Perioperative Management of the Cardiac Patient Henry L. Green, MD, FACC, FACP January 2, 2009 Perform a complete history and physical examination Identify non-cardiac risk factors Medication history, including non-prescription and alternative medications Drug allergies Alcohol, tobacco and illicit drug use Surgical and anesthetic history Identify cardiac risk features High risk: Recent myocardial infarction or acute coronary syndrome Decompensated heart failure Unstable angina – Canadian Class 3 or 4 Symptomatic arrhythmias (high grade atrioventricular block, symptomatic ventricular arrhythmias, supraventricular arrhythmias with uncontrolled rate) Symptomatic or severe valvular heart disease Intermediate risk: Stable angina – Canadian Class 1 or 2 Prior myocardial infarction Prior heart failure Moderate valvular disease Diabetes, a coronary risk equivalent – especially if insulin-dependent Renal insufficiency Minor risk: Advanced age Abnormal electrocardiogram (LVH, LBBB, ST-T abnormalities) Rhythm other than sinus (e.g. atrial fibrillation) Low functional capacity What is the patient’s functional status? Poor functional status implies higher perioperative risk, predicts postoperative complications, and impedes the patient’s rehabilitation. History Can the patient walk, climb stairs or perform other daily activities without symptoms? Does the patient exercise? A patient that can carry a bag of groceries up one flight of stairs, or who can walk at three to four miles per hour is doing the equivalent of four METs. Patients who are not able to do this are considered in poor physical condition. This type of evaluation is limited, as patients will often miscalculate their ability. 1

Objective evaluation A more realistic approach is to actually take the patient for a walk, or even watch him climb stairs. Treadmill stress testing gives even more quantitative information, but adds cost. Be aware of major comorbidities Stroke Renal insufficiency Pulmonary disease Diabetes Is the planned surgery a high-risk procedure? High risk procedures Emergency surgery, especially in the elderly Aortic or major vascular operations, including peripheral vascular disease Extensive operations involving large volume shifts or blood loss Intermediate risk surgery Abdominal or thoracic surgery Carotid endarterectomy Head and neck surgery Orthopedic surgery Prostate surgery Low risk surgery Endoscopy Superficial biopsy Breast surgery Cataract surgery Revised cardiac risk index One point is assigned to each of the following risk factors: High risk surgery History of ischemic heart disease History of heart failure History of cerebrovascular disease Preoperative treatment with insulin Preoperative serum creatinine > 2 The risk of major cardiac complications is derived as follows: 0 risk factors 0.4-0.5% 1 risk factor 0.9-1.3 2 risk factors 4-7% >3 risk factors 9-11%

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When is non-invasive testing needed? No testing is needed for some patients If the patient has low risk clinical features and good functional status, and the surgery is low risk, then further testing is usually not indicated. Consider stress testing in patients with any two of the following: 1. Intermediate risk patients 2. Poor functional capacity 3. High risk surgery Stress testing may demonstrate that the patient falls into a higher or lower risk category than was originally thought. High-risk patient should be considered for invasive testing and possible revascularization. Unstable angina or angina that does not respond well to medical therapy Stress test indicating high-risk Stress test equivocal but surgery is intermediate or high risk Optimize medical therapy Beta-blockers Beta-blockers may reduce complications and mortality in the following settings:  Ischemic heart disease (angina, prior myocardial infarction, or positive stress test)  Vascular surgery in patients with multiple risk factors  It is reasonable to give them for patients having vascular surgery even if they are low risk  Intermediate or high-risk surgery in patients with multiple risk factors, and possibly in those with a single risk factor  Heart failure  Diabetes, especially insulin requiring  Poor functional status, if due to coronary artery disease or heart failure The 2007 guidelines recommended introducing a beta-blocker at least several weeks prior to elective surgery. The dose must be individualized. A typical initial dose would be metoprolol 25 mg twice a day, subsequently titrated to a heart rate between 50 and 60 beats per minute. Merely prescribing beta blockers without titration did not appear to be effective. More recently, the POISE trial was presented at the 2007 American Heart Association meeting and subsequently published in the Lancet. This study demonstrated that , while the incidence of perioperative infarction was reduced by beta-blockade, there were increased numbers of stroke and death. At least some of this was driven by exacerbation of hypotension in patients with sepsis. The paper was criticized because the subjects were acutely given a standard dose of metoprolol, without the careful titration that the guidelines had recommended. 3

Their conclusion was that one should not start a beta-blocker in anticipation of surgery, but should continue it if the patient is already on it. Another view (Harte 2008) is to reserve beta-blockers for patients with known ischemic heart disease or multiple risk factors, and also patients who are already on beta-blockers. The patient should be clinically stable and be free of infection, hypovolemia, anemia or other conditions that could result in mistakes in titration to heart rate. If possible, beta-blocker therapy should be started a month before surgery. The heart rate should be titrated to a rate of 60. Postoperatively, the betablocker should be continued at least a month. If it is then to discontinued, this should be done gradually. Statins Statins may have a role in stabilizing plaques, and may be given preoperatively. However current data is not conclusive. It is reasonable to prescribe them for patients with coronary risk factors. Patients already on statins should continue them. Some drugs should be withheld Aspirin is usually discontinued for seven days, and clopidogrel at least five days. NSAID’s should be stopped for one to three days, depending on the drug. Warfarin is usually held until the INR is under 1.5. If withdrawing anticoagulation for four or five days jeopardizes the patient, he or she should be ―bridged‖ with unfractionated or low molecular weight heparin. For details, see tutorial on Thromboembolism Specific heart diseases Surgery after stenting Major adverse cardiac events are frequent in patients who have had stents within the previous twelve months, even if they are bridged with enoxaparin or unfractionated heparin. Elective noncardiac surgery should be avoided for at least three months after a percutaneous intervention. Drug-eluting stents should not be used in patients for whom surgery is planned within the foreseeable future, owing to the risk of stent thrombosis if anti-platelet therapy is interrupted. If surgery can be delayed, then a bare metal stent can be employed, and anti-platelet therapy should be given for two or preferably four weeks. Clopidogrel should be held for five days before major surgery, to avoid bleeding. If surgery cannot be delayed, it may be reasonable to continue antiplatelet therapy and advise the surgeon of the risk of bleeding. Platelet transfusions can be given.

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Valvular heart disease If possible, patients with aortic or mitral stenosis should have the problem corrected prior to elective surgery. Valvular regurgitation may be helped by afterload reduction with vasodilator drugs. Managing comorbidities Hypertension Mild to moderate hypertension does not appear to affect outcome adversely, unless there is target organ damage. However, more severe degrees of hypertension (e.g. systolic pressure over 180 or diastolic pressure over 110) should be carefully brought under control prior to elective surgery. This must be balanced against any risk of delaying surgery. If urgent control of hypertension is required immediately prior to surgery, intravenous nitroprusside or labetalol are often used. Antihypertensive drugs should be continued, as a rule. Abrupt withdrawal of betablockers or clonidine can cause a dramatic rise in blood pressure. On the other hand, angiotensin II inhibitors can result in hypotension, if the patient receives a general anesthetic. They should be held on the morning of surgery. Postoperative hypertension commonly results from Pain Hypoxia Bladder distention Pheochromocytoma Fluid overload Withdrawal of clonidine Hypercarbia Withdrawal of beta-blocker Treatment: of postoperative hypertension: Sedation and pain control Drugs Labetol iv Nicardipine iv Nitroprusside iv Nitroglycerine iv Diabetes Diabetics should not take oral hypoglycemic agents on the day of surgery. In particular, metformin should be withheld for 24 hours prior to surgery and for two to three days afterward, because of the risk of lactic acidosis. Insulin should be given according to one of several recommended regimens. Both intraoperative and postoperative ―tight‖ glycemic control have been shown to improve morbidity.

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Pulmonary disease Pulmonary risk factors include smoking, poor exercise tolerance, and chronic obstructive lung disease. Cigarette smoking should be stopped at least two months prior to surgery. Patients should be instructed in incentive spirometry. Bronchospasm and active pulmonary infection should be treated. High risk patients that are scheduled for thoracic surgery can be referred to a respiratory therapist for several weeks of preoperative inspiratory muscle training. Many believe that spinal or epidural anesthesia is safer than general anesthesia for these patients. Pancuronium should be avoided. The duration of surgery should be limited to less than three hours. If possible, laparoscopic surgery is preferable. Upper abdominal and thoracic procedures convey the greatest risk of pulmonary complications. Incentive spirometry, deep breathing exercises, continuous positive pressure airway pressure, and other lung expansion maneuvers are helpful in preventing postoperative lung complications. Delirium Delirium is associated with a higher complication rate, increased morbidity and greater length of stay. One should try to anticipate its occurrence. Inouye developed a scoring system in which one point is assigned to each of the following factors: Visual impairment Severe illness Preexisting cognitive impairment Dehydration Patients with none of these are considered to be at low risk for delirium. If there are one to two risk factors, the risk is intermediate. Three or four factors indicate high risk. Other significant risk factors include the use of psychotropic drugs, age over 70, alcohol abuse, poor functional status, and very abnormal potassium, sodium or glucose levels. Thoracic surgery and aortic aneurysm surgery convey higher risk than other operations. Postoperative surveillance Continue to monitor the cardiac status In spite of all precautions, myocardial infarction may occur in the postoperative period, usually within the first three days. Postoperative stress, hypoxia, fluid and electrolyte shifts and the hypercoagulable state probably all contribute to the risk. Diagnosis can be challenging, as about 50% of these are painless. Postoperative narcotics can easily mask the pain. Presentations may include hypotension, 6

hypertension, heart failure, arrhythmias, or, particularly in the elderly, confusion. ECG’s and biomarkers should be obtained on the first two postoperative days. Coronary angiography is often advisable in patients who show evidence of myocardial infarction. One should also seek evidence of heart failure. This is often due to fluid overload. Measurement of intake and output, daily weights and careful examination of the patient are useful here. General measures Postoperative pain should be well controlled, particularly in the cardiac patient Anemia should be corrected. Fluid and electrolyte balance Aspirin, statin drugs and ACE inhibitors should be continued. Inotropic agents should be avoided if possible. Thromboembolism protection, is usually indicated, either with compression devices, or subcutaneous unfractionated or low molecular weight heparin. Observe for urinary retention. Do not forget to remove the Foley catheter as soon as it is no longer needed. Infection control: Watch for respiratory, central line, skin, wound and urinary infections Respiratory care, such as breathing exercises, incentive spirometry, or consultation with the respiratory therapy department. Physical therapy is often indicated after major operations Nutrition is an important factor in recovery, infection prevention and wound healing. Bowel function should not be neglected Skin, mouth and eye care as required in debilitated patients Long-term therapy Cardiovascular risk factors, such as hypertension, hyperlipidemia, smoking and other life style issues should be addressed. Correctable cardiac problems should also be dealt with. Optimize cardiac and other medical therapy based on the current guidelines. References: Mukherjee D and Eagle KA. Perioperative cardiac assessment for noncardiac surgery. Circulation 2003; 107:2771-4 Fleisher LA et al. ACC/AHA 2006 Guideline update on perioperative cardiovascular evaluation for noncardiac surgery. Circulation 2006; 113:2662-74 Fleisher LA et al. ACC/AHA 2007 Guidelines on perioperative cardiovascular evaluation ad care for noncardiac surgery. JACC 2007; 50:1707-1732 Eagle KA et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary.. J Am Coll Cardiol 2002;39:542-553.

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Michota FA and Frpst SD The preoperative evaluation. Cleveland Clin J Med 2004;71:63-9 Weitz HH. How soon can a patient undergo noncardiac surgery after receiving a drug-eluting stent? Cleveland Clin J Med 2005;72:818-820 Fleisher LA. Preoperative evaluation of the patient with hypertension. JAMA 2002; 287:2043-6 Cohn SL and Smetana GW. Update in perioperative medicine. Ann Int Med 2007;147:263-270 Marcantonio ER et al. A clinical prediction rule for delirium after elective noncardiac surgery. JAMA 1994;271:134-139 Inouye SK et al. A predictive model for delirium in hospitalized elderly patients based on admission characteristics. Ann Int Med 1993;119:474-481 Lee TH, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100:1043-1049 Fleischer LA and Poldermans D. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial). Lancet 2008; 371:1839-1847 Harte B and Jaffer K. Perioperative beta-blockers in noncardiac surgery: evolution of the evidence. Cleveland Clin J Med 2008; 75:513-519

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