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PREOPERATIVE CARDIAC EVALUATION : REAPPRAISAL OF CURRENT PRACTICE PARADIGMS. Martin R. Back, MD Associate Professor, USF Division of Vascular & Endovascular Surgery, Chief, Vascular Surgery, JA Haley VA. OVERVIEW. How common are adverse cardiac events ?
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PREOPERATIVE CARDIAC EVALUATION : REAPPRAISAL OF CURRENT PRACTICE PARADIGMS Martin R. Back, MD Associate Professor, USF Division of Vascular & Endovascular Surgery, Chief, Vascular Surgery, JA Haley VA
OVERVIEW • How common are adverse cardiac events ? • What is relationship between underlying cardiac disease and peri-op events ? • How to identify “at risk” patients ? • Who decides (responsibility / ‘turf’ bias) ? • How extensive an evaluation ? • Does CRA impact outcomes ? • Overall utility ?
SURGERY = PHYSIOLOGICAL INSULT • Operative magnitude - invasiveness and operative time • Cardiopulmonary implications - beyond blood loss and operative ‘fluid shifts’ • Stress hormone response • Proinflammatory cytokines • Anesthetic effects • Post-op complications
INCIDENCE CARDIAC COMPLICATIONS US estimates non-cardiac surgery (NEJM 1995,2001) 25-27 million pts / yr - 8 million with athero risk factors (30%) - 3 million with suspected CAD (11%) - 1 million cardiac events (3.7%) - 50,000 MIs (0.19 %) - half of 40,000 op deaths due to MI - $ 20 billion cost of care Vascular surgery (Hertzer Ann Surg 1984,Krupski JVS 2002) AAA : 36 % CAD 2.2 % MI Carotid : 32 % CAD 1.0 % MI LE occl dz : 28 % CAD 4.0 % MI
PERI-OP MI : HOW BAD IS BAD ? Transmural, Q-wave MI • less common • more likely hemodynamically significant, arrhythmias • peri-infarct mortality up to 50 % (older data) • predict long term cardiac events, shortened survival ‘Chemical’ MI • elevated CK MB fraction or troponin ‘leak’ • more common • low mortality risk (newer data) • associated with late adverse events ? Adverse cardiac event - broad definition • MI, CHF/pulm edema, post-op angina, arrhythmias
RISK FACTORS FOR CARDIAC EVENTS YES- CHF - MI (especially recent < 6 mo) - unstable/crescendo angina - arrhythmias - severe valvular disease - type of surgery (not anesthetic route) MAYBE - stable angina - diabetes - age NO- hypertension - smoking - elevated lipids
CARDIAC RISK ASSESSMENT Goldman risk index(NEJM 1977) complex point system, validated, no evaluation algorithm Detsky risk index(J Gen Int Med 1986) modified Goldman Eagle criteria(Ann Int Med 1989) – Vascular Surgery age > 70, DM, angina, prior MI, CHF, ventricular arrhythmia dipyridamole thallium testing for 1 or 2 risk factors Lee risk index(Circulation 1999) Eagle criteria + prior stroke, renal insufficiency (Cr > 2) American College of Physicians guidelines(Ann Int Med 1997) Detsky risk index + evaluation / intervention algorithm American Heart Association / American College of Cardiology (AHA / ACC) guidelines(Circulation 1996, JACC 2002)
EVALUATION MODALITIES • Use of risk index only - other testing since events occur in low risk pts ? • Resting 2-D echocardiography - low (<35%) EF predictive, unsuspected valve dz • Exercise / treadmill testing - few pts can achieve target HR • Stress cardiac imaging Dipyridamole – thallium or sestamibi scintigraphy Dobutamine stress echo (DSE) • Coronary angiography - would the pt be offered coronary revascularization (PCI / CABG) prior to noncardiac surgery ?
CARDIAC STRESS IMAGING Who should be tested ? All patients low yield Selected pts not for low risk pts (0-1 risk factors) yes for intermediate risk pts coronary angio for high risk pts Not useful fairly accurate for detecting CAD but poorprognostic value for adverse events (PPV < 25 % despite NPV > 90 %) no difference in event rates / outcomes in vascular series with and without routine use stress testing post-op MIs due to non-significant (<50%) coronary stenoses
PERI-OP CARDIAC OPTIMIZATION Medical Intra-op normothermia Invasive monitoring - hemodynamic optimization ICU utilization / prolonged telemetry beta – blockers - reduce MI/death rate (Mangano NEJM 1996, Poldermans NEJM 1999) - effective low and high risk pts (Boersma JAMA 2001) alpha 2 – adrenergic agonists (clonidine, mivazerol) nitrates, calcium channel blockers, ACE inhibitors antiplatelet agents (aspirin)
PERI-OP CARDIAC OPTIMIZATION Interventional = coronary revascularization PCI (coronary angioplasty / stenting), CABG Prophylactic pre-op revascularization - nopriorprospective randomized data - CARP trial - added morbidity of coronary revasc Prior coronary revascularization - danger of surgery early after PCI (< 1-2 mo) - Coronary Artery Surgery Study (CASS) – CABG v. med tx for symptomatic multi-vessel CAD - Bypass Angioplasty Revasc Invest (BARI) – CABG v. PCI for sympt CAD - long term protection ?
AHA/ACC GUIDELINES RISK ASSESSMENT Functional capacity Ability to perform at 4 METS (minimal exertion activities) ? Clinical risk factors Major = recent MI, unstable angina, decompensated CHF, severe valvular dz, hemodynamically significant arrhythmias Intermediate = DM, angina, prior MI or CHF Minor = age > 70, abnl EKG, poorly controlled HTN, prior stroke, low functional capacity Procedure – specific risk High = emergency operation, major vascular (aortic, LE bypass), complex/redo surgery Intermediate = CEA, head & neck, major cavitary, major orthopedic Low = endoscopic, superficial, opthalmologic, breast
USF VASCULAR ANALYSES • Evaluate prognostic value and utility of pre-op risk stratification before vascular surgery using AHA/ACC guidelines • Evaluate the potential protective effect of previous coronary revascularization on peri-op outcomes • Evaluate survival and long – term prognostic factors after vascular operations
CONCLUSIONS - USF EXPERIENCE • Risk stratification using AHA/ACC algorithm predicts peri-op adverse cardiac events • 3-vessel CAD predictive fatal and non-fatal early cardiac events • Low yield and lack of prognostic value of stress testing • More recent (< 5 yr) coronary revascularization modest protection against peri-op cardiac events & early mortality • Age, peri-op cardiac events, and risk stratification level predict long-term survival • More recent (< 5 yr) coronary revascularization has subtle effect (at best) on long term survival
N Engl J Med 2004 • CARP trial = multicenter, randomized, prospective study comparing prophylactic coronary revascularization (PCI or CABG) and best medical management before elective major arterial reconstruction (aortic, lower extremity) 5859 pts screened 1190 coronary angio 510 randomized 633 decline 363 0-v CAD 1654 no/low risk 258 revasc 215 non-revasc 1025 urgent OR 252 med tx 54 L main dz 626 asx prior cabg/pci 731 severe comorbidity 19 EF, valve dz
CARP RESULTS REVASC Group CABG PCI 41 % 59 % periop MI 7 % 5 % periop death 2 % 1.4 % REVASC MED TX interval to vascular surgery 54 days 18 days periop MI 11.6 % 14.3 % p=.37 periop death 3.1 % 3.4 % p=.87
CARP RESULTS Equivalent long-term use of cardiac medications in revasc and medical tx groups Median F/U = 2.7 yrs, equivalent all-cause mortality revasc group (22%) v. medical tx group (23%) & no high-risk subgroup benefitting from prophylactic revasc
CONCLUSIONS • Use of AHA/ACC algorithm predicts outcomes, reduces resource utilization (stress testing/angio/revasc) compared to routine testing, and minimizes adverse events (Froehlich JVS 2002) • Routine use beta-blockers not disputed • Standard practice of prophylactic pre-op coronary revascularization can not be supported disparate opinions, consensus • ‘pre-op coronary revascularization appropriate only if indicated independent of the need for non-cardiac surgery’ – acute coronary syndromes, left main dz, multivessel CAD ? (Fleisher/Eagle NEJM 2001)