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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 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