Percutaneous bilateral pulmonary artery banding using a re-expandable covered stent: preliminary animal study

Backgrounds: Bilateral pulmonary artery banding (bPAB) followed by ductal stenting has been reported as a stage 1 palliation of hypoplastic left heart syndrome (HLHS). However, hybrid strategy, which includes median sternotomy for bPAB, has been a common approach. In this preliminary experiment, we investigated the feasibility of a transcatheter bPAB followed by debanding using a reexpandable covered stent for comprehensive transcathter stage 1 palliation. Methods: Polyurethane was coated on Palmaz medium (Palmaz) or Express Vascular LD (large diameter) (Express) stents using the dipping method. The stent was mounted on a balloon, tied at the midpoint with a silk thread so as to implant the stent in the bilateral pulmonary arteries in a dumbbell shape, which consequently created bPAB. Under general anesthesia, we intended to create bPAB in 5 piglets whose median body weight was 10.1 kg. Once bPAB was created successfully, we performed debanding with balloon dilatation. Results: Eight stents (Palmaz and Express, 4 each) were implanted in 4 piglets, but one piglet died while manipulating a long sheath in the right ventricular outflow tract associated with fetal arrhythmia. Meanwhile, debanding was attempted of 4 stents (Palmaz and Express, 2 each) in 3 piglets because another piglet died suddenly of right ventricular failure following bPAB. All of the Palmaz stents were successfully implanted in a dumbbell shape, while only 2 Express stents could be implanted in the dumbbell shape. The Palmaz stents were debanded successfully, while only one Express stent could be redilated sufficiently because cells of the mid-portion overlapped each other. Conclusions: Transcather PAB could be created using a covered stent implanted in a dumbbell shape. The material and design of the stents were key issues not only for the creation of PAB but also for debanding. Further innovation of stents will be necessary for clinical utilization of this technique as a comprehensive transcatheter stage 1 palliation of HLHS.