Utility of the Medtronic microvascular plug™ as a transcatheter implantable and explantable pulmonary artery flow restrictor in a swine model

• Published in: Catheterization and cardiovascular interventions Vol. 93; no. 7; pp. 1320 - 1328
• Main Authors: Khan, Abdul H., Hoskoppal, Deepthi, Kumar, T. K. Susheel, Bird, Lindsey, Allen, Kimberly, Lloyd, Hannah, Knott‐Craig, Christopher J., Waller, B. Rush, Sathanandam, Shyam
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-06-2019; Wiley Subscription Services, Inc
• Subjects: Angioplasty; animal models; Arteries; Balloon treatment; Blood flow; Blood pressure; Cardiovascular diseases; coil/device/transcatheter; congenital heart disease; Coronary artery disease; embolization; Feasibility studies; foreign body retrieval; Heart diseases; Histopathology; Hogs; Implantation; interventional devices/innovation; Livestock; Microvasculature; Ostomy; pediatric intervention; pediatrics; Pulmonary arteries; Pulmonary artery; Stenosis; Swine; Systolic pressure; Veins & arteries; Ventricle; foreign body retrieval; pediatric intervention; animal models; coil/device/transcatheter; embolization; interventional devices/innovation; pediatrics; congenital heart disease
• ISSN: 1522-1946; 1522-726X
• DOI: 10.1002/ccd.28162

Background
A surgical pulmonary artery band (PAB) is used to control excessive pulmonary blood flow for certain congenital heart diseases. Previous attempts have been made to develop a transcatheter, implantable pulmonary flow restrictor (PFR) without great success. We modified a microvascular plug (MVP) to be used as a PFR. The objectives of this study were to demonstrate feasibility of transcatheter implantation and retrieval of the modified MVP as a PFR, and compare PA growth while using the PFR versus PAB.
Methods and results
The PFR was implanted in eight newborn piglets in bilateral branch pulmonary arteries (PAs). Immediately post‐PFR implantation, the right ventricular systolic pressure increased from a median of 20–51 mmHg. Transcatheter retrieval of PFR was 100% successful at 3, 6, and 9 weeks and 50% at 12‐weeks post‐implant. A left PAB was placed via thoracotomy in four other newborn piglets. Debanding was performed 6‐weeks later via balloon angioplasty. On follow‐up, the proximal left PA diameters in the PFR and the PAB groups were similar (median 8 vs. 7.1 mm; p = 0.11); albeit the surgical band sites required repeat balloon angioplasty secondary to recurrent stenosis. By histopathology, there was grade II vessel injury in two pigs immediately post‐retrieval of PFR that healed by 12 weeks.
Conclusions
Transcatheter implantation and retrieval of the MVP as a PFR is feasible. PA growth is comparable to surgical PAB, which is likely to require reinterventions. The use of the MVP as a PFR in humans has to be trialed before recommending its routine use.