Oval stent

A system for providing compliance to a pulmonary artery, the system comprising:

• a catheter comprising a catheter distal portion sized to be percutaneously advanced within a patient's vasculature to a pulmonary artery;
• and
• a stent releasably secured to the catheter distal portion and comprising an elastically deformable stent frame lattice having a biased non-circular cross-sectional shape and being sized for placement in the pulmonary artery, the elastically deformable stent frame lattice forming a lumen extending between a first opening and a second opening of the stent frame lattice;
• wherein the stent frame lattice is adapted to:
• be percutaneously delivered into the pulmonary artery;
• secure to a blood vessel wall of the pulmonary artery;
• assume a biased first configuration outside a body of the patient, the biased first configuration defining an inner flow lumen characterized by a non-circular cross-sectional shape with inwardly-bowed minor-dimension sidewalls, the non-circular cross-sectional shape having a constant angular orientation along a length of the stent frame lattice and defining a first major diameter along a major dimension, a first central minor diameter along a minor dimension, and a first cross-sectional area;
• upon deployment in the pulmonary artery, deform to a second configuration in response to diastolic pressure conditions, in which the stent frame lattice assumes an oval cross-sectional shape with outwardly-bowed minor-dimension sidewalls, a second major diameter, a second central minor diameter that is greater than the first central minor diameter, and a second cross-sectional area that is greater than the first cross-sectional area;
• and
• in response to systolic pressure conditions, transition to a third configuration in which the stent frame lattice assumes a third major diameter along the major dimension that is less than the second major diameter, a third central minor diameter along the minor dimension that is greater than the second central minor diameter, and a third cross-sectional area that is greater than the second cross-sectional area,
• wherein the stent comprises a tension line connecting a first side of the stent frame lattice to a second side of the stent frame lattice and extending across the inner flow lumen along the minor dimension, the tension line being sized to physically hold the stent frame lattice temporarily in the biased first configuration or the second configuration.

A device for providing compliance within a blood vessel, the device comprising:

• a distal stent segment sized for placement in a blood vessel;
• a proximal stent segment;
• an elastically deformable middle stent segment positioned between the distal stent segment and the proximal stent segment, the middle stent segment being adapted to:
• assume a biased first configuration outside of a body in which the middle stent segment has a non-circular cross-sectional shape with inwardly-bowed minor-dimension sidewalls, the non-circular cross-sectional shape defining a first major diameter along a major dimension, a first central minor diameter along a minor dimension, and a first cross-sectional area;
• in response to diastolic pressure conditions within the blood vessel, transition to a second configuration in which the middle stent segment assumes an oval cross-sectional shape with outwardly-bowed minor-dimensional sidewalls, a second major diameter, a second central minor diameter that is greater than the first central minor diameter, and a second cross-sectional area that is greater than the first cross-sectional area;
• and
• in response to systolic pressure conditions within the blood vessel, transition to a third configuration in which the middle stent segment assumes a third major diameter along the major dimension that is less than the second major diameter, a third central minor diameter along the minor dimension that is greater than the second central minor diameter, and a third cross-sectional area that is greater than the second cross-sectional area;
• and
• a lining extending along the middle stent segment to prevent flow of blood through cells of the middle stent segment, the lining not extending along open cells of the distal stent segment or the proximal stent segment.

A method of restoring compliance to a pulmonary artery, the method comprising:

• providing a stent having a biased first configuration having a non-circular cross-sectional shape with inwardly-bowed minor-dimensional sidewalls, a first major diameter, a first central minor diameter, and a first cross-sectional area;
• deploying the stent in the pulmonary artery such that diastolic pressure forces cause the stent to deform to a second configuration having an oval cross-sectional shape with outwardly-bowed minor-dimensional sidewalls, a second major diameter, a second central minor diameter that is greater than the first central minor diameter, and a second cross-sectional area that is greater than the first cross-sectional area;
• increasing flow in the pulmonary artery by allowing the stent to respond to systolic pressure forces by transitioning from the second configuration to a third configuration having a more circular cross-sectional shape including a third major diameter that is less than the first and second major diameters, a third central minor diameter that is greater than the second central minor diameter, and a third cross-sectional area that is greater than the second cross-sectional area;
• and
• cycling the stent between the second configuration and the third configuration in response to cyclically-changing luminal forces of the pulmonary artery on the stent to restore compliance to the pulmonary artery.

A device for restoring pulmonary artery compliance, comprising:

• a stent body comprising an elastically deformable stent frame lattice sized for placement in a pulmonary artery, wherein the stent frame lattice is adapted to:
• assume a biased first configuration defining a non-circular cross-sectional shape with inwardly-bowed minor-dimension sidewalls, the non-circular cross-sectional shape having a constant angular orientation along a length of the stent frame lattice and defining a first major diameter along a major dimension, a first central minor diameter along a minor dimension, and a first cross-sectional area;
• upon deployment in the pulmonary artery, deform to a second configuration in response to diastolic pressure conditions, in which the stent frame lattice assumes an oval cross-sectional shape with outwardly-bowed minor-dimensional sidewalls, a second major diameter, a second central minor diameter that is greater than the first central minor diameter, and a second cross-sectional area that is greater than the first cross-sectional area;
• and
• in response to increasing luminal forces of the pulmonary artery on the stent frame lattice associated with systolic pressure conditions, transition to a third configuration in which the stent frame lattice assumes a third major diameter that is less than the second major diameter, a third central minor diameter that is greater than the second central minor diameter, and a third cross-sectional area that is greater than the second cross-sectional area;
• and
• one or more anchors extending from the stent body and sized to be deployed into engagement with tissue of a branch blood vessel that branches away from, and has a smaller diameter than, the pulmonary artery.