Patent Description:
<CIT> discloses a vascular closure device, comprising an anchor member; a compressible plug; a locking mechanism; and a sensor probe, the sensor probe including a first electrically conductive member having a proximal end and a distal end and a second electrically conductive member having a proximal end and a distal end, the first electrically conductive member being electrically insulated from the second electrically conductive member from the proximal end to the distal end.

<CIT> shows a further vascular closure device.

Various examples of blood vessel access closure devices are disclosed that include the ability for bioimpedance to be measured. The impedance of the body around the site of a blood vessel hole being closed can be used to determine if the hole has been adequately closed, or whether the hole is still leaking blood.

In one example, a blood vessel access closure device includes an inner blood vessel wall support member and an outer blood vessel wall support member. The closure device also includes a deployment member and an electrode. The deployment member is configured to draw the inner and outer blood vessel wall support members towards each other when the inner and outer blood vessel wall members are deployed on opposite sides of a blood vessel wall during closure of a hole in the blood vessel wall. The electrode is configured to be attached to the deployment member and configured to be used to measure impedance.

In another example, a blood vessel access closure device includes a suture wire and an electrode. The suture wire is configured to close a hole in a blood vessel. The electrode is coupled to the suture wire and is configured to be attached to the deployment member and configured to be used to measure impedance.

Blood vessel access closure systems are used to close a hole in a blood vessel. However, it is possible that blood still leaks through the hole in the blood vessel wall even after use of the access closure device. In accordance with the disclosed examples, the access closure systems described herein include the ability to measure electrical impedance in the area around the blood vessel hole. The impedance of blood is different than the impedance of other body tissues and thus an accumulation of blood on the outside of the blood vessel in the area around the hole being closed indicates that blood is still leaking through the hole despite the application of the access closure device.

<FIG> shows an example of a portion of an access closure system. The access closure system in this example includes an inner blood vessel wall support member <NUM>, an outer blood vessel wall support member <NUM>, and a suture wire <NUM> with an electrode <NUM> slid over the suture wire <NUM>. The access closure system is shown to close a hole <NUM> in blood vessel <NUM>. The electrode <NUM> is slid over the suture wire and is attached to electronics (described below) with a conductive wire. The inner blood vessel wall support member <NUM> is positioned inside the blood vessel at the hole <NUM>. The outer blood vessel wall support member <NUM> is positioned opposite the inner blood vessel wall support member at the hole <NUM>. The suture wire <NUM> is a type of deployment member usable to draw the inner and outer blood vessel wall support members <NUM>, <NUM> towards each other to thereby seal the hole <NUM>.

<FIG> shows a person's leg <NUM> in which blood vessel <NUM> has a hole to be closed. An adhesive patch <NUM> is shown on the skin of the person's leg <NUM>. The adhesive patch <NUM> includes one or more electrodes <NUM> connected to a circuit (e.g., integrated circuit, not shown) integrated into the patch. The electrode <NUM> on the suture wire also is connected to the circuit. The circuit measures the electrical impedance between electrode <NUM> and one or more of the patch's electrodes <NUM>. Based on the impedance measurements, a determination can be made as to whether the hole in the blood vessel <NUM> has been adequately sealed. The patch <NUM> includes a suture wire clip <NUM>. The suture wire clip <NUM> grabs the suture wire to provide strain relief and access for later removal.

In <FIG>, a knot <NUM> is formed in the suture wire <NUM> and the electrode <NUM> is positioned on the suture wire above the knot <NUM>. The knot is moved down the suture wire to draw the inner and outer blood vessel support members <NUM>, <NUM> together. In this example, the suture wire <NUM> itself may not be electrically conductive, but the electrode <NUM> is electrically conductive and connected to the patch's circuit via a separate wire <NUM>.

<FIG> shows an example of an access closure system that does not include inner and outer blood vessel wall support members. Instead, suture wire <NUM> is used to close the hole <NUM>. Electrode <NUM> is coupled to the suture wire <NUM> and used to measure impedance to detect a possible bleed.

<FIG> shows another example of an access closure system that includes inner and outer blood vessel wall support members. In this example, the suture wire <NUM> is electrically conductive, and thus no separate electrode <NUM> is included. Impedance can be measured by the patch's circuit between the patch's electrode(s) and the conductive suture wire <NUM>. The conductive suture wire is insulated with a portion of the conductive wire exposed at a predefined location(s) along the wire.

To measure impedance, the patch's circuit may inject a predetermined current magnitude through one pair of electrodes (including the electrode <NUM> near the site of the blood vessel <NUM>) and measure the resulting voltage using a different set of electrodes. One of the electrodes may be used for both the current injection and voltage measurement. The ratio of voltage to current equals impedance. Alternatively, the circuit may use one pair of electrodes (including electrode <NUM>) to apply a voltage of a predetermined amplitude and measure the resulting current. The current or voltage applied to the electrodes may be AC or DC. Impedance measurements made at certain frequencies may provide more useful information than at other frequencies. At certain frequencies, it may be difficult to detect a bleed, whereas at other frequencies, bleed detection is easier. In one example, the frequency used for the impedance measurements are in the range of <NUM> to <NUM>, although a different frequency range may be acceptable as well. Additional information regarding impedance measurements may be found in <CIT>.

<FIG> shows a top-down view of adhesive patch <NUM>. The patch <NUM> in the example of <FIG> includes one or more visual indicators <NUM> which provide visual feedback as to whether a bleed condition has been detected, and the severity of the bleed condition. For example, the more indicators <NUM> that are illuminated means that a more severe (e.g. longer lasting) bleed condition has been detected. The circuit contained in the adhesive patch may be battery operated. The patch <NUM> in <FIG> is generally circular. In one example, the diameter of the patch is <NUM> to <NUM> inches. The electrodes <NUM> are positioned around the outer periphery of the patch.

<FIG> shows another example of an adhesive patch. The adhesive patch in this example includes a wired interface that can be connected via a cable <NUM> to a bedside monitor <NUM>. Signals indicative of the measured impedance may be displayed on the monitor's display. The patch's circuit may measure impedance and provide impedance values to the bedside monitor, or the patch's circuit may provide current and voltage values to the bedside monitor and the bedside monitor may compute impedance. In another example, the interface between the patch and the bedside monitor may be wireless, instead of wired as shown in <FIG>.

<FIG> shows an example of the circuit <NUM> included in the adhesive patch <NUM>. In this example, the circuit includes a controller <NUM>, storage <NUM>, visual indicators <NUM>, a signal generator <NUM>, a measurement unit <NUM>, and a transceiver <NUM>. The controller <NUM> may be a hardware processor that executes software <NUM> stored in storage <NUM>. Storage <NUM> may comprise volatile storage (e.g., random access memory) and/or nonvolatile storage (e.g., read-only memory). The functionality attributed herein to that patch's circuit is implemented by the controller <NUM> upon execution of its software <NUM>. Each visual indicator <NUM> may comprise a light emitting diode (LED). The electrodes (e.g. electrode <NUM>, patch electrode <NUM>) are coupled to one or more of the signal generator <NUM> and measurement unit <NUM>. Upon command by the controller <NUM>, the signal generator <NUM> generates a predetermined signal (e.g. current or voltage) to be provided to two of the electrodes, and the measurement unit <NUM> measures the resulting voltage or current as explained above. At least one of the electrodes used by the measurement unit <NUM> is the electrode near the site of the blood vessel hole being sealed (e.g., electrode <NUM> or conductive suture wire <NUM>). The controller <NUM> may provide the impedance values to the transceiver <NUM> for transmission to an external device (e.g., bedside monitor <NUM>). In one example, the transceiver <NUM> provides a wired interface. In another example, the transceiver <NUM> provides a wireless interface. An example of a wireless interface includes Bluetooth.

In the example of <FIG>, the adhesive patch was approximately circular. In the example of <FIG>, the adhesive patch <NUM> is approximately rectangular. The rectangular shape of the patch <NUM> has a width (W) and a length (L), where L is larger than W. In one example, W is approximately <NUM> inch and L is approximately <NUM> inches. Multiple electrodes <NUM> are positioned along an axis of the patch parallel to length L (i.e., along the long axis of the rectangle). The patch <NUM> is positioned near the site of the blood vessel hole being closed and any or all of the electrodes <NUM> can be used to measure impedance between each such electrode and electrode <NUM> (adjacent the blood vessel). Providing multiple electrodes along the long axis of the patch helps to ensure a bleed is detected regardless of the location of the accumulation of blood near the blood vessel wall's hole.

In another example, the patch has no battery. Instead, the patch has a coil of wire or other type of antenna that can receive wireless power from an external device (e.g., a handheld wand). When the external device is brought near the patch, the patch's circuit is powered up, initiates an impedance measurement, and transfers one or more values indicative of impedance to the external device.

Another example includes an electrode <NUM> that is constructed of a conductive bioabsorbable polymer that is not removed. Instead, following use of the electrode during a medical procedure to detect bleeding, the electrode remains in the body and is reabsorbed. Suitable polymers for such an electrode are described in <CIT>.

<FIG> shows an example of the use of a collagen plug <NUM> to seal a hole <NUM> in a blood vessel <NUM>. A guidewire <NUM> is shown inserted through the patient's skin <NUM>, through the collagen plug <NUM>, and into the blood vessel <NUM>. The guidewire <NUM> may been used during the patient's catherization. The guidewire <NUM> includes an electrode <NUM> and may include additional electrodes as well. An electrical connector <NUM> is connected to the electrode <NUM> via a conductor (e.g., a wire not shown, or the guidewire itself). The example electrode <NUM> is shown on the guidewire inside the blood vessel and can be used to measure impedance between electrode <NUM> and another electrode, for example, one or more of the patch electrodes <NUM>, <NUM>. The connector <NUM> can be connected to a circuit (e.g., circuit <NUM>) to use the guidewire's electrode and another electrode (e.g., an electrode on the patch or another electrode on the guidewire) to measure impedance to detect a bleed.

In one example, at the end of a vascular access procedure, the guidewire is left in the vessel to monitor for bleed complications until it is determined that the risk of bleeding is sufficiently low. The physician deploys an access closure device in the form of a collagen plug <NUM> that seals around the guidewire <NUM> and hole <NUM>. After it is determined that the risk of bleeding is low, the physician may then remove the guidewire <NUM> by pulling the guidewire through the collagen plug <NUM> and leg tissue. The collagen plug <NUM> may remain in place maintaining a seal around the blood vessel wall.

<FIG> shows an example of a guidewire <NUM> having multiple electrodes <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Five electrodes are shown on the guidewire <NUM> in this example, but fewer than five or more than five electrodes may be provided on the guidewire in other examples. An adhesive patch <NUM> (such as that described herein) is shown on the patient's skin <NUM> generally above the site of the access point into blood vessel <NUM>. An electronics module <NUM> is electrically connected to the electrode <NUM> on patch <NUM> as well as to electrodes <NUM>-<NUM> on the guidewire <NUM>. The electronics module <NUM> may include some or all of the components shown in <FIG>. The electronics module <NUM> may measure the impedance between electrodes on the guidewire <NUM> or between one or more electrodes on the guidewire <NUM> and one or more electrodes <NUM> on the patch <NUM>. As such, multiple different impedance "zones" may be measured using any combination of electrodes <NUM> and <NUM>-<NUM>.

<FIG> shows a system, such as may be implemented in a hospital. The system includes one or more bleed monitors <NUM>, <NUM>, a central control system <NUM>, wireless access points <NUM>, and portable devices <NUM>, <NUM>. Each bleed monitor <NUM>, <NUM> includes any of the bleed detection implementations described above. Each bleed monitor <NUM>, <NUM> may transmit (e.g., wirelessly) patient-related bleed information through a corresponding access point <NUM> to the central control system <NUM>. The patient-related bleed information may include impedance values, bleed level indicators, etc. generated locally for each patient.

The central control system <NUM> includes a processor <NUM> and storage <NUM> (e.g., memory, hard drive, etc.). The storage <NUM> may store the received patent-related bleed information and software to be executed by the processor <NUM>. In one example, the central control system <NUM> is a computer. The central control system <NUM> may transmit alerts for a given patient to that patient's physician who carries one of the portable devices <NUM>, <NUM>. As such, a patient's physician may be kept abreast of the status of that physician's patients (e.g., whether the patient is experiencing a bleed, the severity of the bleed, etc.).

Claim 1:
A blood vessel access closure device, comprising:
an inner blood vessel wall support member (<NUM>);
an outer blood vessel wall support member (<NUM>);
a deployment member (<NUM>) configured to draw the inner (<NUM>) and outer (<NUM>) blood vessel wall support members towards each other when the inner and outer blood vessel wall members are deployed on opposite sides of a blood vessel wall during closure of a hole (<NUM>) in the blood vessel wall; and
a first electrode (<NUM>) configured to be attached to the deployment member (<NUM>) and configured to be used to measure impedance, characterised by the blood vessel access closure device further comprising an adhesive patch (<NUM>) configured to be placed on a person's skin over the blood vessel, the adhesive patch (<NUM>) comprising a plurality of electrodes (<NUM>).