Preoperative evaluation for anesthesia for cardiac surgery

INTRODUCTION — Although cardiac surgical techniques and outcomes have improved in the past decade, considerable risks for perioperative morbidity and mortality persist. This topic will review the anesthesiologist's preoperative evaluation of a cardiac surgical patient. This includes assessing cardiac and overall health risks, identifying issues that could cause problems during and after surgery, and working with the cardiologist, cardiac surgeon, or other medical consultants to optimize medical conditions. Examples include stabilizing pulmonary disease with the pulmonology team or assessing risk in a patient with a recent stroke with the neurology team, with planning for surgical timing in such patients. Then an anesthetic care plan is developed, with education of the patient regarding anesthetic care and alleviation of patient anxiety.

Intraoperative anesthetic management for cardiac surgical procedures (eg, coronary artery bypass grafting [CABG] and cardiac valve surgery) is discussed separately. (See "Anesthesia for coronary artery bypass grafting surgery" and "Anesthesia for cardiac valve surgery".)

GOALS OF THE PREANESTHESIA EVALUATION — During the preoperative consultation, the anesthesiologist will:

●Review the patient's history, physical examination, and available cardiac and other diagnostic tests to assess and minimize risks for the proposed anesthetic and operation. (See 'Assessment of patient and procedural risk factors' below.)

●Explain the proposed anesthetic plan to the patient and obtain informed consent for anesthetic care. Answer all questions related to perioperative anesthetic care.

●Alleviate patient anxiety. (See 'Alleviation of patient anxiety' below.)

If conditions that may be optimized are identified, surgery should be delayed if all the following criteria are met: the surgery is elective, the patient's medical condition can be significantly improved, and the risk of postponing surgery is less than the benefit of optimizing the patient's condition. Some older and/or frail patients may benefit from participation in a preoperative prehabilitation program (eg, nutritional supplementation, smoking cessation, physical and cognitive exercise, stress reduction) to improve postoperative functional status and outcomes. Such programs are discussed separately. (See "Overview of prehabilitation for surgical patients", section on 'Target patient populations'.)

Many centers have implemented programs for enhanced recovery after cardiac surgery (ERACS) programs with components in the preoperative, intraoperative, and postoperative periods. Details are discussed separately. (See "Anesthetic management for enhanced recovery after cardiac surgery (ERACS)", section on 'Preanesthetic consultation'.)

ASSESSMENT OF PATIENT AND PROCEDURAL RISK FACTORS — Preoperative assessment of any patient scheduled for surgery must include a comprehensive assessment of both patient and procedural risks, including a detailed history and focused physical examination as well as review of diagnostic studies and preoperative tests. (See "Preoperative medical evaluation of the healthy adult patient".)

Cardiovascular risk factors — Major cardiovascular conditions affecting risk include myocardial ischemia, ventricular dysfunction with heart failure, and significant atherosclerotic disease of the carotid arteries or the proximal aorta.

Myocardial ischemia — Patients with severe coronary artery disease requiring surgical revascularization may have low, intermediate, or high risk for cardiovascular complications and mortality. Anesthetic management of these patients is discussed in detail elsewhere. (See "Anesthesia for coronary artery bypass grafting surgery".)

Factors such as acute myocardial infarction (MI) and degree of hemodynamic stability predict risk and influence urgency for scheduling a surgical intervention, as noted below:

●Low risk – Patients with angina or an anginal equivalent without evidence of a preoperative MI who are scheduled electively have the lowest risk. (See "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention".)

●Intermediate risk – Patients with an acute MI who remain hemodynamically stable have an intermediate risk. These patients are usually hospitalized and may be receiving heparin and antiplatelet medications.

If the patient presents within six hours of symptom onset and has multiple coronary lesions, urgent surgical revascularization may maximize myocardial salvage. If the patient presents later than six hours after symptom onset, myocardial necrosis has already reached its peak. In these cases, surgery is usually delayed for three to four days in order to possibly improve operative morbidity and mortality [1,2]. Surgery may be delayed longer (usually five to seven days) if the patient received recent antiplatelet therapy (ie, a P2Y₁₂ receptor blocking agent). (See 'Medications affecting hemostasis' below.)

The decision for revascularization, as well as the method and timing of revascularization, are discussed elsewhere. (See "Coronary artery bypass graft surgery in patients with acute ST-elevation myocardial infarction", section on 'Timing' and "Non-ST-elevation acute coronary syndromes: Selecting an approach to revascularization".)

●High risk – Patients with an acute MI who are hemodynamically unstable or have another indication for emergency surgical revascularization have a very high risk for morbidity and mortality. Examples include refractory angina despite maximal medical therapy and/or ongoing myocardial ischemia after unsuccessful or complicated percutaneous coronary intervention, cardiogenic shock due to severe left ventricular (LV) or right ventricular (RV) dysfunction, acute severe mitral regurgitation, or rupture of the LV free wall or interventricular septum [3-6]. (See "Coronary artery bypass graft surgery in patients with acute ST-elevation myocardial infarction", section on 'Indications'.)

For patients who have an intraaortic balloon counterpulsation pump (IABP) in place, hemodynamic stability and maximal support of ventricular function and coronary perfusion are achieved by maintaining IABP augmentation at a 1:1 ratio during the preoperative and prebypass periods (see "Intraaortic balloon pump counterpulsation"). In a single-center retrospective series, patients who received preoperative IABP support due to rapid worsening hemodynamics had a 17.8 percent 30-day mortality, compared with 5.9 percent for those who received IABP support for unstable angina and 2.7 percent for patients who received IABP support prophylactically [7].

Congestive heart failure — Preoperative risk evaluation of patients with congestive heart failure includes assessment of severity of LV and/or RV dysfunction and associated conditions. Knowledge of the following pathology is helpful in designing an anesthetic care plan (eg, selecting monitoring modalities, anesthetic agents, and vasoactive infusions, as well as anticipating a possible need for mechanical support):

●Etiology of ventricular dysfunction – The etiology of ventricular dysfunction (eg, ischemic cardiomyopathy, severe cardiac valve pathology, diastolic dysfunction) is important to establish perioperative hemodynamic goals.

●Degree of left or right ventricular dysfunction – Patients with severe LV or RV dysfunction may be optimally treated in a tertiary care center offering mechanical circulatory support. LV systolic function is a known predictor of morbidity and mortality in cardiac surgery and is incorporated into most risk prediction models (see 'Risk calculators' below). Although RV functional parameters are not incorporated in commonly used risk models, several retrospective and small prospective studies have demonstrated that RV dysfunction is associated with poor outcomes after cardiac surgery [8-11].

●Concomitant pulmonary hypertension – Pulmonary hypertension, defined as mean pulmonary artery pressure (PAP) >20 mmHg at rest, increases morbidity and mortality risk [11-13], and is included in the Parsonnet and EuroSCORE II risk models (see 'Risk calculators' below). The severity of pulmonary hypertension is not necessarily commensurate with LV dysfunction (eg, marked pulmonary hypertension may be seen with only mild or moderate LV dysfunction) [14].

Cerebrovascular or proximal aortic atherosclerosis — Severe atherosclerosis of the proximal aorta or carotid arteries is a risk factor for perioperative stroke (see "Neurologic complications of cardiac surgery"). Other comorbidities (eg, diabetes, hypertension, previous cerebrovascular event, peripheral vascular disease, and smoking-related pulmonary pathology) are typically present.

Carotid artery disease — Significant carotid stenosis (ie, >80 percent) is present in 4 to 10 percent of patients undergoing coronary artery bypass grafting (CABG) surgery [15]. Some centers screen for carotid disease in all patients scheduled for coronary surgery (eg, with carotid sonography), while others screen only those at high risk (age >65 years; left main coronary stenosis; peripheral arterial disease; history of transient ischemic attack or stroke, hypertension, tobacco use, or diabetes mellitus) [16-18].

Uncorrected significant carotid stenosis places the cardiac surgical patient at increased risk for perioperative stroke [16,19-21]. Preoperative strategies to minimize this risk include ensuring that doses of chronically administered aspirin, beta blockers, and statins were received on the morning of surgery. (See "Coronary artery bypass grafting in patients with cerebrovascular disease", section on 'Stroke associated with CABG'.)

Patients with a very high stroke risk may be scheduled for carotid endarterectomy (CEA) prior to or concurrently with their cardiac operation. Concomitant CEA and CABG surgery necessitates coordination between the anesthesiologist and both the vascular and cardiac surgical teams so that everyone understands the planned sequence of procedures. For example, it is necessary to ensure that central venous access is obtained on the side contralateral to the carotid occlusion. (See "Coronary artery bypass grafting in patients with cerebrovascular disease", section on 'Prophylactic carotid intervention'.)

Intraoperative management strategies during cardiopulmonary bypass (CPB) for patients with cerebrovascular disease are discussed separately. (See "Management of special populations during cardiac surgery with cardiopulmonary bypass", section on 'Cerebrovascular disease'.)

Proximal aortic atherosclerosis or calcification — Patients with significant coronary and/or carotid atherosclerotic disease may also have significant atherosclerosis or calcification of the proximal or ascending aorta. Typically, this is evident on chest radiograph (CXR) and/or other imaging studies obtained in the preoperative period (eg, computed tomography [CT] imaging of the chest). During cardiac surgery, thrombi or atheromatous debris can be released from aortic plaques during graft anastomoses, clamping and unclamping of the ascending aorta, or by turbulent high-velocity blood flow delivered via the aortic cannula into a diseased aorta. Since the degree of aortic manipulation has been associated with increased stroke rates [22], the cardiac surgeon may decide to employ off-pump coronary artery bypass grafting in order to avoid cannulation, crossclamping of the atherosclerotic aorta, and the need for CPB.

In patients with possible or known proximal aortic disease, the cardiac anesthesiologist will plan to perform a thorough intraoperative transesophageal echocardiogram (TEE) assessment for aortic atheromas (see "Anesthesia for cardiac surgery: General principles", section on 'Initial transesophageal echocardiography examination'). Contraindications to placement of a TEE probe (eg, dysphagia or odynophagia) are discussed below. (See 'Physical examination' below.) 

Noncardiac risk factors — Noncardiac risk factors that cannot be modified include female gender [23,24] and older age [25-27]. (See "Anesthesia for the older adult", section on 'Impact of age-related physiologic changes on anesthetic care' and "Anesthesia for the older adult", section on 'Preanesthesia consultation'.)

Potentially modifiable noncardiac risk factors include preexisting renal insufficiency [28-30], anemia that may result in perioperative transfusion [31-33], and current tobacco use. (See "Operative mortality after coronary artery bypass graft surgery", section on 'Predictors of risk'.)

Anemia — Anemia is common in cardiac surgical patients and has been independently associated with increased risk for red blood cell (RBC) transfusion and adverse outcomes [34-58]. In an observational study that included 1787 women and 2330 men undergoing coronary artery bypass grafting surgery, each 1 g/dL decrease in preoperative hemoglobin <13 g/dL in women was associated with increased risk of RBC transfusion (odds ratio [OR] 2.90, 95% CI 2.33-3.60), acute kidney injury (AKI; OR 1.49, 95% CI 1.23-1.81), reoperation (OR 1.27, 95% CI 1.11-1.45), and longer hospital length of stay (LOS) [55]. For men in this study, each 1 g/dL decrease in preoperative hemoglobin <14 g/dL in was similarly associated with increased risk of RBC transfusion (OR 2.56, 95% CI 2.27-2.88) and longer hospital LOS. RBC transfusion was less likely in women with preoperative hemoglobin >13 g/dL (OR 0.57, 95% CI 0.47-0.69), and less likely in men with preoperative hemoglobin >14 g/dL (OR 0.74, 95% CI 0.60-0.91) [55]. We agree with guidelines developed by the Society of Cardiovascular Anesthesiologists (SCA) [59] and other professional societies [41,45,46,51,60], which state that it is often appropriate to postpone elective cardiac surgery to diagnose causes and ensure correction of preoperative anemia (algorithm 1), typically defined in this setting as hemoglobin <13 g/dL for women or <14 g/dL for men. (See "Perioperative blood management: Strategies to minimize transfusions", section on 'Treatment of anemia' and "Operative mortality after coronary artery bypass graft surgery", section on 'Preoperative anemia'.)

●Iron deficiency anemia – In a prospective observational study of 730 elective cardiac surgical cases, iron deficiency (defined as ferritin <100 mcg/L) with anemia was associated with an increase in 90-day mortality from 4 to 14 percent (OR 3.5, 95% CI 1.5-8.4). In the same study, patients with iron deficiency without anemia also exhibited increased 90-day mortality from 2 to 5 percent (OR [adjusted for anemia and EuroSCORE comorbidities] 3.2, 95% CI 1.3-7.6) [61]. Iron deficiency has also been associated with a greater number of perioperative transfusions , and with major adverse cardiovascular events (defined as death, acute myocardial infarction, or acute stroke) in cardiac surgical patients [56,61-63].

Patients with iron deficiency should be treated with iron rather than transfusion unless anemia is extremely severe with an associated risk of myocardial or other organ ischemia. If iron is administered, sufficient time should be allowed for effective treatment of anemia before surgery (typically two to four weeks for partial correction and six to eight weeks for full correction). In individuals with unexplained iron deficiency, consultation should be obtained to determine the underlying cause (typically with a gastroenterologist to screen for gastrointestinal sources of blood loss or iron malabsorption). (See "Causes and diagnosis of iron deficiency and iron deficiency anemia in adults" and "Treatment of iron deficiency anemia in adults".)

Oral iron replacement can be initiated in an iron-deficient patient if at least four to six weeks of time is available before planned surgery. Details for therapy are available in a separate topic. (See "Treatment of iron deficiency anemia in adults", section on 'Oral iron'.)

Intravenous (IV) iron is an option if less time is available in patients with iron-deficiency before semi-elective surgery, and for patients who cannot tolerate oral iron or do not have a response (eg, due to poor absorption). Although IV iron can replenish body iron stores more rapidly and effectively than oral iron therapy, adequate time (ie, one to two weeks for a hemoglobin increase of approximately 1 g/dL) is still required for the iron to be incorporated into developing RBCs to allow the hemoglobin level to increase [41,43,44,50,64-67]. Details for administration of IV iron therapy are available in a separate topic. (See "Treatment of iron deficiency anemia in adults", section on 'Oral iron' and "Treatment of iron deficiency anemia in adults", section on 'Intravenous iron'.)

●Use of erythropoietin – Some centers administer erythropoietin (EPO) during the perioperative period in patients undergoing elective cardiac surgical procedures [48,68,69]. In our center, patients are referred preoperatively to our anemia clinic if hemoglobin is <13 g/dL, and these patients typically receive an EPO-stimulating agent (eg, epoetin alfa 600 units/kg weekly, or 300 units/kg daily) for up to 10 days before surgery. Our management is similar to guidelines from the European Association for Cardio-Thoracic Surgery (EACTS) and the European Association of Cardiothoracic Anaesthesiology (EACTA), as well as the 2019 SCA, which suggest that EPO be considered in adults undergoing cardiac surgery who have anemia not due to iron deficiency [59,69]. Also, EPO is often used in patients who do not accept transfusions (eg, Jehovah Witnesses) [59,70,71].

Although increased risk of thromboembolic events has been cited as a concern after administration of EPO, patients receiving postoperative anticoagulation are likely to be protected from this risk; other cited complications (eg, hypertension, ischemic events) are unlikely [51,72].

Relevant data regarding benefits and risks of preoperative EPO administration in the cardiac surgical setting are summarized below. Notably, significant heterogeneity with respect to the presence, cause, and severity of preoperative anemia and/or iron deficiency exists in these studies:

•A 2019 meta-analysis of randomized trials comparing preoperative administration of EPO versus placebo (32 trials; 4750 patients, mostly orthopedic and cardiac surgery) found reduced blood transfusions in the EPO groups [73]. Overall, decreased blood transfusions were noted (risk ratio [RR] 0.59, 95% CI 0.47-0.73; 28 trials), and the subgroup of cardiac surgical patients also had fewer transfusions (RR 0.55, 95% CI 0.47-0.73; nine trials; 1520 patients). There was no increase in the incidence of thromboembolic events with EPO.

•A subsequent prospective randomized trial in elective cardiac surgical patients with preoperative anemia or isolated iron deficiency published in 2019 noted reduced RBC transfusions from a median of 1 to 0 units in those who received preoperative treatment with a combination of therapies that included subcutaneous EPO, IV iron, subcutaneous vitamin B12, and oral folic acid on the day before surgery, compared with those receiving placebo drugs (odds ratio [OR] 0.70, 95% CI 0.50-0.98) [74]. However, it is unknown whether administration of IV iron without EPO would have been equally effective in patients with iron deficiency, whether giving vitamin B12 and folate had additional benefits, or whether such approaches to reduce transfusions decrease risk for adverse perioperative events.

●Anemia associated with chronic kidney disease – Improvements in degree of anemia in patients with chronic kidney disease (with or without hemodialysis) may be possible with administration of iron and EPO, particularly if some degree of iron deficiency is present. (See "Treatment of anemia in nondialysis chronic kidney disease", section on 'Treatment' and "Treatment of anemia in patients on dialysis", section on 'Treatment'.)

Red blood cell disorders — Disorders of RBCs that have important physiologic consequences for patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) include [75,76]:  

●Cold agglutinin disease (See "Cold agglutinin disease".)

●Paroxysmal nocturnal hemoglobinuria (See "Treatment and prognosis of paroxysmal nocturnal hemoglobinuria", section on 'Surgery'.)

●Sickle cell disease (See "Red blood cell transfusion in sickle cell disease: Indications and transfusion techniques", section on 'Indications for preoperative transfusion' and "Overview of the management and prognosis of sickle cell disease", section on 'Management during hospitalization'.)

●Hereditary spherocytosis (See "Hereditary spherocytosis".)

●Thalassemia) (See "Management of thalassemia", section on 'Surgery/anesthesia concerns'.)

Disorders of hemostasis — Perioperative management of patients with inherited or acquired disorders that affect hemostasis is discussed in UpToDate topics for the specific disease. (See "Preoperative assessment of bleeding risk" and "Perioperative blood management: Strategies to minimize transfusions", section on 'Management of specific hemostatic disorders'.)

Renal insufficiency — Patients with preexisting renal insufficiency are at increased risk for developing AKI requiring renal replacement therapy, which occurs in approximately 1 to 2 percent of patients undergoing cardiac surgery [29,77-79]. There is a strong relationship between development of AKI and mortality [80]. Preoperative calculation of the creatinine clearance (CrCl) [29,79,81], or selected cardiac, inflammatory, renal, and metabolic biomarkers [82], may provide a better estimate of renal risk than the serum creatinine (Cr) value. (See "Early noncardiac complications of coronary artery bypass graft surgery", section on 'Acute kidney injury' and "Operative mortality after coronary artery bypass graft surgery", section on 'Acute kidney injury'.)

In patients with preexisting renal insufficiency, preoperative attention is directed to any modifiable risk factors. Exposure to nephrotoxic agents is avoided. Volume status is optimized, and any evidence of reduced cardiac output and/or hypotension is promptly treated (see "Possible prevention and therapy of ischemic acute tubular necrosis", section on 'Prevention'). Although preoperative anemia is a modifiable risk factor for exacerbation of perioperative renal injury, perioperative RBC transfusions also confer risk [30,34]. (See 'Anemia' above.)

Specific issues concerning the prevention of radiocontrast nephropathy and the prevention of nonischemic causes of acute tubular necrosis are presented in detail elsewhere. (See "Prevention of contrast-associated acute kidney injury related to angiography".)

Common comorbid conditions — Patients undergoing cardiac surgery typically have one or more comorbid conditions. Details regarding the preoperative evaluation and management of common comorbidities are discussed separately:

●Diabetes – Perioperative goals include avoidance of either hypoglycemia or marked hyperglycemia, as described in detail separately. (See "Perioperative management of blood glucose in adults with diabetes mellitus" and "Management of cardiopulmonary bypass", section on 'Glucose'.)

●Hypertension – Chronically administered oral antihypertensive medications should be continued up to the time of surgery. (See "Anesthesia for patients with hypertension" and "Perioperative management of hypertension".)

●Chronic obstructive pulmonary disease – Optimal baseline level of pulmonary function is the major preoperative goal for patients with chronic obstructive pulmonary disease (COPD). Current smokers should be counseled about preoperative cessation. (See "Anesthesia for patients with chronic obstructive pulmonary disease", section on 'Preoperative interventions to optimize pulmonary function'.)

●Obstructive sleep apnea – Obstructive sleep apnea (OSA) is a common sleep disorder with a wide spectrum of severity. One study of more than 500,000 patients undergoing CABG noted that 6.4 percent had a diagnosis of sleep apnea, which was associated with a higher risk for postoperative atrial fibrillation and for hospital readmission within 30 days [83].

●Thyroid dysfunction – Patients with thyroid dysfunction are at increased risk for cardiovascular comorbidities. These include atrial fibrillation, heart failure, pulmonary hypertension, or angina-like symptoms with hyperthyroidism, or reduced heart rate and contractility or hypertension with hypothyroidism. Although it is unknown whether hyperthyroidism or hypothyroidism predispose to perioperative cardiovascular complications, endocrinologic consultation should be considered in patients with suspected thyroid dysfunction or subclinical abnormalities of thyroid stimulating hormone (TSH) level [84]. (See "Cardiovascular effects of hyperthyroidism" and "Clinical manifestations of hypothyroidism", section on 'Cardiovascular system'.)

Surgical risk factors — Emergency cardiac surgery confers a high risk for morbidity and mortality [16,85-87]. (See 'Emergency surgery' below.)

In elective surgery, complexity of the procedure confers additional risk (eg, previous cardiac surgery [88,89], need for combined procedures such as CABG plus cardiac valve surgery [90,91], prolonged duration of aortic crossclamping and/or total CPB time [92]).

Risk for mortality is also related to the procedural volume (ie, experience) of both the hospital and the individual cardiac surgeon [93-95]. (See "Operative mortality after coronary artery bypass graft surgery", section on 'Hospital and surgeon experience'.)

Risk calculators — Several risk prediction models incorporate patient and procedural characteristics to estimate overall risk of operative mortality, including the EuroSCORE (table 1) [96], the Society of Thoracic Surgeons [STS] risk calculator, and others [85,86,97-99]. Risk is more difficult to predict in patients who have multiple severe comorbidities and when uncommon procedures are planned. Models for risk prediction are reviewed in detail elsewhere. (See "Operative mortality after coronary artery bypass graft surgery", section on 'Risk prediction algorithms'.)

PHYSICAL EXAMINATION — Physical examination of the patient scheduled for heart surgery should include assessment of:

●Ease and likely adequacy of venous access for both peripheral and central venous catheters. Anticipated difficult venous access may influence selection of the type of intravenous catheter(s) (eg, preoperative placement of a peripherally inserted central catheter [PICC] line, intraoperative placement of a multilumen catheter).

●Peripheral arterial pulses in order to determine the best site for invasive arterial pressure monitoring and possible intraaortic balloon pump (IABP) placement.

●Abnormalities of the oral cavity and teeth. Severe periodontal disease or other oropharyngeal abnormalities that are potential sources of bacterial infection should be identified and brought to the attention of the surgeon if not already recognized. This is particularly important before any operation that involves implantation of prosthetic material such as an artificial heart valve or synthetic graft material for aneurysm repair.

●Integrity of the skin. Cellulitis or untreated ulcers are not uncommon due to the high incidence of diabetic vasculopathy in cardiac surgical patients. These should be brought to the attention of the surgeon if not already recognized.

●Predictors of difficulty with airway management. Difficult airway management is planned with particular care in order to avoid hypoxia and hypercarbia, as well as the stress response (with resultant tachycardia and hypertension that will be poorly tolerated in most cardiac surgical patients). (See "Management of the difficult airway for general anesthesia in adults", section on 'Planning the anesthetic approach'.)

●Presence of obesity. Obesity confers challenges for anesthetic management, including a higher likelihood of difficulties with airway management and endotracheal intubation, ventilation management, drug dosing, management of pump flow during cardiopulmonary bypass (CPB), and positioning injuries [100]. (See "Anesthesia for the patient with obesity".)

Morbid obesity (body mass index [BMI] >40 kg/m²) is clearly associated with increased postoperative morbidity, mortality, and cost [100-102]. However, some studies describe an "obesity paradox," in which moderate obesity (BMI 30 to 39 kg/m²) confers reduced risk [100,101,103]. Nevertheless, most centers proceed with cardiac surgery in morbidly obese patients if indicated, rather than delaying surgery for counseling and attempted weight loss.

●Presence of swallowing problems due to esophageal lesions or problems with neck mobility (eg, due to previous esophageal surgery, dysphagia, or hiatal hernia). This is important because most cardiac procedures and nearly all valve repair or replacement procedures are performed with intraoperative transesophageal echocardiography (TEE) monitoring. Absolute and relative contraindications for placement of a TEE probe are noted in the table (table 2) . In all cases, the potential benefit from TEE monitoring must be weighed against the relative risk of injury during placement and manipulation of the probe. (See "Transesophageal echocardiography: Indications, complications, and normal views", section on 'Safety of TEE examination'.)

PREOPERATIVE TESTS

Cardiac diagnostic studies — Most patients undergoing cardiac surgery have an established diagnosis. Supporting advanced diagnostic studies (eg, cardiac catheterization with coronary arteriography, right heart catheterization, echocardiography, etc) will be available. The anesthesiologist should review this information to gain a clear understanding of the indications for surgery, surgical plan, and individual patient risks in order to appropriately tailor the anesthetic plan.

Electrocardiography — The electrocardiogram (ECG) is examined for dysrhythmias, conduction abnormalities, myocardial ischemia, and proper functioning of defibrillators or pacemakers in patients with these cardiac implantable electronic devices. (See 'Management of implantable cardioverter defibrillators and pacemakers' below.)

Echocardiography — Preoperative transthoracic echocardiography is routinely performed for patients scheduled to undergo valve repair or replacement, as well as for the majority of patients scheduled to undergo coronary artery bypass grafting (CABG). An exception may be made in patients scheduled for CABG surgery who have no history of valvular heart disease and the left ventricular (LV) function has been quantified by ventriculography during cardiac catheterization. Key echocardiographic findings of importance to the anesthesiologist are described in the table (table 3).

Diagnostic cardiac catheterization — Nearly all patients scheduled for either CABG or cardiac valve surgery have undergone recent diagnostic coronary angiography. Typically, right heart catheterization data will also be available in patients with known or suspected left or right ventricular (RV) dysfunction, pulmonary hypertension, or cardiac valve disease. Key cardiac catheterization findings of importance to the anesthesiologist are described in the table (table 4).

Other preoperative tests

Laboratory tests — Blood tests that are routinely available include a complete blood count (CBC), tests of coagulation (prothrombin time, activated partial thromboplastin time, international normalized ratio), and a basic metabolic panel (electrolytes, glucose, creatinine, blood urea nitrogen).

●Anemia – Anemia noted on the CBC should prompt evaluation for possible reversible causes (see "Diagnostic approach to anemia in adults"). If possible, anemia is corrected before surgery (eg, with iron supplementation and/or erythropoietin-stimulating agents) to avoid or minimize transfusion of stored red blood cells (RBCs). (See 'Anemia' above and 'Pretransfusion testing' below.)

●Abnormalities in tests of coagulation and platelet count and function – Abnormalities on tests of coagulation, including platelet count and function should prompt evaluation for reversible causes [104]. Abnormalities due to administration of anticoagulant or antiplatelet agents may necessitate delaying elective surgery or correction for urgent surgery. (See "Preoperative assessment of bleeding risk" and 'Medications affecting hemostasis' below.)

●Hyperglycemia – Hyperglycemia in the preoperative period (ie, blood glucose persistently >180 mg/dL for 12 hours before surgery) in a hospitalized patient is treated by either a continuous intravenous insulin infusion or subcutaneous insulin, depending on the patient's prior use of insulin and the availability of these therapies in the patient's hospital ward [105]. Adequate glycemic control in the perioperative period is associated with reduced mortality, reduced morbidity including wound infections, reduced hospital length of stay (LOS), and improved long-term outcomes [105]. (See "Perioperative management of blood glucose in adults with diabetes mellitus" and "Glycemic control in critically ill adult and pediatric patients".)

Other major laboratory abnormalities detected during the preoperative assessment should prompt evaluation and management similar to patients undergoing noncardiac surgery. (See "Preoperative medical evaluation of the healthy adult patient".)

Pretransfusion testing — Typically, at least 2 units of packed RBCs are crossmatched prior to a cardiac surgical procedure since significant blood loss is a possibility in any operation involving the heart and major blood vessels. The anesthesiologist should ensure that these RBC units will be available and determine whether there are issues that may affect the availability of additional crossmatched units (eg, unusual blood type or antibodies). (See "Pretransfusion testing for red blood cell transfusion".)

Chest radiograph and computed tomography imaging — The preoperative chest radiograph (CXR) often provides necessary anatomic information before cardiac surgery (eg, abnormal heart size or presence of pulmonary edema or pleural effusions indicating congestive heart failure or severe calcification of the thoracic aorta). (See 'Congestive heart failure' above and 'Proximal aortic atherosclerosis or calcification' above.)

In patients undergoing repeat cardiac operations via redo sternotomy, the relationship of the aorta and RV free wall to the sternum is noted in the lateral CXR view. Scar adherence of the RV free wall or ascending aorta to the posterior table of the sternum may cause life-threatening hemorrhage due to unintentional right atrial, RV, or aortic injury during sternotomy. Many centers now obtain routine chest computed tomography (CT) scans in redo patients in order to assess the risk of vascular injury during sternotomy, so that alternative cannulation approaches (eg, axillary and femoral) may be planned prior to sternal incision if necessary [106]. (See 'Pretransfusion testing' above.)

Pulmonary function tests — Decisions to obtain preoperative pulmonary function tests (PFTs; eg, spirometry, diffusing capacity for carbon monoxide [DLCO]) and arterial blood gases are guided by individual patient history and physical examination. (See "Evaluation of perioperative pulmonary risk", section on 'Preoperative risk assessment'.)

Moderate or severe airway obstruction, as well as reduced DLCO, on preoperative PFTs confers higher short- and long-term mortality risk in cardiac surgical patients [107,108]. Aside from risk estimation, results of PFTs aid in determining optimal perioperative management strategies (eg, use of inhaled bronchodilators, management of mechanical ventilation, and planning need for prolonged postoperative respiratory support). (See "Anesthesia for patients with chronic obstructive pulmonary disease", section on 'Perioperative medication management' and "Anesthesia for patients with chronic obstructive pulmonary disease", section on 'Intraoperative management'.)

MANAGEMENT OF PREOPERATIVE MEDICATIONS

Cardiovascular medications — Doses of chronically administered cardiovascular medications, particularly beta blockers, are administered on the morning of surgery [109].

Beta blockers (including sotalol) appear to reduce the incidence of postoperative atrial arrhythmias, and may reduce the incidence of perioperative ventricular arrhythmias [110-113]. A 2019 meta-analysis noted a lower incidence of atrial fibrillation or flutter (risk ratio [RR] 0.50, 95% CI 0.42-0.59; 40 studies, 5660 participants) or ventricular arrhythmias (RR 0.40, 95% CI 0.25-0.63; 122 studies, 2296 participants) in patients receiving perioperative beta blocker therapy compared with those receiving none, although the quality of the evidence was graded as low in this study [113]. (See "Coronary artery bypass surgery: Perioperative medical management", section on 'Beta blockers' and "Atrial fibrillation and flutter after cardiac surgery", section on 'Prevention of atrial fibrillation and complications'.)

The majority of patients who present for coronary artery bypass grafting (CABG) surgery have been receiving beta blocker therapy for management of their angina, treatment of hypertension, left ventricular (LV) dysfunction, or secondary prevention after acute myocardial infarction (MI). (See "Beta blockers in the management of chronic coronary syndrome", section on 'Summary and recommendations' and "Acute myocardial infarction: Role of beta blocker therapy", section on 'Summary and recommendations'.)

Also, most patients referred for CABG will be receiving a statin due to long-term mortality benefits from statin therapy. (See "Coronary artery bypass surgery: Perioperative medical management", section on 'Statins'.)

Recommendations regarding optimal perioperative use of other cardiovascular medications (eg, angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor blockers [ARBs], aldosterone antagonists, calcium channel blockers, non-statin hypolipidemic agents, digoxin, and diuretics) are discussed in detail elsewhere. (See "Coronary artery bypass surgery: Perioperative medical management", section on 'Angiotensin converting enzyme inhibitors' and "Perioperative medication management", section on 'Cardiovascular medications'.)

Medications affecting hemostasis — Management of preoperative medications that affect hemostasis is important to minimize bleeding risk during cardiac surgery.

Antiplatelet agents — Chronic administration of dual antiplatelet therapy with aspirin and P2Y₁₂ antagonists is common in patients presenting for cardiac surgery, particularly those with coronary artery disease.

●Aspirin – At our center, aspirin is generally continued on the day of surgery, especially for patients who are undergoing coronary revascularization. Chronically administered aspirin is routinely continued in the perioperative period in patients undergoing such procedures due to improved perioperative outcomes (eg, in-hospital mortality, myocardial infarction, stroke) [114-116]. (See "Coronary artery bypass surgery: Perioperative medical management", section on 'Aspirin'.)

Aspirin administration on the day of surgery is associated with minor increases in perioperative bleeding [117,118], but not with increased risk of mediastinal re-exploration or major transfusion requirements [119-121].

●P2Y₁₂ antagonists – Platelet P2Y₁₂ receptor inhibitors (eg, clopidogrel, prasugrel, ticagrelor) are usually discontinued five to seven days before elective cardiac surgery due to concerns regarding increased perioperative bleeding, transfusions, and associated adverse outcomes (table 5) [122,123]. In one study, patients receiving ticagrelor or clopidogrel within two days and three days of coronary artery bypass grafting (CABG) surgery, respectively, had increased risk of severe bleeding [124]. (See "Long-term antiplatelet therapy after coronary artery stenting in stable patients" and "Coronary artery bypass surgery: Perioperative medical management", section on 'Platelet P2Y12 receptor blocker therapy'.)

Patients receiving prasugrel or ticagrelor typically have more potent platelet inhibition than those receiving clopidogrel [125,126]. In some centers, preoperative platelet function testing with a P2Y₁₂ assay is performed to determine whether residual P2Y₁₂ antagonist drug effect is present. This information may aid in determining timing of surgery and platelet transfusion strategies pre and intraoperatively. (See "Platelet function testing".)

Warfarin and direct oral anticoagulants — Parenteral or enteral anticoagulant agents (eg, heparins, vitamin K antagonists, direct thrombin inhibitors such as dabigatran, factor Xa inhibitors such as rivaroxaban, apixaban, or edoxaban) should be stopped in sufficient time to allow resolution of anticoagulant effects before elective cardiac surgery. For example, warfarin is typically discontinued five days before elective surgery. The table notes the recommended duration for cessation for direct oral anticoagulants (DOACs) and factor Xa inhibitors (table 6) [127,128]. However, there is individual variability in resolution of anticoagulant effects, which may take longer in some patients due to factors such as renal insufficiency. Routine laboratory testing can reliably detect residual anticoagulant effect for warfarin (ie, prothrombin time [PT] and international normalized ratio [INR]), but validated and easily accessible tests are not available for all DOACs (table 7).

Details regarding management of these agents for elective cardiac surgical procedures and in patients with prosthetic heart valves are available in separate topics:

●(See "Perioperative management of patients receiving anticoagulants".)

●(See "Anticoagulation for prosthetic heart valves: Management of bleeding and invasive procedures", section on 'Planning for invasive procedures'.)

Management of medications affecting hemostasis in patients requiring urgent or emergency surgery is addressed below. (See 'Emergency surgery' below.)

Other medications — Decisions regarding continuation of other chronically administered medications in the perioperative period depend on the medication and patient factors, and are discussed elsewhere. (See "Perioperative medication management".)

MANAGEMENT OF IMPLANTABLE CARDIOVERTER DEFIBRILLATORS AND PACEMAKERS — Patients undergoing cardiac surgery may have a single- or dual-chamber pacemaker, biventricular pacemaker, and/or implantable cardioverter defibrillator device (ICD) [129]. Considerations for cardiac surgical procedures include:

●ICD – Since cardiac surgery will occur in the vicinity of the device, electromagnetic interference may inappropriately trigger antitachycardia shocks from an ICD or inhibit needed pacing for bradycardia. Placement of a magnet over the device is usually impractical during cardiac surgery due to its location in the anterior chest wall near the surgical incision. Thus, the device should be reprogrammed to an asynchronous mode. Reprogramming is accomplished in the immediate preoperative period or in the operating room before surgical incision. In emergency situations, a sterile magnet or a magnet encased in a sterile sheath may be used in the surgical field.

●Pacemaker – In the pacemaker-dependent patient, the system is usually reprogrammed to an asynchronous mode (VOO or DOO) before surgical incision. The asynchronous mode will prevent the pacemaker from being unintentionally inhibited resulting in severe bradycardia or asystole. In emergency situations, a sterile magnet placed over the pacemaker will disable all sensing, producing an asynchronous VOO or DOO mode.

During surgery, the ischemia/reperfusion injury that occurs during crossclamping of the aorta and cardiopulmonary bypass (CPB) as well as direct trauma to the myocardium will temporarily increase the capture threshold of a pacemaker, which may result in loss of capture. Thus, temporary epicardial pacing wires are routinely inserted during cardiac surgery, even in patients who have a permanent pacemaker that will be reprogrammed in the postoperative period to restore permanent parameters.

Additional details regarding perioperative management of ICDs and pacemakers are discussed elsewhere [130,131]:

●(See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator".)

●(See "Pacing system malfunction: Evaluation and management", section on 'Electromagnetic interference'.)

ALLEVIATION OF PATIENT ANXIETY — Discussions with the patient regarding the risks of the proposed operation (eg, serious morbidity or mortality) versus the expected benefits (eg, symptom relief and/or survival advantage) are typically completed by the patient's cardiologist and cardiac surgeon prior to the preanesthesia consultation. Although patients are often understandably nervous in the immediate preoperative period, a calm and empathetic anesthesiologist may significantly reduce anxiety.

SPECIAL SITUATIONS

Need for palliative care — Planning for postoperative care may include a palliative care consultation in selected high-risk cardiac surgical patients to improve end-of-life experiences for the individual and their families [132]. The aim of these consultations is to provide symptomatic and psychosocial support and to communicate goals of care for a potentially difficult or prolonged recovery. (See "Benefits, services, and models of subspecialty palliative care".)

In a retrospective study that included more than 95,000 patients undergoing high-risk cardiothoracic, vascular, or other major surgery, families of patients who had died during the postoperative period were more likely to retrospectively rate overall care in the final month of life as excellent if they had received a palliative care consultation compared with families who did not have this consultation (odds ratio [OR] 1.47, 95% CI 1.14-1.88) [133]. Similar positive ratings were noted by families who received end-of-life communication and support. However, in this large study, fewer than six percent of the families of deceased patients had received their consultation in the preoperative period, and only 30 percent had received a palliative care consultation at any point in the perioperative period [133].

More frequent use of perioperative palliative care may improve end-of-life experiences for high-risk surgical patients and their families. Such consultations also improve provision of symptomatic and psychosocial support and communication regarding goals of care for survivors of high-risk surgery who may have a difficult or prolonged recovery.

Patients on dialysis — A functional arteriovenous fistula or other dialysis access site in patients with end-stage renal disease (ESRD) impacts the decision regarding which artery to cannulate for invasive arterial pressure monitoring. During surgery, dialysis access sites must be carefully protected and padded to preserve functionality.

Preoperative management of dialysis-dependent patients, with particular attention to the presence of hyperkalemia, metabolic acidosis, volume overload, or bleeding diathesis, is discussed in detail elsewhere. (See "Anesthesia for dialysis patients", section on 'Preanesthetic management'.)

If necessary, a hemoconcentrator can be added to the cardiopulmonary bypass (CPB) circuit and utilized to perform ultrafiltration, zero-balance ultrafiltration, or hemodialysis in order to correct hypervolemia, hyperkalemia, metabolic acidosis, and azotemia during CPB [134].

Emergency surgery — Patients requiring emergency surgery have a high risk for morbidity and mortality [16,85-87]. In this setting, the anesthesiologist may have limited or no time to question the patient directly and/or review the medical record but must nevertheless perform a rapid preoperative evaluation.

●General considerations

•Assess the cardiac pathophysiology and understand the emergency nature of the proposed procedure, as well as any preoperative interventions (eg, attempted fibrinolysis [thrombolysis]).

•Establish intravenous access adequate for fluid resuscitation and transfusions if not already available, as well as intra-arterial access for continuous monitoring of arterial blood pressure. Other monitors (eg, central venous access and transesophageal echocardiography [TEE]) are typically inserted after induction of anesthesia.

•Check availability of blood products. It is prudent to have an adequate number of RBC units typed and crossmatched that will address any existing anemia and anticipated surgical blood loss (see 'Pretransfusion testing' above). If massive transfusion is a possibility, preoperative communication with the cardiac surgeon regarding estimates of potential blood loss and subsequent communication with the blood bank are essential.

In some emergency situations (eg, rapid bleeding due to aortic dissection), there might not be time to perform full compatibility testing. Decisions regarding transfusion in such settings depend on assessment of the risks and benefits of immediate transfusion versus full blood compatibility testing. Importantly, "emergency release" blood, typically group O, is always available for immediate lifesaving transfusion. (See "Pretransfusion testing for red blood cell transfusion", section on 'Emergency release blood for life-threatening anemia or bleeding'.)

•Briefly speak to the patient, family members, and/or care team members (eg, cardiologist, cardiac surgeon, intensivist, intensive care nurse) to determine:

-Allergies

-Fasting status

-Relevant past medical and surgical history

-Problems with prior anesthetics

-Recently administered medications (eg, chronically administered antiplatelet and/or anticoagulant agents) (see 'Medications affecting hemostasis' above)

-Most recent laboratory results

•Review the patient's chart, if time allows.

●Emergency reversal of medication affecting hemostasis — Management of the ongoing effects of chronically or acutely administered medications affecting hemostasis may be necessary in patients undergoing urgent or emergency cardiac surgery.

•Antiplatelet agents – If discontinuation of P2Y₁₂ antagonists in patients presenting for urgent cardiac surgery is not possible (eg, those with unstable angina or after unsuccessful percutaneous coronary intervention), bleeding risk is increased [135,136]. Intraoperative administration of platelets (eg, 1 apheresis unit or 6 units of pooled platelets) may be necessary to overcome the effects of recently administered antiplatelet agents in patients with unacceptable microvascular bleeding [136,137]. In these cases, preoperative communication with the blood bank is necessary to ensure platelet availability.

•Anticoagulant agents – If discontinuation of anticoagulant agents is not possible (eg, emergency replacement of a malfunctioning prosthetic valve in a patient chronically receiving anticoagulant agents), then urgent anticoagulant reversal may be necessary. For warfarin, a 4-factor prothrombin complex concentrate (PCC) product is the preferred treatment for emergency reversal of anticoagulation with a vitamin K antagonist, rather than reversal with fresh frozen plasma (table 8 and table 9) [63]. Also, concomitant vitamin K is administered together with the PCC since any PCC has a limited duration of action. The DOACs that inhibit thrombin or factor Xa have shorter half-lives than warfarin, but reversal strategies for DOACs for urgent and emergency procedures may be necessary (table 10 and table 11).

Details regarding management of these agents for urgent or emergency cardiac surgical procedures are available in separate topics:

-(See "Perioperative management of patients receiving anticoagulants", section on 'Urgent/emergency invasive procedure'.)

-(See "Management of warfarin-associated bleeding or supratherapeutic INR".)

-(See "Management of bleeding in patients receiving direct oral anticoagulants".)

•Fibrinolytic agents – In patients undergoing emergency CABG procedures after receiving fibrinolytic (thrombolytic) agents during failed attempts to manage acute ST elevation myocardial infarction (MI), it may be necessary to increase fibrinogen levels with transfusion of cryoprecipitate, plasma, or fibrinogen concentrates in addition to administering an antifibrinolytic agent (eg, aminocaproic acid or tranexamic acid). Discussions regarding management of emergency surgery in such patients are available elsewhere:

-(See "Blood management and anticoagulation for cardiopulmonary bypass", section on 'Antifibrinolytic administration' and "Coronary artery bypass surgery: Perioperative medical management", section on 'Antifibrinolytic agents'.)

-(See "Achieving hemostasis after cardiac surgery with cardiopulmonary bypass", section on 'Transfusion of other blood components' and "Achieving hemostasis after cardiac surgery with cardiopulmonary bypass", section on 'Clotting factors and hemostatic agents'.)

-(See "Diagnosis and management of failed fibrinolysis or threatened reocclusion in acute ST-elevation myocardial infarction", section on 'Patients requiring CABG'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Perioperative cardiovascular evaluation and management".)

SUMMARY AND RECOMMENDATIONS

●Goals of the preanesthesia evaluation (see 'Goals of the preanesthesia evaluation' above):

•Assess risks for the proposed operation and then develop an anesthetic plan to minimize risk (table 1). (See 'Assessment of patient and procedural risk factors' above.)

-Cardiovascular risk factors (see 'Cardiovascular risk factors' above):

Myocardial ischemia (see 'Myocardial ischemia' above)

Congestive heart failure (see 'Congestive heart failure' above)

Cerebrovascular or proximal aortic atherosclerosis (see 'Cerebrovascular or proximal aortic atherosclerosis' above)

-Potentially modifiable noncardiac risk factors (see 'Noncardiac risk factors' above and 'Laboratory tests' above):

Preexisting renal insufficiency

Anemia

Current tobacco use.

•Ensure optimal patient condition or discuss opportunities to improve condition with the cardiologist and cardiac surgeon.

•Explain the proposed anesthetic plan, obtain informed consent for anesthetic care, and alleviate anxiety. (See 'Alleviation of patient anxiety' above.)

●Physical examination (see 'Physical examination' above):

•Ease of venous access for both peripheral and central venous catheters

•Peripheral arterial pulses for invasive arterial pressure monitoring

•Presence of a functional arteriovenous fistula in patients with end-stage renal disease (ESRD) (see 'Patients on dialysis' above)

•Severe periodontal disease that may be a source of bacterial infection

•Cellulitis or untreated ulcers that may be sources of bacterial infection

•Difficult airway, in order to plan for appropriate equipment and techniques to accomplish endotracheal intubation

•Presence of esophageal lesions that may preclude intraoperative use of transesophageal echocardiography (TEE) (table 2)

●Preoperative testing – The electrocardiogram (ECG) and other available studies including echocardiograms (table 3), coronary angiogram (table 4), laboratory tests, chest radiograph (CXR), and pulmonary function tests (PFTs) are reviewed to identify abnormalities that will influence anesthetic management. (See 'Preoperative tests' above.)

●Preoperative management of medications (see 'Management of preoperative medications' above):

•Cardiovascular medications – Doses of chronically administered beta blockers and statins are administered on the morning of surgery. (See 'Cardiovascular medications' above.)

•Medications affecting hemostasis (see 'Medications affecting hemostasis' above):

-Aspirin is continued perioperatively in patients already being treated.

-P2Y₁₂ receptor blockers (eg, clopidogrel, prasugrel, ticagrelor) are discontinued five to seven days before elective cardiac surgery due to concern regarding increased bleeding and transfusion (table 5).

-Oral anticoagulant agents are stopped in sufficient time to allow anticoagulation to resolve (table 6 and table 7). Further details regarding management of these agents for elective cardiac surgical procedures and in patients with prosthetic heart valves are available in separate topics:

(See "Perioperative management of patients receiving anticoagulants".)

(See "Anticoagulation for prosthetic heart valves: Management of bleeding and invasive procedures", section on 'Planning for invasive procedures'.)

●Management of implantable cardioverter defibrillators (ICDs) – Cardiac surgery causes electromagnetic interference with devices such as ICDs or pacemakers. These devices are reprogrammed to an asynchronous mode in the immediate preoperative period or prior to surgical incision. (See 'Management of implantable cardioverter defibrillators and pacemakers' above.)

●Emergency cardiac surgery (see 'Emergency surgery' above):

•Rapidly assess cardiac pathophysiology and need for the emergency procedure.

•Determine presence of (or establish) intravenous and intra-arterial access.

•Briefly speak to the patient, family members, and/or care team members to determine:

-Allergies

-Fasting status

-Relevant past medical and surgical history

-Problems with prior anesthetics

-Recently administered medications, including chronically administered antiplatelet, anticoagulant, and fibrinolytic agents

-Most recent laboratory results

•Check availability of blood products.

•If necessary, plan for reversal of recently administered anticoagulant agents (table 8 and table 9 and table 10 and table 11), or intraoperative administration of platelets. If fibrinolytic agents were administered, it may be necessary to increase fibrinogen levels with transfusion of cryoprecipitate, plasma, or fibrinogen concentrates in addition to administering an antifibrinolytic agent (eg, aminocaproic acid or tranexamic acid).

•Review the patient's chart as time allows.