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

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 Coronary artery disease:MI within 6 mo MI > 6 mo Angina:on mild exercise at minimal exertion Pulmonary oedema:within 1 week ever Critical aortic stenosis Arrhythmias:any other than SR or PAC >5 PVCs Poor general medical status Age >70 years Emergency surgery Risk factorPoints 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 Minor risk factors: MI >3 mo revascularisation >3 mo (asymptomatic, no treatment) Chassot, et al. — Br J Anaesth 89: 747, 2002 Intermediate risk factors: MI >6 weeks, 6 weeks, 6 years angina on moderate or strenuous effort previous perioperative ischaemia silent ischaemia ventricular arrhythmia diabetes age (physiological) >70 family history CAD uncontrolled hypertension high cholesterol smoking abnormal ECG Minor risk factors predict coronary artery disease but not perioperative risk

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) 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– ,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 Chung, et al. — Br J Anaesth 83: 262, 1999 BUT 76% of events “hypertension” 9% of events “arrhythmia” No major events

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 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 MI 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 METsHigh risk >7 METs without ischaemiaLow 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