Transcatheter Pulmonary Flow Restrictors: Current Trends and Future Perspectives

Transcatheter Pulmonary Flow Restrictors (TPFRs) represent a significant advancement in managing pulmonary blood flow for congenital heart disease patients. However, there is a paucity of comprehensive studies addressing the diversity of these devices and identifying their critical features. This review aims to consolidate the existing knowledge on TPFRs, pinpoint crucial design and development aspects, identify gaps in current practices, and spotlight directions for future research and advancement. An exhaustive search was conducted across multiple databases, using specific search terms related to transcatheter and percutaneous pulmonary artery banding. Between 2005 and 2024, 82 patients were reported to have received TPFR implants, including fenestrated atrial septal defect occluders, diabolo-shaped stents, and MVP™ Micro Vascular Plug with polytetrafluoroethylene (PTFE) membranes partially removed. Microvascular plugs were the most commonly used and the most successful devices. However, the primary complications and challenges associated with MVPs included pulmonary overflow, unprotected flow to the right upper lobe, difficulty in creating an appropriately sized fenestration, the need for device replacement due to incorrect sizing, distal migration into the right pulmonary artery, left pulmonary artery stenosis, partial device collapse, thrombosis, jailing of the right upper lobe, potential injury to the pulmonary arterial wall, as well as device fracture and infection. TPFRs can be categorized based on the duration they are designed to remain within the pulmonary artery. Strategies should be devised to enable the device's easy removal without harming the pulmonary arterial wall while also preventing embolization. The ideal device should minimize migration, embolization, thrombosis, inflammation, and endothelialization risks. It should also prevent peri-device flow and adapt to the growth of the pulmonary artery, ensuring long-term efficacy and safety. The long-term outcomes and the potential for employing biodegradable and smart biomaterials remain areas for further investigation. Successful development of these devices requires a collaborative effort among biomaterial engineers, device developers, and interventional cardiologists.