Preanesthetic assessment of adults with congenital heart disease undergoing noncardiac surgery

INTRODUCTION — Congenital heart disease is present in approximately 6 to 19 of 1000 live births [1-3]. In the United States, approximately 1,400,000 adults have congenital heart disease, with a growing number surviving into middle age and beyond [4-6]. Many of these patients require anesthetic care for either cardiac or noncardiac surgery.

This topic will discuss the preanesthetic assessment of adults with congenital heart disease undergoing noncardiac surgery. Anesthetic management of these patients during the intraoperative and early postoperative periods is discussed in a separate topic. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery".)

Anesthetic management during labor and delivery for women with congenital and other high-risk heart disease is discussed separately. (See "Anesthesia for labor and delivery in high-risk heart disease: General considerations" and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)

PREANESTHETIC ASSESSMENT

Key goals — The history, physical examination, medical records, and current test findings are reviewed during a preanesthetic clinical evaluation of a patient with adult congenital heart disease (ACHD) [1,4,7-10]. Key goals include:

●Confirming the ACHD diagnosis – The native cardiac lesion, prior palliative or reparative procedures, and any residua (eg, residual shunting) are reviewed. Notes from previous surgical procedures are carefully reviewed (see 'Prior cardiac interventions and surgical procedures' below), as well as the most recent cardiac catheterization and imaging studies are reviewed to understand current cardiac anatomy, abnormalities of great vessels or venous return, and the patient's anatomic classification [10]. (See 'Anatomic classification' below and 'Prior cardiac interventions and surgical procedures' below.)

●Understanding current physiologic status – Anatomic and hemodynamic sequelae of ACHD are reviewed. Important findings may include aortic enlargement, ventricular enlargement, ventricular dysfunction, valve dysfunction, pulmonary hypertension, shunts, venous or arterial stenosis, end-organ dysfunction, arrhythmias, hypoxemia or cyanosis, and current functional status (table 1) [10]. (See 'Physiologic classification' below.)

●Noting noncardiac abnormalities – Patients with ACHD commonly have noncardiac sequelae and other comorbidities requiring specialized perioperative care, as noted below. (See 'Noncardiac sequelae and comorbidities' below.)

●Assessing and managing risks of the planned surgical procedure – Perioperative risk associated with noncardiac surgery is related to the patient's specific type and status of ACHD, the type and urgency of the surgical procedure, and the specialized healthcare resources that are available [10]. (See 'Risk assessment and consultation' below.)

Other clinical challenges may include perioperative management of systemic and pulmonary vascular resistances, intracardiac shunting, significant myocardial dysfunction, and fastidious maintenance of optimal intravascular volume [10]. (See 'Perioperative considerations for specific lesions' below.)

In addition, many patients have undergone previous surgery or cardiac catheterization in childhood. Chronic (often asymptomatic) occlusions of femoral or neck vessels are common and need to be taken into account when planning vascular access (eg, central venous catheter).

●Coordinating ACHD care – The ACHD team undertakes measures to optimize the patient's condition prior to the procedure (as time allows) and aids in specialized care and monitoring during and following the procedure. Excellent interdisciplinary collaboration and communication between anesthesiologists and the ACHD team is necessary for optimal patient care [9-12].

Anatomic and physiologic classification — In the ACHD anatomic and physiologic (ACHD AP) classification described in the 2018 American Heart Association/American College of Cardiology (AHA/ACC) ACHD guidelines, patients' conditions are classified based on their most severe (highest grade) anatomic and physiologic features [10].

Anatomic classification

●I: Simple

•Native disease:

-Isolated small secundum atrial septal defect (ASD)

-Isolated small ventricular septal defect (VSD)

-Mild isolated pulmonary valve stenosis or regurgitation

•Repaired conditions:

-Ductus arteriosus after ligation or occlusion

-Repaired VSD, secundum ASD or sinus venosus defect without significant residual shunt or chamber enlargement

●II: Moderate complexity includes the following repaired or unrepaired conditions:

•Aortic conditions

-Aorto-left ventricular fistula

-Coarctation of the aorta

-Sinus of Valsalva fistula/aneurysm

•Anomalous pulmonary venous connection, partial or total

•Anomalous coronary artery arising from the pulmonary artery or from an anomalous aortic origin (opposite sinus)

•Patent ductus arteriosus with moderate or large persistent patency

•Peripheral pulmonary artery stenosis

•Septal defects

-Atrioventricular septal defect (partial or complete, including ostium primum ASD)

-Moderate or large unrepaired secundum ASD

-Sinus venosus defect

-Ventricular septal defect with associated abnormality or moderate or greater shunt

•Tetralogy of Fallot (TOF) after repair

•Conditions of, above, or below valves including:

-Congenital aortic valve or mitral valve disease

-Prosthetic valves

-Ebstein anomaly

-Infundibular right ventricular outflow obstruction

-Moderate or greater pulmonary valve regurgitation or pulmonary valve stenosis

-Straddling atrioventricular valve

-Supravalvular aortic stenosis

-Subvalvular aortic stenosis (excluding hypertrophic cardiomyopathy, which is addressed separately). (See "Anesthesia for patients with hypertrophic cardiomyopathy undergoing noncardiac surgery".)

●III: Great complexity

•Cyanotic congenital heart defect (including TOF) that is unrepaired or palliated

•Double-outlet right or left ventricle

•Fontan circulation (created by the Fontan procedure which is typically performed in patients with a functional or anatomic single ventricle)

•Interrupted aortic arch

•Single ventricle (including double inlet left ventricle, tricuspid atresia, hypoplastic left heart, and other conditions with a functionally single ventricle)

•Transposition of the great arteries (TGA; this includes classic or d-TGA as well as congenitally corrected TGA or l-TGA)

•Valve atresia (mitral atresia or pulmonary atresia)

•Other abnormalities of atrioventricular and ventriculoarterial connection (eg, crisscross heart, isomerism, heterotaxy syndromes, ventricular inversion)

Physiologic classification

●Stage A

•New York Heart Association (NYHA) class I symptoms (table 1)

•No hemodynamic or anatomic sequelae

•No arrhythmias

•Normal exercise capacity

•Normal renal/hepatic/pulmonary function

●Stage B

•NYHA class II symptoms (table 1)

•Mild hemodynamic sequelae (mild aortic enlargement, mild ventricular enlargement, mild ventricular dysfunction)

•Mild valvular disease

•Trivial or small shunt (not hemodynamically significant)

•Arrhythmia not requiring treatment

•Abnormal objective cardiac limitation to exercise

●Stage C

•NYHA class III symptoms (table 1)

•Significant (moderate or greater) valvular disease

•Moderate or greater ventricular dysfunction (systemic, pulmonic, or both)

•Moderate aortic enlargement

•Venous or arterial stenosis

•Mild or moderate hypoxemia/cyanosis

•Hemodynamically significant shunt

•Arrhythmias controlled with treatment

•Pulmonary hypertension (less than severe)

•End-organ dysfunction responsive to therapy

●Stage D

•NYHA class intravenous (IV) symptoms (table 1)

•Severe aortic enlargement

•Arrhythmias refractory to treatment

•Severe hypoxemia (almost always associated with cyanosis)

•Severe pulmonary hypertension

•Eisenmenger syndrome

•Refractory end-organ dysfunction

Risk assessment and consultation — Patients with moderate or greater complexity and/or stage B physiologic ACHD (ACHD AP classification 1B-D, IIA-D, or III A-D) (see 'Anatomic classification' above and 'Physiologic classification' above) undergoing noncardiac surgical or interventional procedures are ideally managed at (or in consultation with) a medical center with expertise in ACHD [10]. This is particularly important when a major surgical procedure is planned. However, patients with ACHD can experience complications even during minor procedures. As discussed in this topic and the topic on anesthesia for noncardiac surgery in patients with ACHD, management for patients with ACHD is often more complex than general management for noncardiac surgery and is lesion- and patient-specific. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery".)

For patients with ACHD who present with an indication for urgent or emergency surgery at a center without ACHD expertise, perioperative communication with a specialized center is important to guide decisions for a potential transfer, or aid in emergency management during the procedure. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery".)

Observational data have identified higher risk associated with noncardiac surgery in patients with ACHD compared to those without ACHD [10,13,14]. Patients with certain ACHD physiology are at particularly high risk for perioperative complications. Examples include those with Eisenmenger syndrome or Fontan physiology [10,15,16].

Perioperative risk in patients with ACHD was illustrated by a study of noncardiac surgery outcomes using the Nationwide Inpatient Sample database (2002-2009) comparing 10,004 patients with ACHD with 37,581 patients without ACHD matched for age, sex, race, year, elective or urgent or emergency procedure, comorbidity score, and primary procedure [14]. Inpatient mortality was higher in the ACHD cohort (4.1 versus 3.6 percent; odds ratio 1.13, 95% CI 1.01-1.27). Perioperative mortality was also more frequent in the ACHD cohort (21.4 versus 16.0 percent; odds ratio 1.44, 95% CI 1.36-1.52). The highest risk of inpatient mortality was seen in the group of patients with complex ACHD (defined to include truncus arteriosus and lesions treated by Fontan procedure).

Prior cardiac interventions and surgical procedures — As a consequence of previous interventions (eg, surgical procedures, cardiac catheterization, peripheral intravascular cannulation) or the underlying anatomy (eg, bilateral superior vena cava), many patients with ACHD have had prior blood vessel injury or ligation (eg, femoral artery or vein, internal jugular vein) that may limit vascular access. Other patients with ACHD have chronically occluded or otherwise distorted venous or arterial vessel anatomy.

Precise knowledge of these abnormalities is important for planning invasive hemodynamic monitoring (eg, site of insertion of central venous or peripheral arterial catheters), particularly if emergency vascular access may be necessary (eg, transvenous temporary pacemaker, insertion of cannulae for extracorporeal membrane oxygenation [ECMO]). Previous history should be specifically screened for indications of chronic vessel occlusions or distortion (often noted in cardiac catheterization reports). In cases that are uncertain, assessment by ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT) can be helpful.

Specific examples of sequelae of common surgical procedures in patients with ACHD that may affect monitoring or other aspects of anesthetic management include:

●Blalock-Thomas-Taussig shunt – A Blalock-Thomas-Taussig (BTT) or Blalock-Taussig (BT) shunt is a surgical connection between the subclavian artery and the ipsilateral pulmonary artery (figure 1). Patients with a prior BT shunt may have absent pulses after a classic BT shunt, or lower blood pressure (BP) after a modified BT shunt, in the upper extremity on the side of the shunt. A reasonable plan is to measure BP in both upper extremities in the preoperative period. If a discrepancy is noted, clinical measurements of BP in the extremity without the shunt are used, as these typically yield higher values that better represent systemic organ perfusion pressure. In the rare patient with bilateral classical BT shunts, BP is measured in a lower extremity.

●Coarctation repair – After coarctation stenting (image 1) or repair, there may be residual narrowing of the aorta, recoarctation, and/or aortic aneurysm (image 2). Residual narrowing or recoarctation may cause decreased lower extremity BP and/or upper extremity hypertension. Although upper extremity BP is usually used, lower extremity BP is also measured in the preoperative period, since this reflects perfusion pressure of the mesenteric, renal, hepatic, and spinal beds. If there is a marked discrepancy, it is reasonable to measure both upper and lower extremity pressures with either a noninvasive BP (NIBP) cuff or invasive intra-arterial catheters in the upper and lower extremities during a major surgical procedure. (See "Management of coarctation of the aorta".)

In patients who had subclavian flap repair of coarctation (Waldhausen technique), ligation of the left subclavian artery mandates BP monitoring from the right arm.

●Previous ECMO – Patients who previously required ECMO undergo routine ultrasound screening for patency of vascular access prior to any scheduled cardiac or major noncardiac surgical procedure, particularly if emergency peripheral cannulation may become necessary.

Noncardiac sequelae and comorbidities — The anesthesiologist should also be aware of common noncardiac sequelae and other comorbidities in adults with ACHD [7,9]. Common conditions in other organ systems include restrictive lung disease, renal dysfunction, hepatic dysfunction, neurologic sequelae, and hematologic abnormalities such as iron deficiency anemia, secondary erythrocytosis, and coagulation abnormalities with tendencies toward bleeding and/or thrombosis [7-9].

●Coagulation abnormalities

•Erythrocytosis – Chronic hypoxemia (ie, cyanosis) leads to secondary erythrocytosis as a compensatory mechanism to maintain arterial oxygen content. Depending on the severity of hypoxemia, hemoglobin levels may be as high as 25 g/dL, and hematocrit is often >60 percent. Thrombocytopenia may also be present [17]. Perioperative management includes the following considerations:

-Symptoms due to hyperviscosity are unlikely if hematocrit is <65 percent. However, if symptoms are present, treatment is intravascular fluid repletion [11]. Dehydration due to prolonged fasting time or perioperative hypovolemia due to fluid shifts worsens hyperviscosity [18]. Hence, fasting time is minimized, IV fluid therapy is initiated in the preoperative period, and adequacy of intravascular volume status is carefully maintained throughout the perioperative period. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Fluid management'.)

-Frequent phlebotomies are discouraged as these inevitably lead to iron deficiency, which may be detrimental, and result in hemoglobin levels that are inadequate to maintain tissue oxygenation. However, in patients with preoperative hematocrit >65 percent, the American College of Cardiology/American Heart Association (ACC/AHA) guidelines suggest isovolemic phlebotomy to improve coagulation status [10]. In such cases, hemodilution may be considered [19,20].

-Cyanotic patients are critically dependent on high hemoglobin levels to maintain tissue oxygenation. Thus, conventional transfusion thresholds do not apply to cyanotic patients and should be defined individually depending on cardiac conditions, severity of hypoxemia, and the extent of secondary erythrocytosis. For most cyanotic patients, hemoglobin thresholds for erythrocyte transfusion are 12 to 15 g/dL (rather than 7 to 8 g/dL). (See "Medical management of cyanotic congenital heart disease in adults", section on 'Erythrocytosis and relative anemia'.)

-In patients with hematocrit >55 to 60 percent, the international normalized ratio (INR) will be falsely elevated if measured with standard citrate tubes; thus, it is important to use corrected citrate tubes to measure INR in these patients.

•Acquired von Willebrand syndrome – Some ACHD patients develop acquired von Willebrand syndrome [21,22]. Decisions regarding whether to use desmopressin (ie, DDAVP) or von Willebrand factor (vWF) concentrates for prophylaxis against bleeding are based on the patient's history of hemostatic challenges and severity of bleeding during and after surgery. (See "Acquired von Willebrand syndrome", section on 'Management'.)

●Airway abnormalities

•Upper airway abnormalities – Upper airway abnormalities (eg, vocal cord paralysis and subglottic stenosis) may be present in patients who had previous surgical procedure(s) complicated by prolonged postoperative tracheal intubation.

Damage to the recurrent laryngeal nerve causing chronic hoarseness or inspiratory stridor may be present after cardiac surgery, particularly after repair of aortic coarctation or the aortic arch. This cause of stridor does not cause airway obstruction but should be differentiated from stridor due to tracheomalacia (see below).

Some genetic abnormalities (trisomy 21, DiGeorge syndrome, Cornelia de Lange syndrome) are associated with both ACHD and abnormalities of the upper airway (eg, large tongue, retrognathia, difficult intubation) [10].

•Tracheal abnormalities – Tracheomalacia with partial tracheal collapse during expiration may result in chronic episodes of stridor, which may worsen after extubation. Patients at risk include those with a large left atrium or pulmonary artery compressing the trachea (eg, absent pulmonary valve syndrome variant of tetralogy of Fallot), and those with prior repair of a congenital vascular ring that encircled the trachea. Rarely, airway obstruction due to tracheomalacia necessitates reintubation after general endotracheal anesthesia. (See "Tracheomalacia in adults: Clinical features and diagnostic evaluation".)

●Respiratory insufficiency – Chest wall abnormalities such as scoliosis and/or restrictive lung development due to prior thoracotomy procedures may result in respiratory insufficiency [23,24]. (See "Anesthesia for patients with interstitial lung disease or other restrictive disorders".)

Also, many patients with complex congenital heart disease (CHD) have generalized muscle weakness including respiratory muscle weakness [25]. In addition, the phrenic nerve may have been injured during prior procedures such as aortic arch repair, causing chronic respiratory insufficiency due to limited chest expansion. Such neuromuscular and chest wall disease may necessitate invasive or noninvasive perioperative ventilatory support. (See "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Patient selection and alternative modes of ventilatory support".)

●Endocrine abnormalities – The incidence of diabetes in adults with ACHD is similar to the general adult population. Nevertheless, these patients have a high incidence of abnormalities in glucose and lipid metabolism [26].

●Neurologic and psychiatric abnormalities

•Cognitive impairment – Delayed neurologic development may be present [9].

•Anxiety – Severe anxiety during interactions with medical personnel is common among patients with ACHD. Thoughtful and unrushed communication during the preanesthesia consultation, as well as administration of appropriate premedication, are helpful strategies. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Premedication'.)

•Tolerance to opioids – ACHD patients with significant previous exposure to opioids or current methadone use may have developed tolerance to opioids. (See "Management of acute pain in the patient chronically using opioids for non-cancer pain".)

PREANESTHETIC MANAGEMENT

Scheduling considerations — Patients with ACHD are scheduled as the first case of the day to minimize fasting time. This timing also ensures the presence of adequate personnel and availability of consultants to assist if complications occur during or immediately after surgery. Furthermore, extra time in the post-anesthesia care unit (PACU) may be needed to determine whether admission to an intensive care unit (ICU) is prudent.

Chronically administered medications — Most chronically administered medications are continued throughout the perioperative period. Examples include:

●Cardiovascular medications – Cardiovascular medications, including beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers (ARBs), are continued throughout the perioperative period. However, patients receiving chronic ACE inhibitor or ARB therapy are more likely to develop and require treatment for hypotension, particularly during induction of anesthesia. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of induction agents'.)

Further discussion is available in separate topics. (See "Perioperative medication management", section on 'Cardiovascular medications'.)

●Medications to minimize pulmonary vascular resistance (PVR) – All medications that minimize pulmonary vascular resistance (PVR) should be continued up to and during the surgical procedure (especially any continuous intravenous [IV] infusions). Examples are pulmonary vasodilators (eg, epoprostenol, iloprost, sildenafil, tadalafil), endothelin receptor antagonists (eg, bosentan, ambrisentan, macitentan), and calcium channel blockers (eg, amlodipine, diltiazem). (See "Pulmonary hypertension in adults with congenital heart disease: Disease-specific management", section on 'PAH-specific therapy' and "Anesthesia for noncardiac surgery in patients with pulmonary hypertension or right heart failure", section on 'Management of chronic medications'.)

●Antithrombotic therapy – ACHD patients may be receiving anticoagulant and/or antiplatelet agents, with perioperative management coordinated with the surgical team, cardiologist, anticoagulation clinic, and/or consultant hematologist [10,27]. (See "Perioperative management of patients receiving anticoagulants".)

●Antirejection medications – After cardiac transplantation, immunosuppressive therapy must be continued throughout the perioperative period. (See "Heart transplantation in adults: Induction and maintenance of immunosuppressive therapy".)

PERIOPERATIVE CONSIDERATIONS FOR SPECIFIC LESIONS — Hemodynamic goals for specific ACHD lesions affect selection of anesthetic agents and vasoactive drugs, fluid management, decisions to use neuraxial techniques, and management of ventilatory support (table 2). These recommendations refer to general principles according to the underlying pathophysiology of individual heart defects, although modifications may be necessary in individual patients. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Preinduction considerations'.)

Intracardiac and extracardiac shunts — Intra- and extracardiac shunts alter the proportion of blood flow going to the systemic versus pulmonary circulations [28]. Physiologic changes occurring in the perioperative period due to anesthetic agents or techniques, surgical stimulation, or blood loss may adversely affect the balance of pulmonary blood flow (Qp) versus systemic blood flow (Qs).

Right-to-left shunt with cyanosis — For patients with a right-to-left shunt, hemodynamic goals are to maintain or increase systemic vascular resistance (SVR) while avoiding increases in pulmonary vascular resistance (PVR) (table 2). An example is unrepaired tetralogy of Fallot (infundibular or pulmonic valve stenosis with a ventricular septal defect) (figure 2). In these patients, deoxygenated blood is shunted to the left, where it mixes with oxygenated blood before circulating through the systemic circulation. Decreased pulmonary blood flow (Qp:Qs <1) results in cyanosis. Chronic cyanosis (ie, chronic hypoxemia) results in secondary erythrocytosis, increased sympathetic tone, and decreased cardiovascular reserve.

Avoid worsening of right-to-left shunting and cyanosis during the perioperative period by:

●Avoiding decreases in SVR. For example, avoid administering a large bolus dose of propofol or high concentrations of an inhalational anesthetic. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of induction agents' and "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of maintenance agents'.)

●Avoiding increases in PVR by avoiding hypoxemia, hypercarbia, metabolic acidosis, and sympathetic stimulation. If a vasoconstrictor is necessary to treat systemic vasodilation, vasopressin is preferred compared with phenylephrine because vasopressin increases SVR without increasing PVR (table 3) [29].

For major surgical procedures, invasive hemodynamic monitoring (eg, intra-arterial and/or central venous catheter [CVC] access) is planned to aid in maintaining optimal balance between PVR and SVR. Since hypotension may occur during induction of general anesthesia, the intra-arterial catheter is typically inserted before induction so that intra-arterial blood pressure can be continuously monitored throughout induction.

Notably, patients with right-to-left shunting are at high risk of paradoxical systemic embolism by accidental air entry into intravenous (IV) lines or by paradoxical thromboembolism. Precautions to avoid air embolism are particularly important, as discussed separately. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Precautions to avoid air embolism'.)

Left-to-right shunt with pulmonary overcirculation — For patients with a left-to-right shunt, hemodynamic goals are to maintain or decrease SVR while avoiding significant decreases in PVR (table 2). Examples of these lesions are atrial septal defect (ASD), ventricular septal defect (VSD), and patent ductus arteriosus (PDA).

In these patients, increased pulmonary blood flow (Qp:Qs >1) results in right atrial and right ventricular (RV) volume overload. If chronic, this may lead to increased PVR, pulmonary hypertension, and eventual right heart failure. Left-to-right shunts also produce a significant volume burden on the lungs, particularly if Qp:Qs >3:1.

Compared with cyanotic patients with right-to-left shunting, anesthesia in patients with predominant left-to-right shunting is typically better tolerated, particularly if PVR is not chronically elevated and ventricular function is not markedly impaired. However, we avoid worsening of left-to-right shunting and consequent pulmonary overcirculation during the perioperative period by:

●Avoiding increases in SVR (eg, avoid administration of vasopressor agents). Increases in SVR may be treated by administering additional sedative or anesthetic agents. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of induction agents' and "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of maintenance agents'.)

●Avoiding decreases in PVR due to hyperoxia by administering a high fraction of inspired oxygen (FiO₂). Also, avoid hypocarbia caused by hyperventilation, and avoid metabolic alkalosis. Decreases in PVR may be treated by reducing FiO₂ and minute ventilation.

Fontan physiology (cavopulmonary palliation) — For patients with Fontan physiology, hemodynamic goals are to maintain preload, decrease PVR, and maintain myocardial contractility in order to maintain forward cardiac output (CO) (table 2) [30,31].

Fontan palliation (figure 3) is the most common palliative operation performed for patients with any type of univentricular physiology (ie, a single ventricle), including hypoplastic left heart syndrome, tricuspid atresia, or double-inlet left ventricle. (See "Management of complications in patients with Fontan circulation" and "Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis".)

The resulting Fontan physiology has two components [30,32,33]:

●Presence of a single ventricle that pumps blood to the systemic circulation

●Passive pulmonary blood flow (ie, nonpulsatile circulation to the pulmonary arterial system)

Nonpulsatile pulmonary blood flow results in chronic loss of distal pulmonary vasculature, increased PVR, and chronically elevated central venous pressure (CVP). Adequacy of pulmonary blood flow and CO depends on preload and the transpulmonary gradient (TPG), which is the pressure difference between the CVP and the common atrial pressure. Typically, the CVP is maintained at 10 to 15 mmHg to achieve an ideal TPG of 5 to 10 mmHg [30,32,34]. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Fluid management'.)

Patients with failing Fontan physiology have declining ability to maintain adequate CO despite chronically elevated CVP. This may be due to systolic or diastolic dysfunction of the single ventricle (see 'Presence of ventricular dysfunction' below), atrioventricular valve regurgitation, pulmonary hypertension, and/or arrhythmias [30,35]. Chronically low CO and chronically elevated CVP result in liver and lymphatic sequelae (elevated transaminases, cirrhosis, protein losing enteropathy) in patients with Fontan physiology. Eventually, elevated ventricular end-diastolic pressure results in elevated common atrial pressure, necessitating an even higher CVP to drive blood through the pulmonary system to maintain CO.

Adult patients with Fontan physiology are more likely to have complications after noncardiac surgery than those patients with ACHD with biventricular physiology (see "Management of complications in patients with Fontan circulation"). Baseline oxygen saturation <90 percent is a risk factor for perioperative complications [16]. Whenever feasible, noncardiac surgery in Fontan patients (even for trivial procedures) should be performed at centers with interdisciplinary experience in the treatment of this high-risk subgroup of patients with ACHD.

During the perioperative period, patients with Fontan physiology are particularly sensitive to any decrease in systemic venous return (and resulting decreases in CO) that may occur with positive pressure ventilation or due to insufflation of carbon dioxide for laparoscopic procedures. Spontaneous ventilation or ventilation protocols that avoid high positive end-expiratory pressure (PEEP) and early extubation after completion of the procedure are important measures to decrease perioperative morbidity. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Management of ventilation' and "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Considerations for laparoscopic surgery'.)

Pulmonary arterial hypertension — Pulmonary arterial hypertension (PAH) is distinguished from other causes of pulmonary hypertension (PH) (table 4) by hemodynamic cardiac catheterization, since PAH-specific therapy is used for selected patients with PAH, but is not routinely used to treat patients with group 2 PH (PH due to left heart disease) and is used only on a limited case-by-case basis in patients with groups 3, 4, or 5 PH. (See "Anesthesia for noncardiac surgery in patients with pulmonary hypertension or right heart failure".)

Pulmonary vasodilator therapy for patients with Fontan circulation is discussed separately. (See "Management of complications in patients with Fontan circulation", section on 'Pulmonary vasodilator therapy'.)

For patients with PAH, the chief hemodynamic goal is to decrease PVR (table 2). Chronically administered medications for PAH should be continued without interruption throughout the perioperative period, particularly chronic parenteral therapies, since any interruption in therapy may precipitate critical decompensation. (See 'Chronically administered medications' above and "Anesthesia for noncardiac surgery in patients with pulmonary hypertension or right heart failure", section on 'Management of chronic medications'.)

The presence of PAH confers increased risk for intraoperative complications (eg, arrhythmias, hypotension, pulmonary hypertensive crises), as well as perioperative morbidity and death [10,36-45]. Particularly challenging patients include those with Eisenmenger syndrome, in which irreversible severe PAH due to a significant left-to-right shunt with reversal of shunt direction to right-to-left results in chronic cyanosis. Also, PAH associated with severe right ventricular dysfunction and severe tricuspid regurgitation confers a high perioperative risk.

Maintaining the lowest possible PVR during the perioperative period is accomplished by:

●Administering high FiO₂ and using hyperventilation to produce mild hypocarbia (ie, partial pressure of carbon dioxide [PaCO₂] 30 to 35 mmHg) to further decrease PVR. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Management of ventilation'.)

●Avoiding sympathetic stimulation by ensuring a smooth anesthetic induction and emergence without coughing or straining, and by maintaining excellent analgesia throughout the perioperative period.

●Treating perioperative increases in PVR that do not appear to be due to hypoxemia, hypercarbia, or thromboembolism with inhaled nitric oxide (eg, 20 parts per million [ppm]) or inhaled iloprost or treprostinil, if available. (See "Anesthesia for noncardiac surgery in patients with pulmonary hypertension or right heart failure", section on 'Chronic targeted therapy for pulmonary hypertension: Patient selection' and "Inhaled nitric oxide in adults: Biology and indications for use".)

Maintaining adequate preload is also necessary to maintain CO in patients with RV hypertrophy due to severe PAH. This is accomplished by:

●Avoiding hypovolemia, whether absolute (eg, due to blood loss) or relative (eg, due to vasodilation). CVP measurements, if available, are maintained at the patient's baseline, which varies depending on the specific cardiac lesion.

●If hypovolemia with RV underfilling develops, treatment is gradual (eg, with administration of 5-mL/kg increments of isotonic crystalloid to increase intravascular volume).

●Hypervolemia is also avoided since intravascular volume overload may cause RV distention accompanied by worsening tricuspid regurgitation.

Further discussion regarding anesthetic and perioperative management of patients with PAH is available in separate topics. (See "Anesthesia for noncardiac surgery in patients with pulmonary hypertension or right heart failure" and "Pulmonary hypertension in adults with congenital heart disease: General management and prognosis", section on 'Management of procedures'.)

Obstructive lesions — For patients with an obstructive cardiac lesion (eg, aortic stenosis, mitral stenosis, aortic coarctation, pulmonary valve, or conduit stenosis), hemodynamic goals are to maintain sinus rhythm with a normal heart rate (HR), as well as adequate preload and SVR (table 2).

Obstructive lesions result in hypertrophy of the associated ventricle as a compensatory response, with decreased ventricular compliance, diastolic dysfunction, and decreased stroke volume. Perioperative risk depends on the type and severity of the obstruction and on ventricular function.

Perioperative considerations include:

●Maintaining adequate preload to maintain adequate ventricular filling. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Fluid management'.)

●Maintaining the atrial contribution to ventricular filling ("atrial kick"). Sinus rhythm and a normal HR are optimal; supraventricular tachyarrhythmia (SVT) can result in marked hypotension necessitating immediate cardioversion. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Treatment of arrhythmias'.)

●Maintaining SVR, with administration of vasoactive agents if necessary (table 3) (see "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Balancing circulation'). Hypotension is avoided, particularly in patients with severe left heart obstruction, because the resulting reduction in coronary perfusion can lead to subendocardial ischemia of the hypertrophied ventricle and ventricular arrhythmias. Neuraxial analgesia or anesthesia is avoided or employed with extreme caution. (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Neuraxial anesthesia and analgesia'.)

Regurgitant lesions — For a patient with a regurgitant valve lesions (mitral, aortic, tricuspid, or pulmonic valve, or conduit regurgitation), hemodynamic goals are to maintain a normal to fast HR (eg, 80 to 100 beats/minute [bpm]), and to maintain or decrease SVR, particularly for left heart regurgitant lesions (table 2).

Regurgitant lesions result in ventricular volume overload and eventual ventricular dysfunction. Perioperative considerations include:

●Avoid increases in SVR or bradycardia, which detrimentally increase regurgitation of a systemic atrioventricular valve, thereby decreasing forward CO.

●Avoid sudden increases in PVR, which may exacerbate tricuspid regurgitation and decrease forward CO.

Presence of ventricular dysfunction — For patients with ventricular dysfunction, hemodynamic goals are to avoid bradycardia and myocardial depression. Since CO is dependent upon both HR and stroke volume, either bradycardia or decreases in myocardial contractility are detrimental. High doses of propofol or administration of high concentrations of a volatile anesthetic agent are avoided (table 2). (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of induction agents' and "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Choice of maintenance agents'.)

These patients are at risk for perioperative exacerbation of heart failure with pulmonary edema, arrhythmias, and low CO syndrome. During major surgery, invasive cardiovascular monitoring may be helpful (eg, intra-arterial catheter, CVC, transesophageal echocardiography [TEE]). (See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Monitoring'.)

If decreased CO results in hypoperfusion, milrinone is often selected because of its inotropic, lusitropic (ie, myocardium-relaxant), and vasodilatory properties in both the systemic and pulmonary circulations (table 3). If hypotension or bradycardia are present, treatment typically includes selection of epinephrine or dopamine as an alternative or additional agent. (See "Inotropic agents in heart failure with reduced ejection fraction".)

Prior cardiac transplantation — For patients with a transplanted heart, hemodynamic goals are to maintain HR, myocardial contractility, and SVR (table 2). Transplanted hearts have no sympathetic or parasympathetic innervation; thus, tachycardia and increased contractility do not occur as a reflex response to hypotension and/or hypovolemia [46,47]. For this reason, anesthetic depth is gauged by BP rather than HR. (See "Heart transplantation in adults: Arrhythmias", section on 'Sinus rate'.)

Direct-acting agents such as phenylephrine, vasopressin, epinephrine, or norepinephrine should be used to treat hypotension due to decreased SVR or poor contractility, and for treatment of bradycardia (table 3). Indirect-acting sympathomimetic drugs (eg, ephedrine) and vagolytic drugs (eg, atropine, glycopyrrolate) will not be effective.

High doses of anesthetic agents that may cause myocardial depression are avoided. Further discussion regarding anesthetic and perioperative management of patients after heart transplantation is available in a separate topic. (See "Anesthetic considerations after heart transplantation".)

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: Congenital heart disease in adults".)

SUMMARY AND RECOMMENDATIONS

●Key goals – Preanesthetic assessment of patients with adult congenital heart disease (ACHD) includes (see 'Key goals' above):

•Confirming the ACHD anatomic diagnosis – The congenital lesion, prior palliative or reparative procedures, and any residua are assessed to determine the patient's anatomic classification. (See 'Anatomic classification' above.)

•Understanding the physiologic status – Physiologic status is assessed based on anatomic and hemodynamic sequelae (eg, aortic enlargement, ventricular enlargement, ventricular dysfunction, valve dysfunction) and current New York Heart Association (NYHA) functional status (table 1). (See 'Physiologic classification' above.)

•Assessing the risks of the planned surgical procedure – Patients with moderate or greater complexity and/or stage B physiologic ACHD (ACHD AP classification 1B-D, IIA-D, or III A-D) (see 'Anatomic classification' above and 'Physiologic classification' above) are ideally managed at (or in consultation with) a medical center with expertise in ACHD for noncardiac surgical or interventional procedures. This is particularly important if a major surgical procedure is planned. However, patients with ACHD can experience complications even during minor procedures. Management for patients with ACHD is often more complex than general management for noncardiac surgery and is lesion- and patient-specific. (See 'Risk assessment and consultation' above and "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery".)

•Coordinating ACHD care – Excellent interdisciplinary collaboration and communication between anesthesiologists and ACHD team is necessary for optimal patient care.

●Prior cardiac surgical interventions – Prior palliative or reparative procedures such as Blalock Taussig shunt (figure 1), prior coarctation repair or stenting (image 1), with residual aortic narrowing or aneurysm (image 2), or prior use of extracorporeal membrane oxygenation (ECMO) may limit or determine vascular access sites. (See 'Prior cardiac interventions and surgical procedures' above.)

●Noncardiac conditions – The presence of noncardiac sequelae such as airway pathology, respiratory insufficiency, or coagulation, neurologic, psychiatric, or endocrine abnormalities may influence anesthetic care. (See 'Noncardiac sequelae and comorbidities' above.)

●Preanesthetic management

•Scheduling considerations – Scheduling as the first case of the day minimizes fasting time and ensures the presence of adequate personnel and consultant expertise to assist if complications occur during or immediately after surgery. (See 'Scheduling considerations' above.)

•Medication management – Most chronically administered medications are continued throughout the perioperative period. Examples include cardiovascular medications and therapies for pulmonary arterial hypertension (PAH). Management of antithrombotic therapy is coordinated with the surgical team, cardiologist, anticoagulation clinic, and/or consultant hematologist. (See 'Chronically administered medications' above.)

●Perioperative goals for specific lesions – Hemodynamic goals for specific congenital heart disease (CHD) lesions affect selection of anesthetic agents and vasoactive drugs, fluid management, decisions to use neuraxial techniques, and management of ventilatory support (table 2):

•(See 'Right-to-left shunt with cyanosis' above.)

•(See 'Left-to-right shunt with pulmonary overcirculation' above.)

•(See 'Fontan physiology (cavopulmonary palliation)' above.)

•(See 'Pulmonary arterial hypertension' above.)

•(See 'Obstructive lesions' above.)

•(See 'Regurgitant lesions' above.)

•(See 'Presence of ventricular dysfunction' above.)

•(See 'Prior cardiac transplantation' above.)