Abdul H Khan1, Deepthi Hoskoppal2, T K Susheel Kumar3, Lindsey Bird4, Kimberly Allen4, Hannah Lloyd4, Christopher J Knott-Craig3, B Rush Waller1, Shyam Sathanandam1. 1. Department of Pediatrics, Division of Pediatric Cardiology, University of Tennessee Health Science Center, Memphis, Tennessee. 2. Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee. 3. Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee. 4. LeBonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, Tennessee.
Abstract
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.
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.