noncardiac surgery in the cardiac patient

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