noncardiac surgery in the cardiac patient
TRANSCRIPT
Noncardiac Surgeryin the
Cardiac Patient
David Putnam, MD
Albany Medical College
• Coronary heart disease is the most frequent cause of perioperative cardiac mortality and morbidity after noncardiac surgery
Noncardiac SurgeryMagnitude of the Problem
• 25 million patients undergo noncardiac surgery each year in the United States
• 3 million patients have clinical evidence or multiple risk factors for CAD
• 4 million patients are > 65 years old
• Nearly 1/3 of surgical patients are at risk for cardiovascular complications
Noncardiac SurgeryMagnitude of the Problem
• Aging of the population
• Lower threshold for performing major procedures on elderly patients
• Patients with multiple comorbid illnesses
Noncardiac SurgeryMagnitude of the Problem
• Advances in anesthesia, post-op analgesia, and surgical technique have contributed to a reduced rate of major cardiac complications
• Overall risk of cardiac complications with noncardiac surgery remains low
• Risk of perioperative MI: 0.1%
• Risk of cardiac death: 0.4%
Non-Cardiac SurgeryRisk of Perioperative MI/Death
• No history of ischemic heart disease: 0.1%
• History of prior MI: 6%
Reinfarction in Post-MI Patients
Non-Cardiac Surgery
• Although consultants are frequently asked to “clear” a patient for surgery, their role is considerably more complex
Noncardiac Surgery: General
• Successful perioperative evaluation and treatment of cardiac patients
• Teamwork and communication between• Patient• Primary Care Physician• Anesthesiologist• Surgeon• Medical Consultant
Preop: Role of Consultant
• Assess individual patient’s risk of cardiac complications
• Determine if specialized testing is appropriate
• Recommend risk reduction strategies
• Participate in postoperative medical management
Pre-Operative Cardiac Evaluation
• What is the question?
Pre-Operative Cardiac Evaluation
• Can this patient reasonably have noncardiac surgery?
Pre-Operative Cardiac Evaluation
• Would coronary revascularization improve the long-term prognosis from a cardiac standpoint and protect the patient from adverse events during the necessary noncardiac surgery?
Preoperative Risk Assessment
• Dripps-ASA classification
• Goldman classification
• ACC recommendations
ASA Physical Status Assessment
• Class I: Healthy patient/elective operation• Class II: Patient with mild systemic disease• Class III: Severe systemic disease that
limits activity but is not incapacitating• Class IV: Incapacitating systemic disease
that is a constant threat to life• Class V: Moribund patient not expected to
survive 24 hours with or without operation
Dripps-ASA ClassificationShortcomings
• Subjective
• Poorly reproducible in certain subsets• Elderly
• Obese
• Prior MI
• Mild systemic diseases
Preoperative Cardiac AssessmentGoldman Classification
• Predicts life-threatening cardiac complications or perioperative cardiac death based on presence of preoperative risk factors
Goldman Multifactorial Index
Goldman Multifactorial Index
Preoperative Cardiac Assessment
• American College of Cardiology Recommendations JACC 1996;27:910-948
Noncardiac Surgery: General
• Indications for further cardiac testing/treatments are the same as those in the nonoperative setting• Urgency of noncardiac surgery
• Patient’s risk factors
• Specific surgical considerations
Noncardiac Surgery: General
• Preoperative testing should be limited to circumstances in which the results affect patient treatment and outcomes
Noncardiac Surgery: General
• A conservative approach to the use of expensive tests and treatments is recommended
Preop Cardiac Evaluation:Considerations
• Type of surgery
• Functional capacity
• Clinical history and physical examination
Noncardiac Surgery: Higher Risk Procedures
• Vascular
• Prolonged, complicated• Thoracic
• Abdominal
• Head and neck
• Total hip replacement
Preop Cardiac Evaluation
• Patients with a low functional capacity (less than 4 Mets) have a worse prognosis than patients with a good functional capacity
Preop Cardiac Evaluation
• Clinical data from a careful history and physical examination are the critical initial steps
Noncardiac Surgery: Preoperative Clinical Evaluation
• Identification of potentially serious cardiac disorders• Prior MI
• Angina pectoris
• Congestive heart failure
• Symptomatic arrhythmias
• Significant valvular heart disease
Noncardiac Surgery:Preoperative Clinical Evaluation
• Preexisting manifested heart disease• Presence
• Severity
• Stability
• Prior treatment
Noncardiac Surgery: Preoperative Clinical Evaluation
• Always• History• Physical exam• ECG
• Commonly• Echocardiogram/EST
• Sometimes• Cardiac cath/MUGA scan
Preoperative ECG’sRecommended
• Intrathoracic surgery
• Intraperitoneal surgery
• Aortic surgery
• Neurosurgical procedure
• Emergency operations
Preoperative ECG’sRecommended
• History/physical suggesting heart disease
• Men > 40-45 years old
• Women > 55 years old
• Systemic conditions that may be associated with unrecognized cardiac abnormality
• Medications that can cause cardiac toxicity or ECG changes
• Patients at risk for major electrolyte abnormalities
Methods of Assessing Cardiac Risk:Exercise Stress Testing
• Provides substantial information about risk of perioperative MI/cardiac death
• Poor functional capacity, particularly associated with myocardial ischemia predicts high risk
• Gradient of increasing ischemic risk seen in association with degree of functional capacity, symptoms of ischemia, severity of ischemia, and hemodynamic instability
Methods of Assessing Cardiac Risk:Pharmacological Stress Testing
• Dipyridamole or adenosine with thallium/sestamibi• High sensitivity/specificity for perioperative
events, especially in intermediate risk group
• Perioperative ischemic events appear to correlate with the magnitude of ischemia
• Pharmacological stress testing involving echocardiogram is a viable option
Methods of Assessing Cardiac Risk:Resting LV Function
• LVEF < 35% increases risk of surgery
• Severe diastolic dysfunction increases risk of surgery
• Evaluate LV function in presence of CHF
• Probable evaluation of LV function with history of CHF or dyspnea of unknown etiology
Management Options after Noninvasive Testing
• Intensified medical therapy
• Cardiac catheterization• Cancel or delay surgery
• Proceed with surgery
• Coronary revascularization prior to surgery
Noninvasive Pre-Op Testing
• The good news is that noninvasive tests are sensitive to the presence of CAD
• The bad news is that the positive predictive value is poor because the likelihood of perioperative events is less than 10%
Methods of Assessing Cardiac Risk:Coronary Angiography
• Appropriate in certain patients at high risk, including those with evidence of significant ischemia or suspicion of left main/three-vessel CAD
• Indications are similar to those in the nonoperative setting
• Essential that management with PTCA/CABG is a viable option
Coronary AngiographyClass I Indications
• High-risk results during noninvasive testing
• Angina pectoris unresponsive to adequate medical therapy
• Most patients with unstable angina
• Nondiagnostic or equivocal noninvasive test in a high-risk patient undergoing a high-risk noncardiac surgical procedure
Coronary AngiographyClass II Indications
• Intermediate-risk results during noninvasive testing
• Nondiagnostic or equivocal noninvasive test in a lower-risk patient undergoing a high-risk noncardiac surgical procedure
• Urgent noncardiac surgery in a patient convalescing from acute MI
• Perioperative MI
Noncardiac Surgery:Preoperative CABG
• Indications are same as those in the nonoperative setting
• Cardiac risk of CABG often exceeds that of noncardiac surgery
• Rarely indicated simply to get a patient through the perioperative period
Noncardiac Surgery:Preoperative PTCA
• No controlled trials
• Several small observational studies suggest that cardiac death is infrequent in patients who have PTCA prior to noncardiac surgery
• Indications are similar to those in nonoperative setting
Noncardiac Surgery: Emergency/Immediate Surgery
• Consultant may function best by making recommendations for perioperative medical management and surveillance
• Postoperative risk stratification may be appropriate for some patients who have not had such an assessment
Major Clinical Predictors of Increased Perioperative Cardiovascular Risk
• Unstable coronary syndromes• Recent MI with evidence of ischemic risk• Unstable or severe angina
• Decompensated CHF• Significant arrhythmias
• High-grade AV block• Symptomatic ventricular arrhythmias• SVT’s with uncontrolled ventricular rate
• Severe valvular disease
Noncardiac Surgery: Major Clinical Predictors
• Cancel or delay surgery if surgery is elective
• Many of these patients are referred for coronary angiography
Major Clinical Predictors
Intermediate Predictors on Increased Perioperative Cardiovascular Risk
• Mild angina pectoris
• Prior MI by history or pathological Q-waves
• Compensated or prior CHF
• Diabetes mellitus
Noncardiac Surgery:Intermediate Clinical Predictors
• Consideration of functional capacity ( risk increased in patients unable to meet 4-METs of activity )
• Consideration of level of surgery-specific risk• Type of surgery
• Degree of hemodynamic stress
Cardiac Event Risk Stratification
• High Risk ( > 5% )• Emergent major operations, particularly in the
elderly
• Aortic and other major vascular
• Peripheral vascular
• Anticipated prolonged surgical procedures associated with large fluid shifts and/or blood loss
Cardiac Event Risk Stratification
• Intermediate Risk ( < 5% )• Carotid endarterectomy
• Head and neck
• Intraperitoneal and intrathoracic
• Orthopedic
• Prostate
Cardiac Event Risk Stratification:Patients w/ Intermediate Predictors
• Patients with moderate/excellent functional capacity can generally undergo intermediate-risk surgery
• Consider further noninvasive testing• Poor functional capacity/intermediate-risk
surgery
• Moderate functional capacity/high-risk surgery
Intermediate Predictors
Minor Predictors of Increased Perioperative Cardiovascular Risk
• Advanced age
• Abnormal ECG
• Rhythm other than sinus
• Low functional capacity
• Uncontrolled systemic hypertension
Noncardiac Surgery:CABG within Five Years
• Stable clinical status without recurrent symptoms/signs of ischemia
• Further cardiac testing generally not necessary
Noncardiac Surgery:Stable Angina/CABG > 5 Years
• Coronary evaluation within past two years?
• Favorable findings
• Usually not necessary to repeat testing unless there has been a change in symptoms
Cardiac Event Risk Stratification:Patients w/ Minor Predictors
• Noncardiac surgery generally safe
• Further testing on an individual basis ( patients with several minor clinical predictors facing higher-risk operations, ie vascular surgery )
Minor Predictors
• Management of Specific Preoperative Cardiovascular Conditions
Noncardiac Surgery: Hypertension
• Severe hypertension should be controlled before surgery when possible
• Continuation of preoperative antihypertensive treatment through the perioperative period is critical
Hypertension
• Perioperative swings of pressure often occur in hypertensive patients
• Patients who are adequately treated preoperatively have less marked deviations of blood pressure
• Surges of BP most common during:
• Induction
• Intubation
• Skin incicision
• 12 to 24 hours post-op
Noncardiac Surgery:Valvular Heart Disease
• Indications for evaluation/treatment identical to those in nonoperative setting
• Symptomatic stenotic lesions associated with risk of perioperative CHF/shock
• Symptomatic regurgitant lesions usually better tolerated perioperatively
Patients on Anticoagulants Preop
• Risk of surgical hemorrhage vs. danger of serious embolization
Patients on Anticoagulants PreopLow Risk for Thromboembolism
• Discontinue coumadin 3 days preop
• Restart coumadin postop
Patients on Anticoagulants PreopHigh Risk for Thromboembolism
• Discontinue coumadin 3 days preop• Begin heparin by constant infusion, maintaining
PTT 1.5 - 2.5 X control• Discontinue heparin 6 - 8 hrs preop• Shortly after surgery, restart IV heparin and po
coumadin• Discontinue heparin infusion when PT is
therapeutic• Low molecular weight heparin may be used as an
alternative agent to IV fractionated heparin
Patients on Coumadin PreopRisk for Thromboembolism
Higher Risk
• Atrial fibrillation with structural heart disease
• Prosthetic mitral valve with or without a fib
• Prosthetic aortic valve with a fib
Lower Risk
• Atrial fibrillation without structural heart disease
• Prosthetic aortic valve with sinus rhythm and normal ejection fraction
• The optimal management of patients with known coronary artery disease remains complex.
Noncardiac Surgery:Medical Rx of CAD
• Continuation of preoperative medications into the operative and postoperative period recommended for ischemic protection
• Beta blockers reduce the incidence of postoperative ischemia
Beta Blockade in Patients Undergoing Major Vascular Surgery
• Randomized trial of 112 patients
• Started on bisoprolol one week prior to surgery
• Followed for 30 days
• Cardiac complication rate/placebo: 33.9%
• Cardiac complication rate/bisoprolol: 3.4%
Poldermans D. NEJM 1999;341:1789-1794
Noncardiac Surgery:Intraoperative Nitroglycerin
• Insufficient data on use of prophylactic intraoperative nitroglycerin
• Vasodilatory properties when combined with anesthetic agent may lead to hypotension and ischemia
• Hemodynamic effects of other agents needs to be considered
Noncardiac Surgery:Congestive Heart Failure
• Patients with preop CHF are at increased risk for postoperative exacerbation
• Treatment of manifestations of heart failue before surgery may reduce complication rates
• Overdiuresis may lead to hypotension• New onset of CHF in patients without prior
history suggests postop MI
Noncardiac Surgery:Arrhythmias & Conduction Abnormalities
• Careful evaluation for underlying cardiopulmonary disease, drug toxicity, or metabolic abnormality
• Indications for antiarrhythmic therapy and cardiac pacing identical to those in the nonoperative setting
Noncardiac Surgery:Evaluation of Pulmonary Function
• Patients scheduled for thoracic surgery
• Patients scheduled for upper abdominal surgery
• Patients w/ history of heavy smoking/cough
• Obese patients
• Patients > 70 years of age
• Patients with pulmonary disease
• Value of routine PFT’s remains controversialNEJM 1999;340:937
PFT’s: Indicators of High Risk Morbidity/Mortality
• Spirometric• Maximal breathing capacity < 50% predicted
• FEV1 < 2.0 liters
• Arterial Blood Gases• Arterial PCO2 > 45 mm/hg
• Hypoxemia not reliable
Noncardiac Surgery:Anesthetic Agent
• Choice should be left to the discretion of the anesthesia care team
• Opiod-based anesthetics popular because of cardiovascular stability, but high doses result in postoperative ventilation
• All inhalational agents have cardiovascular effects
• Any anesthetic technique that does not effectively eliminate pain will be associated with markedly increased cardiac demands
Noncardiac Surgery:Anesthetic Agent
• Neuraxial Techniques• Spinal and epidural anesthesia
• Cause sympathetic blockade
• Infrainguinal procedures associated with mininal hemodynamic changes
• Abdominal procedures may result in more profound effects: hypotension/reflex tachycardia
Noncardiac Surgery:Anesthetic Agent
• Monitored Anesthesia• Local anesthesia supplemented by intravenous
sedation/analgesia
• Failure to produce complete anesthesia may lead to increased stress response producing myocardial ischemia
Noncardiac Surgery:Perioperative Pain Management
Patient-controlled intravenous and/or epidural analgesia
• Reduces severity and duration of postoperative pain
• Reduction in postoperative catecholamine surges and hypercoagulability
• Theoretically may decrease myocardial ischemia
Noncardiac Surgery:Pulmonary Artery Catheters
• Patients most likely to benefit• Recent MI complicated by CHF
• Patients with significant CAD undergoing procedures associated with significant hemodynamic stress
• Patients with systolic/diastolic dysfunction, cardiomyopathy, and valvular disease undergoing high-risk operations
Noncardiac Surgery: Postop Ischemia
• Myocardial ischemia more common, more severe in early postoperative phase
• Infarction is frequently silent• Non-Q MI often occurs on the first or second
postoperative days• Q-wave MI often occurs on the second to fourth
postoperative days• CHF/pulmonary edema commonly occurs on
postop day 2 or later
Noncardiac Surgery:Surveillance for Perioperative MI
• Few studies have examined the optimal method
• Indicators of ischemia• Clinical symptoms
• ECG changes
• Elevation of cardiac enzymes
Noncardiac Surgery:Surveillance for Perioperative MI
• Patients without known CAD: surveillance should probably be restricted to patients with signs of cardiovascular dysfunction
• Patients with known or suspected CAD undergoing high-risk procedures: baseline, then serial ECG’s recommended
• Cardiac enzymes reserved for patients with evidence of cardiovascular dysfunction
Noncardiac Surgery:ST-Segment Monitoring
• ST changes indicating myocardial ischemia are strong predictors of perioperative MI in patients at high clinical risk
• Postoperative ischemia is a significant predictor of long-term MI/cardiac death
• ST depression in low-risk patients may be a nonspecific finding
Noncardiac Surgery:Postop Rx and Long-Term Management
• Assessment and management of modifiable risk factors for cardiovascular disease
• May be first opportunity for a systematic cardiovascular evaluation in many patients
• Patients who experience repetitive postop myocardial ischemia and/or myocardial infarction are at substantially increased risk