Letter to the Editor
To the Editor:
We read the article by Dong et al.1 with great interest as we too have experienced cor pulmonale in children with acute respiratory distress syndrome (ARDS) supported with veno-venous extracorporeal membrane oxygenation (VV-ECMO). Two previously healthy male children (7 and 8 years of age) on VV-ECMO via dual-lumen cannula were transferred to our facility for evaluation for possible ECMO bridge to lung transplantation (LTx). The 7-year-old boy with a history of autologous bone marrow transplant complicated by bronchiolitis obliterans syndrome developed ARDS in association with acute Mycoplasma pneumoniae pneumonia. He was ventilated for 54 days before starting VV-ECMO and then transferred 6 days later. The second child was healthy until experiencing an immunological response to trimethoprim-sulfamethoxazole leading to ARDS and subsequent irreversible pulmonary fibrosis. He was ventilated on high airway pressures for 6 days before starting VV-ECMO and then transferred to our center 49 days later.
Initially, transthoracic echocardiography identified normal right ventricular (RV) size and function with only trivial tricuspid valve regurgitation for both patients. On VV-ECMO days 28 and 84, respectively, acute bradycardia leading to cardiac arrest occurred for both children. Echocardiograms demonstrated severe RV dilation and dysfunction with flattening of the interventricular septum. Both children died within 2 days of these events. Both patients were found to have significant RV hypertrophy on postmortem examination.
A third 12-year-old child was transferred to our center after 10 weeks of VV-ECMO for ARDS resulting from influenza B pneumonia complicated by methicillin-resistant Staphylococcus aureus. Due to evidence of pulmonary hypertension and reduced RV function upon arrival to our center, as well as our prior experiences, a septal puncture and balloon atrial septostomy was successfully performed to decompress the right heart and allow for oxygenated blood to pass directly to the left atrium. After a 7-month ICU course on VV-ECMO support, he was decannulated with normal RV function and left to right flow at his atrial septostomy and eventually was discharged home from a long-term rehabilitation facility.
Our experience in children is similar as reported by Dong et al.1, where previously healthy patients who develop acute respiratory failure requiring VV-ECMO for an extended period of time are at risk for eventual development of cor pulmonale. In our experience with patients who have chronic lung disease with acute decompensation on VV-ECMO, especially patients with cystic fibrosis who are being bridged to LTx, we have not encountered this issue. We do not know if chronic lung disease may allow the pulmonary vasculature to respond differently or in some way be protective to the development of pulmonary hypertension and cor pulmonale as compared with a patient with previously normal lungs with new ARDS. In conclusion, we agree with Dong et al.1 that clinicians need to be aware of this potential complication as longer durations of support are offered to patients. Centers need to be monitored for this and responding to it aggressively.
Patrick I. McConnell, MD
Department of Cardiothoracic Surgery, Nationwide
Children’s Hospital and Department of Surgery, The Ohio
State University College of Medicine, Columbus, Ohio
Don Hayes, Jr., MD
Section of Pulmonary Medicine, Nationwide Children's
Hospital and Departments of Pediatrics, Internal
Medicine and Surgery, The Ohio State University
College of Medicine, Columbus, Ohio
1. Dong ER, Ng DG, Ramzy D, et al. Acute cor pulmonale in veno-venous extracorporeal membrane oxygenation: Three case reports. ASAIO J 2018.64: e187–e190.