Surgical Removal of Percutaneously Placed Pulmonary Flow Reducers

Transcatheter palliation with pulmonary flow reducers in premature neonates with massive left-to-right shunts or high-risk single ventricle neonates is an effective strategy to prevent pulmonary overcirculation. The use of these modified vascular plugs helps regulate excessive blood flow within the pulmonary circulation to prevent complications that arise from congenital heart disease. This strategy allows for bridging high-risk neonates to the operating room. In this operative video, the authors describe the technique for removing pulmonary flow reducers that have remained in place for varying lengths of time. 
 
The first patient presented here was born prematurely at 28 weeks and 5 days. His birth weight was just more than 1000 grams. He had multiple ventricular septal defects on the prenatal echocardiogram. His other comorbidities included caudal regression syndrome, bilateral leg arthrogryposis, and a solitary kidney 
 
A postnatal echocardiogram confirmed the presence of multiple muscular VSDs, with at least one large apical defect, and a perimembranous ventricular septal defect. 
 
He was initially mechanically ventilated for 16 days after birth and then extubated to noninvasive ventilation. He continued to show signs and symptoms of refractory heart failure and was therefore referred for catheter based initial palliation at fpur weeks of age. At that point, his corrected gestational age was 32 weeks, and he weighed 1.24 kilograms. 
 
He was taken to the cardiac catheterization laboratory, where, through a right internal jugular venous approach, two modified vascular plugs were deployed into each branch pulmonary artery. Post-deployment echocardiogram showed good positioning of both the flow reducers. The measured gradients across each of the branch pulmonary arteries was between 2 and 3 meters per second. Following placement of the flow reducers, his pulmonary edema resolved, and he was discharged home at three months of age, weighing 4.6 kilograms. 
 
At eight months of age, then weighing 5.6kg, he was referred for percutaneous closure of the persistently large ventricular septal defect and removal of the flow reducers. 
 
An attempt was made to snare and remove the left flow reducer; however, the device was only partially removed, and the remnant embolized distally. The plan to remove the right flow reducer was abandoned, and attention was turned to the muscular VSD, which was closed with the deployment of a 10 mm Amplatzer device. Transesophageal echocardiography confirmed complete closure of the muscular VSD with the device. 
 
At 14 months of age, he was referred for surgical closure of the remnant perimembranous VSD and removal of the right flow reducer. He had remained free of heart failure symptoms up to this time and was thriving. The embolized left pulmonary flow reducer did not result in any hemodynamic consequences, and no attempt was made to retrieve this device during the procedure. 
 
A median sternotomy was performed, and cardiopulmonary bypass was initiated and a pulmonary artery vent wasplaced. The perimembranous VSD was closed with a Dacron patch. The main pulmonary artery was opened, and the tip of the flow reducer in the right pulmonary artery was identified and grasped. The flow reducer was completely incorporated into the endothelium. The flow reducer was slowly and gently separated from the vessel wall using a Penfield dissector, with care taken to avoid causing any damage to the vessel wall. Once the device was removed, the pulmonary artery was closed. The remainder of the operation was completed in a routine fashion. Four months after discharge, his VSDs remained closed, and there was unobstructed flow through the right pulmonary artery. 
 
The second patient was a term infant with a postnatal diagnosis of hypoplastic left heart syndrome. He presented with shock and hypoxic-ischemic encephalopathy. 
 
He underwent hybrid palliation with the placement of bilateral pulmonary flow reducers, and stents in the patent ductus arteriosus and interatrial septum. 
 
At four months of age, he underwent a cardiac catheterization prior to his second-stage palliation. The left pulmonary artery device was in a good position, but the right pulmonary artery stent had migrated into the right lower lobe branch, leaving the right upper lobe unprotected. The distal pulmonary artery pressures were elevated, and the patient underwent a delayed Norwood palliation along with removal of the flow reducers. 
 
After initiation of cardiopulmonary bypass and ligation of the ductus arteriosus, the main pulmonary artery was transected. The pin of the left pulmonary flow reducer was found easily and grasped with a hemostat. The pin was somewhat adherent to the endothelium and had to be pried free. A Penfield retractor was used to carefully dissect the device from the pulmonary artery endothelium. In contrast to the first patient, it was relatively easy to dissect this device, but still it involved some blunt dissection to free the device. The right device was more difficult to reach, since it had migrated into the right lower lobe. However, after some struggle, the tip was identified through the open pulmonary artery bifurcation and was removed in a similar fashion as the left. The rest of the operation was completed as planned. The patient made a good recovery and was discharged home on postoperative day seven with good, unobstructed flows into the branch pulmonary arteries. 
 
Thisangiogram is from another patient who had bilateral flow reducers removed after five months. It shows unobstructed blood flow through both of the branch pulmonary arteries. 
 
During the last two years, eight patients have undergone surgical removal of these pulmonary flow restrictors. The duration of flow restrictors ranged from four to 403 days. All retrievals were uncomplicated, with no injury to the pulmonary arteries and no need for patch augmentation. 
 
To conclude, percutaneous pulmonary flow reducers are an effective palliative strategy for premature, low-weight infants with massive left-to-right shunts. Caution should be exercised when removing these devices in the catheterization lab, especially if they have been in for three months or longer. After three months, it is better to remove these devices surgically. Surgical removal of the flow reducers can be safely performed with care and provides a good result without the need for patch augmentation of the branch pulmonary arteries. 

References

1. Sperotto, F., Lang, N., Nathan, M., Kaza, A., Hoganson, D. M., Valencia, E., Odegard, K., Allan, C. K., da Cruz, E. M., Del Nido, P. J., Emani, S. M., Baird, C., and Maschietto, N. (2023). Transcatheter palliation with pulmonary artery flow restrictors in neonates with congenital heart disease: Feasibility, outcomes, and comparison with a historical Hybrid Stage 1 cohort. Circulation: Cardiovascular Interventions, 16(12). https://doi.org/10.1161/circinterventions.123.013383
2. Haddad RN, Bentham J, Adel Hassan A, Al Soufi M, Jaber O, El Rassi I, Kasem M. Outcomes of manually modified microvascular plugs to pulmonary flow restrictors in various congenital heart lesions. Front Cardiovasc Med. 2023 Jul 10;10:1150579. doi: 10.3389/fcvm.2023.1150579. PMID: 37492157; PMCID: PMC10363685.

Disclaimer

The information and views presented on CTSNet.org represent the views of the authors and contributors of the material and not of CTSNet. Please review our full disclaimer page here.