EP4723960A2

EP4723960A2 - Conductive sensor for a pulmonary artery catheter

Info

Publication number: EP4723960A2
Application number: EP24820235.0A
Authority: EP
Inventors: Mohammed Imran ASLAM; Marc David FELDMAN; Luis Alan Diaz SANMARTIN; Aleksandra Borisovna GRUSLOVA; Drew Rory NOLEN; Jonathan Walker Valvano
Original assignee: University of Texas System; University of Texas at Austin
Current assignee: University of Texas System; University of Texas at Austin
Priority date: 2023-06-09
Filing date: 2024-06-10
Publication date: 2026-04-15
Also published as: KR20260046077A; WO2024254606A2; CN121772867A; WO2024254606A3

Abstract

A pulmonary artery catheter system may include a port housing coupled to the catheter and supporting: a right ventricular port, a right atrial port, a pulmonary artery distal lumen, a balloon port, and a volume sensor port. A pulmonary artery catheter system may include a plurality of volume sensors positioned along a length of the catheter and in communication with the volume sensor port.

Description

P.C.T. PATENT APPLICATION for

CONDUCTIVE SENSOR FOR A PULMONARY ARTERY CATHETER

Inventors: MOHAMMED IMRAN ASLAM

MARC DAVID FELDMAN

LUIS ALAN DIAZ SANMARTIN

ALEKSANDRA BORISOVNA GRUSLOVA

DREW RORY NOLEN

JONATHAN WALKER VALVANO

CONDUCTIVE SENSOR FOR A PULMONARY ARTERY CATHETER

BACKGROUND

[0001] This disclosure relates to pulmonary artery catheters. This disclosure also relates to cardiac volume measurement using admittance and conductance.

SUMMARY

[0002] In some aspects, the techniques described herein relate to a pulmonary artery catheter system including: a catheter; a port housing coupled to the catheter and supporting: a right ventricular port, a right atrial port, a pulmonary artery distal lumen, a balloon port, and a volume sensor port; and a plurality of volume sensors positioned along a length of the catheter and in communication with the volume sensor port.

[0003] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein the plurality of volume sensors includes: a first volume sensor configured to be positioned within a right ventricle, a second volume sensor configured to be positioned within the right ventricle, and a third volume sensor configured to be positioned within the right ventricle.

[0004] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein the plurality of volume sensors are used to determine an inflow vector and an outflow vector.

[0005] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein the plurality of volume sensors includes: a first volume sensor positioned a first distance from a distal tip of the catheter, a second volume sensor positioned a second distance from the distal tip of the catheter, and a third volume sensor positioned a third distance from the distal tip of the catheter, wherein the second distance is greater than the first distance, and the third distance is greater than the second distance.

[0006] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein the first volume sensor is spaced from the second volume sensor by between twenty millimeters (20 mm) and one-hundred-fifty millimeters (150 mm), and wherein the second volume sensor is spaced from the third volume sensor by between twenty millimeters (20 mm) and one-hundred-fifty millimeters (150 mm). [0007] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein a distance between the first volume sensor and the second volume sensor is equal to a distance between the second volume sensor and the third volume sensor.

[0008] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein each of the plurality of volume sensors includes a conductive sensor.

[0009] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein each conductive sensor includes an electrode pair.

[0010] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein each conductive sensor is formed from a flexible conductive material.

[0011] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein each conductive sensor is formed from a rigid conductive material.

[0012] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, further including a pressure sensor positioned along the length of the catheter, configured to be positioned within a right ventricle, and providing a signal indicative of a pressure to the right ventricular port.

[0013] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein pressure sensor includes a pressure aperture utilizing a fluid filled catheter.

[0014] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein the pressure sensor includes a micromanometer.

[0015] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein signals received from the right ventricular port and the volume sensor port are configured for creation of right ventricle pressure-volume loops.

[0016] In some aspects, the techniques described herein relate to a pulmonary artery catheter system including: a catheter defining a distal tip and a proximal port housing; a right ventricular port coupled to the proximal port housing; a right atrial port coupled to the proximal port housing; a pulmonary artery' distal lumen coupled to the proximal port housing; a balloon port coupled to the proximal port housing; a volume sensor port coupled to the proximal port housing; a pressure sensor positioned along a length of the catheter, configured to be positioned within a right ventricle, and providing a signal indicative of a pressure to the right ventricular port; a first admittance sensor positioned along a length of the catheter; a second admittance sensor positioned along a length of the catheter; and a third admittance sensor positioned along a length of the catheter, wherein at least two of the first admittance sensor, the second admittance sensor, or the third admittance sensor are configured to be positioned within a right ventricle of a heart.

[0017] In some aspects, the techniques described herein relate to a pulmonary artery catheter system, wherein each of the first admittance sensor, the second admittance sensor, and the third admittance sensor includes a conductive electrode pair.

[0018] In some aspects, the techniques described herein relate to a method including: inserting a pulmonary artery catheter system into a heart; determining a right ventricular volume based on admittance or conductance signals received from a volume sensor of the pulmonary artery catheter system positioned within a right ventricle of the heart; determining a right ventricular pressure based on signals received from a pressure sensor of the pulmonary artery catheter system positioned in the right ventricle: and generating right ventricle pressure-volume loops based on the determined volume and pressure.

[0019] In some aspects, the techniques described herein relate to a method, further including determining an effective arterial elastance (Ea), a ventricle contractility (Ees), and a coupling ratio (Ees/Ea) based on the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor.

[0020] In some aspects, the techniques described herein relate to a method, wherein an inferior vena cava occlusion is used to generate the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor to generate a family of pressurevolume loops.

[0021] In some aspects, the techniques described herein relate to a method, wherein a Valsalva is used to generate the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor to generate a family of pressure-volume loops.

[0022] In some aspects, the techniques described herein relate to a method, wherein determining the right ventricular volume includes V = A * y * Gb /(y - Gb), where V is the right ventricular volume, y is measured admittance or conductance at infinite volume, and A is a coefficient calibrated from stroke volume.

[0023] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.

BRIEF DESCRIPTION OF DRAWINGS

[0024] The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.

[0025] FIG. 1 is a schematic representation of a pulmonary artery catheter including a conductive sensor system arranged in a heart, according to some implementations.

[0026] FIG. 2 is a schematic representation of the pulmonary artery catheter of FIG. 1, according to some implementations.

[0027] FIG. 3 is a photo of the pulmonary artery catheter of FIG. 1 positioned within a porcine heart, according to some implementations.

[0028] FIG. 4 is an x-ray image of the pulmonary artery catheter of FIG. 1 positioned within a porcine heart, according to some implementations.

[0029] FIG. 5 is a graph of a pressure- volume loop data set measured using the pulmonary artery catheter of FIG. 1 under a condition A, according to some implementations.

[0030] FIG. 6 is a graph of a pressure- volume loop data set measured using the pulmonary artery catheter of FIG. 1 under a condition B, according to some implementations.

[0031] FIG. 7 is a graph of a pressure- volume loop data set measured using the pulmonary artery catheter of FIG. 1 under a condition C, according to some implementations.

[0032] FIG. 8 is a three-dimensional representation of the pulmonary artery catheter of FIG. 1 including a dotted outline of a dual electric field admittance measurement inside the right ventricle, according to some implementations. [0033] FIGS. 9-12 are graphs showing volume vs. time determined based on measured admittance or conductance from sensers of the pulmonary artery catheter, according to some implementations .

[0034] FIG. 13 is a graph showing total volume vs. time using the pulmonary artery catheter, according to some implementations.

DETAILED DESCRIPTION

[0035] Following below are more detailed descriptions of concepts related to, and implementations of, apparatuses and systems for volume measurement provided by a pulmonary artery catheter. Before turning to the figures, which illustrate certain exemplary implementations in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0036] Referring to the figures generally, the various implementations disclosed herein relate to systems and apparatuses for measuring right ventricular volume using a pulmonary artery catheter. In some implementations, the pulmonary artery catheter includes pressure and volume sensors arranged along a length of the pulmonary artery catheter. In some implementations the volume sensors include three volume sensors. In some implementations, all volume sensors are configured to be positioned within a right ventricle of a heart. In some implementations, a volume sensor includes a pair of admittance electrodes. In some implementations, a volume sensor includes a single admittance electrode.

[0037] In some implementations, a catheter system is used to measure pressures inside the heart (e.g., to perform a right heart catheterization [RHC]), with three pairs of admittance electrodes engineered onto the catheter. The admittance electrodes allow the catheter system to markedly increase the information it can derive rather than pressure measurement alone. The catheter system provides the capability to determine simultaneous right ventricular (RV) volume and RV pressure measurements. This allows physicians to obtain a level of information not possible previously. This enhanced diagnostic tool will allow measurement of right ventricular (RV, or the right side of the heart) pressure volume (PV) loops which provide valuable diagnostic information about the heart in a variety of important clinical situations. Currently, RHC are necessary to help direct care for patients with severe cardiac dysfunction in heart failure (i.e. cardiogenic shock patients, or patients requiring heart transpl ant/permanent pump implantation due to a failing heart) and pulmonary hypertension (i.e., high pressures in the lung which causes right ventricular dysfunction), and other conditions. However, though this information can be valuable, it is known that typical catheters, or any other widely available diagnostic tool, is unable to currently directly measure the strength of the heart’s contraction (called, contractility or end-systolic pressure volume relationship/ESPVR). The ability to obtain this information using the catheter system disclosed herein can change the landscape of clinical care for these patients. By building into the catheter system the ability to routinely measure this data allows application of sophisticated measures during routine clinical practice for the first time. Up to now, these types of valuable measurements were only available as a research tool. The catheter system disclosed herein can enable widespread extension into clinical practice.

[0038] To better understand right ventricular function in different disease states mentioned above will allow identification of pathologic states at an earlier timepoint as well as response to treatments. This can influence treatment decisions for complex clinical situations which currently do not have a standard or unified approach in the clinical community. To provide a specific example using one of the disease states mentioned above, pulmonary hypertension is a disease with high mortality. There are 3 classes of FDA approved medications which can lower pressures in the lungs. However, there is no standard parameter or metric obtained from right heart catheterization that can reliably assess the heart’s response to these medications. Many times, by the time the right heart catheterization pressures indicate the heart is ‘falling off the cliff’, it is too late to implement therapies which can benefit the patient. Being able to identify occult myocardial dysfunction is critical. For instance, a right ventricular non-responsive to treatment would provide impetus to intensify medical therapies or begin to pursue lung transplant (the definitive therapy for severe pulmonary hypertension non- responsive to medical therapies). On the other hand, if the right ventricular function is improving, and heart contractility is improving, current therapy can be continued.

[0039] One strength of this innovation is the ability to obtain concomitant pressure and volume data using the catheter system. Adding the ability to assess right ventricular PV loops allows simultaneous acquisition of data, obviating the need to place extra catheters (which also need to be calibrated) into the patient, adding additional time and risk deemed prohibitive for routine use. Further, pulmonary artery catheters are already routinely utilized in these patient populations for serial measurements and the general form of the catheter system is familiar to clinicians. The addition of PV loops in the heart will allow identification of a failing right ventricular before it is too late to intervene. In addition, the catheter system facilitates further research applications (to be able to ask and answer questions about the heart’s function in response to different treatments in different disease states).

[0040] The catheter system can be used in many clinical conditions, including but not limited to right ventricular dysfunction in severe heart failure patients requiring heart transplantation or permanent heart pump implantations (also called left ventricular assist devices or LVAD; patients in cardiogenic shock), and those with different etiologies of pulmonary hypertension. In some implementations, the information received from the catheter system allows a clinician to perform a Valsalva maneuver to non-invasively affect heart functioning. Clinically, right ventricular dysfunction is a driver for morbidity and mortality in all of these cardiac diseases. All current therapies are directed towards treatment of left ventricular (LV) dysfunction, as the pathophysiology of right ventricular dysfunction is not well understood. The patient benefit is potentially improved morbidity and mortality due to a greater understanding of the right ventricular chamber’s function, reserve, and its interaction between the load it pumps against (for example, right ventricular end-systolic elastance and right ventricular effective arterial elastance and their ratio), which currently cannot be measured in patients on a routine basis. For example, the treatment of cardiogenic shock is variable, with a lack of understanding when right ventricular recovery is a possibility. Right ventricular PV loop data in cardiogenic shock patients may provide the cues necessary to identify a failing right ventricular versus one with the potential to recover which is crucial. This would help understand which patients require definitive therapy with a heart transplant versus those that can recover. Similarly, advanced heart failure patients who are undergoing LVAD implantation for end-stage heart failure are plagued with inability to predict right ventricular failure as an Achilles heel of this widely used therapy. Several clinical scores and definitions have been developed to define right ventricular failure, with no uniform approach used due to diagnostic methods which lack reliable predictive models. Lastly, the chief clinical problem in pulmonary hypertension patients is right ventricular dysfunction. An ability to assess right ventricular functional response to current therapies would be valuable, as current clinical metrics are unable to incorporate this due to the fundamental difficulty in assessing right ventricular function by traditional methods (i.e. echocardiography and right heart catheterization alone), right heart catheterization is used commonly in these patient populations; therefore, addition of the ability to obtain PV loops onto a catheter already being used ubiquitously would be advantageous.

[0041] A prototype has been built and tested especially for this application. The catheter system includes pressure and supports multiple independent configurations, meaning it can choose four electrodes out of the multiple electrodes on the catheter. It has new features to simplify calibration. The prototype has relays, so the software can automatically cycle through the configurations choosing the best signal. Using this prototype, n=8 porcine studies have been completed measuring right ventricular PV loops. It was demonstrated that we can administer medications that influence blood pressure (arterial afterload increase with the medication phenylephrine), heart rate and strength of contractions (with the medication dobutamine), and directly depress heart function (using beta blockers and intracoronary microspheres to cause myocardial injury). The catheter system is able to detect myocardial response to these conditions using RV-PV loops as discussed above. We have simultaneously used a separate catheter that is a standard research method to obtain RV- PV loop data and seen that our approach has an excellent correlation. Finally, we have obtained cardiac MRIs in all pigs to have a standard for right ventricular volume to compare our right ventricular volume measurement to.

[0042] The inclusion of the volume sensors on the pulmonary artery catheter provides a care provider the ability to obtain concomitant pressure and volume data using a catheter which is ubiquitously used in the clinical setting. Adding the ability to assess right ventricular pressurevolume loops allows simultaneous acquisition of data without requiring placement of extra catheters into a patient. Additional catheters need to be separately calibrated and separately installed, adding additional time and risk, therefore making routine use of right ventricular pressure-volume loops cumbersome. The ability to assess right ventricular pressure- volume loops in the heart can simplify assessment of myocardial contractility and eliminate the requirement of concomitant imaging to assess ventricular volume (e.g., Cardiac MRI would require additional costs, expertise, and time). In addition, the pulmonary artery catheters described herein facilitate research applications (e.g., to be able to ask and answer questions about the heart’s function in response to different treatments in different disease states).

[0043] As shown in FIG. 1, a heart 10 includes a right atrium 14, a tricuspid valve 18, a right ventricle 22, a pulmonary valve 26, and a pulmonary artery 30. A pulmonary artery catheter system 50 includes a catheter 54 structured for insertion into the heart 10 and a port housing 58 including a right ventricular port 62 (e.g., a pressure port), a right atrial port 66 (e.g., a pressure port), a pulmonary artery distal lumen 70, a balloon port 74, and a volume sensor port 78. In some implementations, the port housing 58 is a strain relief that supports the right ventricular port 62, the right atrial port 66, the pulmonary artery distal lumen 70, the balloon port 74, and the volume sensor port 78. For example, the port housing 58 can include a plastic overmolding or a shrink fit that holds the ports in place and allows access to the ports during use.

[0044] In some implementations, the right atrial port 66 provides pressure sensing. For example, a lumen of the catheter 54 can become a fluid filled catheter connected to an aperture positioned along the length of the catheter 54 and a pressure transducer or another pressure measurement sensor can be connected to the right atrial port 66 to determine a pressure at the location of the aperture.

[0045] In some implementations, the right ventricular port 62 provides pressure sensing. For example, a lumen of catheter 54 can become a fluid filled catheter connected to an aperture positioned along the length of the catheter 54 and a pressure transducer or another pressure measurement sensor can be connected to the right ventricular port 62 to determine a pressure at the location of the aperture. In some implementations, the fluid filled catheter is replaced with a different sensor type. For example, a micromanometer can be installed on the catheter 54 at a desired location and a signal indicative of a pressure is transmitted via the right ventricular port 62. In some implementations, more than one pressure sensor may be provided in communication with the right ventricular port 62.

[0046] The volume sensor port 78 is arranged in communication with volume sensors positioned along the length of the catheter 54. In some implementations, a first volume sensor 82 is positioned along the catheter 54 so to be arranged within the right ventricle 22, a second volume sensor 86 is positioned along the catheter 54 so to be arranged within the right ventricle 22, and a third volume sensor 90 is positioned along the catheter 54 so to be arranged within the right ventricle 22. In some implementations, the first volume sensor 82 provides information used to determine an outflow vector and the third volume sensor 90 and the third volume sensor 90 provides information used to determine an inflow vector. The inflow vector and the outflow vector are used to determine a final common right ventricle volume measurement. In some implementations, the second volume sensor 86 is eliminated. In some implementations, the first volume sensor 82, the second volume sensor 86, and the third volume sensor 90 are used together to determine the inflow vector and the outflow vector.

[0047] As shown in FIG. 2, the first volume sensor 82 is spaced from the distal end of the catheter 54 by a distance A. In some implementations, the distance A is between ten centimeters (10 cm) and thirty-five centimeters (35 cm). The first volume sensor 82 is positioned along the length of the catheter 54 to provide placement within the right ventricle 22 during use.

[0048] In some implementations, the second volume sensor 86 is spaced from the distal end of the catheter 54 by a distance B. In some implementations, the distance B is between twelve centimeters (12 cm) and forty -five centimeters (45 cm). The second volume sensor 86 is positioned along the length of the catheter 54 to provide placement within the right ventricle 22 during use. In some implementations, the distance B is greater than the distance A.

[0049] In some implementations, the third volume sensor 90 is spaced from the distal end of the catheter 54 by a distance C. In some implementations, the distance C is between fourteen centimeters (14 cm) and fifty -five centimeters (55 cm). The third volume sensor 90 is positioned along the length of the catheter 54 to provide placement within the right ventricle 22 during use. In some implementations, the distance C is greater than the distance B.

[0050] In some implementations, the first volume sensor 82 includes an admittance sensor having two electrodes 1 ’ and 2’ spaced apart from one another by a distance D. In some implementations, the distance D is between one millimeter (1 mm) and five millimeters (5 mm). In some implementations, the electrodes 1’ and 2’ are arranged on an exterior surface of the catheter 54. In some implementations, the electrodes 1’ and 2’ include flexible conductive material. In some implementations, the electrodes 1 ’ and 2’ include rigid conductive material. In some implementations, the first volume sensor 82 includes only one electrode 1’.

[0051] In some implementations, the second volume sensor 86 includes an admittance or conductance sensor having two electrodes 3’ and 4’ spaced apart from one another by the distance D. In some implementations, the electrodes 3’ and 4’ are arranged on an exterior surface of the catheter 54. In some implementations, the electrodes 3’ and 4’ include flexible conductive material. In some implementations, the electrodes 3’ and 4’ include rigid conductive material. In some implementations, the second volume sensor 86 includes only one electrode 3 ’ . [0052] In some implementations, the third volume sensor 90 includes an admittance or conductance sensor having two electrodes 5’ and 6’ spaced apart from one another by the distance D. In some implementations, the electrodes 5’ and 6’ are arranged on an exterior surface of the catheter 54. In some implementations, the electrodes 5’ and 6’ include flexible conductive material. In some implementations, the electrodes 5’ and 6’ include rigid conductive material. In some implementations, the third volume sensor 90 includes only one electrode 5 ’ .

[0053] In some implementations, other types of volume sensors may be utilized. In some implementations, the volume sensors are fabricated into the catheter 54. In some implementations, the volume sensors are comolded with the catheter 54. In some implementations, the volume sensors are flush with an exterior surface of the catheter 54 to ease insertion. In some implementations, the volume sensors are attached to the exterior surface of the catheter 50 by adhesive. In some implementations, the pulmonary artery catheter system 50 includes a volume sensor in the form of a plurality of electrodes and an operator can select which electrodes will be used to determine a volume of the right ventricle 22 or another part of the heart 10. As shown in FIG. 8, electrical communication between electrodes provides an admittance measurement that is then used to determine volume. Within the context of this application, the term volume sensor can include a conductive pair of electrodes, located adjacent or spaced apart, more than two electrodes space equidistantly or spaced apart unequally, different volume sensors that do not utilize conductance and/or admittance, etc. Volume sensors provide a signal (fluidic, electronic, etc.) indicative of a volume.

[0054] In some implementations, the first volume sensor 82 is positioned along the catheter 54 so that when install, the first volume sensor 82 is spaced apart from the pulmonary valve 26 by a valve spacing distance E. In some implementations, the third volume sensor 90 is positioned along the catheter 54 so that when install, the third volume sensor 90 is spaced apart from the tricuspid valve 18 by the valve spacing distance E. In some implementations, the valve spacing distance is between five millimeters (5 mm) and twenty millimeters (20 mm).

[0055] In some implementations, the spacing of the first volume sensor 82, the second volume sensor 86, and the third volume sensor 90 along the length of the catheter 54 is different than discussed above with respect to the distal tip of the catheter 54. In some implementations, the second volume sensor 86 is spaced from the first volume sensor 82 by an electrode spacing distance F. In some implementations, the third volume sensor 90 is spaced from the second volume sensor 86 by the electrode spacing distance F. In some implementations, the electrode spacing distance F is between twenty millimeters (20 mm) and one-hundred-fifty millimeters (150 mm). The first volume sensor 82, the second volume sensor 86, and the third volume sensor 90 are all configured to be positioned within the right ventricle 22 when the pulmonary artery catheter system 50 is installed into the heart 10.

[0056] In some implementations, a pressure sensor 106 is positioned along the length of the catheter 54 and configured to be positioned within the right ventricle 22 between the tricuspid valve 18 and the pulmonary valve 26. The pressure sensor 106 is coupled to the right ventricular port 62 for providing pressure information thereto (e.g., via electrical signals, via fluid communication, etc.). In some implementations, the pressure sensor 106 is positioned between the first volume sensor 82 and the second volume sensor 86. In some implementations, the pressure sensor 106 is positioned between the second volume sensor 86 and the third volume sensor 90. As discussed above, the pressure sensor 106 can include remotely sensed pressure (e.g., with a fluid filled catheter and pressure ports) or locally sensed pressure (e.g., onboard electronics such as a micromanometer).

[0057] In some implementations, the pulmonary artery catheter system 50 includes additional electronics positioned along the length of the catheter 54 to provide information without installation of a second catheter. For example, a thermistor or other temperature sensor may be incorporated, a heater may be incorporated, or other electronics.

[0058] As shown in FIGS. 3 and 4, the pulmonary artery catheter system 50 has been demonstrated to be successfully placed in porcine hearts with the volume sensors placed as described above.

[0059] As shown in FIGS. 5-7, pressure -volume loop data received from the right ventricular port 62 and the volume sensor port 78 successfully demonstrates the efficacy of the volume sensors 82, 86, 90. In-vivo porcine pressure-volume loop data was measured utilizing the pulmonary artery catheter system 50 including the volume sensors 82, 86, 90. The pressure-volume loops and corresponding right ventricle contractility (E_es) are compared to a baseline for the following conditions: Condition A includes an increased E_es and decreased afterload (shown in FIG. 5), Condition B (includes an increased E_es and increased afterload (shown in FIG. 6), and Condition C includes a decreased E_es and decreased afterload (shown in FIG. 7). Effective arterial elastance (E_a) is a way to estimate an afterload by measuring the slope of a line on a pressure-volume loop. The line extends from an end-diastolic pressure-volume point to its end-systolic pressure -volume point. E_a is also known as the ratio of an end-systolic pressure to its stroke volume (SV). E_es, E_a, and a E_es/E_a coupling ratio can be determined based on the sensor information from the pulmonary artery catheter system 50 and can be used by clinicians for diagnostics.

[0060] The pulmonary artery catheter system 50 can be used in many clinical conditions, including but not limited to right ventricle dysfunction in heart failure patients requiring heart transplantation or permanent/temporary heart pump implantations (e.g., left ventricular assist devices or LVAD for patients in cardiogenic shock), those with different etiologies of pulmonary hypertension, and those with tricuspid regurgitation to determine if they are candidates for repair or replacement of the tricuspid valve. Clinically, right ventricle dysfunction is a driver for morbidity and mortality in several different cardiac diseases. Current therapies are directed towards treatment of left ventricular dysfunction, as the pathophysiology of right ventricle dysfunction is not well understood. The benefit of using the pulmonary artery catheter system 50 includes potentially improved morbidity and mortality of complex patients due to a greater understanding of the right ventricle chamber function, reserve, and interaction. Current systems do not provide right ventricular chamber volumes in any capacity. For example, the treatment of cardiogenic shock is variable, with a lack of understanding when right ventricle recovery is a possibility. Right ventricle pressure- volume loop data in cardiogenic shock patients may provide the cues necessary to identify a failing right ventricle versus one with the potential to recover, which is crucial. This would help understand which patients require definitive therapy with a heart transplant versus those that can recover. Similarly, advanced heart failure patients who are undergoing LVAD implantation for end-stage heart failure are plagued with inability to predict right ventricle failure in this widely used therapy. Several clinical scores and definitions have been developed to define right ventricle failure, with no uniform approach used due to diagnostic methods which lack reliable predictive models. The chief clinical problem in pulmonary hypertension patients is right ventricle dysfunction. An ability to assess right ventricle functional response to current therapies would be valuable, as current clinical metrics are unable to incorporate this due to the fundamental difficulty in assessing right ventricle function by traditional methods (e.g., echocardiography and RHC alone). Right heart catheterization is used commonly in these patient populations; therefore, addition of the ability to obtain right ventricle loops onto a catheter already being used ubiquitously would be advantageous. Tricuspid valve regurgitation is another application. It is currently unclear which patients would benefit from surgical or percutaneous valve repair or replacement due to a lack of understanding of right ventricular systolic function and its coupling to the afterload it pumps against. If the lower resistance right atrial leak is critical to continued right ventricular function, then removing tricuspid valve regurgitation in this patient subset may result in acute right ventricular failure. In contrast, there may be patients who are denied invasive tricuspid valve regurgitation treatment due to a concern that the right ventricular may fail, when having access to right ventricular pressure volume loops and derived E_es and E_a may predict it is safe to invasively terminate tricuspid valve regurgitation.

[0061] The pulmonary artery catheter system 50 include pressure sensing and supports multiple independent configurations (e.g., using a subset of the available volume sensors). In some implementations, more than six or less than six electrodes are included. In some implementations, more than three or less than three volume sensors are included. The pulmonary artery catheter system 50 includes features to simplify calibration. For example, the pulmonary artery catheter system 50 includes relays, so associated software can automatically cycle through the configurations choosing the best signal. Using the pulmonary artery catheter system 50, the inventors have completed porcine studies measuring right ventricle pressure-volume loops in different hemodynamic conditions (as shown in FIGS. 5-7). The pulmonary artery catheter system 50 is able to detect myocardial response to these conditions using right ventricle pressure -volume loops as discussed above. In some implementations, the pulmonary artery catheter system 50 can be positioned for volume sensor coupling to right atrial pressure for atrial pressure-volume loops.

[0062] In some implementations, the first volume sensor 82, the second volume sensor 86, and the third volume sensor 90 provide a measured admittance or conductance signal (Gb). As shown in FIG. 8, the exemplary first volume sensor 82, the second volume sensor 86, and the third volume sensor 90 include six electrodes that generate fields fully filling the volume. In some implementations, the right ventricular volume is determined as V = A * y * Gb /(y - Gb), where V is volume, y is measured admittance or conductance at infinite volume, and A is a coefficient calibrated from stroke volume. In some implementations, y is measured at o=0.8333 S/m. A=pL² is then calibrated using (SV, y). Measurements are then taken two beats at end expiration (GbEs = min(Gb) 7-point average, GSED = max(Gb)). In the example shown in FIGS. 9-12, SV = 45.92 mL, A = SV/(y*GbED/(y-GbEo)-y*GbEs/(y-GbEs)), measured outflow y=25 mS, and measured inflow y=27 mS. In some implementations, V = A * y * I Yl/(y -IYI). In some implementations, Gb is determined based on the two fields shown in FIG. 8 and Gb = GbA (first admittance or conductance field) + GbB (second admittance or conductance field). Using the above systems and methods, the real-time volume measurements shown in FIG. 13 were determined.

[0063] For purposes of this description, certain advantages and novel features of the aspects and configurations of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed aspects, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

[0064] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0065] Features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The claimed features extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0066] As used in the specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about”, it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting aspect the terms are defined to be within 10%. In another non-limiting aspect, the terms are defined to be within 5%. In still another non -limiting aspect, the terms are defined to be within 1%.

[0067] The terms “coupled”, “connected”, and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic. For example, circuit A communicably “coupled” to circuit B may signify that the circuit A communicates directly with circuit B (i.e., no intermediary) or communicates indirectly with circuit B (e.g., through one or more intermediaries).

[0068] Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower”, and “upper” designate direction in the drawings to which reference is made. The words “inner” and “outer” refer to directions toward and away from, respectively, the geometric center of the described feature or device. The words “distal” and “proximal” refer to directions taken in context of the item described and, with regard to the instruments herein described, are typically based on the perspective of the practitioner using such instrument, with “proximal” indicating a position closer to the practitioner and “distal” indicating a position further from the practitioner. The terminology includes the above-listed words, derivatives thereof, and words of similar import.

[0069] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises”, means “including but not limited to”, and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0070] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention.

Claims

What is claimed is:

1. A pulmonary artery catheter system comprising: a catheter; a port housing coupled to the catheter and supporting: a right ventricular port, a right atrial port, a pulmonary artery distal lumen, a balloon port, and a volume sensor port; and a plurality of volume sensors positioned along a length of the catheter and in communication with the volume sensor port.

2. The pulmonary artery catheter system of claim 1 , wherein the plurality of volume sensors includes: a first volume sensor configured to be positioned within a right ventricle, a second volume sensor configured to be positioned within the right ventricle, and a third volume sensor configured to be positioned within the right ventricle.

3. The pulmonary artery catheter system of claim 1, wherein the plurality of volume sensors are used to determine an inflow vector and an outflow vector.

4. The pulmonary artery catheter system of claim 1, wherein the plurality of volume sensors includes: a first volume sensor positioned a first distance from a distal tip of the catheter, a second volume sensor positioned a second distance from the distal tip of the catheter, and a third volume sensor positioned a third distance from the distal tip of the catheter, wherein the second distance is greater than the first distance, and the third distance is greater than the second distance.

5. The pulmonary artery catheter system of claim 4, wherein the first volume sensor is spaced from the second volume sensor by between twenty millimeters (20 mm) and one- hundred-fifty millimeters (150 mm), and wherein the second volume sensor is spaced from the third volume sensor by between twenty millimeters (20 mm) and one-hundred-fifty millimeters (150 mm).

6. The pulmonary artery catheter system of claim 5, wherein a distance between the first volume sensor and the second volume sensor is equal to a distance between the second volume sensor and the third volume sensor.

7. The pulmonary artery catheter system of claim 1, wherein each of the plurality of volume sensors includes a conductive sensor.

8. The pulmonary artery catheter system of claim 7, wherein each conductive sensor includes an electrode pair.

9. The pulmonary artery catheter system of claim 7, wherein each conductive sensor is formed from a flexible conductive material.

10. The pulmonary artery catheter system of claim 7, wherein each conductive sensor is formed from a rigid conductive material.

1 1 . The pulmonary artery catheter system of claim 1 , further comprising a pressure sensor positioned along the length of the catheter, configured to be positioned within a right ventricle, and providing a signal indicative of a pressure to the right ventricular port.

12. The pulmonary artery catheter system of claim 11, wherein the pressure sensor includes a pressure aperture utilizing a fluid filled catheter.

13. The pulmonary artery catheter system of claim 11, wherein the pressure sensor includes a micromanometer.

14. The pulmonary artery catheter system of claim 11, wherein signals received from the right ventricular port and the volume sensor port are configured for creation of right ventricle pressure-volume loops.

15. A pulmonary artery catheter system comprising: a catheter defining a distal tip and a proximal port housing; a right ventricular port coupled to the proximal port housing; a right atrial port coupled to the proximal port housing; a pulmonary artery distal lumen coupled to the proximal port housing; a balloon port coupled to the proximal port housing; a volume sensor port coupled to the proximal port housing; a pressure sensor positioned along a length of the catheter, configured to be positioned within a right ventricle, and providing a signal indicative of a pressure to the right ventricular port; a first admittance sensor positioned along a length of the catheter; a second admittance sensor positioned along a length of the catheter; and a third admittance sensor positioned along a length of the catheter, wherein at least two of the first admittance sensor, the second admittance sensor, or the third admittance sensor are configured to be positioned within a right ventricle of a heart.

16. The pulmonary artery catheter system of claim 15, wherein each of the first admittance sensor, the second admittance sensor, and the third admittance sensor includes a conductive electrode pair.

17. A method comprising: inserting a pulmonary artery catheter system into a heart; determining a right ventricular volume based on admittance or conductance signals received from a volume sensor of the pulmonary artery catheter system positioned within a right ventricle of the heart; determining a right ventricular pressure based on signals received from a pressure sensor of the pulmonary artery catheter system positioned in the right ventricle; and generating right ventricle pressure-volume loops based on the determined volume and pressure.

18. The method of claim 17, further comprising determining an effective arterial elastance (E_a), a ventricle contractility (E_es), and a coupling ratio (E_es/E_a) based on the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor.

19. The method of claim 17, wherein an inferior vena cava occlusion is used to generate the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor to generate a family of pres sure- volume loops.

20. The method of claim 17, wherein a Valsalva is used to generate the admittance or conductance signals received from the volume sensor and the signals received from the pressure sensor to generate a family of pressure-volume loops.

21. The method of claim 17, wherein determining the right ventricular volume includes V = A * y * Gb /(y - Gb), where V is the right ventricular volume, y is measured admittance or conductance at infinite volume, and A is a coefficient calibrated from stroke volume.