The Pediatric Congenital Heart Association is thrilled to bring our latest in the series titled Research Matters. In our commitment to make research meaningful and accessible to patients and families, volunteers along with members of our Medical Advisory Board have created summaries of important research and describe what it means for you.
Plastic bronchitis (PB) is a rare but life-threatening complication that can arise following the Fontan procedure. PB patients develop large, rubbery plugs or “casts” that obstruct the airways and can lead to asphyxiation. Problems of the lymphatic system, a network of organs and vessels that drains fluid (lymph) from tissues and protects the body from infection, are thought to play a role in the disease process, but how PB develops remains poorly understood. The journal Circulation recently published a study reporting findings of abnormal circulation of lymph fluid in most patients with surgically corrected congenital heart disease (CHD) and PB and significant improvement of symptoms in these patients following interventional approaches to block the abnormal flow of lymph. These findings highlight an innovative procedure that has the potential to offer significant long-term improvement of symptoms in patients with PB. You can view the abstract here.
About this Study:
- This retrospective study expands on a previous case report1 and determines the extent of abnormalities in the lymphatic system of PB patients and the clinical response following interventions to block improper lymphatic flow. A retrospective study looks back in time using existing medical data and records.
- The retrospective case series comprises 18 patients (between the ages of two and 15) with PB and surgically corrected CHD who underwent lymphatic imaging and interventions at the Children’s Hospital of Philadelphia.
- The authors use advanced lymphatic imaging tests, including dynamic contrast-enhanced magnetic resonance (MR) lymphangiography to determine the anatomy of the patients’ lymphatic systems and the patterns of lymphatic flow.
- In 16 of 18 patients, lymphatic imaging revealed abnormal (retrograde) flow of lymph fluid from the thoracic duct into lung tissue.
- Lymphatic embolization, a procedure that seals leaks in the lymphatic system using coils, special oil-based contrast agents or glue, was performed in 17 of 18 patients.
- Significant improvements in PB symptoms were observed in 15 of the 17 patients who underwent lymphatic embolization at a median follow-up of 315 days.
- Immediate complete resolution of PB symptoms was reported in 10 of 16 patients, with one patient being cast-free for over two years.
What this Means:
- Abnormal pulmonary lymphatic flow, which the authors termed pulmonary lymphatic perfusion syndrome, is likely to be a major underlying cause of PB in Fontan patients with elevated central venous pressure (CVP).
- Advances in lymphatic imaging tests will enable the detection of lymphatic flow disorders in PB patients that may go undetected using conventional methods.
- Selective lymphatic embolization provides a safe and effective alternative to surgical thoracic duct ligation, which has also been used to treat PB.
- Although short-term results are encouraging, the medium- and long-term effects of lymphatic embolization in PB patients remain unknown. A study that follows patients over a period of years (a longitudinal study) will be required to determine long-term outcomes of this treatment.
- This study provides hope for PB patients and favorable long-term treatment outcomes have the potential to mitigate the need for heart transplantation in sufferers of PB.
1 Dori Y, Keller MS, Rychik J, and Itkin M. Successful treatment of plastic bronchitis by selective lymphatic embolization in a Fontan patient. Pediatrics. 2014;134:e590-e595.
Michael Kim is a scientist and a father of two little girls. His oldest daughter Sydney was born with total anomalous pulmonary venous return (TAPVR) in 2011. He received his B.A. in Biochemistry from the University of California, Berkeley and his Ph.D. in Cell and Structural Biology from the University of Illinois, Urbana-Champaign. He and his family currently live in Miami, FL.