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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. Risk Assessment.
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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
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 Points 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 Detsky, et al. — J Gen Int Med 1: 211, 1986
Classification 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) family history CADuncontrolled hypertensionhigh cholesterolsmokingabnormal ECG 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 Minor risk factors predict coronary artery disease but not perioperative risk Chassot, et al. — Br J Anaesth 89: 747, 2002
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 CVSmorbidity 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) • 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 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 • No angina • Angina on strenuous exertion • Angina causing slight limitation • Angina causing marked limitation • 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
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 • 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