NL2009285C2 - Pressure sensor catheter and method for measuring a pressure difference in a body lumen. - Google Patents
Pressure sensor catheter and method for measuring a pressure difference in a body lumen. Download PDFInfo
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- NL2009285C2 NL2009285C2 NL2009285A NL2009285A NL2009285C2 NL 2009285 C2 NL2009285 C2 NL 2009285C2 NL 2009285 A NL2009285 A NL 2009285A NL 2009285 A NL2009285 A NL 2009285A NL 2009285 C2 NL2009285 C2 NL 2009285C2
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- pressure
- sensor
- catheter
- transfer tube
- tube
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- 238000000034 method Methods 0.000 title claims description 23
- 238000012546 transfer Methods 0.000 claims description 89
- 208000031481 Pathologic Constriction Diseases 0.000 claims description 67
- 208000037804 stenosis Diseases 0.000 claims description 67
- 230000036262 stenosis Effects 0.000 claims description 67
- 210000003709 heart valve Anatomy 0.000 claims description 36
- 238000005259 measurement Methods 0.000 claims description 28
- 239000012530 fluid Substances 0.000 claims description 26
- 239000012528 membrane Substances 0.000 claims description 14
- 210000004204 blood vessel Anatomy 0.000 description 6
- 239000008280 blood Substances 0.000 description 5
- 210000004369 blood Anatomy 0.000 description 5
- 239000012266 salt solution Substances 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 239000003146 anticoagulant agent Substances 0.000 description 1
- 229940127219 anticoagulant drug Drugs 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000017531 blood circulation Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000024883 vasodilation Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/0215—Measuring pressure in heart or blood vessels by means inserted into the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
- A61B5/6852—Catheters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
- A61B2560/02—Operational features
- A61B2560/0242—Operational features adapted to measure environmental factors, e.g. temperature, pollution
- A61B2560/0247—Operational features adapted to measure environmental factors, e.g. temperature, pollution for compensation or correction of the measured physiological value
- A61B2560/0257—Operational features adapted to measure environmental factors, e.g. temperature, pollution for compensation or correction of the measured physiological value using atmospheric pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0247—Pressure sensors
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Cardiology (AREA)
- Vascular Medicine (AREA)
- Physiology (AREA)
- Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
Description
PRESSURE SENSOR CATHETER AND METHOD FOR MEASURING A PRESSURE DIFFERENCE IN A BODY LUMEN
The invention relates to a pressure sensor 5 catheter. This type of catheter is used for measuring pressures inside a body lumen. These measurements can for example be used to calculate the fractional flow reserve (FFR). FFR provides a measure of the degree to which a stenosis obstructs the fluid flow in the body lumen, for 10 example in a blood vessel. FFR is calculated on the basis of the pressure on the proximal side of the stenosis and the pressure on the distal side of the stenosis, typically at maximum vasodilation. For example, the pressures upstream and downstream of the stenosis are measured. The FFR ratio 15 is defined as the downstream pressure divided by the upstream pressure. If the FFR ratio is low, a physician can decide to take appropriate actions, such as placing a stent. Typically, an FFR ratio below 0.75 is indicative of a stenosis which requires intervention.
20 In conventional pressure sensor catheters at least one pressure sensor has to be moved to the distal side of the stenosis to measure the pressure locally.
For example, in one type of conventional device, a sensor is mounted on the tip of a guide wire.
25 Moving the sensor through a stenosis requires a sensor which is as small as possible. Another reason for using a small sensor is to minimize the influence of the device on the blood flow and hence the measured pressure. To keep the sensor small in conventional devices, various 30 compromises have been made in the design thereof. For example, the sensors are half-bridge sensors and/or do not comprise outside pressure equalization, both leading to less accurate measurements. In addition, mounting such a small 2 sensor in a way that makes it insensitive to bending is complicated.
A goal of the invention is to overcome the above problems and to provide a pressure sensor catheter which can 5 be introduced in a body lumen to accurately measure the pressure on the distal side of a stenosis, even for narrow passages .
This goal is achieved with the pressure sensor catheter for measuring a pressure difference between the 10 pressure on a proximal side of a stenosis in a body lumen and a pressure on a distal side of the stenosis, the pressure sensor catheter comprising: - a pressure sensor; and - at least one pressure transfer tube for passing through 15 the stenosis, the tube being connected to and extending from the pressure sensor for transferring the pressure at the distal side of the stenosis via the tube to the pressure sensor .
Preferably, the body lumen is a blood vessel.
20 The pressure sensor catheter according to the invention is further applicable to measure a pressure difference over a different narrowing in a body lumen, such as the pressure difference over a heart valve.
By providing a pressure transfer tube, the part of 25 the catheter that comprises the pressure sensor does not have to be guided past the stenosis or heart valve. The pressure transfer tube is guided to the distal side of the stenosis instead. Therefore, the sensor dimensions are not limiting the applicability of the pressure sensor catheter. 30 Furthermore, since the pressure sensor does not have to be maneuvered past the stenosis, a bigger sensor may be used. For example, the catheter comprises a full bridge 3 sensor which has superior characteristics to a half bridge sensor .
Furthermore, there is ample room on the proximal side of the stenosis to provide the sensor with equalisation 5 to ambient pressure, reducing drift and other unwanted effects .
Moreover, a relatively small pressure transfer tube will have no or little influence on the fluid flow and, accordingly, on the pressure measurement.
10 Preferably, the catheter according to the invention comprises means arranged to provide ambient pressure equalization to the sensor. For example, one side of the sensor is connected to a lumen which in use is in fluid communication with ambient pressure, such that the 15 sensor measures the pressure transferred via the tube relative to ambient pressure.
The pressure sensor catheter can be introduced into the body lumen and positioned close to the stenosis either through a guide catheter or over a guide wire or 20 both. In particular in the case no guide wire is used to introduce the pressure sensor catheter into the body, it preferably comprises a soft atraumatic tip yet be firm enough to be passed through the guide catheter and stenosis. In the case a guide wire is used to introduce this 25 embodiment of the pressure sensor catheter into the body, it for example comprises a seal at its proximal end allowing the guide wire to be fed through the full length of the pressure sensor catheter. Alternatively, the catheter comprises an opening in a side wall near the distal end of 30 the pressure transfer tube for passing a guide wire through a distal region of the tube via the distal end of the tube and the side wall opening.
4
In a preferred embodiment of the catheter according to the invention the sensor is a differential pressure sensor comprising a first and second sensing area for measuring the pressure difference between the first and 5 second sensing areas, wherein the at least one pressure transfer tube is connected to the first sensing area, such that the sensing areas are exposed to the pressure at different locations in the body lumen.
By using a differential pressure sensor the 10 catheter according to the invention can measure the pressure difference over a stenosis or heart valve in a single measurement. In contrast, one type of conventional pressure sensor catheters provides two sensors and the pressure differences are calculated from the pressure readings from 15 both sensors. This leads to inaccurate results as compared to the pressure sensor catheter according to the invention. Assuming that a measurement Si using sensor 1 has a standard deviation, i.e. measurement error, of os and a measurement S2 using sensor 2 has equal standard deviation, the standard 20 deviation Odiff of the calculated difference diff = |Si - S2\ can be derived as Odiff = V2 os. For a direct measurement of the difference with a single sensor, as in the invention, a measurement error ot = os applies. The direct measurement is therefore more accurate than the indirect calculation.
25 Moreover, as the invention enables the use of larger, more accurate sensors, in general ot will be smaller than os and the measurement will be even more accurate.
In other types of conventional catheters the pressure on one side of the stenosis or heart valve is 30 measured first, then the catheter is repositioned and subsequently the pressure on the other side is measured.
With the catheter according to the invention on the other hand, the pressure difference can be measured in a single 5 measurement, without the need to displace the catheter between measurements.
For example, the pressure transfer tube of the catheter according to the invention is fed past the stenosis 5 or heart valve and the second sensing area is in use located before the stenosis or heart valve, such that a pressure difference over the stenosis or heart valve is measured directly.
In a further preferred embodiment the pressure 10 sensor catheter according to the invention comprises a second pressure transfer tube connected to the second sensing area of the sensor.
Two tubes are used to transfer the pressure of two different locations to the sensor. Since the pressure 15 transfer tubes can be provided relatively small the influence of the tubes on the measurement can be minimized.
In a preferred embodiment according to the invention, the at least one pressure transfer tube is provided as a single tube having a first pressure transfer 20 lumen and a second pressure transfer lumen.
This enables a very compact design of the pressure sensor catheter. The lumens of the single tube are provided with openings at different locations along the tube. Therefore, the first lumen transfers the pressure at a first 25 location, being the location of the opening of the first lumen, to the pressure sensor, while the second lumen transfers the pressure at a second location being the location of the opening of the second lumen, to the sensor. Therefore, a pressure difference is measured between the two 30 locations.
In a preferred embodiment the at least one pressure transfer tube is movable and/or adjustable in length.
6
By providing a tube which is movable and/or adjustable in length, the location from which the pressure is transferred by the tube can be varied. For example, the tube is movable and/or adjustable in length during use. In 5 an alternative example, the tube is movable and/or adjustable in length and lockable. The distance between the locations where the pressures are measured is set, and subsequently the tube is locked in this position. Then the catheter is introduced in the body lumen.
10 In another example the tube is provided such that it can be cut to an appropriate length.
In a preferred embodiment, the pressure transfer tube comprises a flexible membrane. Preferably, the membrane seals the pressure transfer tube, which is preferably 15 prefilled with a fluid. By providing the flexible membrane, such as a silicone membrane, the pressure at the flexible membrane is transferred via the tube to the sensor, without the fluid in the tube entering the body lumen.
The pressure sensor catheter according to the 20 invention can be introduced in a body lumen over a guide wire and/or in a guiding catheter. Alternatively the catheter is introduced without using a guide wire and/or guiding catheter. In the case no guide wire is used the distal end of the sensor catheter, for example the distal 25 end of the pressure transfer tube, preferably comprises a soft tip, such as an atraumatic guide wire tip. Preferably, the tube is provided from a material which is sufficiently stiff, such that the tube can pass a narrowing, but will not kink.
30 In a preferred embodiment according to the invention the at least one pressure transfer tube comprises an opening in its side wall for passing a guide wire through 7 a distal region of the tube via the distal end of the tube and the side wall opening.
This has the advantage that a physician can use the guide wire that he is most experienced with. This 5 enables an easy displacement of the pressure sensor catheter in the body lumen. Furthermore, only the distal region of the tube has to have dimensions to accommodate a guide wire, whereas the intermediate part between the distal region and the sensor can be provided with smaller diameter.
10 In a preferred embodiment according to the invention the at least one pressure transfer tube comprises a closing means for controlling fluid flow, such as a valve, plunger or piston.
Using the closing means the pressure transfer tube 15 can be filled with a fluid for transferring the pressure via the tube. For example, an isotonic salt solution is provided. Before measuring, the closing means is closed, such that the tube transfers the pressure instead of displacing the fluid. Alternatively, the pressure transfer 20 tube can be filled with blood or fluid from the body lumen. Preferably, when the fluid is blood, the tube comprises an anticoagulant.
In a preferred embodiment the sensor catheter according to the invention comprises a catheter body for 25 introduction of the catheter into the body lumen, wherein the catheter body comprises the sensor such that the sensor in use is positioned in the body lumen.
In use, the sensor is positioned on a proximal side of the stenosis or heart valve while the at least one 30 pressure transfer tube is positioned on the distal side of the stenosis or heart valve.
By providing the sensor in the body lumen it is positioned close to the measurement location. In some types 8 of conventional guiding catheters an absolute pressure sensor located outside of the body measures the pressure at the distal end of the guiding catheter which will be on the proximal side of the stenosis. However, due to the influence 5 of gravity on the fluid in the guiding catheter, the measurement will be disturbed by movement of the guiding catheter relative to the external pressure sensor. The catheter according to the invention does not suffer from this problem, as the sensor is positioned inside the body 10 lumen.
In a further preferred embodiment the pressure sensor catheter according to the invention comprises a second pressure sensor for measuring an absolute pressure.
This allows both the pressure difference over the 15 stenosis and the absolute pressure, preferably the absolute pressure on the proximal side of the stenosis, to be measured accurately in one device.
Preferably, the second pressure sensor is provided in the catheter body.
20 In a preferred embodiment according to the invention the at least one pressure transfer tube has an outer diameter smaller than the width of the sensor.
This has the advantage that the tube can pass into regions of the body lumen for which the sensor is too large. 25 In a further preferred embodiment according to the invention the pressure transfer tube has a French size smaller than 2 F, preferably smaller than 1.8 F, more preferably smaller than 1.5 F, even more preferably smaller than 1.2 F and most preferably smaller or equal to 1 F. As 30 IF corresponds to an external diameter of 1/3 mm, the above dimensions correspond to 0,66 mm, 0.6 mm, 0.5 mm, 0,4 mm and 0,33 mm. It is noted that typical dimensions of conventional pressure sensor catheters are in the order of 4 F to 8 F.
9
The invention further relates to a method for measuring a pressure difference between a pressure on a proximal side of a stenosis or a heart valve in a body lumen and a pressure on a distal side of the stenosis or the heart 5 valve, comprising: - providing a pressure sensor which is connected to at least one pressure transfer tube; and - positioning the at least one pressure transfer tube into the body lumen such that the sensor is exposed to 10 the pressure on the distal side of the stenosis or heart valve.
Such a method provides the same effects and advantages as described above for the pressure sensor catheter according to the invention. Furthermore, the 15 features of the catheter and method according to the invention can be combined as desired. Preferably, the method according to the invention is executed using the pressure sensor catheter according to the invention.
Preferably, the body lumen is a blood vessel.
20 According to the invention, the method is in particular applicable to any narrowing in a blood vessel, such as a stenosis or heart valve.
In a preferred embodiment according to the method of the invention, the step of providing a pressure sensor 25 comprises providing a differential pressure sensor for measuring the pressure difference between a first sensing area of the sensor and a second sensing area of the sensor, wherein the at least one pressure transfer tube is connected to the first sensing area, the method comprising positioning 30 the at least one pressure transfer tube such that the first sensing area is exposed to the pressure on the distal side of the stenosis or heart valve and the second sensing area 10 is exposed to the pressure on the proximal side of the stenosis or heart valve.
As described above in relation to the pressure sensor catheter according to the invention, this has the 5 advantage that the pressure difference over the stenosis or heart valve is measured directly.
In a preferred embodiment the method according to the invention comprises providing a fluid in the at least one pressure transfer tube. For example, the fluid is 10 provided by operating a valve in the pressure transfer tube. The fluid is for example an isotonic fluid or blood. Blood may for example enter the pressure transfer tube by suction, for example using a piston or plunger.
Preferably, the method comprises the step of 15 measuring the pressure at a distal side of the stenosis or heart valve and the pressure at a proximal side of the stenosis or heart valve. For example, the FFR ratio is calculated subsequently.
When both the pressure difference pdiff over the 20 stenosis or heart value and the absolute pressure Ppr0x at the proximal side of the narrowing are measured, the FFR ratio and/or time integrals thereof can be calculated according to: FFRratio (t) = l~ Pdi//(t) “prox \t) 25 The measurement errors <*pdiff and σΡρΓ0Χ propagate as follows:
Oratio = (^) <iff + (¾) rtprox (1)
For a conventional measurement of P'prox and P' distal, the FFR ratio is calculated as FFR'ratio = p'dlstalr anci the P'prox measurement error is 2 2 3 0 a}FR, = {——) Op, + (ΐ!ψΜ\ σ2 (2) ‘‘«'ratio \P’prox) «'distal \ p·^ J P'prox 11
As Pdiff will always be smaller than Pdistai expressed as an absolute pressure, the second term will be smaller for σFFRratio' Furthermore, as the invention allows the use of a more accurate sensor for measuring Pdiff, in general <fpdiff< apdistalr 5 such that the first term is smaller. Therefore, the resulting error will be smaller for the calculation according to the invention.
Moreover, expressing a}FRratio and a}FR,ratio in terms of relative errors gives: 10 ajFR = (1 - FFRrati0)2 + Qp*istal FFRratl° Pdiff Pdistai
Assuming that the relative errors at the right hand side are approximately equal, it follows that aPPRrati0 ^ FFRratio °FFR'ratio FFR'ratio
In the most relevant measurement range, with FFR ratio 15 » 0.75, the error of the method according to the invention is approximately 3 times smaller than in conventional methods. It is noted that the relative error *lff will in pdiff general be smaller due to the use of a better sensor. Therefore, the accuracy of the method of the invention will 20 be even higher.
Further advantages, features and details of the invention will be elucidated on the basis of the preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which: 25 Figure 1 shows a first embodiment of a pressure sensor catheter according to the invention;
Figure 2 shows a variant of the first embodiment, comprising a guide wire;
Figure 3 shows a second embodiment of a pressure 30 sensor catheter according to the invention;
Figure 4 shows the catheter of figure 3 in more detail; 12
Figure 5 shows a third embodiment according to the invention;
Figure 6 shows a fourth embodiment according to the invention; 5 Figure 7 shows a fifth embodiment according to the invention, comprising a double lumen;
Figure 8 shows a sixth embodiment according to the invention, comprising a second sensor for measurement of an absolute pressure on the proximal side of a stenosis or 10 heart valve.
Figure 9A-B show an alternative embodiment, wherein the pressure transfer tube can be displaced;
Figure 10 shows an alternative embodiment comprising a pressure transfer tube with a membrane; and 15 Figure 11 shows a further embodiment of the catheter according to the invention, in which the sensor measures the pressure relative to ambient pressure.
Pressure sensor catheter 2 (figure 1) uses a guiding catheter 4 for introduction into a body lumen. The 20 sensor catheter comprises a pressure transfer tube 6 which is fed through the guiding catheter by means of a feed through 8. Pressure transfer tube 6 is provided with a pressure sensor 10. The tube 6 further comprises a valve 12 to introduce a pressure transfer fluid, such as an isotonic 25 salt solution. A further pressure sensor 14 is provided to guiding catheter 4. The distal end of the tube 6 comprises opening 7 and is located at a region with pressure P2. Therefore, sensor 10 measures pressure P2. Sensor 14 measures the pressure of the blood in guiding catheter 4, i.e.
30 pressure Pi. The tube 6 is provided with a soft atraumatic tip 9 .
Alternatively, a pressure sensor catheter 2' is provided (figure 2). In this case the pressure transfer tube 13 is guided over a guide wire 16. The proximal end of the pressure transfer tube comprises a feed through 18 for passage of the guide wire. The guide wire preferably comprises a soft tip (not shown).
5 Catheter 102 (figure 3) is positioned in a blood vessel 120. The pressure transfer tube 106 is guided over a guide wire 116. The tip of the pressure transfer tube is positioned at a distal side of a stenosis 122 in blood vessel 120. The sensor is provided in a catheter body 124.
10 The catheter body 124 is provided through guiding catheter 104. Outside the body a hub 126 for manipulation of guiding catheter 104 is provided. Further, a sheath 127 is provided.
The catheter body 124 holds a pressure sensor 128 (figure 4). One side 130 of sensor 128 is exposed to a first 15 pressure Pi possibly via a silicone membrane or other flexible membrane 132 which is placed in front of an opening 134 in catheter body 124. The other side 136 of sensor 128 is exposed to pressure P2 which is transferred via pressure transfer tube 106 to the catheter body 124. The pressure 20 transfer tube 106 is filled with a fluid. The tube 106 continues through catheter body 124 towards the proximal side of the catheter by means of tube section 138. The sensor 128 is connected to wires 140. It is noted that the guide wire 116 is optional. A feed through 142 is provided 25 for the guide wire. With valve 112 the fluid, such as a liquid, can be provided in pressure transfer tube 106.
Sensor catheter 102' (figure 5) does not require a guide wire. Catheter 102' is fed into the body lumen using a guiding catheter 104. The tip 144 of the tube 106 is an 30 atraumatic tip as known from conventional guide wires.
Alternatively, a different soft tube end can be provided to tube 6, such as a soft tube section.
14
In an alternative embodiment of the sensor catheter 202 (figure 6), the pressure transfer tube 206 comprises a side opening 246. The guide wire 216 can be fed through the distal opening 248 and the side opening 246 of 5 the pressure transfer tube 106.
Sensor catheter 302 (figure 7) comprises a pressure transfer tube 306 with a double lumen. The first lumen 350 comprises an opening 352 for transferring pressure P2 to the upper side 330 of sensor 328. The second lumen 354 10 comprises an opening 356 for transferring pressure Pi to sensing area 336 of sensor 328. The lumens 350, 354 are separated from each other by internal wall 358.
Sensor catheter 402 (figure 8) comprises a sensor tube 406 provided with an opening 407 and a soft tip 409.
15 Catheter body 424 comprises two sensors 428, 428'. The sensor 428 at the distal end of catheter body 424 has a first side 430 which is exposed to pressure Pi via flexible membrane 432. The other side 436 of sensor 428 is in contact with the fluid in tube 406, such that it experiences 20 pressure P2 .
Sensor 428' has a first sensing side 430' exposed to pressure Pi via flexible membrane 432'. The other side 436' of sensor 428' is connected to ambient pressure P3.
Sensor catheter 502 (figure 9A-B) is provided with 25 a catheter body 524 which comprises sensor module 560. The sensor 528 is attached to sensor module 560. The catheter body 524 comprises a tip region 562 with an opening 564 for transferring pressure Pi to a first sensing side 530 of sensor 528. Pressure P2 is transferred via pressure transfer 30 tube 506 to the second sensing side 536 of sensor 528.
The sensor module 560 can be displaced inside catheter body 524 to vary the distance d between opening 564 and opening 566, as shown in figures 8A and 8B. For example, 15 the sensor module 560 is displaced before the catheter enters the body lumen. For example, the sensor catheter comprises means for locking the tube in its position relative to the other measurement location. Optionally, the 5 sensor catheter is provided with means 568 to displace the sensor module while the catheter 502 is inside the body lumen.
Sensor catheter 602 (figure 10) comprises a tube 606 which is provided with a flexible membrane 632 to 10 transfer the pressure at the tubes distal end via the tube 6 towards the sensor. The tube 606 is prefilled with fluid, preferably a liquid such as an isotonic salt solution.
Sensor catheter 702 (figure 11) comprises catheter body 704. Pressure transfer tube 706 is provided to transfer 15 the pressure P2 at opening 707 at the distal end to the lower side 736 of sensor 728. The upper side 730 of the sensor 728 is exposed to ambient pressure P3 via the inside 770 of the catheter body.
Sensor catheter 702 can be used to measure the 20 pressure difference between a distal side and a proximal side of a stenosis or heart valve by first positioning the catheter 702 such that the opening 707 of tube 706 is positioned at the distal side of the stenosis or heart valve and then repositioning the catheter 702 such that the tube 25 706 measures the pressure at the proximal side. Of course, one can alternatively measure the pressure at the proximal side first and the pressure at the distal side subsequently.
An example of the method according to the invention will be illustrated by reference to figure 6. To 30 measure a pressure difference between a pressure on a proximal side of a stenosis or a heart valve and a pressure on a distal side of the stenosis or heart valve, first a guide wire 216 is introduced into the body lumen and past 16 the stenosis. Subsequently, the proximal end of the guide wire is fed through tube 206 via openings 246, 248. The sensor catheter is then introduced inside the body lumen by advancing the sensor catheter 202. Once the opening 246 has 5 passed the stenosis or heart valve, a measurement is recorded. At that moment the pressure P2 is equal to the pressure on the distal side of the stenosis or heart valve and the pressure PI is the pressure on the proximal side of the stenosis or the heart valve. Therefore, the measurement 10 by sensor 228 provides the pressure difference between Pi and P2, i.e. the pressure drop over the stenosis or heart valve. This is used to calculate the FFR. In case the FFR is below a critical value, such as 0.75, a physician can decide to take appropriate actions. The method may further comprise 15 feeding a guiding catheter into the body lumen prior to feeding the sensor catheter 202 into the body lumen. Furthermore, the guiding catheter may comprise a pressure sensor or the sensor catheter 202 may comprise an additional pressure sensor to provide an absolute measurement of the 20 pressure PI.
In the embodiment of figures 7, 9A-9B and 10, the pressure transfer tube is in fluid communication with a closed inner volume in the catheter body. In contrast, in the embodiments of figures 1-6, the tube continues beyond 25 the sensor, for feeding a fluid from outside the body in the tube. Alternatively, the embodiments of figures 7, 8, 9A-9B and 10 may comprise a tube for providing a fluid externally and the embodiments of figures 1-6 may comprise a closed inner volume. In all cases embodiments are envisioned that 30 are prefilled with fluid and have a flexible membrane sealing the respective pressure transfer tube opening.
The present invention is by no means limited to 17 the above described preferred embodiments thereof. The rights sought are defined by the following claims, within the scope of which many modifications can be envisaged. For example, it is explicitly mentioned that the combinations of 5 the illustrated embodiments are possible.
18
CLAUSES
1. Pressure sensor catheter for measuring a pressure difference between a pressure on a proximal side of a 5 stenosis in a body lumen and a pressure on a distal side of the stenosis, comprising: - a pressure sensor; and - at least one pressure transfer tube for passing through the stenosis, the tube being connected to and extending from 10 the pressure sensor for transferring the pressure at the distal side of the stenosis via the tube to the pressure sensor.
2. Pressure sensor catheter according to clause 1, wherein 15 the sensor is a differential pressure sensor comprising a first and second sensing area for measuring the pressure difference between the first and second sensing areas, wherein the at least one pressure transfer tube is connected to the first sensing area, such that the sensing areas are 20 exposed to the pressure at different locations in the body lumen.
3. Pressure sensor catheter according to clause 2, comprising a second pressure transfer tube connected to the 25 second sensing area of the sensor.
4. Pressure sensor catheter according to clauses 2 or 3, wherein the at least one pressure transfer tube is provided as a single tube having a first pressure transfer lumen and 30 a second pressure transfer lumen.
19 5. Pressure sensor catheter according to any of the preceding clauses, wherein the at least one pressure transfer tube is movable and/or adjustable in length.
5 6. Pressure sensor catheter according to any of the preceding clauses, wherein the tube comprises a flexible membrane .
7. Pressure sensor catheter according to any of the 10 preceding clauses, wherein the at least one pressure transfer tube comprises a soft tip at its distal end.
8. Pressure sensor catheter according to any of the preceding clauses, wherein the at least one pressure 15 transfer tube comprises an opening in its side wall for passing a guide wire through a distal region of the tube via the distal end of the tube and the side wall opening.
9. Pressure sensor catheter according to any of the 20 preceding clauses, wherein the at least one pressure transfer tube comprises a closing means.
10. Pressure sensor catheter according to any of the preceding clauses, comprising a catheter body for 25 introduction of the pressure sensor catheter into the body lumen, wherein the catheter body comprises the sensor, such that the sensor in use is positioned in the body lumen.
11. Pressure sensor catheter according to any of the 30 preceding clauses, comprising a second pressure sensor for measuring an absolute pressure.
20 12. Pressure sensor catheter according to any of the preceding clauses, wherein the at least one pressure transfer tube has an outer diameter smaller than the width of the sensor.
5 13. Pressure sensor catheter according to any of the preceding clauses, wherein the pressure transfer tube has a French size smaller than 2F, preferably smaller than 1.8F, more preferably smaller than 1.5F, even more preferably 10 smaller than 1.2F and most preferably smaller or equal to IF.
14. Method for measuring a pressure difference between a pressure on a proximal side of a stenosis or heart valve in 15 a body lumen and a pressure on a distal side of the stenosis or heart valve, comprising: - providing a pressure sensor which is connected to at least one pressure transfer tube; and - positioning the at least one pressure transfer tube 20 into the body lumen such that the sensor is exposed to the pressure on the distal side of the stenosis or heart valve.
21 15. Method according to clause 14, wherein the step of providing a pressure sensor comprises providing a differential pressure sensor for measuring the pressure difference between a first sensing area of the sensor and a 5 second sensing area of the sensor, wherein the at least one pressure transfer tube is connected to the first sensing area, the method comprising positioning the at least one pressure transfer tube such that the first sensing area is exposed to the pressure on the distal side of the stenosis 10 or heart valve and the second sensing area is exposed to the pressure on the proximal side of the stenosis or heart valve .
16. Method according to clause 14 or 15, comprising 15 providing a fluid in the at least one pressure transfer tube .
Claims (16)
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2009285A NL2009285C2 (en) | 2012-08-06 | 2012-08-06 | Pressure sensor catheter and method for measuring a pressure difference in a body lumen. |
| US14/419,726 US10413201B2 (en) | 2012-08-06 | 2013-08-06 | Pressure sensor catheter and associated method |
| EP13747898.8A EP2879575B1 (en) | 2012-08-06 | 2013-08-06 | Pressure sensor catheter |
| PCT/NL2013/050582 WO2014025255A1 (en) | 2012-08-06 | 2013-08-06 | Pressure sensor catheter and associated method |
| JP2015526492A JP6235013B2 (en) | 2012-08-06 | 2013-08-06 | Pressure sensor catheter and related methods |
| CN201380041391.5A CN104519791B (en) | 2012-08-06 | 2013-08-06 | Pressure sensor catheter and associated method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2009285A NL2009285C2 (en) | 2012-08-06 | 2012-08-06 | Pressure sensor catheter and method for measuring a pressure difference in a body lumen. |
| NL2009285 | 2012-08-06 |
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| Publication Number | Publication Date |
|---|---|
| NL2009285C2 true NL2009285C2 (en) | 2014-02-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
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| NL2009285A NL2009285C2 (en) | 2012-08-06 | 2012-08-06 | Pressure sensor catheter and method for measuring a pressure difference in a body lumen. |
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| Country | Link |
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| NL (1) | NL2009285C2 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016065227A3 (en) * | 2014-10-24 | 2016-06-16 | Medtronic Vascular Inc. | Microcatheter sensor design for minimizing profile and impact of wire strain on sensor |
| US10130269B2 (en) | 2013-11-14 | 2018-11-20 | Medtronic Vascular, Inc | Dual lumen catheter for providing a vascular pressure measurement |
| US10194812B2 (en) | 2014-12-12 | 2019-02-05 | Medtronic Vascular, Inc. | System and method of integrating a fractional flow reserve device with a conventional hemodynamic monitoring system |
| US10201284B2 (en) | 2014-06-16 | 2019-02-12 | Medtronic Vascular Inc. | Pressure measuring catheter having reduced error from bending stresses |
| US10646122B2 (en) | 2017-04-28 | 2020-05-12 | Medtronic Vascular, Inc. | FFR catheter with covered distal pressure sensor and method of manufacture |
| US10973418B2 (en) | 2014-06-16 | 2021-04-13 | Medtronic Vascular, Inc. | Microcatheter sensor design for minimizing profile and impact of wire strain on sensor |
| US11219741B2 (en) | 2017-08-09 | 2022-01-11 | Medtronic Vascular, Inc. | Collapsible catheter and method for calculating fractional flow reserve |
| US11235124B2 (en) | 2017-08-09 | 2022-02-01 | Medtronic Vascular, Inc. | Collapsible catheter and method for calculating fractional flow reserve |
| US11272850B2 (en) | 2016-08-09 | 2022-03-15 | Medtronic Vascular, Inc. | Catheter and method for calculating fractional flow reserve |
| US11330989B2 (en) | 2014-06-16 | 2022-05-17 | Medtronic Vascular, Inc. | Microcatheter sensor design for mounting sensor to minimize induced strain |
| US11330994B2 (en) | 2017-03-08 | 2022-05-17 | Medtronic Vascular, Inc. | Reduced profile FFR catheter |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989010089A1 (en) * | 1988-04-27 | 1989-11-02 | Millar Instruments, Inc. | Single sensor pressure differential device |
| WO1999056612A1 (en) * | 1998-05-04 | 1999-11-11 | Florence Medical Ltd. | Apparatus and method for identification and characterization of lesions and therapeutic success by flow disturbances analysis |
| US20030191400A1 (en) * | 2001-01-19 | 2003-10-09 | Florence Medical Ltd. | System for determining values of hemodynamic parameters for a lesioned blood vessel, processor therefor, and method therefor |
-
2012
- 2012-08-06 NL NL2009285A patent/NL2009285C2/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989010089A1 (en) * | 1988-04-27 | 1989-11-02 | Millar Instruments, Inc. | Single sensor pressure differential device |
| WO1999056612A1 (en) * | 1998-05-04 | 1999-11-11 | Florence Medical Ltd. | Apparatus and method for identification and characterization of lesions and therapeutic success by flow disturbances analysis |
| US20030191400A1 (en) * | 2001-01-19 | 2003-10-09 | Florence Medical Ltd. | System for determining values of hemodynamic parameters for a lesioned blood vessel, processor therefor, and method therefor |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10130269B2 (en) | 2013-11-14 | 2018-11-20 | Medtronic Vascular, Inc | Dual lumen catheter for providing a vascular pressure measurement |
| US11330989B2 (en) | 2014-06-16 | 2022-05-17 | Medtronic Vascular, Inc. | Microcatheter sensor design for mounting sensor to minimize induced strain |
| US10201284B2 (en) | 2014-06-16 | 2019-02-12 | Medtronic Vascular Inc. | Pressure measuring catheter having reduced error from bending stresses |
| US10973418B2 (en) | 2014-06-16 | 2021-04-13 | Medtronic Vascular, Inc. | Microcatheter sensor design for minimizing profile and impact of wire strain on sensor |
| US11701012B2 (en) | 2014-06-16 | 2023-07-18 | Medtronic Vascular, Inc. | Microcatheter sensor design for minimizing profile and impact of wire strain on sensor |
| US12053265B2 (en) | 2014-06-16 | 2024-08-06 | Medtronic Vascular, Inc. | Microcatheter sensor design for mounting sensor to minimize induced strain |
| WO2016065227A3 (en) * | 2014-10-24 | 2016-06-16 | Medtronic Vascular Inc. | Microcatheter sensor design for minimizing profile and impact of wire strain on sensor |
| US10194812B2 (en) | 2014-12-12 | 2019-02-05 | Medtronic Vascular, Inc. | System and method of integrating a fractional flow reserve device with a conventional hemodynamic monitoring system |
| US11272850B2 (en) | 2016-08-09 | 2022-03-15 | Medtronic Vascular, Inc. | Catheter and method for calculating fractional flow reserve |
| US11330994B2 (en) | 2017-03-08 | 2022-05-17 | Medtronic Vascular, Inc. | Reduced profile FFR catheter |
| US10646122B2 (en) | 2017-04-28 | 2020-05-12 | Medtronic Vascular, Inc. | FFR catheter with covered distal pressure sensor and method of manufacture |
| US11219741B2 (en) | 2017-08-09 | 2022-01-11 | Medtronic Vascular, Inc. | Collapsible catheter and method for calculating fractional flow reserve |
| US11235124B2 (en) | 2017-08-09 | 2022-02-01 | Medtronic Vascular, Inc. | Collapsible catheter and method for calculating fractional flow reserve |
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