Yoav Dori

Percutaneous Lymphatic Embolization of Abnormal Pulmonary Lymphatic Flow as Treatment of Plastic Bronchitis in Patients With Congenital Heart Disease

Background— Plastic bronchitis is a potentially fatal disorder occurring in children with single-ventricle physiology, and other diseases, as well, such as asthma. In this study, we report findings of abnormal pulmonary lymphatic flow, demonstrated by MRI lymphatic imaging, in patients with plastic bronchitis and percutaneous lymphatic intervention as a treatment for these patients. Methods and Results— This is a retrospective case series of 18 patients with surgically corrected congenital heart disease and plastic bronchitis who presented for lymphatic imaging and intervention. Lymphatic imaging included heavy T2-weighted MRI and dynamic contrast-enhanced magnetic resonance lymphangiogram. All patients underwent bilateral intranodal lymphangiogram, and most patients underwent percutaneous lymphatic intervention. In 16 of 18 patients, MRI or lymphangiogram or both demonstrated retrograde lymphatic flow from the thoracic duct toward lung parenchyma. Intranodal lymphangiogram and thoracic duct catheterization was successful in all patients. Seventeen of 18 patients underwent either lymphatic embolization procedures or thoracic duct stenting with covered stents to exclude retrograde flow into the lungs. One of the 2 patients who did not have retrograde lymphatic flow did not undergo a lymphatic interventional procedure. A total of 15 of 17(88%) patients who underwent an intervention had significant symptomatic improvement at a median follow-up of 315 days (range, 45–770 days). The most common complication observed was nonspecific transient abdominal pain and transient hypotension. Conclusions— In this study, we demonstrated abnormal pulmonary lymphatic perfusion in most patients with plastic bronchitis. Interruption of the lymphatic flow resulted in significant improvement of symptoms in these patients and, in some cases, at least temporary resolution of cast formation.

Successful Treatment of Plastic Bronchitis by Selective Lymphatic Embolization in a Fontan Patient

Plastic bronchitis is a rare and often fatal complication of single-ventricle surgical palliation after total cavopulmonary connection. Although lymphatic abnormalities have been postulated to play a role in the disease process, the etiology and pathophysiology of this complication remain incompletely understood. Here we report on the etiology of plastic bronchitis in a child with total cavopulmonary connection as demonstrated by magnetic resonance (MR) lymphangiography. We also report on a new treatment of this disease. The patient underwent noncontrast T2-weighted MR lymphatic mapping and dynamic contrast MR lymphangiography with bi-inguinal intranodal contrast injection to determine the anatomy and flow pattern of lymph in his central lymphatic system. The MRI scan demonstrated the presence of a dilated right-sided peribronchial lymphatic network supplied by retrograde lymphatic flow through a large collateral lymphatic vessel originating from the thoracic duct. After careful analysis of the MRI scans we performed selective lymphatic embolization of the pathologic lymphatic network and supplying vessel. This provided resolution of plastic bronchitis for this patient. Five months after the procedure, the patient remains asymptomatic off respiratory medications.

End-organ consequences of the Fontan operation: liver fibrosis, protein-losing enteropathy and plastic bronchitis

The Fontan operation, although part of a life-saving surgical strategy, manifests a variety of end-organ complications and unique morbidities that are being recognised with increasing frequency as patients survive into their second and third decades of life and beyond. Liver fibrosis, protein-losing enteropathy and plastic bronchitis are consequences of a complex physiology involving circulatory insufficiency, inflammation and lymphatic derangement. These conditions are manifest in a chronic, indolent state. Management strategies are emerging, which shed some light on the origins of these complications. A better characterisation of the end-organ consequences of the Fontan circulation is necessary, which can then allow for development of specific methods for treatment. Ideally, the goal is to establish systematic strategies that might reduce or eliminate the development of these potentially life-threatening challenges.

MRI of Lymphatic Abnormalities After Functional Single-Ventricle Palliation Surgery

OBJECTIVE Protein-losing enteropathy (PLE) and plastic bronchitis are serious complications that occur after single-ventricle surgery. A lymphatic cause for these conditions has been proposed, but imaging correlation has not been reported. The objective of this study was to evaluate lymphatic abnormalities in patients after functional single-ventricle palliation compared with patients with non-single-ventricle congenital heart conditions using T2-weighted MR lymphangiography. MATERIALS AND METHODS We retrospectively reviewed imaging data from 48 patients who underwent T2-weighted MR lymphangiography in our institution between May 1, 2012, and October 24, 2012. The patients were divided into four groups: patients who underwent superior cavopulmonary connection, patients who underwent total cavopulmonary connection, patients with total cavopulmonary connection and lymphatic complications, and patients with non-single-ventricle cardiac anomalies. RESULTS There were 38 patients with single ventricles in this study. The lymphatic abnormalities observed in these patients included thoracic duct dilation greater than 3 mm (31%), lymphangiectasia and lymphatic collateralization (78%), and tissue edema (86%). There were five patients with PLE, one patient with plastic bronchitis, and one patient with chronic chylous effusions and superior cavopulmonary connection. The patients with PLE and plastic bronchitis had statistically significant larger thoracic duct maximal diameters (median, 3.9 mm; range, 3-7.2 mm) than did the other patients with total cavopulmonary connection (p < 0.01). In the two-ventricle patient group, there were no abnormal lymphatic findings. CONCLUSION Lymphatic abnormalities are found in many patients after functional single-ventricle palliation. T2-weighted unenhanced MRI is capable of anatomic assessment of the lymphatic system in this patient population and has promise for guiding treatment in the future.

Dynamic Contrast-enhanced MR Lymphangiography: Feasibility Study in Swine

PURPOSE To demonstrate the feasibility of dynamic four-dimensional ( 4D four-dimensional ) intranodal contrast material-enhanced magnetic resonance (MR) lymphangiography with inguinal lymph node injection of gadopentetate dimeglumine. MATERIALS AND METHODS All procedures were performed in accordance with the guidelines on the use of animals in research and were approved by the animal care and use committee. Five swine underwent nonenhanced MR lymphangiography with a heavily T2-weighted MR sequence, bilateral inguinal lymph node injection of 2 mL of undiluted gadopentetate at a rate of 1 mL/min, and 60 minutes of MR imaging with T1-weighted high-spatial- and high-temporal-resolution MR angiography. Images were reviewed by a radiologist with expertise in lymphatic imaging and a pediatric cardiac MR imaging specialist for visualization of the thoracic duct ( TD thoracic duct ). Categorical variables were compared by using the exact conditional McNemar test. A difference with a P value less than .05 was considered significant. RESULTS The TD thoracic duct was visualized in three of the five animals (60%) on T2-weighted images. In contrast, the TD thoracic duct was visualized in all five of the animals (100%) after contrast agent injection (P = .25). The median time for flow of the contrast agent through the lymphatic system to the TD thoracic duct outlet was 244 seconds (range, 201-387 seconds). Enhancement was seen in the TD thoracic duct up to 1 hour after injection. All animals survived without any complications. CONCLUSION Dynamic 4D four-dimensional contrast-enhanced MR lymphangiography with intranodal injection of gadopentetate dimeglumine is feasible, produces good images of the central lymphatic system, and demonstrates the time course of flow of contrast agent up the central lymphatic ducts. On the basis of the results of this initial animal experiment, it appears that dynamic 4D four-dimensional contrast-enhanced MR lymphangiography is potentially feasible and safe with commercially available contrast agents.

A Multifaceted Approach to the Management of Plastic Bronchitis After Cavopulmonary Palliation

BACKGROUND Plastic bronchitis is a rare, potentially life-threatening complication after Fontan operation. Hemodynamic alterations (elevated central venous pressure and low cardiac output) likely contribute to the formation of tracheobronchial casts composed of inflammatory debris, mucin, and fibrin. Pathologic studies of cast composition support medical treatment with fibrinolytics such as inhaled tissue plasminogen activator (t-PA). METHODS This was a retrospective case series of medical, surgical, and catheter-based treatment of patients with plastic bronchitis after cavopulmonary palliation. RESULTS Included were 14 patients (86% male, 93% white). Median age at Fontan operation was 2.7 years (range, 1.2 to 4.1 years), with median interval to plastic bronchitis presentation of 1.5 years (range, 9 days to 15.4 years). Cast composition was available for 11 patients (79%) and included fibrin deposits in 7. All patients were treated with pulmonary vasodilators, and 13 (93%) were treated with inhaled t-PA. Hemodynamically significant lesions in the Fontan pathway were addressed by catheter-based (n=9) and surgical (n=3) interventions. Three patients (21%) underwent heart transplantation. Median follow-up was 2.7 years (range, 0.6 to 8.7 years). Symptoms improved, such that 6 of 13 patients (46%) were weaned off t-PA. Rare or episodic casts are successfully managed with outpatient t-PA in most of the other patients. Of the 3 patients who underwent heart transplant, 2 are asymptomatic and 1 has recurrent casts in the setting of elevated filling pressures and rejection. CONCLUSIONS A systematic step-wise algorithm that includes optimization of hemodynamics, aggressive pulmonary vasodilation, and inhaled t-PA is an effective treatment strategy for patients with plastic bronchitis after cavopulmonary connection.

X-ray magnetic resonance fusion modality may reduce radiation exposure and contrast dose in diagnostic cardiac catheterization of congenital heart disease.

Radiation exposure in the pediatric population may increase the risk of future malignancy. Children with congenital heart disease who often undergo repeated catheterizations are at risk. One possible strategy to reduce radiation is to use X‐ray Magnetic Resonance Fusion (XMRF) to facilitate cardiac catheterization.

Percutaneous closure of patent ductus arteriosus in small infants with significant lung disease may offer faster recovery of respiratory function when compared to surgical ligation

To describe our experience with percutaneous closure of patent ductus arteriosus (PDA) in small infants and compare outcomes to matched surgical patients.

Acute Effects of Embolizing Systemic-to-Pulmonary Arterial Collaterals on Blood Flow in Patients With Superior Cavopulmonary Connections A Pilot Study

Background—The significance and optimal treatment of systemic-to-pulmonary arterial collateral (SPC) vessels in single ventricle patients are poorly understood. The acute efficacy of SPC embolization has not been demonstrated in a quantifiable fashion. We sought to assess the acute efficacy of SPC embolization on blood flow as quantified by phase contrast magnetic resonance imaging and hypothesized that embolization acutely decreases SPC flow and increases systemic blood flow (QS). Methods and Results—Six superior cavopulmonary connection patients underwent SPC flow quantification by phase contrast magnetic resonance imaging, including quantification of superior and inferior caval, total pulmonary artery, total pulmonary vein, ascending and descending aortic flows (QSVC, QIVC, QPA, QPV, QAo, and QDao, respectively), both immediately before and after cardiac catheterization with coil and particle embolization of angiographically evident SPC vessels. All studies were performed under a single anesthetic. After embolization, we found a significant decrease in SPC flow of 0.9 (range, 0.6–1.3) L/(min·m2) (P=0.03); a median reduction of 47% (range, 32–60). There was a significant decrease in the median QP:QS from 1.3 before to 0.8 after embolization (P=0.03), and an increase in QS from a median of 3.4 to 4.4 L/(min·m2) (P<0.05), and QSVC from a median of 1.7 to 2.3 L/(min·m2) (P=0.03). Conclusions—We report on the acute efficacy of SPC embolization, demonstrating a significant decrease in SPC flow and QP:QS and increase in QSVC and QS. Further studies are needed to assess the durability of the procedure and the effect on Fontan and longer-term outcomes.

Accuracy of conventional oximetry for flow estimation in patients with superior cavopulmonary connection: a comparison with phase-contrast cardiac MRI.

Background—Cardiac catheterization is routinely used as a diagnostic tool in single ventricle patients with superior cavopulmonary connection. This physiology presents inherent challenges in applying the Fick principle to estimate flow. We sought to quantitatively define the error in oximetry-derived flow parameters using phase-contrast cardiac MRI (CMR) as a reference. Methods and Results—Thirty patients with superior cavopulmonary connection who underwent combined CMR and catheterization between July 2008 and June 2012 were retrospectively analyzed. Estimates of flow and resistance calculated using the Fick equation were compared with CMR measurements. Oximetry underestimated CMR-measured pulmonary blood flow (Qp) by an average of 1.1 L/min per m2 or 32% of the CMR value (P<0.0001). Oximetry overestimated systemic blood flow (Qs) by an average of 0.5 L/min per m2 or 15% of the CMR value (P=0.009). There was no correlation between the Qp:Qs ratio derived by Fick and that measured by CMR (&rgr;c=0.01). The error in the Fick Qp correlated moderately with the measured systemic-to-pulmonary arterial collateral flow (r=0.39). The median total oxygen consumption calculated using combined CMR and oximetry data was 173 mL/min per m2, higher than the assumed values used to calculate flows by the Fick equation. The upper body circulation received on average 51% of systemic blood flow while conducting only 39% of total body metabolism. Conclusions—Fick-derived estimates of flow are inherently unreliable in patients with superior cavopulmonary connections. Integrating flows measured by CMR and pressures measured by catheter will provide the best characterization of superior cavopulmonary connection physiology.