Pressure-based vascular assessment system and method
The dPRc metric, which integrates data from multiple heart cycles and segments, enhances vascular occlusion assessment accuracy by averaging pressure ratios, addressing limitations of existing FFR methods.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- OPSENS INC
- Filing Date
- 2024-10-30
- Publication Date
- 2026-07-23
AI Technical Summary
Existing methods for determining vascular occlusion treatment, such as fractional flow reserve (FFR), are limited by relying on diastolic pressure measurements alone, which do not provide comprehensive data for accurate clinical decision-making.
A method using a dPRc metric that incorporates data from multiple heart cycles and segments, combining both systolic and diastolic portions, to calculate a multi-beat vascular occlusion assessment.
Provides more accurate and stable vascular occlusion assessment by averaging pressure ratios over multiple heartbeats, reducing the influence of signal instability and artifacts, enabling better clinical decision-making.
Smart Images
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Abstract
Description
Technical Field
[0001]
[0001] This application is directed to systems and methods for determining whether to treat a patient based on a blood pressure measurement and how to treat the patient.
Background Art
[0002]
[0002] Fractional flow reserve (FFR) is a known technique for determining whether to treat a vascular occlusion using balloon angioplasty and / or a stent. FFR is a test performed under hyperemia. In this technique, blood pressures are measured within the distal and proximal coronary vasculature of the occlusion. Conventionally, the ratio of these pressures has been calculated and compared to a threshold value, below which balloon angioplasty and / or stent placement has been indicated and above which such treatment has not been performed.
[0003]
[0003] A more recent trend has been to calculate the pressure ratio based only on pressures obtained during the diastolic portion of the cardiac cycle without hyperemia, but based on data obtained at the same location within the vasculature relative to the occlusion.
Summary of the Invention
Problems to be Solved by the Invention
[0004]
[0004] Improved devices and methods are needed to determine when and how to treat coronary artery occlusion. Such methods can advantageously include data from more than just the diastolic segment and can consider data from one or more heart cycles. Sampling from multiple heart cycles and / or from multiple segments of one or more heart cycles can provide more information about the state of blood flow through the heart. Sampling from multiple heart cycles and / or from multiple segments of one or more heart cycles can enable clinicians to analyze the cardiovascular state during resting heart cycles. Better clinical decisions come from more comprehensive and refined data.
[0005]
[0005] A method for evaluating a patient is provided. A metric called dPRc can be calculated herein. The metric uses an aortic or proximal pressure curve called a Pa curve and a distal pressure curve called a Pd curve. The proximal pressure curve can be provided by a guide catheter pressure sensor, a pressure guidewire, or another device capable of sensing pressure within the aorta. The distal pressure curve can be provided by a pressure guidewire or other device capable of sensing pressure distal to vascular occlusion. dPRc can be a multi-beat metric that incorporates data sampling from one or more adjacent pulse segments and from one or more adjacent whole pulses.
[0006]
[0006] One technique is used to detect the heartbeat. The heartbeat can be detected from a series of Pa values. The heartbeat can be detected by Pd values. The heartbeat can be detected from both Pa and Pd values.
[0007]
[0007] In one technique, overlapping notches and the end of diastolic (EoD) position are identified from the pressure data. These positions can define, or can be used to define, heart rate segments used to calculate a heart rate segment metric called dPR as referred to herein. The segments from which dPR is calculated may be called dPR zones. A dPR value can be calculated for each heartbeat in a detected set of heart rates.
[0008]
[0008] The whole-beat metric can be calculated. The whole-beat metric includes data from both the systolic and diastolic portions of the heartbeat. The whole-beat metric may include a pulse transmission coefficient, referred to herein as the PTC(B) value. The PTC(B) value can be calculated for each heartbeat in a detected sequence of heartbeats.
[0009]
[0009] In some cases, the median PTC(B) (hereinafter referred to as PTC(B)med) is calculated over a series of temporally consecutive heartbeats. The PTC(B)med value reduces, or in some cases minimizes, the effects of signal instability and artifacts. A new PTC(B)med value can be calculated for each consecutive heartbeat. The number of consecutive heartbeats used to calculate PTC(B)med may depend on the type of analysis performed, as will be further explained below.
[0010]
[0010] The ratio of mean Pd to mean Pa is calculated at the sampling rate. The mean Pd to mean Pa ratio can be calculated over a period corresponding to the most recent heartbeat used when calculating the PCT(B)med value. A new mean Pd to mean Pa ratio can be calculated for each pressure sample or measurement performed. The pressure sample can be at any suitable sampling rate, such as 125 Hz (every 8 ms).
[0011]
[0011] The dPRc metric can be calculated for a time that matches the duration of the most recent group of heartbeats used to calculate the PTC(B)med value. The dPRc value can be calculated and displayed quickly, for example, after each pressure sample, for example, every 8 ms.
[0012]
[0012] In one embodiment, a system for evaluating vascular status is provided. The system includes a pressure-sensing catheter, a pressure guidewire, and one or more hardware processors. The pressure-sensing catheter is configured to be located at a proximal position in the patient's vascular system. The pressure guidewire is configured to be located at a distal position in the vascular system. The distal position is distal to the proximal position. One or more hardware processors are configured to detect the patient's heartbeat while the pressure-sensing catheter and pressure guidewire are located at the proximal and distal positions in the vascular system, respectively. One or more hardware processors are configured to locate diastolic pressure ratio (dPR) zones within the heartbeat from an analysis of signals from at least one of the pressure-sensing catheter and pressure guidewire. One or more hardware processors are configured to calculate a dPR value, which includes calculating the average of multiple ratios of Pa to Pd taken over time within the dPR zone. One or more hardware processors are configured to calculate a multibeat metric, which includes the dPR value and the high-frequency sample whole heartbeat pressure ratio. One or more hardware processors are configured to output the multibeat metric.
[0013]
[0013] In one embodiment, a method for evaluating vascular condition is provided. A pressure-sensing catheter is positioned proximal, for example, proximal to the occlusion in the patient's coronary artery. A pressure guidewire is positioned distally in the vascular system, for example, distal to the occlusion. The patient's heartbeat is detected while in the vascular system, including when the pressure-sensing catheter and pressure guidewire are positioned proximal and distal, respectively, for example, proximal and distal to the occlusion. A diastolic pressure ratio (dPR) zone is located within the heartbeat from analysis of signals from at least one of the pressure-sensing catheter and pressure guidewire. The dPR value is calculated. Calculation of the dPR value may include calculating the average of multiple ratios of Pa to Pd taken over time within the dPR zone. A multibeat metric is calculated, which includes the dPR value and also includes a high-frequency sample whole heartbeat pressure ratio. The multibeat metric can be displayed to the user.
[0014]
[0014] These and other features, aspects and advantages are described below with reference to the drawings, which are intended to be illustrative and should not be construed as limiting the scope of the embodiments. Furthermore, various features of different disclosed embodiments can be combined to form additional embodiments which are part of this disclosure. In the drawings, similar reference numerals indicate features that correspond consistently throughout similar embodiments. Each drawing is described below. [Brief explanation of the drawing]
[0015] [Figure 1]
[0015] This is a schematic diagram showing a blood vessel in which a pressure guidewire is inserted, a notch is positioned at intervals proximal to the notch, and a guide catheter is located proximal to the notch, for example, in the patient's aorta. [Figure 2]
[0016] This is a schematic diagram of an occlusion analysis system that includes a pressure guidewire and a monitor assembly capable of processing vascular pressure data in relation to vascular occlusion analysis. [Figure 3]
[0017] This is a graphical representation of pressure signals over time, including the identification of diastolic blood pressure ratio zones (dPR zones) for calculating metrics during segments or parts of the heart rate cycle. [Figure 4]
[0018] This graph is similar to Figure 3, and the whole-heart-rate cycle metric is explained in relation to it. [Figure 5]
[0019] This shows the analysis of multiple consecutive heart rate cycles when calculating multi-beat metrics that are useful in determining whether or not to treat a patient. [Figure 6] This shows the analysis of multiple consecutive heart rate cycles when calculating multi-beat metrics that are useful in determining whether or not to treat a patient. [Figure 7]
[0020] This document describes techniques for expanding data streams for use in static measurements, including high-frequency sample pressure ratio metrics and segment and whole-heart-beat metrics across multiple consecutive heartbeats. [Figure 8]
[0021] This document describes a technique for unfolding data streams for use in pullback measurements, including high-frequency sample pressure ratio metrics and segment and whole-beat metrics across multiple consecutive heartbeats. [Figure 8A]
[0022] Another technique similar to that shown in Figure 8 for pullback measurement is presented. [Figure 9]
[0023] Figure 2 illustrates the exemplary output provided on the user interface of the monitor assembly of the system shown. [Figure 10] Figure 2 illustrates the exemplary output provided on the user interface of the monitor assembly of the system shown. [Figure 11] Figure 2 illustrates the exemplary output provided on the user interface of the monitor assembly of the system shown. [Figure 12] Figure 2 illustrates the exemplary output provided on the user interface of the monitor assembly of the system shown. [Figure 13]Illustrates an exemplary output provided on the user interface of the monitor assembly of the system of FIG. 2. [Figure 14]
[0024] It is a schematic diagram of a blood vessel being evaluated using the method discussed herein. [Figure 15]
[0025] It is a schematic diagram of a blood vessel being treated after the evaluation performed as shown in FIG. 14.
Best Mode for Carrying Out the Invention
[0016]
[0026] This application is directed to systems and methods for determining whether and how to treat a patient, in which data from multiple segments of a cardiac cycle and / or multiple cardiac cycles is taken into account. By incorporating data indicative of both the stressed and resting states of the heart, the patient's condition can be more accurately evaluated and the results improved.
[0017] I. Overview of Pressure Wire Systems and Their Use
[0027] FIGS. 1 and 2 show a lesion diagnostic system 100 and its use in a patient's vasculature. FIG. 1 shows a left coronary vasculature having a pressure guide wire 108 disposed in the proximal portion of the left anterior descending (LAD) branch. The pressure guide wire 108 is positioned within the left anterior descending LAD branch, and its distal portion is distal to the occlusion OCL. Blood flow within the left anterior descending LAD branch is from proximal to distal, through the occlusion OCL, and over the distal tip of the pressure guide wire 108. The occlusion OCL impedes the flow at least to some extent. The lesion diagnostic system 100 is configured to determine whether the degree of occlusion is large enough to indicate that balloon angioplasty, a stent, or other catheter intervention should be performed.
[0018]
[0028] The lesion diagnostic system 100 may include a monitor assembly 104 configured to connect to a pressure guidewire 108. In one embodiment, the lesion diagnostic system 100 includes a connector (shown by dashed line A) that facilitates connection and disconnection from the monitor assembly 104 to the pressure guidewire 108. The connection and disconnection from the monitor assembly 104 is useful for clinicians to use the pressure guidewire 108 to first assess the effect of occluded OCL on its distal flow within the left anterior descending artery (LAD) (or other coronary vessel), and then use the pressure guidewire 108 later to deliver a therapeutic device such as a balloon catheter or stent delivery system.
[0019]
[0029] The connection indicated by the dashed arrow A also allows the pressure-sensing component of the guide catheter assembly 128 to be coupled to the monitor assembly 104. The guide catheter assembly 128 may include a tubular catheter body used to access the vascular system. The distal tip of the guide catheter assembly 128 may be positioned proximal to the occluded OCL, for example, so that a pressure signal corresponding to the proximal pressure of the occluded OCL in the aorta can be acquired. The proximal pressure may be referred to herein as Pa.
[0020]
[0030] The pressure guidewire 108 can take any suitable form. In one embodiment, the pressure guidewire 108 includes a proximal segment having a proximal end located outside the patient's body and a distal end which may be located inside the guide catheter assembly 128. The middle portion of the pressure guidewire 108 may be configured to have flexibility for navigating the tortuous vascular system of the left anterior descending artery LAD (or other coronary vessel) while maintaining structural integrity. The distal portion may include a sensor housing and a non-traumatic tip. Any sensing mode can be used. For example, an optical sensor may be configured to sense pressure when exposed to blood in the left anterior descending artery LAD (or other coronary vessel). The optical sensor may be located within the internal space of the pressure guidewire 108, which is in fluid communication with the outside of the pressure guidewire 108. The optical sensor can be selectively configured to communicate with the monitor assembly 104 by an optical fiber signal line positioned between the sensor and the proximal end of the pressure guide wire 108, which is configured to be coupled to an optical fiber interface cable (not shown) that may include a guide wire connector for connecting the pressure guide wire 108 to the rest of the system. Further details of the optical sensor-based configuration of the pressure guide wire 108 can be found in U.S. Patent Application Publication No. 2015 / 0057532, which is incorporated herein by reference in its entirety.
[0021]
[0031] When the pressure guide wire 108 is configured with the optical sensor, its ability to provide a robust optical connection with the monitor assembly 104 is of interest. Any suitable connection structure or method can be used. One approach is described in detail in U.S. Patent No. 9405078, which is incorporated herein by reference in its entirety.
[0022]
[0032] Figure 2 illustrates the signal data flow in more detail. The clinician in charge of the patient places the guide catheter assembly 128 into the vascular system and places the pressure guidewire 108 into the vascular system through the guide catheter assembly 128. The pressure guidewire 108 provides a signal to the processor 152, which processes the signal to determine the Pd value. The processor 152 also receives the Pa value from the guide catheter signal processor 156. The Pd and Pa signals are processed within the processor 152 to generate the dPRc value (as further described below). These values can be displayed in the dPRc value window 144. A signal trace window 148 is also provided to display traces of Pa, Pd, dPRc, and / or any metric combined with dPRc (as described below). The processor 152, and other processors that may be located in the monitor assembly 104 elsewhere in the system 100, may be separate or combined into a single entity.
[0023] II. Exemplary Methodologies A. Metrics that combine heart rate segment analysis and whole heart rate data
[0033] Improved patient analysis allows for the combination of data from heart rate cycle segments with data containing whole heart rate cycles across one or more consecutive heart rate cycles.
[0024] 1. Calculation of heart rate segment metrics - diastolic blood pressure ratio (dPR)
[0034] In one technique, heart rate segment data is included as part of a multi-beat analysis of the patient's condition. Diastolic blood pressure ratio (dPR) calculation is an example of a heart rate segment metric. The dPR value for a given heart rate is determined by the mean ratio of distal pressure (Pd) to proximal pressure (Pa) within the diastolic blood pressure ratio zone (dPR zone), as shown in Equation 1. For example, Pd can be measured distal to an occluded vascular segment (OCL), and Pa can be measured proximal to an occluded OCL. Pd and Pa can also be measured in unoccluded vascular segments.
number
[0025]
[0035] As described above, Pd is the pressure measured distal to the occluded OCL and is based on the pressure sensed by the pressure guidewire 108. Pa can be measured by any suitable means, such as the guide catheter 128. Another pressure wire or other pressure sensing device may also be used to measure Pa.
[0026]
[0036] Figure 3 shows that in one technique, the dPR value is calculated based on the pressure signal generated in or during a dPR zone 200. The dPR zone 200 corresponds to a segment of the heartbeat as shown in Figure 3. The dPR zone 200 can extend from or away from any of several distinct parts of the heartbeat signal. In one embodiment, the dPR zone 200 is found within the first heartbeat 204. The dPR zone 200 can end before the second heartbeat 208, which is immediately after the first heartbeat 204. The dPR zone 200 can be defined between the overlapping notch 220 and the end-diastolic position 224. Figure 3 shows that the duration of the dPR zone 200 is shorter than the duration of the beat length 210. The beat length 210 can be defined as the duration of time between the systolic onset of the first heartbeat 204 and the systolic onset of the second heartbeat 208.
[0027]
[0037] New dPR values may be obtained for each detected heartbeat, for example, the first heartbeat 204, the second heartbeat 208, and, as further described below, the third heartbeat 304, the fourth heartbeat 308, and the fifth heartbeat 312.
[0028] 2. PTC(B) calculation
[0038] Patient analysis can include whole heart rate data and heart rate segment data. For example, pulse transfer coefficient (PTC) values can be obtained using the following method.
[0029]
[0039] First, we calculate the ratio of Pd to Pa. This ratio can be calculated by dividing the mean distal pressure (Pd) during all pulses by the mean proximal pressure (Pa) during all pulses. This value can be calculated using Equation 2 shown below.
number
[0030]
[0040] The Pd and Pa values combined with the average may be samples taken according to a sampling frequency such as 125 Hz. Figure 4 shows that samples may be acquired over the entire first heartbeat 204. For example, the samples used to calculate these averages may be acquired from immediately after the end of diastolic end 222 of the heartbeat preceding the first heartbeat 204 (sometimes referred to herein as X0_EoD) to the end of diastolic end 224 of the first heartbeat 204 (sometimes referred to herein as X1_EoD).
[0031]
[0041] Any suitable method can be used to identify the end of diastolic period of the beat preceding the first heartbeat 204 and the end of diastolic period 224 of the first heartbeat 204. For example, EoD can be detected using analysis of the pressure signal itself from a pressure guidewire 108, a guide catheter assembly 128, or both of these devices. The end of diastolic period 222 for the preceding beat can also be calculated by subtracting the beat length (but calculated) from the end of diastolic period 224 (but determined).
[0032]
[0042] If available, ECG signals can be used to detect these end-of-diastolic stages using other techniques.
[0033]
[0043] Subsequently, metric values including heart rate segment data and whole heart rate data can be provided. In one technique, a value called PTC(B) can be calculated as the ratio of heart rate segment data to whole heart rate data according to Equation 3.
number
[0034]
[0044] This value can be calculated after the end of the first heartbeat (204), and can be calculated for subsequent heartbeats, as will be discussed further below.
[0035] 3. PTC(B)med calculation
[0045] Figure 5-6 shows further calculations of values that take into account not only heart rate segment data and whole heart rate data, but also data from multiple heartbeats. As will be explained further below, the multi-beat metric can include a different number of consecutive beats depending on the test being performed.
[0036]
[0046] In one embodiment, the multibeat metric 300 is calculated as the median of four consecutive PTC(B) values weighted, for example, based on the heart rate length of the corresponding heartbeat. In another embodiment, the multibeat metric related to the pullback procedure described later in relation to Figure 8A is calculated as the median of two consecutive PTC(B) values weighted, for example, based on the heart rate length of the corresponding heartbeat. This value may be referred to herein as PTC(B)med. The purpose of this weighted median is to minimize the influence of unstable signals, such as arrhythmias or other artifacts, on metrics including PCT(B) values. One metric described later that includes PTC(B)med is the dPRc value.
[0037]
[0047] One method for calculating PTC(B)med involves the following steps: Each heart rate period has a PTC(B)i value (PTC(B)1, PTC(B)2, …, PTC(B)N) and a period length Li (L1, L2, …, LN). See Figure 5. PTC(B)med is the weighted median taken for all PTC(B)i. The weight for each PTC(B)i corresponds to its heart rate period (Li). See Figure 6. In this way, PTC(B)med is sufficiently stable even when using some PTC(B) values corresponding to shorter heartbeats than others. In Figure 5, the values of PTC(B)1 and PTC(B)3 correspond to shorter heart rate cycles, and the values of PTC(B)2 and PTC(B)4 correspond to longer heartbeats.
[0038]
[0048] In one methodology for static measurement, the new PTC(B)med is calculated per heartbeat using all four consecutive preceding heartbeats. In another method of the pullback procedure, described later in relation to Figure 8A, the new PTC(B)med is calculated per heartbeat using all two consecutive preceding heartbeats.
[0039] 4. dPRc calculation - static measurement
[0049] Some analyses can provide metrics that combine heart rate segments across multiple beats with whole heart rate data. One example of this type of metric is dPRc. The dPRc value is calculated as the ratio of the mean Pd to the mean Pa over a period corresponding to the duration of four consecutive heartbeats used to calculate PTC(B)med, and multiplied by the previously obtained PTC(B)med value. dPRc can be calculated according to Equation 4.
number
[0040]
[0050] In this formula, L_dPRc can be calculated as the sum of the durations of multiple beats used to calculate the current PTC(B)med value. One static measurement protocol uses four consecutive beats.
[0041]
[0051] Calculating dPRc over multiple beat periods (e.g., four beats) provides good stability in the dPRc results. It also provides a very rapid, continuous, or rapid continuous stream of new dPRc values. This rapid stream of data is useful for measuring the state over time.
[0042]
[0052] For very stable signals, the dPR and dPRc results are similar or even identical. However, for unstable signals such as arrhythmias, the dPRc result is more reliable than discrete dPR values, which can potentially vary significantly.
[0043]
[0053] Figure 7 shows how the end points (labeled x1 and x2) from which the pressure-averaged multibeat ratio is calculated are determined. x2 is the current sample position, and x1 is obtained by subtracting L_dPRc from x2, where L_dPRc is the sum of the beating durations of the beats used when calculating PTC(B)med. In the figure, L_dPRc = L1 + L2 + L3 + L4. There is always a delay between x2 and the last detected heartbeat, as a delay is required to detect any given heartbeat (analyzing many samples).
[0044]
[0054] Figure 9-13 shows how the aforementioned can be displayed on the signal trace window 148 or within another part of the user interface 140 of the monitor 104. In each figure, Pa and Pd traces are displayed and labeled. Generally, the Pd value is lower than the Pa value when an occluded OCL is obstructing its downstream flow at any given time. The blue vertical lines above the traces represent separate heartbeats. The horizontal lines below the traces labeled "dPR" correspond to each dPR zone 200.
[0045]
[0055] Figure 9 shows the first part of the analysis of pressure data from the pressure guidewire 108 and guide catheter assembly 128. The initial part includes the rising pressure associated with systole and the falling pressure associated with the diastolic onset portion and initial portion in the first heartbeat 204. Figure 9 shows only a portion of the first heartbeat 204. Figure 10 shows the first heartbeat 204, the second heartbeat 208, and the third heartbeat 304. For each heartbeat, the dPR value can be calculated in the corresponding dPR zone 200 as described above.
[0046]
[0056] Figure 11 shows the first, second, and third heartbeats and the fourth heartbeat 308. After the first heartbeat 204, second heartbeat 208, third heartbeat 304, and fourth heartbeat 308 are detected and analyzed, dPRc, or another multi-beat metric combining segment and whole heartbeat data, can be calculated for these four heartbeats. The user interface 140 is configured to include a dPRc trace window 150 that can display dPRc, or another multi-beat metric combining segment and whole heartbeat data. Figure 10 shows that a value of 0 can be displayed for dPRc before a sufficient number of consecutive heartbeats are detected, and no trace is presented in the dPRc trace window 150. After four (or another sufficient number of) heartbeats are detected and analyzed, the dPRc trace window 150 can be modified to display either or both dPRc values and / or dPRc traces, as shown in Figure 11.
[0047]
[0057] Figure 12 shows how the user interface 140 indicates that the dPRc analysis is updated for consecutive heartbeats from the fifth heartbeat onward. The new dPRc value is calculated based on the first heartbeat 204, the third heartbeat 304, the fourth heartbeat 308, and the fifth heartbeat 312. The new dPRc value is generated according to the same protocol as above, where the PTC(B) median is the weighted median of the second, third, fourth, and fifth heartbeats, and the pressure multiplier in Equation 4 is based on the new period of L_dPRc as the sum of the heartbeat lengths (sum of L1, L2, L3, and L4) of the second heartbeat 208, the third heartbeat 304, the fourth heartbeat 308, and the fifth heartbeat 312. The new dPRc value and / or dPRc trace is updated within the dPRc trace window 150 on the user interface 140. Figure 13 shows further calculation of the dPRc metric in time using the third heartbeat 304, the fourth heartbeat 308, the fifth heartbeat 312, and the sixth heartbeat 316. Again, the new dPRc value and / or dPRc trace are updated within the dPRc trace window 150 on the user interface 140.
[0048]
[0058] Based on the analysis, a threshold can be established above which the patient is not treated, and below which treatment such as angioplasty or stent placement is performed. As shown in Figures 14 and 15, both dPRc evaluation and treatment can be performed on the pressure guidewire 108. By updating the dPRc value over time, the user can see the stability of the metric and gain confidence in the next clinical step, such as whether to treat with a balloon, stent, or other method. The output within the dPRc trace window 150 can also be updated at the same rate as the Pa and Pd samples are acquired, for example, every 8 ms based on a sampling rate of 125 Hz. In some cases, the screen may be updated less frequently, but still much faster than every second, for example, 30 times per second. This protocol effectively provides a continuous stream of data, such as a stream of data that is updated more frequently than every heartbeat, more than once per second, more than twice per second, more than five times per second, more than ten times per second, more than fifty times per second, and more than 100 times per second.
[0049] 5. dPRc calculation - pullback measurement
[0059] The above primarily focuses on static position measurements, i.e., measurements performed with at least the pressure guidewire 108 stationary; however, another mode involves acquiring pressure data and analyzing the data at least while the pressure guidewire 108 is moving. Generally, the movement of the guidewire 108 provided is proximal, from a distal position in the vascular system toward a proximal position adjacent to the distal end of the guide catheter assembly 128. This movement can be provided by a clinician manually pulling back the pressure guidewire 108 directly, or by using a device configured to generate controlled proximal movement.
[0050]
[0060] Figure 8 shows one embodiment of pullback mode analysis. In this example, dPRc is calculated by Equation 4.
number
[0051]
[0061] However, one difference is that PTC(B)med can be based on the three most recent beats. Also, L_dPRc is the average duration of the three beats (e.g., the first beat 204A, the second beat 208A, and the third beat 304A) used to calculate PTC(B)med. In other words, the first term of Equation 4 is the mean distal pressure over time L_dPRc divided by the mean proximal pressure over time L_dPRc. Figure 8 shows the window between x1 and x2 during time for the current pressure sample data, returning by the amount of L_dPRc.
[0052]
[0062] Figure 8A shows another technique for performing analysis in pullback mode. This technique is similar to that in Figure 8, except that it will be described differently below. Here, two beats (204A, 208A) are used when calculating PTC(B)med. This value is multiplied by the Pd / Pa ratio, which is calculated as shown in Equation 4. However, in this calculation, L_dPRc is the sum of the periods of the two beats, shown as the time between X1 and X2. This can be calculated as the time between the start of systole of beat 204A and the systole of beat 304A. The window for calculating Pd / Pa is shifted in time for each new sample, for example, every 8 milliseconds. The value of L_dPRc can be calculated each time a new value of PTC(B)med is calculated, for example, after the end of each complete beat. One advantage of the approach described in relation to Figure 8A is that it provides a faster response time than the approach which requires two or more beats to present the pullback mode value. If a more stable value is desired, more beats can be used, as with the method in Figure 8. Another advantage of the algorithm described in relation to Figure 8A is that it involves similar calculations to those used in static or stationary modes, but uses two beats instead of the four used in static or stationary modes.
[0053]
[0063] The aforementioned approach to dPRc provides a rapid stream of time-series data, offering greater clarity for the pullback mode.
[0054] B. Advantages
[0064] The above discussed using the average of multiple ratios of Pd to Pa as part of calculating a useful vascular occlusion assessment metric. Averaging these ratios offers advantages. For example, whenever noise is present, averaging the ratios is more accurate than other methods of combining multiple measurements, such as calculating the ratio of the average of multiple distal pressure measurements to the average of multiple proximal pressure measurements. This is especially true whenever Pa exhibits a large pressure deviation caused by movement of the pressure tube or other similar noise sources.
[0055]
[0065] The dPRc method, which includes the calculation of PTC(B)med, enables reliable dPR calculation without the need to analyze and remove any data related to heartbeats that may actually be irregular in some way. Therefore, this method can be performed without the need to predetermine any criteria that justify removing or discarding data related to irregular heartbeats.
[0056]
[0066] The pullback technique allows for a faster stream of data, enabling a quicker response in dPRc measurements and thus improved spatial resolution.
[0057] term
[0067] As used herein, the relative terms “proximal” and “distal” are defined from the perspective of the system user. Thus, proximal refers to the direction toward the system user, and distal refers to the direction toward the system user.
[0058]
[0068] Conditional language such as "can," "could," "might," or "may," unless otherwise specifically stated or understood in the context in which they are used, is generally intended to convey that a particular embodiment includes a particular feature, element, and / or step, but other embodiments do not. Therefore, such conditional language does not generally imply that the feature, element, and / or step is required in any way for one or more embodiments.
[0059]
[0069] Terms such as "comprising," "including," and "having" are synonymous and used in an unrestricted and inclusive manner, without excluding additional elements, features, actions, or behaviors. Similarly, the term "or" is used in its inclusive sense (not its exclusive sense), for example, when used to connect a list of elements, so that it refers to one, some, or all of the elements in the list.
[0060]
[0070] As used herein, the terms “approximately,” “about,” “generally,” and “substantially” refer to quantities close to the stated quantity that still perform the desired function or achieve the desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to quantities that are less than 10% of the stated quantity, as the context may indicate.
[0061]
[0071] The scope disclosed herein also includes any and all overlaps, subscopes, and combinations thereof. Terms such as “up to,” “at least,” “greater than,” “less than,” and “between” include the numbers listed. Numbers preceded by terms such as “about” or “approximately” include the numbers listed. For example, “about 4” includes “4.”
[0062]
[0072] Any method disclosed herein does not need to be performed in the order listed. Methods disclosed herein include specific actions performed by a practitioner, but may also include any third-party commands for those actions, explicitly or implicitly. For example, an action such as "moving the locking element distally" includes "commanding the distal movement of the locking element."
[0063]
[0073] While specific embodiments and examples are described herein, it will be understood by those skilled in the art that many aspects of the humeral assemblies shown and described herein may be combined and / or modified in different ways to form yet another embodiment or acceptable example. All such modifications and variations are intended to be included herein within the scope of this disclosure. A wide variety of designs and methods are possible. Features, structures, or steps disclosed herein are not essential or indispensable.
[0064]
[0074] Several embodiments have been described in reference to the accompanying drawings. However, it should be understood that the drawings are not drawn to a specific scale. Distances, angles, etc., are illustrative only and do not necessarily have an exact relationship to the actual dimensions and layout of the devices shown. Components can be added, removed, and / or rearranged. Furthermore, any particular features, aspects, methods, characteristics, features, qualities, attributes, elements, etc. disclosed herein relating to various embodiments can be used in all other embodiments described herein. In addition, it will be recognized that any method described herein can be practiced using any device suitable for carrying out the enumerated steps.
[0065]
[0075] For the purposes of this disclosure, several aspects, advantages, and novel features are described herein. It should be understood that not all such advantages may necessarily be achieved according to any particular embodiment. Therefore, for example, a person skilled in the art will recognize that this disclosure may be embodied or performed in a manner that achieves one or a group of advantages as taught herein without necessarily achieving other advantages that may be taught or suggested herein.
[0066]
[0076] Furthermore, while exemplary embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., aspects across various embodiments), adaptations and / or changes will be understood by those skilled in the art based on this disclosure. Limitations in the claims should be interpreted broadly based on the language used in the claims and not limited to the examples described herein or in the proceedings of this application, and these examples should be interpreted as non-exclusive. Furthermore, the actions of the disclosed processes and methods may be modified in any way, including by rearranging the actions and / or inserting additional actions and / or deleting actions. Thus, this specification and the examples are illustrative only, and the true scope and spirit are intended to be shown by the entire scope of the claims and their equivalents.
Claims
1. A system for evaluating vascular condition: A pressure-sensing catheter configured to be positioned proximal within the patient's vascular system; A pressure guidewire configured to be positioned at a distal position within the vascular system, wherein the distal position is located distal to the proximal position, and the pressure guidewire is located at a distal position to the proximal position; One or more hardware processors: The patient's heartbeat is detected while the pressure-sensing catheter and the pressure guidewire are positioned at the proximal and distal positions within the vascular system, respectively; The dPR value is calculated by calculating the average of multiple ratios of proximal pressure (Pa) to distal pressure (Pd) taken over time within the diastolic blood pressure ratio (dPR) zone; The total heart rate pressure ratio is calculated by dividing the average distal pressure (Pd) during all heartbeats by the average proximal pressure (Pa) during all heartbeats; Calculate a multibeat metric for one or more consecutive heartbeats, including the dPR value and the total heart rate pressure ratio; One or more hardware processors configured to output the multibeat metric; A system that includes this.
2. The system according to claim 1, wherein one or more hardware processors are configured to calculate the total heart rate pressure ratio using samples from the systolic and diastolic phases of at least two consecutive heartbeats.
3. The one or more hardware processors described above are, [Math 1] The multi-beat metric is configured to be calculated according to the following: L_dPRc is the sum of the heart rate durations of the beats used when calculating PTC(B)med. PTC(B)med is the median of PTC(B), The system according to claim 1, wherein PTC(B) is a pulse transmission coefficient.
4. The system according to claim 1, wherein one or more hardware processors are configured to detect a heartbeat by analyzing a continuous signal from at least one of the pressure guide wire and the pressure sensing catheter.
5. The system according to claim 1, wherein the one or more hardware processors are configured to locate the dPR zone by identifying overlapping notch locations and end-stage diastolic locations from analysis of signals from at least one of the pressure-sensing catheter and the pressure guidewire.
6. The one or more hardware processors described above are: [Math 2] It is configured to calculate the dPR value related to the heart rate, X_EoD is the end of the diastolic position; x_notch is the location of the overlapping notch; The system according to claim 1, wherein L_dPR is the length of time between x_notch and X_EoD.
7. The one or more hardware processors described above are: [Math 3] It is configured to calculate the total heart rate pressure ratio as follows: X1_EoD is the end of diastole of the first heartbeat. The system according to claim 1, wherein X0_EoD is the end of the diastolic phase of the heartbeat preceding the first heartbeat.
8. The one or more hardware processors described above are: [Math 4] It is configured to calculate the multi-beat metric by calculating the median of multiple consecutive heartbeats. The system according to claim 1, wherein PTC(B) is a pulse transmission coefficient.
9. The system according to claim 8, wherein the median value is based on four consecutive heartbeats.
10. The aforementioned multi-beat metric is, [Math 5] It is calculated as follows, and L_dPRc is the time corresponding to the sum of the periods of four consecutive heartbeats. PTC(B)med is the median of PTC(B), The system according to claim 9, wherein PTC(B) is a pulse transmission coefficient.
11. The system according to claim 8, wherein the median is based on two or three consecutive heartbeats.
12. The aforementioned multi-beat metric is, [Math 6] It is calculated as follows, and L_dPRc is the time corresponding to the average of the periods of three consecutive heartbeats. PTC(B)med is the median of PTC(B), The system according to claim 1, wherein PTC(B) is a pulse transmission coefficient.
13. The aforementioned multi-beat metric is, [Number 7] It is calculated as follows, and L_dPRc is the time corresponding to the sum of the periods of two consecutive heartbeats. PTC(B)med is the median of PTC(B), The system according to claim 1, wherein PTC(B) is a pulse transmission coefficient.
14. It is a monitor assembly, User interface and; One or more hardware processors: Detect the patient's heartbeat; The dPR value is calculated by calculating the average of multiple ratios of proximal pressure (Pa) to distal pressure (Pd) taken over time within the diastolic blood pressure ratio (dPR) zone; The total heart rate pressure ratio is calculated by dividing the average distal pressure (Pd) during all heartbeats by the average proximal pressure (Pa) during all heartbeats; Calculate a multibeat metric for one or more consecutive heartbeats, including the dPR value and the total heart rate pressure ratio; One or more hardware processors configured to output the multibeat metric; A monitor assembly, including the monitor assembly.
15. The monitor assembly according to claim 14, wherein one or more hardware processors are configured to calculate a total heart rate pressure ratio using pressure measurement samples from the systolic and diastolic phases of at least two consecutive heartbeats.
16. The one or more processors described above are, [Number 8] The multi-beat metric is configured to be calculated according to the following: L_dPRc is the sum of the heart rate durations of the beats used when calculating PTC(B)med. PTC(B)med is the median of PTC(B), The monitor assembly according to claim 14, wherein PTC(B) is a pulse transmission coefficient.
17. The monitor assembly according to claim 14, wherein the monitor assembly is configured to be connected to a pressure guide wire.
18. The monitor assembly according to claim 14, wherein the monitor assembly is configured to receive data from a pressure-sensing component of a guide catheter assembly.
19. The monitor assembly according to claim 14, wherein the user interface is configured to display a signal trace window indicating the proximal pressure (Pa) and the distal pressure (Pd).
20. The monitor assembly according to claim 14, wherein the user interface is configured to display the multibeat metric.
21. A method for operating a system for evaluating vascular conditions, The process involves a processor processing signals provided to the processor to determine one or more blood pressure values at a first location within the patient's vascular system; The steps include: receiving a signal in the processor indicating one or more blood pressure values at a second location within the patient's vascular system; The processor performs the steps of detecting the patient's heart rate from one or more blood pressure values at the first position, one or more blood pressure values at the second position, or one of the blood pressure values at the first and second positions; The processor performs the steps of: locating the diastolic blood pressure ratio (dPR) zone within the heartbeat; The steps include: calculating a dPR value using the processor, which includes calculating the average of a plurality of ratios of blood pressure values at a second location to blood pressure values at a first location taken over time within the dPR zone; The processor performs the steps of: calculating the total heart rate pressure ratio as the ratio obtained by dividing the mean blood pressure value at a first position during all heartbeats by the mean blood pressure value at a second position during all heartbeats; The steps include: the processor calculating a multi-beat metric over one or more consecutive heartbeats, including the dPR value and the total heart rate pressure ratio; The processor performs the steps of displaying the multi-beat metric for the user; Methods that include...