Andersons pediatric cardiology 1917

Table 73.2 Lymphatic Insufficiency in the Fontan Circulation Etiology Manifestations Treatment Plastic bronchitis Elevated intralymphatic pressure Cough Pulmonary vasodilation Increased

behind a proteinaceous material composed of fibrin and inflammatory cells that ultimately coalesce into “plastic casts” of the airway (Fig 73.21).191 These casts cause obstruction of the airways, leading to cough, to ventilation-perfusion mismatch, and, in severe cases, to asphyxia (Table 73.2).186,191–193

Exacerbations are more common in the winter months and may be precipitated

by respiratory infections The onset often occurs within a few years of the

Fontan procedure, and the condition is more common in those who had

chylothorax at the time of surgery.193

FIG 73.21 Expectorated cast from a patient with plastic bronchitis after

Fontan operation (From Avitabile CM, Goldberg DJ, Dodds K, et al A multifaceted approach to the management of plastic bronchitis after

cavopulmonary palliation Ann Thorac Surg 2014;98[2]:634–640.)

Table 73.2

Lymphatic Insufficiency in the Fontan Circulation

Etiology Manifestations Treatment

Plastic bronchitis Elevated intralymphatic pressure Cough Pulmonary vasodilation

Increased lymphatic production Low oxygen

saturations

Inhaled tPA Abnormal lymphatic connections to the

airways

Asphyxia Lymphatic intervention Protein-losing

enteropathy

Elevated intralymphatic pressure Diarrhea Diuretics Increased lymphatic production Ascites Pulmonary vasodilation Abnormal lymphatic connections to the

intestines

Peripheral edema Controlled-release

budesonide Muscle wasting Lymphatic intervention

tPA, Tissue plasminogen activator.

Treatment for plastic bronchitis has evolved rapidly over the past decade as the mechanism of the disease has become clear.194 Medical management

strategies for plastic bronchitis include treatment with bronchodilators, inhaled steroids, and pulmonary vasodilators.191,195 For those with chronic cast

production, inhaled tissue plasminogen activator can be added to the medical regimen to dissolve the fibrin within the casts This treatment can be quite

successful at controlling the symptoms and severity of the disease.191,196

However, although medical therapies may be effective at controlling symptoms, they do not change the underlying abnormalities of the lymphatic vessels nor do they eliminate the connections between the lymphatic vessels and the airways Recent advances in lymphatic imaging and intervention have allowed for a more selective approach to the treatment of plastic bronchitis Using T2 MRI imaging or dye injection into the lymph nodes, the lymphatic system can be visualized and abnormal lymphatic networks can be mapped.187 Once mapped, new interventional techniques for accessing the lymphatic system can be used for the delivery of agents to embolize the network of abnormal lymphatic

vessels, thereby reducing the leakage of lymphatic fluid into the airways and eliminating the formation of casts.189,194,197 The early experience with this

technique is encouraging Its use is expanding, and it has the potential to become

a definitive therapy for those who develop this complication (Fig 73.22).197

FIG 73.22 Dynamic contrast-enhanced magnetic resonance lymphangiogram (A) and lymphangiogram (B) images of the central lymphatic system of a patient with plastic bronchitis Both figures

demonstrate a dilated and tortuous thoracic duct (arrow), pulmonary lymphatic vessels with retrograde flow (arrowheads) and areas of pulmonary lymphatic perfusion (box) (From Dori Y, Keller MS, Rome JJ, et

al Percutaneous lymphatic embolization of abnormal pulmonary lymphatic

flow as treatment of plastic bronchitis in patients with congenital heart

disease Circulation 2016;133[12]:1160–1170.)

Protein-Losing Enteropathy

Like plastic bronchitis, PLE is a consequence of lymphatic insufficiency In the case of PLE, the abnormal lymphatic connections form between the lymphatics originating in the liver and the small intestine.188 These abnormal connections allow protein-rich lymphatic fluid to drain from the high-pressure lymphatic system into the low-pressure gastrointestinal tract Over time, this results in a profound loss of proteins and a phenotype characterized by diarrhea, extreme muscle wasting, particularly of the extremities, and often a combination of

peripheral edema and chronic ascites.186,198 Although 5-year survival after PLE diagnosis has improved dramatically over the past 2 decades (from 50% to

88%), the disease remains severely debilitating, with a significant impact on quality and duration of life.199,200 In addition to the phenotypic abnormalities, patients with PLE have abnormalities in bone structure and in the characteristics

of the immune system.148,201 The diseases present some years after the Fontan operation Although there is an association with complex heart disease, including