Apparatus and methods are described including manufacturing an impeller by coupling a material to a helical elongate element, such that the helical elongate element with the material coupled thereto defines a blade of the impeller. A portion of a structure that includes the helical elongate element is dipped into the material while the material is in a liquid state. The material is dried, while the material is being supported by the at least one helical elongate element. During the drying of material, the structure is rotated about its longitudinal axis, such as to facilitate the formation of a film of the material having a substantially uniform thickness within the impeller blade. Other applications are also described.

Apparatus and methods are described including manufacturing an impeller by coupling a material to a helical elongate element, such that the helical elongate element with the material coupled thereto defines a blade of the impeller. A portion of a structure that includes the helical elongate element is dipped into the material while the material is in a liquid state. The material is dried, while the material is being supported by the at least one helical elongate element. During the drying of material, the structure is rotated about its longitudinal axis, such as to facilitate the formation of a film of the material having a substantially uniform thickness within the impeller blade. Other applications are also described.

Apparatus and methods are described, including a catheter (20) configured to be placed inside a blood vessel of a subject. A first impeller (28) is disposed on the catheter, and a second impeller (28) is disposed on the catheter, proximally to the first impeller. A support structure (160) is disposed upon the catheter such that a longitudinal center of the support structure is disposed between the first and second impellers, the support structure being configured to support an inner wall of the blood vessel in an open configuration in a region between the first and second impellers. Other applications are also described.

Apparatus and methods are described, including a catheter (20) configured to be placed inside a blood vessel of a subject. A first impeller (28) is disposed on the catheter, and a second impeller (28) is disposed on the catheter, proximally to the first impeller. A support structure (160) is disposed upon the catheter such that a longitudinal center of the support structure is disposed between the first and second impellers, the support structure being configured to support an inner wall of the blood vessel in an open configuration in a region between the first and second impellers. Other applications are also described.

Apparatus and methods are described including placing, into a subject's body, a blood-pump tube, with an impeller disposed within the blood-pump tube. At least one blood-pressure-measurement element extends to at least an outer surface of the blood-pump tube, such that the distal end of the blood-pressure-measurement element is in direct fluid communication with a bloodstream of the subject outside the blood-pump tube at a location that is proximal to blood-inlet opening(s) defined by the blood-pump tube. Blood is pumped through the blood-pump tube, using the impeller. Pressure of the bloodstream of the subject outside the blood-pump tube is measured by measuring blood pressure at the distal end of the left-ventricular blood-pressure-measurement element. Other applications are also described.

Apparatus and methods are described including placing, into a subject's body, a blood-pump tube, with an impeller disposed within the blood-pump tube. At least one blood-pressure-measurement element extends to at least an outer surface of the blood-pump tube, such that the distal end of the blood-pressure-measurement element is in direct fluid communication with a bloodstream of the subject outside the blood-pump tube at a location that is proximal to blood-inlet opening(s) defined by the blood-pump tube. Blood is pumped through the blood-pump tube, using the impeller. Pressure of the bloodstream of the subject outside the blood-pump tube is measured by measuring blood pressure at the distal end of the left-ventricular blood-pressure-measurement element. Other applications are also described.

Apparatus and methods are described including a blood pump that is placed inside a body of subject. The blood pump includes an impeller that includes proximal and distal bushings, and that defines an axial lumen that extends from the proximal bushing to the distal bushing, a frame disposed around the impeller, and an axial shaft that passes through the proximal and distal bushings of the impeller. A distal end of a delivery catheter, and the frame and the impeller, are configured to be moved with respect to one another, to thereby cause the frame to assume a radially-constrained configuration by the frame becoming axially elongated, and cause the impeller to assume a radially-constrained configuration by the impeller becoming axially elongated. Other applications are also described.

Apparatus and methods are described including a blood pump that is placed inside a body of subject. The blood pump includes an impeller that includes proximal and distal bushings, and that defines an axial lumen that extends from the proximal bushing to the distal bushing, a frame disposed around the impeller, and an axial shaft that passes through the proximal and distal bushings of the impeller. A distal end of a delivery catheter, and the frame and the impeller, are configured to be moved with respect to one another, to thereby cause the frame to assume a radially-constrained configuration by the frame becoming axially elongated, and cause the impeller to assume a radially-constrained configuration by the impeller becoming axially elongated. Other applications are also described.

This disclosure relates to a catheter system that for precisely positioning fluid flow restrictors within a blood vessel. In particular, this disclosure provides a catheter system that includes a sheath with a first fluid flow restrictor mounted thereto, and a catheter that is slidably disposed within the sheath and has a second fluid flow restrictor mounted thereto. Inside a blood vessel, the sheath and the catheter are separately slidable, thereby allowing the first and second fluid flow restrictors to be positioned at precise locations within the blood vessel.

This disclosure relates to a catheter with a fluid flow restrictor (e.g., a balloon) that includes a flow path. The catheter is useful for creating, and maintaining, an area of reduced pressure within a blood vessel for removing excess fluid from a patient's body. In particular, the catheter is dimensioned for insertion into a blood vessel and includes a fluid flow restrictor that, when deployed, partially occludes the blood vessel. Pressure is reduced within the blood vessel downstream of the occlusion. The flow path allows some blood to flow past the restrictor, which prevents the blood vessel from stretching due to excessive pressure buildup, thereby allowing the area of reduced pressure to be maintained for extended periods of time.