562915 research-article2014
SCVXXX10.1177/1089253214562915Seminars in Cardiothoracic and Vascular AnesthesiaMaxwell and Steppan
Article
Postoperative Care of the Adult With Congenital Heart Disease
Seminars in Cardiothoracic and Vascular Anesthesia 2015, Vol. 19(2) 154–162 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1089253214562915 scv.sagepub.com
Bryan Maxwell, MD, MPH1 and Jochen Steppan, MD1
Abstract An increasing number of children with congenital heart disease survive to adulthood, but many adults require surgical intervention and can present complex management challenges in the perioperative period. This review will address common considerations that surgeons, anesthesiologists, and intensivists are likely to face in caring for this growing population. Keywords adult congenital heart disease, congenital heart disease, critical care, postoperative, complications
Background As a result of improved surgical techniques and pediatric care, the proportion of children with congenital heart disease (CHD) who survive to adulthood has increased dramatically over the past 4 decades.1 Adults now outnumber children with CHD,2 accounting for approximately 66% of the overall CHD population and 60% of those with severe CHD (increased from 35% in 1985 and 49% in 2000).3 Adult congenital heart disease (ACHD) represents one of the fastest growing areas in adult cardiovascular medicine, and it is now possible even to speak meaningfully of geriatric CHD care.4 Many CHD lesions are treated with long-term palliative strategies that are not truly curative, and these patients often require reintervention(s) in adult life. Even structurally curative interventions often have significant late cardiovascular sequelae (eg, arrhythmias) that require intervention.5 As a result, perioperative physicians are likely to see a growing number of ACHD patients presenting for care in operating rooms and intensive care units in the immediate future. Experience with different models of care suggests that surgical outcomes for ACHD patients are better in the hands of pediatric heart surgeons,6 but that other aspects of perioperative care may be best suited to the resources and environment offered by an adult hospital.7 This latter point remains debated and is unlikely to be addressed by randomized trials. National guidelines have established that ACHD patients with anything more than a simple congenital lesion (eg, repaired atrial septal defect) should have perioperative care provided in regional ACHD centers by cardiologists, surgeons, and anesthesiologists with experience in ACHD.8 Prior survey data suggest that knowledge of
and comfort with ACHD is low among anesthesiologists even at specialized centers;9 expertise in this area must be sought, and training pathways for ACHD are still emerging.10 Outcome data from the Society of Thoracic Surgeons Congenital Heart Surgery Database11 demonstrate a high prevalence (28%) of postoperative complications in ACHD patients undergoing cardiac operations (Figure 1). The larger Society of Thoracic Surgeons Adult Heart Surgery Database (which reflects procedures done at a broader range of hospitals, not limited to centers specializing in congenital heart surgery), identifies a high rate of postoperative mortality in ACHD patients (2.1% in atrial septal defect repair, 2.8% in pulmonary valve replacement, and 3.7% in other congenital defect repairs; see Table 1).11 This review will cover major areas of postoperative care that involve specific considerations in ACHD.
General Considerations for Care of the ACHD Patient The anatomic and physiologic consequences of ACHD closely depend on the initial CHD lesion, the changes brought about by surgical palliation or repair, and the ways in which the palliated or repaired circulation has changed over time. Often, serial comparison of past echocardiogram 1
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA Corresponding Author: Bryan Maxwell, Johns Hopkins Medical Institutions, 1800 Orleans Street, Zayed 6208P, Baltimore, MD 21287, USA. Email: [email protected]
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10% 9.4%
8%
6%
4% 3.1% 2.4%
2.1% 2%
1.7% 1.3%
2.1%
1.9%
1.4%
1.1%
1.0%
1.0%
0% In-hospital mortality
Arrhythmia
Low cardiac output
Permanent Cardiac arrest pacemaker
Pleural effusion
Pneumonia Reintuba on
Mechanical Unplanned ven la on > 7 reopera on days
Bleeding requiring reopera on
Renal failure requiring temporary dialysis
Figure 1. Morbidity and mortality of cardiac operations in the Society of Thoracic Surgeons Congenital Heart Surgery Database. Adapted and used with permission from Mascio CE, Pasquali SK, Jacobs JP, Jacobs ML, Austin EH. Outcomes in adult congenital heart surgery: analysis of the Society of Thoracic Surgeons Database. J Thorac Cardiovasc Surg. 2011;142:1090-1097.
Table 1. Mortality of Cardiac Operations in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Atrial Septal Defect Repair (n = 26 117) Isolated procedure, n (%) •• Age, years (range) •• In-house mortality Concomitant procedure •• Age, years (range) •• In-house mortality
Congenital Defect Repair (n = 10 133)
Pulmonary Valve Replacement (n = 3622)
9602 (37%) 48 (36-59) 2.1%
2835 (28%) 44 (32-58) 3.7%
1738 (48%) 38 (28-49) 2.8%
66 (56-75) 5.0%
65 (54-74) 4.5%
47 (37-56) 3.5%
Adapted and used with permission from Mascio CE, Pasquali SK, Jacobs JP, Jacobs ML, Austin EH. Outcomes in adult congenital heart surgery: analysis of the Society of Thoracic Surgeons Database. J Thorac Cardiovasc Surg. 2011;142:1090-1097.
reports, cardiac catheterization reports, and detailed operative notes is needed to understand the history and current status of a patient’s circulation, as summary descriptors (eg, simply knowing that the patient has undergone a “Fontan procedure” or “pulmonary arterioplasy”) can reflect procedures of varying types and extensiveness. These records can also contain important information about vascular access issues, such as a history of vessel occlusions (from surgical ligation or thrombus), classical or modified Blalock-Taussig shunts, surgical cutdowns, and associated great vessels aberrancies (eg, interrupted IVC, persistent
left superior vena cava, right aortic arch, aberrant subclavian artery) that will be important to the intensivist and perioperative physician. Table 2 summarizes the vascular access implications of common CHD pathology, repairs, or associated variants. It is not unusual for patients to receive care as adults in a different hospital from that where they received care as a child, so obtaining detailed records may be challenging. When written records cannot be obtained, many ACHD patients have become quite informed participants in their own care and know details of their history that other adult patients might not know (eg, that catheterization
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Table 2. Vascular Access Implications of Common CHD Pathology, Repairs, and Associated Variants. Vascular Anomaly Prior classical or modified Blalock–Taussig shunt Prior radial or ulnar artery cutdown Prior ECMO cannulation Persistent left superior vena cava Interrupted IVC Pulmonary valve prosthesis or conduit
Implication Subclavian artery may be stenosed or occluded after BT shunt takedown, and pressures monitored on that side may be inaccurate. Consider an alternative site, or correlate noninvasive pressures from multiple sites before selecting the ipsilateral arm. Difficulty threading Seldinger wire may be encountered during arterial cannulation. Consider placing arterial line proximal to cutdown site or alternative artery. Neonates and infants typically receive ECMO support using internal jugular/ carotid cannulation. These vessels may be partially or completely occluded after decannulation. One configuration involves LSVC without bridging (innominate) vein, that is, bilateral SVCs. In this case, internal jugular cannulation will lead to direct coronary sinus access, which may be undesirable if rapid infusion or PA catheter placement is planned. The IVC may connect to the SVC through an azygous continuation. Access to the heart from the femoral vessels (eg, PA catheter, venous ECMO cannula) may be difficult or impossible. May be difficult to float PA catheter; fluoroscopy guidance may be helpful.
Abbreviations: CHD, congenital heart disease; ECMO, extracorporeal membrane oxygenation; LSVC, left superior vena cava; SVC, superior vena cava; IVC, inferior vena cava; PA, pulmonary artery.
of a particular venous structure was previously deemed impossible, what strategies were used for airway management in the past, etc). Others may have little knowledge of care that occurred when they were young children, and communicating with pediatric providers may be the only way of determining the details of prior interventions. Understanding the anatomy is a necessary part of understanding the associated, current physiology, but is not sufficient; for instance, a patient with a Fontan circulation may be quite well-compensated, with low systemic venous pressures, no arrhythmias, normal pulmonary vascular resistance, normal systemic ventricular function, and normal cardiac output. Alternatively, a patient with the same underlying structural Fontan anatomy may be experiencing end-stage failure of that circulation, involving systemic venous hypertension, elevated pulmonary vascular resistance, impaired ventricular function, atrioventricular valve regurgitation, refractory atrial flutter, plastic bronchitis, and protein-losing enteropathy. Impaired right ventricular function and pulmonary hypertension are not uncommon in the CHD population— one should not assume these parameters to be normal and should examine records for evidence of preexisting abnormalities in the right heart. In addition to the self-evident dangers of underappreciating the significance of CHD physiology, parallel risks exist in overattributing clinical problems to CHD without adequate physiologic understanding. For instance, clinicians may wrongly attribute hypoxemia to residual CHD in a patient who does not have a right-to-left shunt (in whom the cause of hypoxemia is actually, eg, simple
ventilation/perfusion mismatch), and therefore miss an opportunity to intervene appropriately.12
Paradoxical Air Embolism: “No Bubble Left Behind” Many ACHD patients have a residual intracardiac shunt (eg, patent foramen ovale, Fontan fenestration, patch leak in repaired atrial or ventricular septal defect, baffle leak after an atrial switch procedure, etc). By adulthood, most defects that remain unrepaired probably are small and unlikely to result in a hemodynamically significant shunt, but they have the potential to act as a conduit for paradoxical embolism. One can prevent iatrogenic harm in the form of air embolism by paying particular attention to avoiding air in intravenous (IV) lines. The need for meticulous debubbling of IVs and vigilance to detect and prevent air emboli is wellentrenched in the culture of pediatric anesthesia and critical care, but it is less well-established in adult perioperative settings. Those caring for ACHD patients must recognize that even very small air bubbles can cause devastating effects if introduced into the systemic circulation. IV filters are commercially available but not routinely used in adult ICUs, and they are never a substitute for vigilance. We recommend backflushing the IV line at a stopcock (open to the fluid reservoir/close to the patient, aspirate to clear the stopcock junction of air, then open to the patient, aspirate, and inject) every time any medication is given, while watching for the appearance of any air bubbles along the entire length of the IV tubing. Central venous lines should be aspirated prior to any injection.
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Management of Postoperative Arrhythmias in ACHD The arrhythmia burden in the ACHD population is considerable: the majority of complex CHD patients will develop significant arrhythmias during their lifetime,13 and arrhythmias complicate the postoperative course in one third of ACHD patients undergoing cardiac surgery.14 In particular, patients with a single ventricle or a systemic right ventricle may tolerate the loss of sinus rhythm poorly. Pharmacologic control of perioperative arrhythmias may be challenging, particularly in the setting of the concomitant use of inotropes that are arrhythmogenic. Device therapies have a role in the short-term and longterm management of many ACHD patients, but specific populations may present unique challenges. For instance, trans-venous lead placement is not possible in patients with an extracardiac Fontan, as the systemic veins do not provide direct access to the cardiac chambers. In these patients and those with other complex CHD anatomy, the leads must be placed in an epicardial (or occasionally subcutaneous) position and the generator is often located in the abdomen or flank. Lead placement can also be challenging in patients with an atrial baffle (eg, atrial switch patients) or patients with congenital or acquired abnormalities of the great veins. Cardiac resynchronization therapy may require customized settings in patients with a systemic right ventricle.
Postoperative Echocardiography in ACHD While there are few outcome studies to specifically establish a role for echocardiography in the postoperative management of ACHD patients, recent years have seen a dramatic adoption of echocardiography for postoperative and ICU care in the broader adult15 and pediatric16 surgical populations. We expect that the postoperative care of ACHD patients will involve a similar trend of acceptance of echocardiography as a management tool. Echocardiographers with ACHD experience will be needed to provide expert assessment of abnormal anatomy, particularly in patients with a systemic right ventricle, complex baffle geometry, or single-ventricle circulations. In these populations, assessment of even comparatively simple parameters (eg, global ventricular function, volume status) may not be straightforward. Collaboration with pediatric cardiologists may offer productive avenues for sharing expertise.
Postoperative Considerations in Specific ACHD Conditions Some ACHD lesions present unique clinical considerations for postoperative care.
Reperfusion Injury in Pulmonic Stenosis Patients with severe stenosis of a native or repaired pulmonic valve, pulmonary bioprosthesis, right ventricle to pulmonary artery conduit, and/or branch pulmonary arteries are at risk for a postoperative reperfusion injury after normal flow is restored to the lungs, particularly with more distal and more severe obstructions (more so than patients with an isolated proximal, eg, valvar, obstruction). This phenomenon has been observed in children and young adults after surgical17,18 and catheter19 interventions, and closely resembles the reperfusion injury often seen after pulmonary thromboen-darterectomy for chronic thromboembolic disease.20 Clinicians must anticipate this lung injury and the need for careful and appropriate supportive care. For instance, it may be wise to take a more cautious approach to early tracheal extubation in patients at high risk of this complication.
The Systemic Right Ventricle Several patient populations have a 2-ventricle circulation in which a morphological right ventricle (RV) functions as the systemic pumping chamber: patients with D-transposition of the great arteries who were treated with an atrial switch procedure (Senning or Mustard) in the era before the Jatene arterial switch operation, patients with L-transposition of the great arteries, some patients with double-outlet right ventricle, some patients with heterotaxy syndrome. Adults with a systemic RV generally have some degree of systolic dysfunction, tricuspid (ie, systemic atrioventricular valve) regurgitation (TR), atrial arrhythmias, and/or volume overloading of the RV. The largest study of adults with a systemic RV followed 129 patients in Scotland; this group had an average age of 30 years, and most patients had not yet required surgical reintervention in adulthood. Even in this relatively young, well-compensated cohort of outpatients, 68% had RV dysfunction (27% were moderate to severe), 64% had TR (22% were moderate to severe), 20% had tachyarrhythmias, and the average right ventricular end-diastolic volume was 40% greater than left ventricular end-diastolic volume.21 The implications of these common abnormalities (which may not be clinically apparent to the patient) involve a need for close monitoring and management of heart rate, rhythm, inotropic state, and volume status. Even transient insults to a marginal and/or volume overloaded RV can precipitate a vicious cycle of chamber dilation, pump dysfunction, worsened TR, leftward shift of the interventricular septum resulting in loss of coordinated pumping efficiency, and poor cardiac output. Loss of sinus rhythm may be particularly poorly tolerated. Atrial switch (Senning/Mustard) patients are also at risk for a baffle leak that would result in a left-to-right shunt under most baseline conditions but has the potential
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to reverse and become a right-to-left shunt under conditions of elevated right atrial pressure (and/or decreased left atrial pressure) during the perioperative period. If this occurs, it is a potential source of paradoxical embolism (as above) and systemic desaturation.
Patients With a Single Ventricle The Fontan procedure was first performed in 1971 for tricuspid atresia,22 and its use for long-term palliation was expanded to a range of functionally univentricular lesions beginning in the mid- to late-1980s,23 including pulmonary atresia, hypoplastic left heart syndrome, double-inlet left ventricle, unbalanced atrioventricular canal, double-outlet right ventricle, and severe Ebstein’s anomaly. The adult Fontan population, therefore, is now entering into a period of nearly exponential growth, reflecting the survivorship to adulthood of children who benefitted from the widespread adoption of the Fontan procedure in the late 1980s through the 1990s, and this population will continue to grow as the children of the 2000s age into adulthood. However, adult patients with a Fontan circulation not infrequently require reoperation, as revision or conversion of the early surgical approaches (right atrium to pulmonary artery connection or lateral tunnel Fontan) to an extracardiac conduit has become an appealing strategy for managing common issues that face adult Fontan patients: massive right atrial dilation, atrial arrhythmias, baffle leak, pulmonary venous obstruction, and baffle or conduit obstruction.24,25 Even well-compensated single-ventricle patients presenting for other interventions (eg, aortic valve disease) merit special attention, because aspects of the Fontan circulation make these patients vulnerable to physiologic alterations in the perioperative period that might be better tolerated by other patients. Given that pulmonary blood flow is passive in those patients, cardiac output is dependent on maintaining an adequate transpulmonary gradient, which is the difference between the Fontan pressure (ie, the mean pulmonary arterial pressure) and the pressure in the atrium receiving pulmonary venous return (in some lesions, such as tricuspid atresia, this is the left atrial pressure; in others, such as hypoplastic left heart syndrome, this is common atrial pressure because an atrial septectomy would have been performed). Cardiac output at an acceptable transpulmonary gradient is, in turn, dependent on low pulmonary vascular resistance (PVR). Even mild hypercarbia, hypoxia, atelectasis, and pain can produce clinically significant perturbations in PVR and compromise transpulmonary flow. If atrial pressure and/or PVR rise, cardiac output will only be maintained if the central venous (Fontan) pressure rises concomitantly to maintain the transpulmonary gradient, which decreases the margin for adequate end-organ perfusion and can predispose the patient to end-organ ischemia.
Pulmonary vasodilators (eg, inhaled nitric oxide) may offer benefit in these physiologic scenarios, though outcome data to guide their use are limited.26,27 Inotropic support may be required even for comparatively short procedures, as ventricular reserve may be limited in the Fontan patient (particularly patients whose single ventricle is a morphologic right ventricle, eg, hypoplastic left heart syndrome). Volume status can be a delicate balance: hypovolemia is poorly tolerated, because Fontan patients cannot increase heart rate or ejection fraction to maintain pulmonary blood flow in response to decreased preload (as there is no ventricle responsible for pulmonary blood flow), but volume overload, particularly in the presence of ventricular systolic or diastolic dysfunction, may increase atrial pressure and therefore compromise pulmonary blood flow by decreasing the transpulmonary gradient. Volume administration and a higher transpulmonary gradient may be needed if PVR rises to maintain cardiac output (at the cost of systemic venous hypertension).
The Unoperated ACHD Patient While the most common scenario in many centers for ACHD patients is to undergo repeat sternotomy for reoperation of a previously intervened-upon lesion, there are a few lesions that may not be identified in childhood. These congenital patients consequently present for their first cardiac operation as an adult. An atrial septal defect (ASD) may first be discovered in adulthood, often in patients who previously had been told since childhood that they had a benign murmur. Fortunately, the majority of patients tolerate closure, even in the presence of significant right ventricular enlargement or elevated pulmonary artery pressures. Most secundum ASDs are amenable to device closure in the catheterization laboratory; large secundum defects (especially those with an inadequate rim of tissue to support anchoring a closure device) as well as other types of ASDs (sinus venosus, primum, or coronary sinus ASDs) require surgical closure. Similarly, some adults with a persistent patent ductus arteriosus or small ventricular septal defect also may be candidates for endovascular or open surgical closure. Generally, for any long-standing left to right shunt, if significant pulmonary hypertension is present, closure may still be possible,28-30 but additional preoperative evaluation (right heart catheterization, often with assessment of pulmonary vasodilator responsiveness, which predicts improved outcome in ACHD31,32 as it does in idiopathic pulmonary hypertension33) may be warranted. Marginal candidates will require careful assessment for the need for postoperative RV inotropic support, pulmonary vasodilator therapy, and/or temporary mechanical circulatory support. If postoperative RV dysfunction is anticipated, surgeons may
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Maxwell and Steppan deliberately leave a fenestration or other residual intracardiac defect to create a “popoff” through which a patient can maintain cardiac output at the expense of mild desaturation. This mechanism is thought to underlie the observation that patients with Eisenmenger’s syndrome have a relatively favorable prognosis compared with patients with equivalently elevated pulmonary arterial pressures from idiopathic pulmonary arterial hypertension.34 Last, coarctation of the aorta may become evident in adulthood, and may be amenable to endovascular or open repair.35 Adults with unoperated, more complex congenital lesions may occasionally be encountered, often because as children they lived in lower resource settings where routine diagnosis and treatment of CHD was less readily available or because the appropriate repair may have been regarded as too complex or high risk in that era. Late diagnosis is not necessarily a contraindication to surgical repair (unless progression to Eisenmenger’s syndrome has occurred), but these operations should be approached with cautious multidisciplinary planning. The postoperative care of such patients may be challenging because of pulmonary vascular disease, impaired ventricular function, the presence of aortopulmonary or venovenous collaterals, and coexisting end-organ dysfunction.
Managing Comorbid Conditions: Considerations Specific to ACHD Perhaps the greatest challenge in managing the extracardiac comorbid conditions common to ACHD patients is recognizing their existence. A large fraction (in some studies, the majority) of ACHD patients are lost to follow-up for several years in early adulthood present.36-38 A new cardiovascular symptom or event that prompts cardiovascular intervention may be the impetus to return to care after a prolonged absence, and it is common that dysfunction in other organ systems will not have been diagnosed and investigated. Restrictive lung disease is common in ACHD patients, and it is a strong predictor of functional impairment.39 A longitudinal study of 1188 ACHD patients followed between 2000 and 2012 at the Royal Brompton in London found a prevalence of nearly 50% of restrictive lung disease, and demonstrated it to be an independent predictor of mortality in adults remote from initial repair.40 Restrictive physiology may occur from a combination of musculoskeletal changes to the thorax from prior sternotomies and/ or thoracotomies, diaphragm palsies, cardiomegaly, coexistent scoliosis, and parenchymal disease from prior perioperative insults. Renal dysfunction is similarly common and underrecognized. A related Royal Brompton cohort study involving 1102 young ACHD patients found a 50% incidence of
chronic kidney disease, with nearly 10% of patients demonstrating moderate to severe dysfunction (ie, glomerular filtration rate
SCVXXX10.1177/1089253214562915Seminars in Cardiothoracic and Vascular AnesthesiaMaxwell and Steppan
Article
Postoperative Care of the Adult With Congenital Heart Disease
Seminars in Cardiothoracic and Vascular Anesthesia 2015, Vol. 19(2) 154–162 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1089253214562915 scv.sagepub.com
Bryan Maxwell, MD, MPH1 and Jochen Steppan, MD1
Abstract An increasing number of children with congenital heart disease survive to adulthood, but many adults require surgical intervention and can present complex management challenges in the perioperative period. This review will address common considerations that surgeons, anesthesiologists, and intensivists are likely to face in caring for this growing population. Keywords adult congenital heart disease, congenital heart disease, critical care, postoperative, complications
Background As a result of improved surgical techniques and pediatric care, the proportion of children with congenital heart disease (CHD) who survive to adulthood has increased dramatically over the past 4 decades.1 Adults now outnumber children with CHD,2 accounting for approximately 66% of the overall CHD population and 60% of those with severe CHD (increased from 35% in 1985 and 49% in 2000).3 Adult congenital heart disease (ACHD) represents one of the fastest growing areas in adult cardiovascular medicine, and it is now possible even to speak meaningfully of geriatric CHD care.4 Many CHD lesions are treated with long-term palliative strategies that are not truly curative, and these patients often require reintervention(s) in adult life. Even structurally curative interventions often have significant late cardiovascular sequelae (eg, arrhythmias) that require intervention.5 As a result, perioperative physicians are likely to see a growing number of ACHD patients presenting for care in operating rooms and intensive care units in the immediate future. Experience with different models of care suggests that surgical outcomes for ACHD patients are better in the hands of pediatric heart surgeons,6 but that other aspects of perioperative care may be best suited to the resources and environment offered by an adult hospital.7 This latter point remains debated and is unlikely to be addressed by randomized trials. National guidelines have established that ACHD patients with anything more than a simple congenital lesion (eg, repaired atrial septal defect) should have perioperative care provided in regional ACHD centers by cardiologists, surgeons, and anesthesiologists with experience in ACHD.8 Prior survey data suggest that knowledge of
and comfort with ACHD is low among anesthesiologists even at specialized centers;9 expertise in this area must be sought, and training pathways for ACHD are still emerging.10 Outcome data from the Society of Thoracic Surgeons Congenital Heart Surgery Database11 demonstrate a high prevalence (28%) of postoperative complications in ACHD patients undergoing cardiac operations (Figure 1). The larger Society of Thoracic Surgeons Adult Heart Surgery Database (which reflects procedures done at a broader range of hospitals, not limited to centers specializing in congenital heart surgery), identifies a high rate of postoperative mortality in ACHD patients (2.1% in atrial septal defect repair, 2.8% in pulmonary valve replacement, and 3.7% in other congenital defect repairs; see Table 1).11 This review will cover major areas of postoperative care that involve specific considerations in ACHD.
General Considerations for Care of the ACHD Patient The anatomic and physiologic consequences of ACHD closely depend on the initial CHD lesion, the changes brought about by surgical palliation or repair, and the ways in which the palliated or repaired circulation has changed over time. Often, serial comparison of past echocardiogram 1
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA Corresponding Author: Bryan Maxwell, Johns Hopkins Medical Institutions, 1800 Orleans Street, Zayed 6208P, Baltimore, MD 21287, USA. Email: [email protected]
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10% 9.4%
8%
6%
4% 3.1% 2.4%
2.1% 2%
1.7% 1.3%
2.1%
1.9%
1.4%
1.1%
1.0%
1.0%
0% In-hospital mortality
Arrhythmia
Low cardiac output
Permanent Cardiac arrest pacemaker
Pleural effusion
Pneumonia Reintuba on
Mechanical Unplanned ven la on > 7 reopera on days
Bleeding requiring reopera on
Renal failure requiring temporary dialysis
Figure 1. Morbidity and mortality of cardiac operations in the Society of Thoracic Surgeons Congenital Heart Surgery Database. Adapted and used with permission from Mascio CE, Pasquali SK, Jacobs JP, Jacobs ML, Austin EH. Outcomes in adult congenital heart surgery: analysis of the Society of Thoracic Surgeons Database. J Thorac Cardiovasc Surg. 2011;142:1090-1097.
Table 1. Mortality of Cardiac Operations in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Atrial Septal Defect Repair (n = 26 117) Isolated procedure, n (%) •• Age, years (range) •• In-house mortality Concomitant procedure •• Age, years (range) •• In-house mortality
Congenital Defect Repair (n = 10 133)
Pulmonary Valve Replacement (n = 3622)
9602 (37%) 48 (36-59) 2.1%
2835 (28%) 44 (32-58) 3.7%
1738 (48%) 38 (28-49) 2.8%
66 (56-75) 5.0%
65 (54-74) 4.5%
47 (37-56) 3.5%
Adapted and used with permission from Mascio CE, Pasquali SK, Jacobs JP, Jacobs ML, Austin EH. Outcomes in adult congenital heart surgery: analysis of the Society of Thoracic Surgeons Database. J Thorac Cardiovasc Surg. 2011;142:1090-1097.
reports, cardiac catheterization reports, and detailed operative notes is needed to understand the history and current status of a patient’s circulation, as summary descriptors (eg, simply knowing that the patient has undergone a “Fontan procedure” or “pulmonary arterioplasy”) can reflect procedures of varying types and extensiveness. These records can also contain important information about vascular access issues, such as a history of vessel occlusions (from surgical ligation or thrombus), classical or modified Blalock-Taussig shunts, surgical cutdowns, and associated great vessels aberrancies (eg, interrupted IVC, persistent
left superior vena cava, right aortic arch, aberrant subclavian artery) that will be important to the intensivist and perioperative physician. Table 2 summarizes the vascular access implications of common CHD pathology, repairs, or associated variants. It is not unusual for patients to receive care as adults in a different hospital from that where they received care as a child, so obtaining detailed records may be challenging. When written records cannot be obtained, many ACHD patients have become quite informed participants in their own care and know details of their history that other adult patients might not know (eg, that catheterization
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Table 2. Vascular Access Implications of Common CHD Pathology, Repairs, and Associated Variants. Vascular Anomaly Prior classical or modified Blalock–Taussig shunt Prior radial or ulnar artery cutdown Prior ECMO cannulation Persistent left superior vena cava Interrupted IVC Pulmonary valve prosthesis or conduit
Implication Subclavian artery may be stenosed or occluded after BT shunt takedown, and pressures monitored on that side may be inaccurate. Consider an alternative site, or correlate noninvasive pressures from multiple sites before selecting the ipsilateral arm. Difficulty threading Seldinger wire may be encountered during arterial cannulation. Consider placing arterial line proximal to cutdown site or alternative artery. Neonates and infants typically receive ECMO support using internal jugular/ carotid cannulation. These vessels may be partially or completely occluded after decannulation. One configuration involves LSVC without bridging (innominate) vein, that is, bilateral SVCs. In this case, internal jugular cannulation will lead to direct coronary sinus access, which may be undesirable if rapid infusion or PA catheter placement is planned. The IVC may connect to the SVC through an azygous continuation. Access to the heart from the femoral vessels (eg, PA catheter, venous ECMO cannula) may be difficult or impossible. May be difficult to float PA catheter; fluoroscopy guidance may be helpful.
Abbreviations: CHD, congenital heart disease; ECMO, extracorporeal membrane oxygenation; LSVC, left superior vena cava; SVC, superior vena cava; IVC, inferior vena cava; PA, pulmonary artery.
of a particular venous structure was previously deemed impossible, what strategies were used for airway management in the past, etc). Others may have little knowledge of care that occurred when they were young children, and communicating with pediatric providers may be the only way of determining the details of prior interventions. Understanding the anatomy is a necessary part of understanding the associated, current physiology, but is not sufficient; for instance, a patient with a Fontan circulation may be quite well-compensated, with low systemic venous pressures, no arrhythmias, normal pulmonary vascular resistance, normal systemic ventricular function, and normal cardiac output. Alternatively, a patient with the same underlying structural Fontan anatomy may be experiencing end-stage failure of that circulation, involving systemic venous hypertension, elevated pulmonary vascular resistance, impaired ventricular function, atrioventricular valve regurgitation, refractory atrial flutter, plastic bronchitis, and protein-losing enteropathy. Impaired right ventricular function and pulmonary hypertension are not uncommon in the CHD population— one should not assume these parameters to be normal and should examine records for evidence of preexisting abnormalities in the right heart. In addition to the self-evident dangers of underappreciating the significance of CHD physiology, parallel risks exist in overattributing clinical problems to CHD without adequate physiologic understanding. For instance, clinicians may wrongly attribute hypoxemia to residual CHD in a patient who does not have a right-to-left shunt (in whom the cause of hypoxemia is actually, eg, simple
ventilation/perfusion mismatch), and therefore miss an opportunity to intervene appropriately.12
Paradoxical Air Embolism: “No Bubble Left Behind” Many ACHD patients have a residual intracardiac shunt (eg, patent foramen ovale, Fontan fenestration, patch leak in repaired atrial or ventricular septal defect, baffle leak after an atrial switch procedure, etc). By adulthood, most defects that remain unrepaired probably are small and unlikely to result in a hemodynamically significant shunt, but they have the potential to act as a conduit for paradoxical embolism. One can prevent iatrogenic harm in the form of air embolism by paying particular attention to avoiding air in intravenous (IV) lines. The need for meticulous debubbling of IVs and vigilance to detect and prevent air emboli is wellentrenched in the culture of pediatric anesthesia and critical care, but it is less well-established in adult perioperative settings. Those caring for ACHD patients must recognize that even very small air bubbles can cause devastating effects if introduced into the systemic circulation. IV filters are commercially available but not routinely used in adult ICUs, and they are never a substitute for vigilance. We recommend backflushing the IV line at a stopcock (open to the fluid reservoir/close to the patient, aspirate to clear the stopcock junction of air, then open to the patient, aspirate, and inject) every time any medication is given, while watching for the appearance of any air bubbles along the entire length of the IV tubing. Central venous lines should be aspirated prior to any injection.
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Management of Postoperative Arrhythmias in ACHD The arrhythmia burden in the ACHD population is considerable: the majority of complex CHD patients will develop significant arrhythmias during their lifetime,13 and arrhythmias complicate the postoperative course in one third of ACHD patients undergoing cardiac surgery.14 In particular, patients with a single ventricle or a systemic right ventricle may tolerate the loss of sinus rhythm poorly. Pharmacologic control of perioperative arrhythmias may be challenging, particularly in the setting of the concomitant use of inotropes that are arrhythmogenic. Device therapies have a role in the short-term and longterm management of many ACHD patients, but specific populations may present unique challenges. For instance, trans-venous lead placement is not possible in patients with an extracardiac Fontan, as the systemic veins do not provide direct access to the cardiac chambers. In these patients and those with other complex CHD anatomy, the leads must be placed in an epicardial (or occasionally subcutaneous) position and the generator is often located in the abdomen or flank. Lead placement can also be challenging in patients with an atrial baffle (eg, atrial switch patients) or patients with congenital or acquired abnormalities of the great veins. Cardiac resynchronization therapy may require customized settings in patients with a systemic right ventricle.
Postoperative Echocardiography in ACHD While there are few outcome studies to specifically establish a role for echocardiography in the postoperative management of ACHD patients, recent years have seen a dramatic adoption of echocardiography for postoperative and ICU care in the broader adult15 and pediatric16 surgical populations. We expect that the postoperative care of ACHD patients will involve a similar trend of acceptance of echocardiography as a management tool. Echocardiographers with ACHD experience will be needed to provide expert assessment of abnormal anatomy, particularly in patients with a systemic right ventricle, complex baffle geometry, or single-ventricle circulations. In these populations, assessment of even comparatively simple parameters (eg, global ventricular function, volume status) may not be straightforward. Collaboration with pediatric cardiologists may offer productive avenues for sharing expertise.
Postoperative Considerations in Specific ACHD Conditions Some ACHD lesions present unique clinical considerations for postoperative care.
Reperfusion Injury in Pulmonic Stenosis Patients with severe stenosis of a native or repaired pulmonic valve, pulmonary bioprosthesis, right ventricle to pulmonary artery conduit, and/or branch pulmonary arteries are at risk for a postoperative reperfusion injury after normal flow is restored to the lungs, particularly with more distal and more severe obstructions (more so than patients with an isolated proximal, eg, valvar, obstruction). This phenomenon has been observed in children and young adults after surgical17,18 and catheter19 interventions, and closely resembles the reperfusion injury often seen after pulmonary thromboen-darterectomy for chronic thromboembolic disease.20 Clinicians must anticipate this lung injury and the need for careful and appropriate supportive care. For instance, it may be wise to take a more cautious approach to early tracheal extubation in patients at high risk of this complication.
The Systemic Right Ventricle Several patient populations have a 2-ventricle circulation in which a morphological right ventricle (RV) functions as the systemic pumping chamber: patients with D-transposition of the great arteries who were treated with an atrial switch procedure (Senning or Mustard) in the era before the Jatene arterial switch operation, patients with L-transposition of the great arteries, some patients with double-outlet right ventricle, some patients with heterotaxy syndrome. Adults with a systemic RV generally have some degree of systolic dysfunction, tricuspid (ie, systemic atrioventricular valve) regurgitation (TR), atrial arrhythmias, and/or volume overloading of the RV. The largest study of adults with a systemic RV followed 129 patients in Scotland; this group had an average age of 30 years, and most patients had not yet required surgical reintervention in adulthood. Even in this relatively young, well-compensated cohort of outpatients, 68% had RV dysfunction (27% were moderate to severe), 64% had TR (22% were moderate to severe), 20% had tachyarrhythmias, and the average right ventricular end-diastolic volume was 40% greater than left ventricular end-diastolic volume.21 The implications of these common abnormalities (which may not be clinically apparent to the patient) involve a need for close monitoring and management of heart rate, rhythm, inotropic state, and volume status. Even transient insults to a marginal and/or volume overloaded RV can precipitate a vicious cycle of chamber dilation, pump dysfunction, worsened TR, leftward shift of the interventricular septum resulting in loss of coordinated pumping efficiency, and poor cardiac output. Loss of sinus rhythm may be particularly poorly tolerated. Atrial switch (Senning/Mustard) patients are also at risk for a baffle leak that would result in a left-to-right shunt under most baseline conditions but has the potential
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to reverse and become a right-to-left shunt under conditions of elevated right atrial pressure (and/or decreased left atrial pressure) during the perioperative period. If this occurs, it is a potential source of paradoxical embolism (as above) and systemic desaturation.
Patients With a Single Ventricle The Fontan procedure was first performed in 1971 for tricuspid atresia,22 and its use for long-term palliation was expanded to a range of functionally univentricular lesions beginning in the mid- to late-1980s,23 including pulmonary atresia, hypoplastic left heart syndrome, double-inlet left ventricle, unbalanced atrioventricular canal, double-outlet right ventricle, and severe Ebstein’s anomaly. The adult Fontan population, therefore, is now entering into a period of nearly exponential growth, reflecting the survivorship to adulthood of children who benefitted from the widespread adoption of the Fontan procedure in the late 1980s through the 1990s, and this population will continue to grow as the children of the 2000s age into adulthood. However, adult patients with a Fontan circulation not infrequently require reoperation, as revision or conversion of the early surgical approaches (right atrium to pulmonary artery connection or lateral tunnel Fontan) to an extracardiac conduit has become an appealing strategy for managing common issues that face adult Fontan patients: massive right atrial dilation, atrial arrhythmias, baffle leak, pulmonary venous obstruction, and baffle or conduit obstruction.24,25 Even well-compensated single-ventricle patients presenting for other interventions (eg, aortic valve disease) merit special attention, because aspects of the Fontan circulation make these patients vulnerable to physiologic alterations in the perioperative period that might be better tolerated by other patients. Given that pulmonary blood flow is passive in those patients, cardiac output is dependent on maintaining an adequate transpulmonary gradient, which is the difference between the Fontan pressure (ie, the mean pulmonary arterial pressure) and the pressure in the atrium receiving pulmonary venous return (in some lesions, such as tricuspid atresia, this is the left atrial pressure; in others, such as hypoplastic left heart syndrome, this is common atrial pressure because an atrial septectomy would have been performed). Cardiac output at an acceptable transpulmonary gradient is, in turn, dependent on low pulmonary vascular resistance (PVR). Even mild hypercarbia, hypoxia, atelectasis, and pain can produce clinically significant perturbations in PVR and compromise transpulmonary flow. If atrial pressure and/or PVR rise, cardiac output will only be maintained if the central venous (Fontan) pressure rises concomitantly to maintain the transpulmonary gradient, which decreases the margin for adequate end-organ perfusion and can predispose the patient to end-organ ischemia.
Pulmonary vasodilators (eg, inhaled nitric oxide) may offer benefit in these physiologic scenarios, though outcome data to guide their use are limited.26,27 Inotropic support may be required even for comparatively short procedures, as ventricular reserve may be limited in the Fontan patient (particularly patients whose single ventricle is a morphologic right ventricle, eg, hypoplastic left heart syndrome). Volume status can be a delicate balance: hypovolemia is poorly tolerated, because Fontan patients cannot increase heart rate or ejection fraction to maintain pulmonary blood flow in response to decreased preload (as there is no ventricle responsible for pulmonary blood flow), but volume overload, particularly in the presence of ventricular systolic or diastolic dysfunction, may increase atrial pressure and therefore compromise pulmonary blood flow by decreasing the transpulmonary gradient. Volume administration and a higher transpulmonary gradient may be needed if PVR rises to maintain cardiac output (at the cost of systemic venous hypertension).
The Unoperated ACHD Patient While the most common scenario in many centers for ACHD patients is to undergo repeat sternotomy for reoperation of a previously intervened-upon lesion, there are a few lesions that may not be identified in childhood. These congenital patients consequently present for their first cardiac operation as an adult. An atrial septal defect (ASD) may first be discovered in adulthood, often in patients who previously had been told since childhood that they had a benign murmur. Fortunately, the majority of patients tolerate closure, even in the presence of significant right ventricular enlargement or elevated pulmonary artery pressures. Most secundum ASDs are amenable to device closure in the catheterization laboratory; large secundum defects (especially those with an inadequate rim of tissue to support anchoring a closure device) as well as other types of ASDs (sinus venosus, primum, or coronary sinus ASDs) require surgical closure. Similarly, some adults with a persistent patent ductus arteriosus or small ventricular septal defect also may be candidates for endovascular or open surgical closure. Generally, for any long-standing left to right shunt, if significant pulmonary hypertension is present, closure may still be possible,28-30 but additional preoperative evaluation (right heart catheterization, often with assessment of pulmonary vasodilator responsiveness, which predicts improved outcome in ACHD31,32 as it does in idiopathic pulmonary hypertension33) may be warranted. Marginal candidates will require careful assessment for the need for postoperative RV inotropic support, pulmonary vasodilator therapy, and/or temporary mechanical circulatory support. If postoperative RV dysfunction is anticipated, surgeons may
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Maxwell and Steppan deliberately leave a fenestration or other residual intracardiac defect to create a “popoff” through which a patient can maintain cardiac output at the expense of mild desaturation. This mechanism is thought to underlie the observation that patients with Eisenmenger’s syndrome have a relatively favorable prognosis compared with patients with equivalently elevated pulmonary arterial pressures from idiopathic pulmonary arterial hypertension.34 Last, coarctation of the aorta may become evident in adulthood, and may be amenable to endovascular or open repair.35 Adults with unoperated, more complex congenital lesions may occasionally be encountered, often because as children they lived in lower resource settings where routine diagnosis and treatment of CHD was less readily available or because the appropriate repair may have been regarded as too complex or high risk in that era. Late diagnosis is not necessarily a contraindication to surgical repair (unless progression to Eisenmenger’s syndrome has occurred), but these operations should be approached with cautious multidisciplinary planning. The postoperative care of such patients may be challenging because of pulmonary vascular disease, impaired ventricular function, the presence of aortopulmonary or venovenous collaterals, and coexisting end-organ dysfunction.
Managing Comorbid Conditions: Considerations Specific to ACHD Perhaps the greatest challenge in managing the extracardiac comorbid conditions common to ACHD patients is recognizing their existence. A large fraction (in some studies, the majority) of ACHD patients are lost to follow-up for several years in early adulthood present.36-38 A new cardiovascular symptom or event that prompts cardiovascular intervention may be the impetus to return to care after a prolonged absence, and it is common that dysfunction in other organ systems will not have been diagnosed and investigated. Restrictive lung disease is common in ACHD patients, and it is a strong predictor of functional impairment.39 A longitudinal study of 1188 ACHD patients followed between 2000 and 2012 at the Royal Brompton in London found a prevalence of nearly 50% of restrictive lung disease, and demonstrated it to be an independent predictor of mortality in adults remote from initial repair.40 Restrictive physiology may occur from a combination of musculoskeletal changes to the thorax from prior sternotomies and/ or thoracotomies, diaphragm palsies, cardiomegaly, coexistent scoliosis, and parenchymal disease from prior perioperative insults. Renal dysfunction is similarly common and underrecognized. A related Royal Brompton cohort study involving 1102 young ACHD patients found a 50% incidence of
chronic kidney disease, with nearly 10% of patients demonstrating moderate to severe dysfunction (ie, glomerular filtration rate
