Abstract
Infants and children with congenital heart disease (CHD) require multidisciplinary care, and they often require the services of the pediatric surgeon. Pediatric surgical care in infants with CHD revolves around management of major gastrointestinal (GI) anomalies that may co-occur with CHD and around management of acquired or developmental conditions in these patients, chiefly, need for vascular access, necrotizing enterocolitis, and dysfunctional feeding. It is important for the cardiac specialist to understand that for many of the major congenital GI anomalies, more than one initial management option may be available, depending on the severity of the patient’s CHD. Patients with esophageal atresia may have complex thoracic vascular anatomy, requiring operative collaboration between the pediatric surgeon and the congenital heart surgeon. Malrotation presents across a wide spectrum of symptom severity. In infants with severe uncorrected CHD, it is safer to delay surgery for malrotation, as long as the patient is asymptomatic from the malrotation. Necrotizing enterocolitis (NEC) is a potentially life-threatening emergency in infants with CHD. Complex decisions about operative or nonoperative treatment of NEC are driven by multiple physiologic and metabolic factors. The site and catheter for optimal vascular access should account for the patient’s current needs and future cardiovascular reconstruction. Although dysfunctional feeding is common in infants with CHD, surgery for feeding access should reflect an appreciation of the patient’s operative risk and a rational assessment of the severity of the patient’s gastroesophageal reflux.
Key Words
Malrotation, necrotizing enterocolitis, esophageal atresia, central venous catheter, gastrostomy, gastroesophageal reflux disease
Although congenital heart disease (CHD) most commonly occurs as an isolated condition, approximately one in four newborns with CHD will have other congenital anomalies. These noncardiac anomalies may pose a threat to life or function and require the skills of a pediatric surgeon. Specifically, newborns with esophageal atresia (EA), duodenal atresia, malrotation, Hirschsprung disease (HD), and anorectal malformations may also have CHD and thus require multidisciplinary care from the pediatric surgical team and the congenital heart team. In addition to caring for noncardiac congenital anomalies, the pediatric surgeon may care for nonstructural conditions such as necrotizing enterocolitis (NEC), dysfunctional feeding, pathologic gastroesophageal reflux, and difficult vascular access in children with CHD. In all cases a spirit of true collaboration between the surgical and nonsurgical specialists is paramount to achieving the best possible outcome for the child. A comprehensive review of these myriad conditions would exceed the scope of this project. Rather, the following discussion focuses on the bedside evaluation and clinical management of major pediatric surgical conditions in the child with CHD.
Esophageal Atresia and Tracheoesophageal Fistula
EA with tracheoesophageal fistula (TEF) is an uncommon anomaly, occurring in approximately 1 per 3500 to 1 per 4000 live births. Several configurations of EA/TEF are recognized, with the most common being proximal EA with distal TEF type C, which occurs in 80% to 85% of cases. At least 50% of newborns with EA/TEF have other associated anomalies. Cardiovascular anomalies occur in approximately 30% of these patients, most commonly ventricular septal defect. EA/TEF may occur alongside cardiovascular anomalies as part of a recognized association of anomalies. The VACTERL association includes vertebral anomalies, atresia (anus, duodenum), cardiovascular anomalies, TEF, renal anomalies, and limb anomalies. EA/TEF may occur as part of the CHARGE association, which includes coloboma, heart defects, atresia choanae, retardation (developmental delay), genitourinary anomalies, and ear deformities. Severe cardiac anomalies are associated with mortality in newborns with EA/TEF, as is low birth weight. Historically infants with EA/TEF, major CHD, and birth weight less than 1500 g have had mortality as high as 78%, compared with 3% mortality in EA/TEF patients without major CHD or low birth weight. Although mortality has decreased with improvements in neonatal and cardiovascular care, it serves as an important reminder of the complex nature of these patients.
The congenital heart surgery team and the pediatric surgery team collaborate in two main arenas regarding infants with combined EA/TEF and CHD: preoperative care and intraoperative care. Preoperatively both teams should discuss which anomalies are most life threatening and whether temporizing treatment or definitive treatment should be pursued initially. Newborns with EA/TEF may develop respiratory distress related to several factors. If the TEF is large, they may lose significant tidal volume through the fistula into the GI tract. This can create progressive abdominal distention, which can impair diaphragmatic excursion. In addition, gastric distention may lead to regurgitation of gastric fluid directly into the airways through the fistula. Such patients with progressive respiratory distress may be temporized by an urgent surgical gastrostomy. This approach may get the patient through a period of critical illness, whether from prematurity or physiologically significant CHD. Infants with a decompressive gastrostomy are not safe to feed enterally until they have definitive correction of their TEF.
Intraoperative collaboration between pediatric surgery and congenital heart surgery for EA/TEF typically pertains to aberrant thoracic anatomy. Newborns with EA/TEF should receive an echocardiogram soon after birth to assess the sidedness of the aortic arch. Patients with a left-sided aortic arch have exposure and repair of their esophagus through a right thoracotomy. Patients who have a right-sided aortic arch or a double aortic arch should have preoperative consultation with a congenital heart surgeon. Traditionally patients with a right-sided aortic arch should have a left thoracotomy to repair their EA/TEF. On occasion, preoperative echocardiography will fail to recognize a right-sided aortic arch, and the pediatric surgeon will identify a right-sided arch through a standard right thoracotomy for anticipated repair of EA/TEF. If the length of the upper esophageal pouch is sufficient, it is reasonable to proceed with mobilization of the upper pouch and repair of the EA/TEF without dividing the right-sided aortic arch. If the upper esophageal pouch is short, or if it cannot be adequately mobilized without dividing the right-sided aortic arch, it is advisable to obtain intraoperative consultation with a congenital heart surgeon. The aortic arch should not be divided without a complete understanding of the patient’s thoracic vascular anatomy. This knowledge may be obtained by stopping the operation and obtaining a high-resolution computed tomography (CT) angiogram of the chest or by closing the right thoracotomy and performing a left thoracotomy for vascular exploration ( Fig. 32.1 ). Surgeons who are facile with minimally invasive techniques may consider the use of thoracoscopy in this setting. Once the patient’s thoracic vascular anatomy is determined, it is appropriate to proceed with esophageal and vascular repairs at the same operation. Collaboration between the congenital heart surgeon and the pediatric surgeon is paramount in complex newborns such as these.
Malrotation
Intestinal rotation abnormalities (IRAs) manifest across a range of anatomic arrangements and symptomatic presentations. Fundamentally these relate to disruptions in the normal 270-degree counterclockwise rotation of the midgut and retroperitoneal fixation of the duodenum and the right colon during the 4th to 12th weeks of gestation. If the patient’s IRA results in a narrow mesentery, the patient is at risk for developing midgut volvulus. True malrotation occurs when the duodenal-jejunal junction is located in the right upper quadrant of the abdomen, the third and fourth portions of the duodenum are intraperitoneal rather than retroperitoneal, and the cecum is nonfixed or poorly fixed to the right upper quadrant. True malrotation creates a narrow mesentery and risk for midgut volvulus. Nonrotation occurs when the midgut rotates less than 180 degrees, such that the small bowel comes to lie on the right side of the abdomen and the colon on the left side of the abdomen. Patients with nonrotation typically do not have a narrow mesentery and are at lower risk for midgut volvulus. IRAs less than 270 degrees may be considered incomplete rotation. These terms can be confusing and are often incorrectly used interchangeably. It is critical to remember that it is the risk of midgut volvulus that drives the concern for IRAs.
IRAs may present with a wide variety of symptoms, ranging from completely normal gastrointestinal function up to complete midgut necrosis with perforation and sepsis. Other symptoms may be due to intermittent or incomplete volvulus, including feeding intolerance, gastroesophageal reflux disease, abdominal pain, abdominal distention, chylous ascites, protein-losing enteropathy, gastrointestinal bleeding, NEC, or intestinal obstruction. These symptoms can result from other causes as well. In the absence of a clear-cut episode of volvulus on upper gastrointestinal (UGI) contrast study or operative exploration, it is difficult to know the contribution of the IRA to a patient’s symptoms ( Fig. 32.2 ).
Infants with CHD, particularly heterotaxy syndrome (HS), have an incidence of malrotation as high as 40% to 90%. Two recent systematic reviews evaluated the published literature regarding malrotation in patients with severe CHD and HS. The authors recommend against screening asymptomatic patients for malrotation. GI symptoms are very common in patients with severe CHD. If an UGI contrast study is performed to evaluate these symptoms, and malrotation is discovered, a decision about performing a Ladd procedure must be placed in the context of the CHD. Only 1.2% of patients with HS had the feared presentation of midgut volvulus. A Ladd procedure can result in significant morbidity in this population. Postoperative complications occur in 14% of patients, including a 10% incidence of small bowel obstruction. Overall mortality following a Ladd procedure in these patients is 21%, including a 3% mortality perioperatively. The vast majority of this mortality is from their cardiovascular disease, rather than their GI disease. Accordingly, patients with severe CHD who have malrotation and minor symptoms should be observed until their CHD is palliated. At that point a Ladd procedure may be considered, though it may also be reasonable to continue to observe these patients. Patients with severe GI symptoms or acute volvulus before CHD palliation should undergo a Ladd procedure with the acknowledgment that this is a high-risk intervention. Finally, during the period of observation, health care providers and family members should be aware of the possibility of the patient’s developing acute midgut volvulus and the accompanying symptoms that would signal this event. The pediatric surgeon should be consulted to help with these discussions and to be aware of the patient if an acute surgical need should arise. A decision algorithm for the treatment of malrotation in the patient with CHD is illustrated in Fig. 32.3 .
Other Congenital Pediatric Surgical Conditions
Because organogenesis of the cardiovascular system occurs simultaneously with organogenesis in the GI system, defects in one system may occur with defects in the other. Although a full review of the interplay between congenital cardiac and GI defects is beyond the scope of the current discussion, several important clinical points of pediatric surgical care bear mentioning for the provider whose area of expertise is congenital cardiovascular care.
HD involves the absence of ganglion cells in the hindgut and a variable amount of distal bowel. Neural crest cells form the enteric ganglion cells and are also involved with development of the cardiac outflow tract and aortopulmonary septum. Approximately 5% to 8% of patients with HD will also have CHD, with the majority of these defects being cardiac septation defects. Patients with Down syndrome account for two-thirds of patients with both HD and CHD, followed by patients with Mowat-Wilson syndrome. The cardiovascular physician team should be aware that the pediatric surgeon may have more than one option for initial management of these complex patients. These patients present with varying degrees of intestinal obstruction. It is the rare neonate who presents with overwhelming enterocolitis and requires an emergency colostomy. Most patients can be managed in the initial phase with rectal irrigations to manage their obstruction or enterocolitis symptoms. The key clinical point is that most patients with HD can be managed nonoperatively in the early phase, allowing for evaluation of the anatomy and severity of their CHD and potentially allowing for safe delay of their colorectal operation for HD if their CHD is a higher physiologic priority.
Neonates with anorectal malformations manifest a wide spectrum of severity and may have concurrent CHD in 12% to 22 % of cases. CHD is more likely to occur in newborns with more severe (“high”) anorectal malformations. Tetralogy of Fallot and ventricular septal defect are the most common cardiac lesions in these patients. The association between CHD and anorectal malformations presents several points of clinical importance. For the newborn in the delivery room the imperforate anus may be the only abnormal finding on initial physical examination by delivery room providers. Yet if the imperforate anus is diagnosed, this could potentially facilitate early transfer, diagnosis, and treatment for the potentially occult CHD associated with the anorectal malformation. Management of anorectal malformations requires operative treatment under general anesthesia in most cases. Failure to diagnose a neonate’s CHD could result in unexpected physiologic derangements under conditions of general anesthesia in the operating room. Similarly, although the GI obstruction of an anorectal malformation may appear to be an emergency, neonates without a rectal fistula apparent on physical examination are typically observed for 1 to 2 days to determine if a rectal fistula will become apparent. This allows for a neonatal cardiac evaluation to ascertain if the patient has a true emergency of ductus dependent CHD.
Necrotizing Enterocolitis
NEC is the most common gastrointestinal emergency of infancy and occurs primarily in preterm infants (>90%). Birth weight is inversely related to the incidence of NEC with very low-birth-weight (VLBW; <1500 g) infants experiencing an incidence of 6%, whereas extremely low-birth-weight (ELBW; <1000 g) infants have an approximately 8% to 15% incidence. Although the incidence of NEC is lower in full-term infants (<10%), it is disproportionately higher (10 to 100 times) in term neonates with CHD. NEC is most common in CHD patients with cyanotic heart disease and is highest among patients with hypoplastic left heart syndrome. As neonatal intensive care has improved over the years, so has survival of infants with ELBW and with complex CHD, and therefore the already high incidence of NEC in these populations continues to rise. It is imperative for those caring for neonates with CHD to have a high index of suspicion for NEC because early diagnosis and prompt treatment is paramount for the best outcomes.
Risk factors for NEC include initiation of enteral nutrition, prematurity, bacterial infection, maternal cocaine use, hypoxia, and CHD, predominantly single-ventricle physiology and left ventricular outflow tract lesions. Although CHD and NEC are distinct diseases, they are undoubtedly related. The increased risk of NEC in infants with CHD may be due to circulatory perturbations that lead to gut hypoperfusion such as diastolic flow reversal in the abdominal aorta, a baseline elevation of circulating proinflammatory mediators, and the stress of cardiac surgery and cardiopulmonary bypass. Prostaglandin administration in CHD infants, especially at higher infusions rates (>0.05 mcg/kg/min), may be a NEC risk factor as well, although its effects are controversial in the literature. Protective strategies to prevent NEC include the use of human breast milk instead of formula, cautious feeding regimens, and probiotics; however, none of these strategies has proven 100% effective. Further studies are needed to investigate the pathogenesis of NEC in an effort to develop novel treatments and improve the efficacy of potential preventative therapies. Although the pathogenesis of NEC remains unclear, the contemporary hypothesis is that an ischemic or hypoxic insult occurs in the intestine that damages epithelial mucosal integrity. This allows indigenous pathogenic bacteria from the intestinal lumen to invade the intestinal epithelial barrier and stimulate a release of proinflammatory cytokines that then further aggravate the original epithelial injury. Thus bacterial colonization is required for the development of NEC.
Although the pathogenesis of NEC remains uncertain, the signs and symptoms of NEC are well described. The age of onset is usually in the first 2 weeks of life after bacterial colonization of the gastrointestinal tract but may occur earlier in neonates with CHD (7 days). The Bell staging system was first established in 1978, and a modified version continues to be used today ( Table 32.1 ). This classification system defines three stages of NEC based on systemic, abdominal, and radiographic signs. The Bell staging system is valuable both at the bedside for clinical management decisions and for research in the field because it promotes uniform language. Although some signs and symptoms are more suggestive of NEC, such as peritonitis and pneumoperitoneum, others are nonspecific and overlap with other diagnoses such as sepsis, bacterial or viral enterocolitis, or ileus. These nonspecific signs may be subtle in neonates with complex CHD. Therefore it is important for the intensivist to have a high index of suspicion for NEC and to consult early with a pediatric general surgeon. In an infant with suspected NEC, the following laboratory studies should be checked: complete blood cell count with differential to look for leukocytosis, leukopenia, neutropenia, anemia, and/or thrombocytopenia; electrolyte and blood gas levels to evaluate for metabolic acidosis, as well as hypoxia and hypercapnia; prothrombin time and partial thromboplastin time to assess for coagulopathy; and blood cultures to rule out bacteremia. Notably, bacteremia is confirmed in almost 50% of patients. Patients with severe thrombocytopenia (<100 × 10 9 /L) experience poorer outcomes. Radiographic imaging is critical and should include two-view abdominal radiographs: a supine anteroposterior view and either a left lateral decubitus or cross-table lateral view. Radiographs can identify dilated air-filled loops (a nonspecific finding), a “fixed loop” (a segment of bowel that remains unchanged over serial abdominal radiographs and may be associated with bowel obstruction or transmural necrosis), pneumatosis intestinalis (intramural gas pathognomonic for NEC), portal venous gas (intramural gas absorbed by the venous system), and pneumoperitoneum (free intraperitoneal air from intestinal perforation). Abdominal ultrasonography is a supplementary imaging modality that may identify intraabdominal fluid collections, bowel wall thickness, and intestinal peristalsis with greater sensitivity than radiographs but unlike radiographs is user and experience dependent. Therefore its findings may not have the same clinical significance, and it should be used with caution.
| Stage | Systemic Signs | Abdominal Signs | Radiographic Signs | Management |
|---|---|---|---|---|
| IA Suspected | Temperature instability, apnea, bradycardia, lethargy | Mild abdominal distention, emesis, high gastric residuals, fecal occult blood | Normal, nonspecific mild intestinal dilation, mild ileus | Bowel rest (NPO + OGT) Antibiotics (4-7 days) Serial exams + labs AXR q12-24h |
| IB Suspected | Same as IA | Same as IA + gross fecal blood | Same as IA + intestinal dilation | Same as IA |
| IIA Definite Mildly ill | Same as IA | Same as IB + absent bowel sounds, ± abdominal tenderness | Same as IB + pneumatosis intestinalis | Bowel rest (NPO + OGT) Antibiotics (7-10 days) Serial exams + labs AXR q8-12h Supportive treatment for sepsis |
| IIB Definite Moderately ill | Same as IA + mild metabolic acidosis and thrombocytopenia | Same as IIA + abdominal tenderness, ± abdominal cellulitis, ± RLQ mass | Same as IIA + portal venous gas, ± ascites | Bowel rest (NPO + OGT) Antibiotics (14 days) Serial exams + labs AXR q6-8h Supportive treatment for sepsis Consider surgery based on relative indications and clinical judgment |
| IIIA Advanced Severely ill Bowel intact | Same as IIB + combined metabolic and respiratory acidosis, DIC, severe apnea, bradycardia, hypotension, and neutropenia | Same as IIB + marked abdominal tenderness and distention, peritonitis | Same as IIB + ascites | Bowel rest (NPO + OGT) Antibiotics (14 days) Serial exams + labs AXR q6-8h Supportive treatment for septic shock Consider surgery based on relative indications and clinical judgment |
| IIIB Advanced Severely ill Bowel perforated | Same as IIIA | Same as IIIA | Same as IIIA + pneumoperitoneum | Same as IIIA + surgery |
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