A flexible connecting rod is manufactured from a rigid material and having a substantially cylindrical hollow body, a leading segment with a securing area and a trailing segment having a trailing edge and a securing area. The body has at least one flexible center section, each having at least one slot to provide flexibility. The slot follows a sinuous, serpentine path to form a plurality of interlocking teeth that can follow a helical or a concentric path. Each slot has a proximal end spaced from the trailing segment and a distal end spaced from the leading segment. With multiple slots the proximal end of a slot can be spaced from, and separated by an inflexible section, or adjacent to, a distal end of a subsequent slot.

A flexible connecting rod is manufactured from a rigid material and having a substantially cylindrical hollow body, a leading segment with a securing area and a trailing segment having a trailing edge and a securing area. The body has at least one flexible center section, each having at least one slot to provide flexibility. The slot follows a sinuous, serpentine path to form a plurality of interlocking teeth that can follow a helical or a concentric path. Each slot has a proximal end spaced from the trailing segment and a distal end spaced from the leading segment. With multiple slots the proximal end of a slot can be spaced from, and separated by an inflexible section, or adjacent to, a distal end of a subsequent slot.

Downhole tools for use in downhole operations and electrical submersible pumping systems having an additively manufactured first part including a first layer having a first predetermined material property and a second layer having a second predetermined material property, wherein the first and second layers are layers of an integral piece and the first predetermined material property is different from the second predetermined material property and a second part configured to rotationally engage with the additively manufactured first part. One of the first part and the second part is rotated relative to the other of the first part and the second part in operation.

A flexible shaft includes first and second shaft portions, first and second angular displacement couplings, and an axial displacement coupling generally extending and centered to a rotational axis. The first shaft portion extends between the first angular displacement coupling and the axial displacement coupling. The second shaft portion extends between the axial displacement coupling and the second angular displacement coupling. The axial displacement coupling includes an outer periphery, first wall attached to and extending radially between the first shaft portion and the periphery, and a second wall attached to and extending radially between the second shaft portion and the periphery. The first and second walls are resiliently flexible to facilitate axial displacement between the first and second shaft portions.

A flexible shaft includes first and second shaft portions, first and second angular displacement couplings, and an axial displacement coupling generally extending and centered to a rotational axis. The first shaft portion extends between the first angular displacement coupling and the axial displacement coupling. The second shaft portion extends between the axial displacement coupling and the second angular displacement coupling. The axial displacement coupling includes an outer periphery, first wall attached to and extending radially between the first shaft portion and the periphery, and a second wall attached to and extending radially between the second shaft portion and the periphery. The first and second walls are resiliently flexible to facilitate axial displacement between the first and second shaft portions.

Downhole tools for use in downhole operations and electrical submersible pumping systems having an additively manufactured first part including a first layer having a first predetermined material property and a second layer having a second predetermined material property, wherein the first and second layers are layers of an integral piece and the first predetermined material property is different from the second predetermined material property and a second part configured to rotationally engage with the additively manufactured first part. One of the first part and the second part is rotated relative to the other of the first part and the second part in operation.

Apparatus and methods are provided, including a left-ventricular assist device that includes an impeller configured for insertion into a subject's left ventricle. A delivery tube passes through the subject's aorta, from outside the subject into the left ventricle. The delivery tube includes an outer layer that varies along a length of the delivery tube such that a flexural rigidity of the delivery tube at a first portion of the delivery tube, which is configured to traverse the aortic valve, is less than the flexural rigidity at a second portion, which is configured to traverse at least a portion of the aortic arch, and the flexural rigidity at the second portion is less than the flexural rigidity at a third portion, which is configured to traverse the descending aorta. Other applications are also described.

Apparatus and methods are described including a blood pump that includes an axial shaft configured for insertion into, and rotation within, a left ventricle of a subject, and an impeller coupled to the axial shaft such that, as the axial shaft rotates, the impeller pumps blood from the left ventricle. A frame surrounds the impeller and a tip portion is coupled to a distal end of the frame. The tip portion includes a distal curved portion, which, when deployed within the left ventricle, lies in a plane, and a proximal curved portion, which, when deployed within the left ventricle, does not lie in the plane and is curved such that, following the insertion of the axial shaft into the left ventricle via an aorta of the subject, a distal end of the proximal curved portion points toward an apex of the left ventricle. Other applications are also described.

Apparatus and methods are described including a left-ventricular assist device, that includes a collapsible pump-outlet tube configured for insertion, through an aorta of a subject, into a left ventricle of a heart of the subject such that the pump-outlet tube traverses an aortic valve of the subject. The device includes one or more bands, each of which is bonded to an outer wall of the proximal portion of the pump-outlet tube, without extending around a full circumference of the pump-outlet tube, such that, while the proximal portion of the pump-outlet tube is maintained in the open state, the proximal portion of the pump-outlet tube curves at respective locations of the bands. Other applications are also described.

Apparatus and methods are described including an axial shaft configured for insertion into, and rotation within, a ventricle of a heart of a subject. An impeller is coupled to the axial shaft and a frame surrounds the impeller. A pump-outlet tube surrounds the frame such that, as the axial shaft rotates, the impeller pumps blood proximally, from the ventricle, through the pump-outlet tube. A flat inlet guard, which is shaped to define one or more holes, is disposed around, and perpendicular to, the axial shaft and within the frame distally to the impeller, such that the blood flows to the impeller via the holes. Other applications are also described.