Transcatheter device and minimally invasive method for constricting and adjusting blood flow through a blood vessel
Inventors
Goldie, James H. • LaBrecque, Brendan • Galea, Anna M • Klem, Eric • Doyle, Thomas • Cohen, Ian • Robinson, Tim
Assignees
Publication Number
US-11278289-B2
Publication Date
2022-03-22
Expiration Date
2037-01-31
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Abstract
A pulmonary artery flow restrictor system includes a funnel shaped membrane with a proximal base and a restrictive distal opening which is stretchable to larger sizes. A self-expanding frame is attached to the proximal base of the membrane for securing the membrane within the pulmonary artery.
Core Innovation
The invention is a pulmonary artery flow restrictor system that includes a funnel-shaped membrane with a proximal base having a wide area opening and a restrictive distal narrow opening designed to control blood flow through the pulmonary artery. A self-expanding stent-like frame is attached to the proximal base of the membrane to secure it within the pulmonary artery and includes spaced arms that extend upwardly and over the membrane's restrictive distal opening. The membrane is made of an inelastic, stretchable polymer such as expanded polytetrafluoroethylene (ePTFE) that can be irreversibly expanded by balloon catheter to adjust the size of the restrictive opening, thereby varying blood flow rate.
The pulmonary artery flow restrictor is deployed minimally invasively via a transcatheter delivery device, which includes an inner guide wire lumen and a retractable lumen to constrain and release the device. The frame may be removably attached to the inner lumen by deployment pins cooperating with eyelets on the frame, allowing precise placement and potential repositioning. The frame is preferably made of a shape memory alloy such as Nitinol, which expands to maintain contact with the artery wall, including arms that cross and extend into pulmonary artery branches to anchor the membrane against blood flow.
The problem being addressed by this invention is that children with congenital heart disease (CHD) who have excessive pulmonary blood flow often require surgical pulmonary artery banding to restrict flow. Existing surgical methods can distort pulmonary artery anatomy and require additional surgeries for adjustment, causing complications and limiting future interventions. The invention seeks to provide a minimally invasive, transcatheter device and method that enables pulmonary blood flow restriction that is adjustable in situ without open surgery and avoids distortion of the arteries.
This minimally invasive pulmonary artery resistor allows for incremental adjustment of flow resistance in response to patient growth or therapy needs by balloon expansion within the artery. It replaces multiple surgical interventions with a single implantation and subsequent percutaneous adjustments, reducing intensive care recovery and hospital time. The device also has potential application in regions with limited surgical access, improving palliation options for children with CHD worldwide.
Claims Coverage
The patent includes one independent claim detailing a pulmonary artery flow restrictor system with specific structural and functional features.
Funnel-shaped membrane with variable restrictive opening
The system includes a funnel-shaped membrane installed in an artery with a wide base opening to receive arterial blood flow and a distal narrower spout to restrict blood flow to a predetermined rate.
Self-expanding stent structure supporting the membrane
A self-expanding stent structure is associated with the membrane to support it within the artery, featuring spaced arms that extend upwardly over the funnel membrane's distal narrower spout.
Inelastic membrane material enabling irreversible expansion
The funnel-shaped membrane is made of an inelastic material so that if the distal spout is expanded by a balloon catheter, the membrane retains its expanded shape.
Specific dimensions of membrane openings
The wide base opening is about 10-18 mm in diameter, and the distal narrower spout is about 0.5-6 mm in diameter.
Materials for membrane and stent structure
The membrane is made of polymers such as polytetrafluoroethylene (ePTFE), and the self-expanding stent structure is made of shape memory alloy including Nitinol.
Stent structure comprising spaced upper and lower apexes
The self-expanding stent structure includes a bent wire forming spaced lower apexes secured to the membrane base and spaced upper apexes, with arms extending from upper apexes crossing above the membrane's distal opening.
Flexible lines for collapsing the stent structure
The system may include one or more flexible lines connected to the self-expanding stent structure to enable its collapse for removal.
Transcatheter delivery device with inner and retractable lumens
The system further includes a transcatheter device for delivering the membrane and stent structure into the pulmonary artery, comprising an inner lumen about a guide wire and a retractable lumen movable relative to the inner lumen.
Removable attachment of stent structure to delivery device
The self-expanding stent structure is removably attached to the inner lumen via pins on the lumen engaging eyelets on the stent structure.
Predetermined blood flow rate restriction
The pulmonary artery flow restrictor is configured to restrict blood flow to a predetermined rate of 1.5-2 liters per minute.
These inventive features describe a minimally invasive, adjustable pulmonary artery flow restrictor system comprising a funnel-shaped membrane and self-expanding stent frame, manufactured from specific materials and sizes, delivered by a transcatheter device with provisions for deployment and possible retrieval.
Stated Advantages
Avoids complications associated with conventional surgical pulmonary artery banding, such as distortion of pulmonary arteries.
Enables non-surgical, minimally invasive implantation and adjustable blood flow restriction.
Allows incremental adjustment of pulmonary blood flow resistance in situ via balloon catheter expansion.
Reduces or eliminates recovery time in intensive care and hospital stay compared to open surgery.
Replaces multiple surgical procedures with a single operation and scheduled adjustments.
Potentially improves treatment options in regions with limited surgical access.
Documented Applications
Treatment of congenital heart disease in infants and children with excessive pulmonary blood flow by restricting pulmonary artery blood flow.
Minimally invasive palliation for patients with ventricular septal defects and other congenital heart malformations where surgical repair is not immediately feasible.
Use in parts of the world where surgical access is limited or nonexistent to improve care of children with congenital heart disease.
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