Systems for determining fractional flow reserve are disclosed. An example system may include a pressure sensing guidewire for measuring a first pressure, a second pressure sensing medical device for measuring a second pressure, and a processor coupled to the pressure sensing guidewire and coupled to the second pressure sensing medical device. The processor may be designed to generate a plot of the magnitude of the second pressure over time, identify one or more time intervals of the plot that have a slope less than zero, determine a mean of the second pressure, and calculate the ratio of the first pressure to the second pressure when (a) the second pressure is less than or equal to the mean of the second pressure and (b) during the one or more time intervals when the slope of the plot is less than zero.

The invention relates to an assembly for use in minimally invasive surgical procedures, including bone implant fixation procedures. The assembly is configured to provide a faster and more accurate measurement of depth of holes for placement of bone screws and fasteners. The assembly includes a guidewire having a deployable distal hook member configured to securely anchor into a desired position relative to a hole drilled in a bone and thereby provide an accurate datum for a measuring instrument for determining a depth of the hole for subsequent screw placement. The assembly further includes a surgical depth instrument to cooperatively function with the guidewire and obtain one or more measurements while operably coupled to the guidewire.

In part, the disclosure relates to computer-based methods, devices, and systems suitable for performing intravascular data analysis and measurement of various types of data such as pressure and flow data. The disclosure relates to probes and methods suitable for determining an event in a cardiac cycle such as flow threshold such as a peak flow, a fraction thereof, other intravascular parameters or a point in time during which peak flow or a change in one of the parameters occurs. An exemplary probe includes one or more of a pressure sensor, a resistor, a flow sensor and can be used to generate diagnostic data based upon measured intravascular and other parameters. In part, the disclosure relates to methods and systems suitable for determining a coronary flow reserve value in response to one or more of intravascular pressure and flow data or data otherwise correlated therewith.

A medical device optical connector lead for coupling with a guidewire including optical fiber is described herein. The connector can include or use a housing defining an aperture, an optical receptacle disposed within the housing, the optical receptacle configured to receive an exposed optical fiber end of the guidewire extending through the aperture, and a chuck configured to clamp around the guidewire. The chuck can be slidable within the housing between a first chuck position wherein the chuck is positioned closer to the optical receptacle than to the aperture and a second chuck position wherein the chuck is positioned closer to the aperture than to the optical receptacle. An actuator can laterally move the chuck between the first position and the second position and concurrently tighten or loosen the chuck.

Pressure sensing guidewires and methods for making and using pressure sensing guidewires are disclosed. An example pressure sensing guidewire may include a tubular member having a proximal region and a housing region. An optical fiber may be disposed within the tubular member and extend to the housing region. The optical fiber may have a distal end region with a cavity formed therein. A polymeric member disposed within the cavity. A reflective surface disposed along the polymeric member.

Disclosed catheter insertion systems enable the user to identify the location of the needle based on the electrical properties of subcutaneous tissue relative the electrical properties of other fluids such as blood or air. Disclosed systems can include one or more of the following features: 1) the catheter assembly is modular (e.g., the catheter can be connected and disconnected from the detection unit at will); 2) the detection unit employs an electrical circuit that allows for the discernment between subcutaneous tissue and blood; 3) the system assists the end user with catheter advancement. Some embodiments can be used to insert catheters into a spaces where the needle passes first through subcutaneous fat and muscle before entering fluid or air.

An optical probe 40 used for the vascular optical tomographic imaging apparatus 100 includes an optical fiber 10 having a central axis 14 and a translucent lens member 20 fixed to a tip surface 12 of the optical fiber. The lens member has an outer circumferential surface surrounding an extension axis 22 obtained by extending the central axis 14 of the optical fiber forward, a rear end surface 26 intersecting the extension axis, and a tip surface 28 intersecting the extension axis. The tip surface of the lens member is a surface extending obliquely with respect to the extension axis. The outer circumferential surface of the lens member has, at least in part, a cylindrical surface portion 24 around the extension axis or a cylindrical surface portion about an axis parallel to the extension axis. The optical probe is configured so that light emitted from the tip of the optical fiber is incident on the tip surface along the extension axis, and light reflected by the tip surface is emitted from the lens member through the cylindrical surface portion.

A sensing unit for use in-body comprises a variable impedance circuit for connection to the distal end of a transmission line and reflecting a carrier signal received from the transmission line. The variable impedance circuit comprises a variable impedance component having an impedance which varies non-linearly with applied voltage, a sensor for generating a voltage in response to a stimulus and a voltage bias system for creating a voltage bias for the variable impedance component. The voltage bias sets the operation point of the variable impedance component, such that the voltage changes from the sensor change the impedance of the variable impedance component non-linearly.

Pressure sensing guidewire assemblies are described herein where the guidewire assembly may be comprised of an elongate guidewire body and multiple pressure sensors secured near or at a distal end of the guidewire body. The signals obtained from the guidewire connectors and aortic sensor modules may be synchronized to minimize signal acquisition delays. The signals may be further processed to equalize the pressure waveforms by shifting the connector waveform to align correctly with the aortic module waveform and improve output signals.

An optical fiber (F2) having a length defining a longitudinal direction is disclosed. The optical fiber (F2) has at least two fiber cores (C21, C22) extending along the length of the optical fiber (F2), and an optical coupling member (OCM2) is arranged at a proximal optical fiber end of the optical fiber (F2). The coupling member (OCM2) has a first distal end face (OF2) optically connected to the proximal optical fiber end, and a proximal second end face (IF2) spaced apart from the first distal end face (OF2) in the longitudinal direction of the optical fiber (F2), the optical coupling member (OCM2) being configured to couple light into each of the fiber cores (C21, C22, C23).