2142 results about "Blood flow" patented technology

Methods, devices, and systems for a) revascularization and / or b) performing other medical procedures at vascular or non-vascular intracorporeal locations within a mammalian body. The methods generally comprise the formation of at least one extravascular passageway from a blood vessel to a vascular or non-vascular target location. In the revascularization methods the extravascular passageway is utilized for blood flow. In the medical procedure methods the extravascular passageway is utilized as a conduit for accessing or performing procedures at the vascular or non-vascular target location. Also disclosed are catheter devices and systems which are useable to form the extravascular passageways of the invention, as well as apparatus for modifying, maintaining and / or closing such extravascular passageways.

A device and a method to provide a more reliable and accurate measurement of hematocrit (Hct) by noninvasive means. The changes in the intensities of light of multiple wavelengths transmitted through or reflected light from the tissue location are recorded immediately before and after occluding the flow of venous blood from the tissue location with an occlusion device positioned near the tissue location. As the venous return stops and the incoming arterial blood expands the blood vessels, the light intensities measured within a particular band of near-infrared wavelengths decrease in proportion to the volume of hemoglobin in the tissue location; those intensities measured within a separate band of wavelengths in which water absorbs respond to the difference between the water fractions within the blood and the displaced tissue volume. A mathematical algorithm applied to the time-varying intensities yields a quantitative estimate of the absolute concentration of hemoglobin in the blood. To compensate for the effect of the unknown fraction of water in the extravascular tissue on the Hct measurement, the tissue water fraction is determined before the occlusion cycle begins by measuring the diffuse transmittance or reflectance spectra of the tissue at selected wavelengths.

A percutaneous heart valve prosthesis (1) has a valve body (2) with a passage (9) extending between the first and second ends (7, 8) of the valve body (2). The valve body (2) is collapsible about a longitudinal axis (10) of the passage (9) for delivery of the valve body (2) via a catheter (18). One or more flexible valve leaflets (3, 4) are secured to the valve body (2) and extend across the passage (9) for blocking bloodflow in one direction through the passage (9). An anchor device (5), which is also collapsible for delivery via catheter (18), is secured to the valve body (2) by way of an anchor line (6). A failed or failing mitral heart valve (101) is treated by percutaneously locating the valve body (2) in the mitral valve orifice (102) with the anchor device (5) located in the right atrium (107) and engaging the inter-atrial septum (103), such that the taught anchor line (6) acts to secure the valve body (2) within the mitral valve orifice (102).

This invention relates to apparatus and methods for use in sealing a vascular puncture site and to apparatus and methods for properly locating and deploying a sealing device. The locating apparatus comprises a lumen which extends from an opening in the distal region of the apparatus but located proximally of the sealing device, which lumen extends to another opening in the proximal region of the device. When the distal opening is in communication with blood in a blood vessel, blood flow through the lumen and out of the proximal opening signifies such location to the user. When the sealing device is withdrawn such that the sealing device is deployed such that it blocks the blood flow into the distal port, the user will know the location of the sealing device. In a preferred embodiment, the sealing device is then withdrawn proximally a predetermined distance to assure that no part of the sealing device extends into the blood vessel lumen. The sealing device is then detached from the delivery device.

The present invention provides a method and apparatus for controlling the internal body temperature of a patient. According to the present invention, a catheter is inserted through an incision into a large blood vessel of a patient. By selectively heating or cooling a portion of the catheter lying within the blood vessel, heat may be transferred to or from blood flowing within the vessel and the patient's body temperature may thereby be increased or decreased as desired. The invention will find use in treating undesirable conditions of hypothermia and hyperthermia, or for inducing a condition of artificial hypothermia when desired.