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Review of the ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery Journal of the American College of Cardiology; Circulation. October 23, 2007. http://www.americanheart.org/presenter.jhtml?identifier=3004542
Definition of the problemPurpose, method, evidence, epidemiology
1. Definition of the problem • Framework for considering cardiac risk of non cardiac surgery • Evidence based • Guidelines reviewed annually
1. Definition of the problem • Overriding theme - intervention is rarely necessary to simply lower the risk of surgery unless such intervention is indicated irrespectiveof the preoperative context. • Exclude presence of such serious CAD that some form of direct intervention would be warranted even if no noncardiac operation were necessary.
2. General Approach to the PatientDecreasing amount of referralsSimpler algorithm
Review of 2002 Guidelines Cardiac Risk • Major risk (>5%) • MI <1month, Unstable angina, Decompensated CCF, Malignant SVT/VT, Heart block, Severe valvular disease • Intermediate (1-5%) • Previous MI, stable angina, (Q waves), CCF compensated (optimal Mx), Diabetes • Minor risk (<1%) • Advanced age, abnormal ECG, rhythm other than sinus, low functional capacity, CVA, hypertension
Review of the 2002 guidelines Surgical Risk • High: >5% • Major emergency surgery (esp. in elderly) • Aortic/major vascular surgery • Prolonged surgery with large fluid shifts • Intermediate: <5% • Intraperitoneal and intrathoracic • Carotid endarterectomy • Head and neck • Orthopaedic • Prostatic • Low: <1% • Endoscopic • Cataract extraction • Superficial surgery • Breast surgery
2007 Update Active Cardiac Conditions for Which the Patient Should undergo Evaluation and Treatment Before Noncardiac Surgery (Class I, Level of Evidence: B) Condition Examples Unstable coronary syndromes Unstable or severe angina* (CCS class III or IV)†, Recent MI‡ Decompensated HF (NYHA functional class IV; worsening or new onset HF) Significant arrhythmias High-grade AV block, Mobitz II, Third-degree AV heart block, Symptomatic ventricular arrhythmias, Supraventricular arrhythmias (including AF) with uncontrolled ventricular rate (HR > 100 at rest) Symptomatic bradycardia, ventricular tachycardia. Severe valvular disease Severe AS (mean pressure gradient greater than 40 mm Hg, aortic valve area less than 1.0 cm2, or symptomatic) Symptomatic MS - dyspnoea on exertion, exertional presyncope, or HF CCS III refers to marked limitation of ordinary physical activity eg 1 or 2 blocks, or 1 flight of stairs at normal pace NYHA IV refers to being unable to carry on any activity without symptoms
2007 Update Clinical Risk Factors • CCF • History of HF, pulmonary oedema, PND, peripheral oedema, bilateral rales, S3, CXR with pulm vasc redistribution. • Cerebrovascular disease • History of TIA or stroke • Preop insulin treatment for DM • Renal insufficiency creat >2mg/dL (approx 170umol/L) • IHD • History of MI, positive stress test, GTN use, chest pain thought to be secondary to ischaemia, ECG with abnormal Q waves. • NB acute MI vs recent MI (reasonable to wait 4 to 6 weeks after MI to perform elective surgery
2007 Update Cardiac Risk* Stratification for Noncardiac Surgical Procedures Risk Stratification Procedure Examples Vascular (cardiac risk often >5%) Aortic and other major vascular surgery Peripheral vascular surgery Intermediate (cardiac risk 1-5%) Intraperitoneal and intrathoracic surgery Carotid endarterectomy Head and neck surgery Orthopedic surgery Prostate surgery Low† (cardiac risk generally <1%) Endoscopic procedures Superficial procedure Cataract surgery Breast surgery Ambulatory surgery *Combined incidence of cardiac death and nonfatal myocardial infarction. †These procedures do not generally require further preoperative cardiac testing.
Role of the Cardiologist • Questionnaire • “clearing patient for surgery” and “advising as to the safest type of anaesthesia” were regarded as important by most cardiologists and surgeons but as unimportant by anaesthetists. • Role of cardiologist • Determine stability of CVS status • Optimise medical condition • Recommend changes in medication • Suggest preop tests or procedures • NOT to ‘clear patient for surgery’ or make suggestions about anaesthetic
3. Disease Specific ApproachesCAD, Hypertension,CCF, Valve disease, arrhythmias, pacemakers, ICDs.
Hypertension • Treatment of hypertension – decreased death, CVA, CAD in nonsurgical setting • SBP<180, DBP<110 not an independent RF for periop CVS complications, no benefit to delay surgery if no CVS abnormalities. • SBP>180 or DBP>110 assess benefits vs risks of delaying surgery • Avoid withdrawal of beta blockers and clonidine • More likely to develop intraop hypotension esp if on ACE
Heart failure • HF associated with poorer outcome Cardiomyopathy • preoperative assessment of LV function may be recommended to quantify severity Valvular Heart Disease • Severe AS greatest risk, • If symptomatic postpone surgery and replace valve • If asymptomatic postpone surgery if valve not evaluated in past year • If valve not replaced approximate mortality of 10% perioperatively • New AHA endocarditis prophylaxis guidelines • Prosthetic cardiac valve, previous IE, certain congenital heart diseases, cardiac transplant patients with valvulopathy
Arrhythmias and conduction defects • Ventricular arrhythmias usually do not require therapy unless haemodynamic compromise • Low threshold to institute prophylactic beta blockers if increased risk of developing a perioperative SVT or VT Congenital heart disease • CV function decreased in those operated with CHD • may not tolerate hypoxia as well as normal people Pulmonary hypertension • experts agree it poses an increased risk for surgery • no major study performed
Different operations associated with different cardiac risks • Context (opportunity for adequate preoperative preparation) • Surgery specific factors (fluid shifts etc) • Patient specific factors (incidence of CAD associated with condition)
Surgical Risk • Major vascular procedures represent the highest risk • Associated with same risk factors as CAD • Usual symptoms of CAD may be obscured • May have substantial fluctuations in fluid volumes • However both endovascular AAA repair and CEA are intermediate risk as opposed to other vascular procedures • Intermediate risk category – M and M vary according to the surgical location and extent of surgery • Superficial and ophthalmic procedures are low risk • Backer et al – no cardiac complications after 288 opthalmic procedures in 195 patients with prior MI vs reinfarction rate of 6.1% for other procedures.
Urgency • Cardiac complications 2-5 times more likely with emergency surgical procedures (Mangano) • partly due to insufficient time for preop optimisation • Mortality rate for elective AAA 3.5% • Mortality rate for symptomatic but intact AAA 19% (Dillavou et al)
5. Supplemental Preoperative Evaluation If further CVS investigations deemed necessary – what investigations 12 lead ECG, LV function, CAD risk assessment
Preoperative ECG • Scheine et al 18,189 patients – no difference in outcomes in asymptomatic patients having cataract surgery • ECG not indicated • Asymptomatic patients undergoing low-risk surgical procedures (Class III, B) • ECG reasonable • No clinical risk factors undergoing vascular surgery (Class IIa, B) • May be reasonable if 1 clinical risk factor undergoing intermediate risk surgery (Class IIb, B) • ECG indicated • 1 or more clinical risk factors undergoing vascular surgery (Class I, B) • CAD, PVD, CVA undergoing intermediate risk surgery (Class I, C) • ECG within 30 days of surgery is adequate for those with stable disease.
Assessment of LV Function • Several studies demonstrate positive relationship between decreased preop ejection fraction and postop morbidity and mortality • Most indicate an EF < 35 to 40% associated with poor outcomes • Assessment of LV function • Reasonable for dyspnoea of unknown origin (Class IIa, C) • Reasonable for patients with current or prior HF with worsening dyspnoea or other change in clinical status, if LV function not assessed within last 12 months (Class IIa, C) • Reassessment of LV function in clinically stable patients with previously documented cardiomyopathy is not well established (IIb, C)
Stress Testing Before Surgery • Numerous studies indicate worse outcomes in patients unable to reach 85% of age predicted HR, or have an abnormal exercise ECG. • Indications for stress testing in keeping with AHA algorithm (almost!) • Patients with active cardiac conditions should be evaluated and treated per ACC/AHA guidelines before surgery (Class I, B) • 3 or more clinical risk factors and poor functional capacity (< 4 METS) who require vascular surgery reasonable if it will change management (Class IIa, B) • Consider if 1 to 2 clinical risk factors and <4 METs) who require intermediate-risk noncardiac surgery if it will change management (Class IIb, B) • May be considered if with at least 1 to 2 clinical risk factors and good functional capacity (≥ 4 METs) who are undergoing vascular surgery (Class IIb, B)
Which stress test? • (Leave up to cardiologist at RPA) • Patient can exercise • Exercise stress test • OK if AAA • Avoid if important abnormalities on ECG eg LVH with strain, digitalis effect – perform stress cardiac imaging • LBBB • Exercise myocardial perfusion low specificity • Pharmacological stress perfusion scintigraphy, or DSE • Can’t exercise • Dipyridamole, Adenosine, Dobutamine myocardial perfusion imaging (thallium 201, technetium 99m) • Dobutamine stress echo • Use especially if question about valvular dysfunction • Avoid if echo quality likely to be poor • Avoid dipyridamole and adenosine if significant bronchospasm, critical carotid occlusive disease • Avoid Dobutamine if serious arrhythmias, severe hypertension, or hypotension
6. Implications of Guidelines and Other RiskAssessment Strategies for Costs and Outcomes - risk of performing test may exceed benefit
7. Perioperative Therapy After considering testing – how can we improve our patient ? Valve intervention, PCI/CABG, Medical therapy
Prophylactic Valvular Intervention BeforeNoncardiac Surgery • Clinical experience indicates that patients with valvular heart disease severe enough to warrant surgical treatment should have valve surgery before elective noncardiac surgery.
Preoperative Coronary Revascularization With CABG or PCI • Perhaps most influential evidence regarding preop coronary revascularisation from CASS database review, CARP trial, DECREASE V trial • CASS database review – 1997 Eagle Circulation 1997;96:1882–7. • Patients with CAD highest risk if thorax, abdomen, vascular surgery. Reduced if prior CABG • Patients having low risk surgery had mortality of <1% regardless of CI • CARP trial N Engl J Med. 2004;351: 2795–804. • Prospective RCT patients having elective vascular surgery • Routine coronary revascularization no improvement if stable cardiac symptoms • Longer delay between CI and op - increased MI • Excluded patients >50% stenosis of LMCA, LVEF <20%, severe AS. • DECREASE V - J Am Coll Cardiol. 2007;49:1763–9. • >3 risk factors – dobutamine echo or stress nuclear imaging • Stress induced ischaemia – additional revascularisation • Preop revascularization no improvement in outcome • Pilot study. All patients received beta blockade and antiplatelet therapy
Preoperative Coronary Revascularization With CABG or PCI • Guidelines based on AHA Indications for CABG surgery • First published 1991 • Based on review of data including CASS database, European Randomized Trial, Veterans Affairs Study • Class I, A indications: • stable angina who have significant left main coronary artery stenosis. • stable angina who have 3-vessel disease. (Survival benefit is greater when LVEF is less than 0.50.) • stable angina who have 2-vessel disease with significant proximal LAD stenosis and either EF less than 0.50 or demonstrable ischemia on noninvasive testing. • high-risk unstable angina or non–ST-segment elevation MI. • acute ST-elevation MI.
Percutaneous Coronary Intervention • Drug eluting stents • Designed to reduce neointimal formation and lower restenosis rates • Sirolimus or paclitaxel • Lower incidence of death or MI in patients on thienopyridines (0%) compared with those with BMS with (4.7%) or without (3.6%) thienopyridine • If antiplatelet therapy ceased prematurely then high incidence of stent thrombosis (30%) with high mortality rate (50%) • Optimal duration of thienopyridine use beyond 12 months unknown • Late stent thrombosis in order of 0.5% (not seen with BMS)
Approach to the management of patients previous PCI, (based on expert opinion). • Balloon Angioplasty • Wait 14 days – allows time for healing of the vessel • Delay for more than 8 weeks leads to increased chance of restenosis • BMS • Wait for 4 to 6 weeks allows time for thienopyridine to be given (whilst endothelialisation takes place) and then stopped with time for its effects to wear off • DES • Avoid elective surgery for at least 1 year so that thienopyridine can be given to prevent stent thrombosis
Antiplatelet therapy after PCI • Dual antiplatelet therapy • Some procedures carry low risk of bleeding - no indication to interrupt dual antiplatelet therapy for dental procedures • Aspirin • Increased bleeding in patients on aspirin • Burger et al (review of surgical literature) - no increase in risk of bleeding complications or periop mortality related to bleeding complications (possible exceptions include intracranial surgery and prostatectomy) • Only discontinue aspirin if known bleeding risks are similar or more severe than observed cardiovascular risks of withdrawal
Perioperative Beta Blockade Influential Beta Blocker Trials (prior to the POISE trial) Mangano 1996 - 200 patients - Atenolol 2 hours preop and continued to discharge. - Reduced mortality after discharge over 6 to 8 months post op. - Patients already on beta blockers withdrawn in placebo group. Poldermans 1999 - 112 patients - Bisoprolol commenced 1 to 12 weeks preop, continued 30 days - Marked reduction in perioperative MI and mortality (3% versus 34%) - Enrolled very high risk patients (identified by stress echo). Not blinded. Yang 2006 - 496 patients - Metoprolol 2 hours preop and continued to discharge - No significant difference in cardiac morbidity or death (12% v 10%) DIPOM 2006 - 921 diabetic patients having surgery >1hr - metoprolol 1 day preop and continued to discharge - no difference in combined mortality or cardiac morbidity (20% v 21%)
Perioperative Beta blockade • Conflicting meta analysis, few randomized trials • Weight of evidence suggests benefit of periop beta blockade particularly in high risk patients • Reduce risk of ischaemia, MI, and death in high risk patients • Fleisher et al - strong suggestion that beta blockade should be started days to weeks before surgery (may be a problem in the real world)
POISE trial • POISE trial • 8351 patients • metoprolol 2 hours preop, continued 30 days • reduced non-fatal MI (5.1% to 3.6%). Increased total mortality (2.3% to 3.1%) • Increased risk CVA in metoprolol group (?dose too aggressive)
Recommendations for Beta-Blocker Therapy • (Prior to POISE trial) • Class I • Beta blockers should be continued in patients undergoing surgery who are already receiving beta blockers (Level of Evidence: C) • Beta blockers should be given to patients undergoing vascular surgery who are at high cardiac risk owing to the finding of ischemia on preop testing. (Level of Evidence: B) • Class IIa • Beta blockers are probably recommended for patients undergoing intermediate-risk or vascular surgery with more than 1 clinical risk factor (Level of Evidence: B) • Class IIb • The usefulness of beta blockers is uncertain for patients who are undergoing either intermediate-risk procedures or vascular surgery, with one or no clinical risk factors. • Titration of Beta Blockers • Accumulating evidence suggests that effective heart rate control with beta blockers should be targeted at less than 65 beats per minute.
Perioperative Statin Therapy • Statins highly effective in secondary prevention of cardiac events • Improve endothelial function, reduce vascular inflammation, stabilize atherosclerotic plaques. • Hindler (meta-analysis) • 59% reduction in risk of mortality after vascular surgery • 44% reduction after other non-cardiac surgery • Unclear: Time of initiation, duration of therapy, dose, indications. • Sufficiently powered randomized trials needed
Recommendations for Statin Therapy Class I For patients currently taking statins and scheduled for noncardiac surgery, statins should be continued. (Level of Evidence: B) Class IIa For patients undergoing vascular surgery with or without clinical risk factors, statin use is reasonable. (Level of Evidence: B) Class IIb For patients with at least 1 clinical risk factor who are undergoing intermediate-risk procedures, statins may be considered. (Level of Evidence: C)
Peripheral Arterial Disease • 2005 ACC/AHA guidelines for management of patients with PAD • Class 1 indications: • Statin treatment LDL < 100mg/dL • BP <140/90mmHg • Cease cigarette smoking • Antiplatelet therapy • Trial of 1404 patients - critical limb ischaemia (Conte et al) • 33% no antiplatelet therapy • 54% no lipid lowering therapy • 52% no beta blocker
8. Anaesthetic Considerations and Intraoperative Management Anaesthetic technique, pain, GTN, TOE, temp, balloon pumps, glucose
Choice of anaesthetic technique • Monitoring • No outcome change from routine use of PAC, ST segment monitoring, TOE, IV GTN. • Choice of anaesthetic and monitoring best left to anaesthetist • Opioid based anaesthetics • Previously popular because of reported CVS stability • Prolonged ventilation and ICU stay • Volatile anaesthetics • CABG: troponin release : cardioprotective effect, enhance LV function compared with propofol, midazolam, or anaesthesia with opioids • Recommendation: Class IIa - Beneficial to use volatile anaesthetic agents during non cardiac surgery for hemodynamically stable patients at risk for myocardial ischemia (Level of evidence : B)
Choice of anaesthetic technique • Neuraxial Anaesthesia • Sympathetic block decreases preload and afterload (which may reduce myocardial stress) • High dermatomal block may cause significant haemodynamic effects
Choice of anaesthetic technique • Monitored Anaesthesia Care • Local anaesthesia supplemented with IV sedation/analgesia • Large scale study (Cohen et al) – highest incidence of 30 day mortality. May be due to selection bias. • Poor blockade of stress response may cause increased myocardial ischaemia • May be no significant difference in overall safety with monitored anaesthesia care
Perioperative Pain Management • Postoperative period: • incidence of cardiac events • Stress, adverse hemodynamics, hypercoagulable responses • PCA - greater patient satisfaction • Epidural – better ablation of catecholamine response • Need an effective analgesic regime specific to patient, procedure, and institution
Maintenance of Body Temperature • Avoidance of hypothermia decreases risk of MI • Class I • Maintenance of body temperature in a normothermic range is recommended for most procedures other than during periods in which mild hypothermia is intended to provide organ protection (eg during high aortic cross-clamping). • (Level of Evidence: B)
Perioperative Blood Glucose • Patients who have their BSL aggressively controlled in ICU have demonstrated significant decreases in morbidity and mortality • Class IIa: • BSL should be controlled in patients • high risk for myocardial ischaemia • Undergoing vascular and major non cardiac procedures • With planned ICU admission • Level of Evidence : B • Class IIb: • Usefulness of strict blood glucose control uncertain in those having noncardiac surgery without planned ICU admission • Level of Evidence : C • American College of Endocrinology • ICU : < 6.1 mmol/L • Hospitalised patients: 6.1 – 10mmol/L