
ventricular arrhythmia
diabetes
age (physiological) >70
Minor risk factors:
MI >3 mo
revascularisation >3 mo
(asymptomatic, no treatment)
family history CAD
uncontrolled hypertension
high cholesterol
smoking
abnormal ECG
Minor risk factors predict
coronary artery disease but
not perioperative risk
Chassot, et al. — Br J Anaesth 89: 747, 2002
Too
Complicated?
4 Factors
• Severe angina
• Previous MI
• Heart failure
• Hypertension
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 CVS
morbidity and mortality
– Collins, et al. — Lancet 335: 827, 1990
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 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: 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 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: Evidence
• Normotensive
– 130 ± 11 / 73 ± 7
(high normal)
– 174 ± 21 / 89 ± 12
(stage 2 or worse)
– 204 ± 25 / 102 ± 5
(severe hypertension)
• Treated hypertensive
• Untreated hypertensive
– Prys-Roberts, et al. — Br J Anaesth 43: 122, 1971
More 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?
• 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
Recommendations
• 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 Hypertension
• Control
– how?
– how fast?
– how long?
• Deferring
– how long?
– outcome?
• Perioperative management?
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
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 <180 / 110, or surgery urgent
– refer later, if needed
4 Factors
• Severe angina
• Previous MI
• Heart failure
• Hypertension
Angina Grading
0 No angina
1 Angina on strenuous exertion
2 Angina causing slight limitation
3 Angina causing marked limitation
4 Angina at rest
New York Heart Association
Previous MI
• 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
Chassot, et al. — Br J Anaesth 89: 747, 2002
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
Heart 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?
Functional 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?
• <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 Stairs
Climbing Stairs
• Inability to climb 2 flights of stairs
– 89% probability of cardiopulmonary complications
– Girish, et al. — Chest 120: 1147, 2001
Cardiovascular Risk Assessment
• “Can you climb 2 flights of stairs?”
Optimisation
• Confirm diagnosis
• Establish limitation
• Optimal therapy
Cardiovascular Medication
• Continue -blockers
• Continue
antihypertensives
– “continuation…throughout
the perioperative period is
critical”
– Howell, et al. —
Br J Anaesth 92: 570, 2004
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?
• Insufficient evidence to stop
• Continue like other CVS
drugs
• Simplifies instructions
Cardiovascular Assessment
• Symptoms: angina, SOB
• Severity and functional limitation
• Stability of control
• Current status
– ? optimal
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