Method and device for measuring restriction of fluid medium flow in vessel

FIELD: medicine.

SUBSTANCE: group of inventions relates to medical diagnostics. Method of determining degree of vessel narrowing contains stages at which obtained are: sequence of first pressure measurements P1 and sequence of respective first rate measurements U1 in first location inside vessel, sequence of second pressure measurements P2 and sequence of respective second rate measurements U2 in second location inside vessel. Wave rate c in fluid medium is determined for each location depending on square of pressure change divided by square of respective rate change. For first location change of direct pressure is determined depending on the sum of pressure change and rate change. For second location change of direct pressure is determined depending on the sum of pressure change and rate change. Reserve of separated direct flow, representing drop of pressure through target area is determined, with said drop of pressure indicating degree of local narrowing or compression of vessel between said first location and second location. Device for determining degree of vessel narrowing is described.

EFFECT: inventions provide measurement of localised flow restriction.

14 cl, 6 dwg

 

The present invention relates to methods and apparatus for determining the degree of the local restriction of the fluid flow in the vessel, such as a pipe or tube. The invention, in particular, though not exclusive, application in the measurement of stenosis in a blood vessel and, in particular, is useful in determining the magnitude of coronary stenosis in the coronary system of a human or animal.

Fractional blood flow reserve (FFR) is a technique widely used in coronary catheterization laboratories in the evaluation of coronary stenosis and the adequacy of stent deployment. FFR is defined as the pressure behind (or distal to) the stenosis relative to the pressure in front (or proximal to) stenosis. The result is a ratio, i.e. the absolute number. The ratio FFR of 0.5 indicates that the result of the stenosis is 50% lowering of blood pressure across the stenosis. More generally, FFR denotes the ratio of the maximum flow of fluid through the vessel in the presence of compression or narrowing in the vessel compared to the maximum flow that could occur in the absence of such compression or narrowing.

The use of FFR is expanding rapidly in the last few years as research has demonstrated the limitations of visual assessment of stenosis and the harm that can praiseit� as a result of improper angioplastica. FFR is usually carried out by measuring the average pressure drop on each side of the coronary stenosis at maximum hyperemia. However, under certain circumstances, such as after acute myocardial infarction, it becomes unreliable. This can also lead to inappropriate clinical decisions.

While in most vascular beds pressure occurs with a single entry (i.e., the aortic end of the vessel), the pressure in the coronary arteries is the result of the contribution, as with the proximal (aortic end) and distal (microcirculation) in approximately equal proportions. Distal pressure is determined by 2 factors:

(1) own (or passive) resistance due to the self-regulation of the coronary microcirculation

(2) external (or "active") resistance due to the compression of small microcirculatory vessels that pass through the myocardium.

In the present assessment, FFR trying to reduce this distal pressure to the extent possible, by entering vasodilators, such as adenosine, to ensure maximum hyperemia. However, while the input of vasodilators leads to the decrease of microcirculatory passive resistance, they can't suppress microcirculatory blood pressure distal origin, which in�Snicket due to the compression of small vessels, passing through the cutting infarction.

Thus, small inaccuracies in FFR are an integral, since it is not possible to eliminate the component of active resistance. In addition, FFR may become more inaccurate in pathological processes, when there is an influence on the internal or external resistance. Examples dysfunction passive resistance include diabetes mellitus, acute coronary syndrome, a condition after a heart attack of a myocardium and hibernating myocardium. The dysfunction examples of active resistance include the case when the artery pulls hypokinetic or akinetic segment.

There are a large number of published literature, which is described in detail in such errors, which helps to explain why the close relationship between intravascular ultrasound (IVUS) and FFR highly controlled research laboratory is often not confirmed in a clinical environment.

The purpose of the present invention is to provide an improved or alternative method and device for measuring the degree of local constraints for the flow of fluid in a vessel, such as a pipe or tube. An additional objective of the invention is to provide such a method and apparatus for use in the measurement of stenosis in a blood with�court, and in particular, though not exclusively, in determining the magnitude or effects of coronary stenosis in the coronary system of a human or animal.

In accordance with one aspect, the present invention proposes a method for determining measures of narrowing of the vessel through which flows a fluid, the method contains the following stages: a) receive a first sequence of measurements of P1pressure and the appropriate first sequence of measurements U1speed in the first location inside the vessel, the first location is on the first side of the target area; b) receive the second sequence of measurements of P2pressure and a sequence of corresponding second dimension of U2the speed in the second location within the vessel, wherein the second location is on the second side of the target area; (C) for each location determine the wave speed in fluid, depending on the square of the pressure variation dP divided by the square of the corresponding speed change dU; (d) for the first location, determine the change in pressure dP1+ depending on the amount of pressure change dP1and speed variation dU1; (e) for the second location, determine the change in pressure dP2+ depending on the amount of pressure change�I dP 2and speed variation dU2; (f) determine the reserve allocated to direct flow, indicating the pressure drop across the target area depending on the relationship dP2+/dP1+ while the specified pressure drop is a pointer extent a local narrowing or compression of the vessel between the first location and the second location.

The first side of the target area may be located upstream from the target region, and the second side may be located downstream from the target area. Wave velocity can be determined at each location in accordance with the equation C=(1/ρ)√(ΣdP2/ΣdU2), where ρ is the specific density of the fluid in the vessel. Stages d) and e) may contain the definition of direct pressure changes dP1+ and dP2+ in accordance with the equations: dP1+=.(dP1+ρcdU1)/2 and dP2+=.(dP2+ρcdU2)/2. Step f) may include the integration or summation of a plurality of values of multiple dP1+ and dP2+ to obtain the value of direct pressure P1+ and R2+ and determination of the allowance allocated to direct flow based on the ratio R2+/P1+. The method can be applied to a vessel in which there is a source fructueuse pressure on both sides of the target area, such as a vessel in sist�IU the blood circulation of a heart of a human or animal. The sequence of the first and second pressure measurements and a sequence of first and second velocity measurements can be obtained during at least one complete cardiac cycle of the human body or animal. Appropriate measurements of pressure and speed can be obtained simultaneously.

The present invention also relates to an apparatus for determining the degree of narrowing of the vessel that carries the fluid, the device comprises: i) a pressure sensor and a speed sensor to perform a sequence of measurements of pressure and velocity in the vessel at least in a first location that is upstream from the target region, and in the second location, downstream from the target region; (ii) a processing module, configured to: receive a sequence of first measurements of the pressure P1and the sequence corresponding to the first measurement of the velocity U1obtained in the first location inside the vessel;

to obtain the second sequence of measurements of pressure P2and the sequence corresponding to the second measurement of the velocity U2 at the second location within the vessel; for each location to determine the wave speed in fluid, depending on the square of the pressure variation dP divided by the square corresponding change soon�STI dU; for the first location, determine the change in pressure dP1+ depending on the amount of pressure change dP1and speed variation dU1; and for the second location, to determine the change in pressure dP2+ depending on the amount of pressure change dP2and speed variation dU2; and to determine the allowance allocated to direct flow, indicating the pressure drop across the target area depending on the relationship dP2+/dP1+ and the specified pressure drop indicates the local degree of narrowing or compression of the vessel between the first location and the second location.

The processing module may be configured to determine the wave speed at each location in accordance with the equation C=(1/ρ)√(ΣdP2/ΣdU2), where ρ is the specific density of the fluid in the vessel. The processing module may be further arranged to determine the said change direct pressure dP1+ and dP2+ in accordance with the equation: dP1+=.(dP1+ρcdU1)/2 and dP2+=.(dP2+ρcdU2)/2. The processing module may be further configured to integrate or summarize a set of values dP1+ and dP2+ to retrieve the value of direct pressure P1+ and R2+for direct determination of individual reserve flow as a function of the relationship of P 2+/P1+. The device may include means for monitoring heart rhythm and to control the mentioned pressure sensor and the speed sensor, for collecting the said sequence of pressure measurements and mentioned sequence of velocity measurements during a full cardiac cycle.

Embodiments of the present invention will be described below as an example and with reference to the accompanying drawings, in which:

Fig. 1 shows a diagram of the vessel, transporting the fluid in which the vessel has a narrowing, leading to pressure drop;

Fig. 2 shows a block diagram of the sequence of operations method of measurement of reserve allocated to direct flow, suitable for the analysis of stenosis or other flow restriction in a vessel;

Fig. 3 shows a device suitable for implementing the method of Fig. 2;

Fig. 4 shows the difference in attitude between proximally initiated by the waves and the distal initiated by the waves in a normal ventricle and severely hypokinetic ventricle;

Fig. 5 shows a schematic illustration of the fall of the fractional blood flow reserve with increased coronary stenosis with normal and hypothetically impaired left ventricular function, showing that in normal twitch LV fractional R�reserve blood flow decreases with the increasing of coronary stenosis (solid line), whereas in the model with hypothetically impaired left ventricular function (dashed line) and fractional flow reserve flow falls to a much lesser extent; and

Fig. 6 shows a series of graphs illustrating the division of the total measured pressure on the components, moving right and back, depending on time.

In recent years there has been described the possibility to separate aortic and microvascular components of the pressure wave inside the coronary arteries. Cm. J. E. Davies et al. Evidence of a dominant backward-propagating "suction" wave responsible for diastolic coronary filling in humans, attenuated in left ventricular hypertrophy; Circulation 2006 April 11;113(14):1768-78 and J E Davies et ah Use of simultaneous pressure and velocity measurements to estimate arterial wave speed at a single site in humans; Am J Physiol Heart Circ Physiol February 2006; 290(2):H878-H885.

The authors of the present invention have determined that it is possible to evaluate the severity of stenosis without (or remove) a component of the distal pressure, through the use of technology reserve pressure flow described here. Reserve flow of direct pressure overcomes the limitations of conventional FFR, separating the proximal and distal (or "direct" and "reverse ") components of the pressure wave. Component back pressure can be removed. The study of coronary stenosis is simplified, becoming similar to the study of aortic stenosis, where there is one source of pressure (the EU�ü the left ventricle of the heart).

The separation of the coronary pressure has several advantages. First, it does not require the introduction of adenosine to vasodilation of the coronary microcirculation. Secondly, it may be performed regardless of the function of the left ventricle of the heart, making it applicable in acute coronary syndromes, conditions after myocardial infarction, hibernating myocardium, where conventional FFR is contraindicated as a method of research.

In practice, the selected pressure may be determined by measuring simultaneously the pressure (P) and velocity (U) flow, and calculation of pressure that occurs with direct (e.g., aortic) end, R+, (Equation 1), and pressure arising from the reverse (e.g., microcirculatory) end, R-(Equation 2).

P+=Σ(1/2).(dP+ρcdU)(Equation 1)
P-=Σ(1/2).(dP-ρcdU)(Equation 2)

dP is the measured pressure change; dU is the measured change in velocity; C is the wave velocity; and p is the density of the fluid, e.g., blood. The severity of coronary stenosis may be determined in accordance with the equation, which is similar to conventional� FFR. Under normal FFR measure of stenosis (FFR is the ratio defined above) determined as follows:

Conventional FFR = (distal pressure)/(proximal pressure)(Equation 3)

Measure FFR alternatively may be expressed in terms of the provision of direct flow pressure, i.e. without the influence of back pressure resulting from microcirculatory end:

Reserve flow of direct pressure = distal, P+)/(proximal P+)(Equation 4)

Fig. 1 shows a diagram of the vessel 10 to transfer the fluid 11 in the axial direction 12 along the vessel. The vessel 10 may be a pipe or tube and, in one important context, can contain a portion of the coronary vessel system of a human or animal. Constriction 15 of the vessel 10 is an example of a target area 16 to which it is desirable to measure the effects of this contraction on the flow of fluid through the vessel. Within the context of the narrowing 15 may constitute a coronary artery stenosis, and this requires to define a measure of the pressure drop of the fluid through the place of compression to determine the extent of the maximum flow through the vessel,�, as compared to the maximum flow, which would be the case without this compression. Region 5 and 6 represent the first and second locations at which measurements of pressure and speed can be obtained in accordance with the method described below. The first location 5 is located on the first side of the target area 15, and a second location 6 is located at the second side of the target area 15. The first location 5 may be a proximal or aortic side of the coronary (or other) stenosis, and a second location 6 can then be located with or distal microcirculatory side of the coronary (or other) stenosis. Preferably, the distance from the first location (proximal or aortic side) to the stenosis was at least 1.5 times the value of the diameter of the vessel in unlimited parts of a vessel.

Fig. 2 shows an exemplary method 20 for determining the extent of the constriction 15 of the vessel 10. The sequence of first measurements of the pressure P1and the sequence corresponding to the first measurement of the velocity U1get in the first location 5 (step 21). The second sequence of measurements of pressure P2and the sequence corresponding to the second measurement of the velocity U2receive second location 6 (step 22). Each pressure measurement and its corresponding speed measurement, the assumption�plant produce, essentially, at the same time.

The wave speed in each of the first and second locations 5, 6 is defined as a function of the square of the change in pressure dP, divided by the square of the corresponding speed change dU (stage 23). The pressure variation dP is preferably determined from a pair of the first sequence of measurements of pressure P1and, respectively, of a pair of the second sequence of measurements of pressure P2. The velocity change dU is preferably determined from a pair of sequences of the first measurements of the speed U1and, respectively, of a pair of the second sequence of measurements of the speed U2. More preferably, the sequence of pressure measurements and the corresponding measurements of the speed gain over a certain period of time to generate a number of results of measurements of dP and dU, which can be combined to improve the signal-to-noise. The wave speed can be calculated for a sequence of pairs of pressure and velocity measurements that summarize and get the square root of this sum. The wave speed can be thus defined for a sequence of points of measurement in each location, the first and second 5, 6, in accordance with the formula:

C=(1/ρ)�(ΣdP 2/ΣdU2),(Equation 5)

where ρ is the specific density of the fluid in the vessel. In the preferred context of a fluid is a blood with a density of 1050 kg/m3.

The change in pressure dP+ then determined as a function of the amount of pressure change dP and the corresponding (simultaneous) change speed dU. More preferably, the change in pressure dP1+ in the first location is determined in accordance with the equation:

dP1+=.(dP1+ρcdU1)/2(Equation 6)

and the change in pressure dP2+ in the second location is determined in accordance with the equation:

dP2+=.(dP2+ρcdU2)/2(Equation 7)

as shown in steps 24 and 25.

The values of dP1+ preferably summarize or integrate all the successive measurements to obtain the values of pressure P1+ in the first location (step 26). The values of dP2+ also preferably summarize or integrate all the successive measurements to obtain the values of pressure P2+ �about the second location (step 27).

Reserve flow to direct pressure is then determined as a function of the ratio R2+/P1+ (or if you use single measurement results of the pressure change, dP2+/dP1+). If the first location 5 is located on the proximal or aortic side of the stenosis, and a second location 6 is at or distal microcirculatory side of the stenosis, then reserve flow of direct pressure, FPFRforward=P+adistal/P+aproximal. Thus, in a preferred arrangement, the first location 5 is located upstream from the target region 15, and a second location 6 is located downstream from the target region 15 (assuming a constant positive flow).

In the context of measurement of coronary stenosis preferably, the sequence of measurements of pressure and speed received at least one full cardiac cycle and preferably across a number of cardiac cycles. Average and maximum values of P1+ and R2+ can be used in the calculation of the FPFR to print the value FPFRmeanand FPFRmax. The values of dP1+ and dP2+ used to get the value of direct pressure P1+ and the value of direct pressure P2+ can be obtained from selected parts of one or more cardiac cycles or, as noted above, one or �more all cardiac cycles. Preferably, at least five or ten dimensions dP1+ and dP2+ used for each cardiac cycle.

Device

A device suitable for performing the method described above, in General, shown in Fig. 3.

The device 30 of the pressure determination is used for generating signals representing the instantaneous pressure at the selected locations 5 or 6 in the vessel 10. These pressure signals are passed into a corresponding analog-to-digital Converter 31 for generating a sequence of pressure measurements, depending on the actual time received in the selected location, for example, in a sequence of first measurements of pressure P1and the second sequence of measurements of pressure P2. Similarly, the device 32 for determining the speed is used to generate signals representing the instantaneous velocity of the fluid essentially in the location you selected 5 or 6, the host device 30 to measure the pressure. These signals the speed of a fluid medium is passed into a corresponding analog-to-digital Converter 33 for generating a sequence of measurements of the speed of the fluid, depending on time obtained in the selected location, for example, the sequence of first measurements of the speed U1and a sequence� second measurement of the velocity U 2. Appropriate measurements of pressure and speed is preferably essentially get to the same points in time.

Device 30, a pressure-sensitive, can be any suitable transducer or other device that is capable of providing direct or indirect measurement of pressure in the selected location inside the vessel 10. Device, pressure-sensitive, can be any conveniently located in-situ pressure transducer, located inside the fluid in the vessel 10, in the location you selected 5, 6, or may be a remotely located active or a passive sensor that uses any detected radiation from the fluid flow or limiting vessel that can be used for determining the pressure of acoustic, electromagnetic, magnetic or other means. For example, in the coronary arteries and in the aorta, you can use sensors in-situ type PrimeWire™, FloWire™ and ComboWire™ XT production of Volcano Corporation.

The device 32, speed-sensitive fluid can similarly be any suitable transducer or other device that is capable of providing direct or indirect measurement of the velocity of the fluid at the selected location inside suck�and 10. The device 32, speed-sensitive fluid may be a transducer in situ, located in the fluid inside the vessel at the selected location 5, 6, or may be a remotely located active or a passive sensor that uses any detected radiation from the fluid flow, which can be used to determine the velocity of a fluid medium, acoustic, electromagnetic, magnetic or other means, for example, using Doppler ultrasound technology. In the coronary arteries and in the aorta of the above-mentioned products WaveWire™, FloWire™ and ComboWire™ XT can be used as sensors in-situ. The expression "detected radiation from the flow of fluid" is intended to encompass any active or reflected radiation or re-radiation of energy from the fluid or from any of the agents or markers that are carried in a fluid medium.

Such a device 30, a pressure-sensitive, can be used to obtain a first sequence of measurements of pressure P1in the first location 5 and the second sequence of measurements of pressure P2in the second location 6, at different times. Similarly, the same device 32, speed-sensitive, can be used to obtain a first sequence of measurements of the speed U in the first location 5 and the second sequence of measurements of the speed U2in the second location 6 at different times. Alternatively, combined sensors, such as sensor ComboWire™, can be designed with the capability of performing measurements in both the first and second locations at the same time. Sensor ComboWire™ is a steerable guide wire with a pressure transducer mounted proximally to the tip, and an ultrasonic transducer mounted at the tip. It can be used to measure simultaneously the pressure and velocity of blood flow in the blood vessels, including the coronary and peripheral vessels.

The data streams from the analog-to-digital converters 31, 33 are received in the module 35 to the registration data, preferably embodied on the basis of the computer 34. The computer 34 includes a separate module 36 analysis of reverse flow pressure, to implement the algorithms described here.

The first module 37 processing (analysis module wave velocity) determines the wave velocity in the first and second locations, preferably in accordance with the equation given above for C (equation 5). The second module 38 processing (analysis module pressure) determines the change of direct pressure in the first location, preferably rela�on the expression for dP 1+ presented above (equation 6). The second module 38 processing also determines the change of direct pressure in the second location, preferably in accordance with the expression for dP2+ presented above (equation 7). The wave speed can be determined by using the sampling values of pressure and speed of fluid in one or more complete cycles of the heart at a selected location averaged over these cycles.

The computer 34 preferably includes an additional module 39 of calculation for the integration or summation of direct pressure changes in the first and second locations in accordance with the stages 26 and 27 of Fig. 2, and to determine the reserve flow direct pressure FPFRforwardpreferably, in accordance with step 28 of Fig. 2.

FPFRforwardprovides a measure of the severity of coronary stenosis. The measurement thus obtained, i.e. using only moving forward (aortic origin) of the pressure wave, essentially, to a lesser extent influenced or not influenced by local changes in myocardial opposition or autonomic dysregulation coronary microcirculation. Data processing in the computer 34 can be performed in any suitable device, such as appropriate programs�trolled a computer system or specialized hardware/software console measurements of pressure and flow velocity measurement. It should be understood that the distribution of computing functions in hardware or software can be managed differently than in the approximate analysis modules, as shown in Fig. 3, and they may be embodied in any suitable combination of hardware and software.

Description the clinical importance of using separate forward and reverse pressures in the study of coronary stenosis are presented in Appendix 1.

While the technology of the invention is mainly described with reference to the analysis of stenosis or other restrictions coronary system, the described technologies can be applied also in other systems, such as the renal vascular system or any other system where the flow of fluid through the control limits by moving forward and backward pressure waves.

Other implementation options are intentionally within the scope of the appended claims.

ANNEX 1

This new technology reserve flow pressure (reserve allocated direct flow) has several key therapeutic advantages compared with conventional FFR.

1. assessment of coronary stenosis immediately after acute myocardial infarction

2. assessment of coronary stenosis within 5 days after acute coronary syndrome

3. evaluation of crowns�rnogo stenosis in the patient's body with local anomalies, wall motion

4. assessment of coronary stenosis in subjects with microvascular diseases

5. the rejection of the necessity of the introduction of adenosine.

These advantages can significantly increase the number of patients suitable for evaluation of FFR type, and can have a positive impact on the total number of performed coronary revascularization. Currently in the UK approximately 30% of the burden of these diseases comes from the admission of patients in the acute state with acute myocardial infarction or acute coronary syndrome. Among these patients, FFR is contraindicated and has been determined as not inappropriate at best, and often unreliable.

Reserve flow of direct pressure overcomes or reduces these limitations by separating the proximal and distal components in the wave pressure oscillations. Because the reserve flow direct pressure allows the separation of the back pressure from the direct pressure, this eliminates the need of administration of potent vasodilators such as adenosine.

It has some specific advantages.

1. Overcome the limitations of intolerance of adenosine (asthma, chronic obstructive pulmonary disease, etc.)

2. To overcome the limitations of resistance to adenosine

3. Excluded inserting secondary TSE�Central venous sheath

4. Decreases the total time of the disease.

According to preliminary data, the inventors have identified significant differences in the ratio between the waves of proximal and distal origin in the normal ventricle and the ventricle with severe hypokinetic state of the ventricle. In some cases, a reduction of more than 80% was observed in the proximal/distal ratio in the artery that passes through the location that is exposed to severe hypokinetic effects, compared with the artery passing by normally shrinking the myocardium. This is shown in Fig. 4. The pressure and flow rate are recorded using intra-arterial wire in the left anterior descending artery, and calculate the intensity of waves for each artery. In the ventricle of the heart with preserved function of the value of the ratio of proximal/distal amounted to approximately 1, whereas in the artery with a segment with severe hypokinetic function, this ratio is markedly increased. This leads to the fact that regional myocardial function in different effects on the pressure proximal and distal origin.

Fractional blood flow reserve (FFR) suggests that coronary pressure occurs exclusively from the proximal (aortic) end artery, and that the force exerted on intramurals�e coronary vessels transferred as a result of pressure within the cavity and a shrinking infarction does not develop pressure coronary artery. The inventors have demonstrated that this does not occur, but instead, the coronary pressure consists of approximately 50% moving forward (aortic origin) and 50% moving backward pressure components (see figure 4, left chart). It is assumed that regions with local variations in contractility of the myocardium: (i) the pressure of the reverse displacement is significantly reduced (as shown on the chart on the right side in Fig. 4), and (and) that it is impossible to determine whether the decline in FFR because of hemodynamically significant coronary stenosis or regional variation myocardial of the motion). Using split pressure components, as described in this patent application, it is possible to independent quantization of hemodynamic significance of coronary stenosis for regional variations contractiveness of the myocardium. This technology can be adopted as a conventional technology clinical practice, and it eliminates the need for continuous receiving intravenous adenosine.

Fractional blood flow reserve (FFR) is increasingly used in the evaluation of the physiological significance of coronary stenosis1,2,3,4and the adequacy of placement of5stent in the laboratory of cardiac catheters. The�the first technology is based on the simple assumption, the greater the stenosis, the greater the pressure drop between the aorta and after the stenosis.

FFR is based on the assumption that the pressure change occurs only with aortic end of the coronary artery. However, several studies, including our own, have clearly demonstrated that the pressure in the coronary artery affected by changes in pressure from both ends of the vessel6-9. Probably the most widely accepted model of coronary artery flow are intramyocardially pump6and models9with the changing time elasticity. They both predict the existence of retroactive coronary blood flow during systole as a result of increased intramyocardial pressure and contraction of the myocardium, leading to compression of small microcirculatory vessels6. This is directed in the opposite direction the flow was confirmed by measurements in dogs in vivo, using videomicroscopy10using the needle probe and the probe11Doppler flow. This indicates the presence of a significant pressure gradient, directional back in systole. In our work,8was described this gradient directional back pressure, as moving back wave, visible in the coronary arteries of man at an early stage of development of the systole, due to the compression cor�narney of microvasculature. In diastole occurs corresponding to the "absorption" of blood into the coronary microvasculature as a result of decompression of the intramural vessels accompanying the relaxation of the myocardium. We previously showed that such a reverse suction wave is attenuated in left ventricular hypertrophy. Therefore, there may exist smaller, moving back a pressure component in other circumstances, which weakens Lusitania the behavior of the myocardium, the blood supply which comes from a specific coronary artery. The existence of pressure gradients generated by the compression and relaxation of the myocardium, significantly affects the measurement of FFR, perhaps 50% or more (Fig. 5).

Limiting assumptions of unidirectional pressure gradient are taken into account in the calculation of FFR (i.e. there is no significant contribution to the movement in the opposite direction for coronary pressure) are recognized as a potential source of error in microvascular disease and dysfunction2,12,13of the left ventricle. However, until recently there was no solution to this problem, i.e. there was no separation technology fluctuations coronary pressure at its forward and reverse moving components in the human body.

Recently we have developed a new technology (single-point technologist�u), which, in combination with the analysis of the intensity of the wave, provides for separation of the coronary pressure on his direct and inverse components on the basis of simultaneous recordings of pressure and speed14flow (Fig. 6). Such measurements are now feasible using commercially available combined wire pressure-flow designed for intracoronary use (Combiwire, Volcano), and reduce the necessity of taking adenosine. Using this technology in the study of human in vivo, we identified the waves responsible for coronary blood flow, and divided the fluctuations coronary pressure on his direct (aortic origin) and moving back (microcirculatory origin) components8.

These studies demonstrated that the component of pressure moving back in the coronary vessels of a human, has the same value as a large component of pressure moving forward. Since coronary pressure is, increasingly, is the result of components14pressure return movement, and for moving forward components, if so are we to spread forward pressure, it would be more appropriate to measure FFR, using a stand-alone component of pressure moving forward. Removing,thus, component pressure moving backward, it is possible to eliminate the influence of regional variations in left ventricular function, microvascular dysfunction and pressure right artery, allowing for more accurate assessment of the hemodynamic significance of the stenosis.

Fig. 6 shows a set of graphs illustrating the division of the total measured pressure on his back straight and moving components depending on time. Pressure and flow velocity simultaneously measured in envelope shoulder artery men aged 47 years. Analysis wave intensity was used for the separation of the coronary pressure on his back straight and moving components. Direct pressure looked different than aortic pressure, due to the large impedance mismatch between the coronary artery and the aorta. In such places the back of a moving wave is reflected back into the coronary system, as wave expansion (or suction), reduces this pressure.

The list of references

(1) Dawkins KD, Gershlick T, de BM et al. Percutaneous coronary intervention: recommendations for good practice and training. Heart December 2005; 91 Suppl 6:vil-27.

(2) Blows LJ, Redwood SR. The pressure wire in practice. Heart April 2007; 93(4):419-22.

(3) Pijls NH, van Son JA, Kirkeeide RL, de BB, Gould KL. Experimental basis of determining maximum coronary, myocardial, and collateral blood flow by pressure measurements for assessing functional stenosis severity before and after percutaneous transluminal coronary angioplasty. Circulation 1993 April; 87(4): 1354-67.

(4 Pijls NH, de BB, Peels K et al. Measurement of fractional flow reserve to assess the functional severity of coronary-artery stenoses. N Engl J Med 1996 June 27;334(26): 1703-8.

(5) Pijls NH, Klauss V, Siebert U et al. Coronary pressure measurement after stenting predicts adverse events at follow-up: a multicenter registry. Circulation 2002 June 25; 105(25):2950-4.

(6) Spaan JA, Breuls NP, Laird JD. Diastolic-systolic coronary flow differences are caused by intramyocardial pump action in the anesthetized dog. Circ Res 1981 September; 49(3):584-93.

(7) Gregg DE, Sabiston DC. Effect of cardiac contraction on coronary blood flow. Circulation January 1957; 15(l):14-20.

(8) Davies JE, Whinnett ZI, Francis DP et al. Evidence of a dominant backward-propagating "suction" wave responsible for diastolic coronary filling in humans, attenuated in left ventricular hypertrophy. Circulation 2006 April 11; 113(14):1768-78.

(9) Krams R, Sipkema P, Westerhof. N. Varying elastance concept may explain coronary systolic flow impediment. Am J Physiol November 1989; 257(5 Pt 2):H1471-H1479.

(10) Hiramatsu O, Goto M, Yada T et al. In vivo observations of the intramural arterioles and venules in beating canine hearts. J Physiol 1998 June 1; 509 (Pt 2):619-28.

(11) Chilian WM, Marcus ML. Phasic coronary blood flow velocity in intramural and epicardial coronary arteries. Circ Res 1982 June; 50(6):775-81.

(12) Siebes M, Chamuleau SA, Meuwissen M, Piek JJ, Spaan JA. Influence of hemodynamic conditions on fractional flow reserve: parametric analysis of underlying field model. Am J Physiol Heart Circ Physiol October 2002; 283(4):H1462-H1470.

(13) Coronary flow is not that simple! Spaan JA. Heart. 2009 May; 95(9):761-2.

(14) Davies JE, Hadjiloizou N, Francis DP, Hughes AD, Parker KH, Mayet J. The role of The coronary microcirculation in determining blood flow. Artery Research 1 [S1], S31-S32. 2006. Ref Type: Abstract.

(15) Kim RJ, Wu E, Rafael A, et al. The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction. N Engl J Med 2000 November 16;343(20):1445-53.

(16) D Perera, Biggart S, Postema P et al. Right atrial pressure: can it be ignored when calculating fractional flow reserve and collateral flow index? J Am Coll Cardiol 2004 November 16;44(10):2089-91.

(17) avies JE, Whinnett ZI, Francis DP et al. Use of simultaneous pressure and velocity measurements to estimate arterial wave speed at a single site in humans. Am J Physiol Heart Circ Physiol February 2006; 290(2):H878-H885.

(18) Parker KH, Jones CJ, Dawson JR, Gibson DG. What stops the flow of blood from the heart? Heart Vessels 1988; 4(4):241-5.

(19) Davies JE, Parker KH, Francis DP, Hughes AD, Mayet J. What is the role of the aorta in directing coronary blood flow? Heart December 2008; 94(12): 1545-7.

(20) Hadjiloizou N, Davies JE, Malik IS, et al. Differences in cardiac microcirculatory wave patterns between the proximal left mainstem and proximal right coronary artery. Am J Physiol Heart Circ Physiol 2008 Aug; 295(3):H1198-H1205.

1. Method of determining the degree of narrowing of the vessel through which flows a fluid, comprising stages on which:
(a) receiving a sequence of first measurements of the pressure P1and the sequence corresponding to the first measurement of the velocity U1in the first location inside the vessel, wherein the first location is located on the first side of the target region;
b) receive a second sequence of measurements of pressure P2and the sequence corresponding to the second measurement of the velocity U2in the second location within the vessel, wherein the second location is on a second side of the target region;
c) for each location determine the wave speed in fluid, depending on the square of the pressure variation dP divided by the square of the corresponding speed change dU;
(d) to first determine the location change direct d�implementing dP 1+ depending on the amount of pressure change dP1and speed variation dU1;
e) for the second locations define a change dP2+ direct pressure depending on the amount of pressure change dP2and speed variation dU2;
f) determine the reserve allocated direct stream representing the pressure drop across the target area depending on the relationship dP2+/dP1+ while the specified pressure drop indicates the local degree of narrowing or compression of the vessel between the first location and the second location.

2. A method according to claim 1, wherein the first side of the target area is located upstream from the target region, and the second side is located downstream from the target area.

3. A method according to claim 1, wherein in step (C) determine the wave speed at each location in accordance with the equation C=(1/ρ)√(ΣdP2/ΣdU2), where ρ is the specific density of the fluid in the vessel.

4. A method according to claim 1, wherein the steps (d) and (e) determine the said change direct pressure dP1+ and dP2+ in accordance with the equations: dP1+=(dP1+ρcdU1)/2 and dP2+=(dP2+ρcdU2)/2.

5. A method according to claim 1, wherein in step (f) integrate or summarize a set of values dP1+ and dP2+ to obtain the value of P1+and R2+ p�yoga pressure and determine the allowance allocated to direct flow based on the ratio R 2+/P1+.

6. A method according to claim 1, characterized in that applied to the vessel in which the source fructueuse pressure is on both sides of the target area.

7. A method according to claim 6, characterized in that applied to the vessel in the cardiac circulatory system of a human or animal.

8. A method according to claim 7, in which the sequence of the first and second pressure measurements and the sequence of the first and second velocity measurements are shooting for at least one full cardiac cycle.

9. A method according to claim 1, wherein the measurements of pressure and speed simultaneously perform.

10. Apparatus for determining the degree of narrowing of the vessel in which flows a fluid that contains:
the pressure sensor and the speed sensor for recording a sequence of measurements of pressure and velocity in the vessel at least in a first location that is upstream from the target region, and in the second location, downstream from the target region;
a processing module adapted to:
take the first sequence of measurements of pressure P1and the sequence corresponding to the first measurement of the velocity U1taken in the first location within the vessel;
to receive the second sequence of measurements of pressure P2and consistency suitable for�volatility second measurement of the velocity U 2taken in the second location within the vessel;
for each location to determine the wave speed in fluid, depending on the square of the pressure variation dP divided by the square of the corresponding speed change dU;
and for the first location, determine the change in dP1+ direct pressure depending on the amount of pressure change dP1and speed variation dU1; and
for the second locations define a change dP2+ direct pressure depending on the amount of pressure change dP2and speed variation dU2; and
determine the reserve allocated to direct flow, indicating the pressure drop across the target area, depending on the relationship dP2+/dP1+ while the specified pressure drop indicates the local degree of narrowing or compression of the vessel between the first location and the second location.

11. The device according to claim 10, wherein the processing module is additionally configured to determine the wave speed at each location in accordance with the equation C=(1/ρ)√(ΣdP2/ΣdU2), where ρ is the specific density of the fluid in the vessel.

12. The device according to claim 10, wherein the processing module further configured to determine are listed direct pressure dP1+ and dP2 + in accordance with the equations: dP1+=(dP1+ρcdU1)/2 and dP2+=(dP2+ρcdU2)/2.

13. The device according to claim 10, wherein the processing module further configured to integrate or summarize a set of values dP1+and dP2+ to obtain the value of P1+ and R2+ direct pressure and to determine the allowance allocated to direct flow based on the ratio R2+/P1+.

14. The device according to claim 10, further comprising a means for monitoring heart rhythm and to control the pressure sensor and the speed sensor for collecting said sequence of pressure measurements and a sequence of velocity measurements over a complete cardiac cycle.



 

Same patents:

FIELD: medicine.

SUBSTANCE: invention relates to means for the estimation of energy efficiency of a cardiovascular system. The method of automatic processing of blood pressure signals contains stages at which: a detected pressure signal P(t) for one or more heart contractions is discretised, with each heart contraction starting at an initial moment, coinciding with the moment of the diastolic pressure, and finishing at the last moment, coinciding with the moment of the following diastolic pressure, and containing a dicrotic point, the morphology of a discretised pressure signal P(t) for each heart contraction is analysed and separated, the moment and value of pressure in one or more characteristic points of the signal P(t) are determined. For each heart contraction a value of energy efficiency is determined by the determination of the impedance Zd-D(t) of a direct dynamic wave of pressure for each of one or more characteristic points, except the point of an initial diastolic pressure, and the impedance ZD of a direct pressure wave is determined by the addition with alternating signs of values of the impedances Zd-D(t) of the direct dynamic pressure wave, ordered in accordance with the direct time order, starting with the initial moment of the analysed heart contraction, to a dicrotic moment, the dynamic reflected impedance Zd_R(t) is determined for each of one or more characteristic points and the value of impedance ZR of reflected pressure waves is determined, energy efficiency is determined as a ratio between the impedance ZD of the direct pressure wave and the impedance ZR of the reflected waves RES=ZD/ZR. The method is realised by an automatic device for processing the blood pressure signal with the application of a storage medium, which contains stored software.

EFFECT: application of the invention makes it possible to increase the reliability of energy efficiency estimation.

14 cl, 6 dwg

FIELD: medicine.

SUBSTANCE: composition contains Compound I a pharmaceutically acceptable carrier and dissolved sodium compound and calcium compound providing the sodium ion concentration of 40-50 mM and the calcium ion concentration of 0.1-0.7 mM. The present invention also refers to imaging methods using such diagnostic composition.

EFFECT: invention describes the X-ray diagnostic composition, which exhibits the excellent cardiac safety profile.

16 cl, 6 dwg, 3 ex, 5 tbl

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to therapy and general medical practice. Tongue gustation thresholds are determined. Solution series are prepared: sweet solution with using sucrose, brine with using sodium chloride, acid liquor with using citric acid, bitter solution with using caffeine, uami with using sodium glutamate, metal solution with using ferric sulphate. The diagnosis is stated by the following criteria: if observing four or more positive threshold reactions on the solutions: sweet with 1.36 per cent of the sucrose solution, salt with 0.32 per cent of sodium chloride, acid with 0.31 per cent of citric acid, bitter with 0.11 per cent of caffeine, uami with 0.32 per cent of sodium glutamate, metal with 0.0028 per cent of ferric sulphate, sympathicotonia is diagnosed. If observing four or more positive threshold reactions on the solutions: sweet with 0.34 per cent of the sucrose solution, salt with 0.08 per cent of sodium chloride, acid with 0.13 per cent of citric acid, bitter with 0.06 per cent of caffeine, uami with 0.08 per cent of sodium glutamate, metal with 0.0007 per cent of ferric sulphate, vagotonia is diagnosed. If observing four or more positive threshold reactions on the solutions: sweet with 0.68 per cent of the sucrose solution, salt with 0.16 per cent of sodium chloride, acid with 0.20 per cent of citric acid, bitter with 0.09 per cent of caffeine, uami with 0.16 per cent of sodium glutamate, metal with 0.0014 per cent of ferric sulphate, normotonia is diagnosed.

EFFECT: method enables the instant assessment of the vegetative balance status.

2 tbl, 2 ex

FIELD: medicine.

SUBSTANCE: group of inventions relates to medical equipment. Intravascular device for sensor delivery contains distal sleeve, sensor and proximal part. Distal sleeve has opening for reception of a separate medical wire guide and sliding along it. Sensor measures patient's physiological parameter and generates a signal used, for calculation of fraction reserve of blood flow. Proximal section has main section and distal transitional section, connecting main section with external surface of distal sleeve. Proximal section contains a channel of connection for transmission of signal from sensor into location outside patient and facilitates positioning of sensor in anatomical structure of patient. Intravascular device for sensor delivery can contain multi-opening rod with openings for wire guide and for sensor, and two sensors, first of which is connected with sensor rod and second - with external section of multi-opening rod. Sensors can be placed at a variable distance from each other due to sliding of sensor rod relative to multi-opening rod. System of flowing medium injection contains tube for flowing medium supply, control panel and processor, which can receive signal, presenting information about blood pressure, from device for sensor delivery.

EFFECT: application of the claimed group of inventions will make it possible to increase accuracy of device positioning.

15 cl, 17 dwg

FIELD: medicine.

SUBSTANCE: invention refers to medicine and may be used in retrograde X-ray endoscopic diagnostic and therapeutic procedures. A device consists of a catheter and a built-in flexible rod. The catheter and rod are mounted in a working channel of the endoscope. The endoscopic catheterisation of the deformed sinuate bile ducts is enabled through a duodenum and accompanied by transpapillary X-ray diagnostic and therapeutic interventions with using a catheter of a graduated internal diameter to be lowered in one point provided with an elastic cuff peripherally fixed in a lowering point and having a hole formed in the centre of lowering. The provided flexible rod having on its distal side is equipped with a calibrated rod, a drill and a cone to cover the hole in the graduated internal diameter of the catheter with making a contrast substance flowing into the hole onto the catheter in the centre of lowering of the extended cuff to an internal diameter of a choledoch duct by pressure of the contrast substance and providing the contrast substance outflow closing into the duodenum. Further, the flexible rod opens the contrast substance passage by the cone through the catheter under pressure into the deformed bile duct. From the proximal side of the catheter, there is a control handle with a port, the in-built rod with a handle with an attached drill on the distal end for the purpose of flexibility.

EFFECT: facilitated contrast of the deformed bile ducts in transpapillary X-ray diagnostic and therapeutic interventions, provided optimal conditions for catheterisation of the deformed duct strictures; reducing a radiation dose for the patient and medical personnel, enhancing minimally invasive surgery; ensuring economic effect due to contrast substance saving.

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to cardiology and can be used to predict degree of restenosis development in coronary stent. For this purpose rate of nitrogen-containing preparation metabolism is determined by introduction the preparation into the test. As test-preparation introduced is caffeine in dose 150-300 mg orally once. After 6 hours ratio of N-acetyl-derivative of the preparation to non-metabolised preparation in urine is determined. If value of said ratio equals 73 % and lower favourable outcome of stenting is predicted.

EFFECT: said procedure ensures increase of accuracy in predicting degree of risk of restenosis development in coronary stent.

3 ex

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to cardiology and can be used to predict degree of restenosis development in coronary stent. For this purpose rate of nitrogen-containing preparation metabolism is determined by introduction the preparation into the test. As test-preparation introduced is caffeine in dose 150-300 mg orally once. After 6 hours ratio of N-acetyl-derivative of the preparation to non-metabolised preparation in urine is determined. If value of said ratio equals 73 % and lower favourable outcome of stenting is predicted.

EFFECT: said procedure ensures increase of accuracy in predicting degree of risk of restenosis development in coronary stent.

3 ex

FIELD: medicine.

SUBSTANCE: invention refers to medicine and may be used in retrograde X-ray endoscopic diagnostic and therapeutic procedures. A device consists of a catheter and a built-in flexible rod. The catheter and rod are mounted in a working channel of the endoscope. The endoscopic catheterisation of the deformed sinuate bile ducts is enabled through a duodenum and accompanied by transpapillary X-ray diagnostic and therapeutic interventions with using a catheter of a graduated internal diameter to be lowered in one point provided with an elastic cuff peripherally fixed in a lowering point and having a hole formed in the centre of lowering. The provided flexible rod having on its distal side is equipped with a calibrated rod, a drill and a cone to cover the hole in the graduated internal diameter of the catheter with making a contrast substance flowing into the hole onto the catheter in the centre of lowering of the extended cuff to an internal diameter of a choledoch duct by pressure of the contrast substance and providing the contrast substance outflow closing into the duodenum. Further, the flexible rod opens the contrast substance passage by the cone through the catheter under pressure into the deformed bile duct. From the proximal side of the catheter, there is a control handle with a port, the in-built rod with a handle with an attached drill on the distal end for the purpose of flexibility.

EFFECT: facilitated contrast of the deformed bile ducts in transpapillary X-ray diagnostic and therapeutic interventions, provided optimal conditions for catheterisation of the deformed duct strictures; reducing a radiation dose for the patient and medical personnel, enhancing minimally invasive surgery; ensuring economic effect due to contrast substance saving.

FIELD: medicine.

SUBSTANCE: group of inventions relates to medical equipment. Intravascular device for sensor delivery contains distal sleeve, sensor and proximal part. Distal sleeve has opening for reception of a separate medical wire guide and sliding along it. Sensor measures patient's physiological parameter and generates a signal used, for calculation of fraction reserve of blood flow. Proximal section has main section and distal transitional section, connecting main section with external surface of distal sleeve. Proximal section contains a channel of connection for transmission of signal from sensor into location outside patient and facilitates positioning of sensor in anatomical structure of patient. Intravascular device for sensor delivery can contain multi-opening rod with openings for wire guide and for sensor, and two sensors, first of which is connected with sensor rod and second - with external section of multi-opening rod. Sensors can be placed at a variable distance from each other due to sliding of sensor rod relative to multi-opening rod. System of flowing medium injection contains tube for flowing medium supply, control panel and processor, which can receive signal, presenting information about blood pressure, from device for sensor delivery.

EFFECT: application of the claimed group of inventions will make it possible to increase accuracy of device positioning.

15 cl, 17 dwg

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to therapy and general medical practice. Tongue gustation thresholds are determined. Solution series are prepared: sweet solution with using sucrose, brine with using sodium chloride, acid liquor with using citric acid, bitter solution with using caffeine, uami with using sodium glutamate, metal solution with using ferric sulphate. The diagnosis is stated by the following criteria: if observing four or more positive threshold reactions on the solutions: sweet with 1.36 per cent of the sucrose solution, salt with 0.32 per cent of sodium chloride, acid with 0.31 per cent of citric acid, bitter with 0.11 per cent of caffeine, uami with 0.32 per cent of sodium glutamate, metal with 0.0028 per cent of ferric sulphate, sympathicotonia is diagnosed. If observing four or more positive threshold reactions on the solutions: sweet with 0.34 per cent of the sucrose solution, salt with 0.08 per cent of sodium chloride, acid with 0.13 per cent of citric acid, bitter with 0.06 per cent of caffeine, uami with 0.08 per cent of sodium glutamate, metal with 0.0007 per cent of ferric sulphate, vagotonia is diagnosed. If observing four or more positive threshold reactions on the solutions: sweet with 0.68 per cent of the sucrose solution, salt with 0.16 per cent of sodium chloride, acid with 0.20 per cent of citric acid, bitter with 0.09 per cent of caffeine, uami with 0.16 per cent of sodium glutamate, metal with 0.0014 per cent of ferric sulphate, normotonia is diagnosed.

EFFECT: method enables the instant assessment of the vegetative balance status.

2 tbl, 2 ex

FIELD: medicine.

SUBSTANCE: composition contains Compound I a pharmaceutically acceptable carrier and dissolved sodium compound and calcium compound providing the sodium ion concentration of 40-50 mM and the calcium ion concentration of 0.1-0.7 mM. The present invention also refers to imaging methods using such diagnostic composition.

EFFECT: invention describes the X-ray diagnostic composition, which exhibits the excellent cardiac safety profile.

16 cl, 6 dwg, 3 ex, 5 tbl

FIELD: medicine.

SUBSTANCE: invention relates to means for the estimation of energy efficiency of a cardiovascular system. The method of automatic processing of blood pressure signals contains stages at which: a detected pressure signal P(t) for one or more heart contractions is discretised, with each heart contraction starting at an initial moment, coinciding with the moment of the diastolic pressure, and finishing at the last moment, coinciding with the moment of the following diastolic pressure, and containing a dicrotic point, the morphology of a discretised pressure signal P(t) for each heart contraction is analysed and separated, the moment and value of pressure in one or more characteristic points of the signal P(t) are determined. For each heart contraction a value of energy efficiency is determined by the determination of the impedance Zd-D(t) of a direct dynamic wave of pressure for each of one or more characteristic points, except the point of an initial diastolic pressure, and the impedance ZD of a direct pressure wave is determined by the addition with alternating signs of values of the impedances Zd-D(t) of the direct dynamic pressure wave, ordered in accordance with the direct time order, starting with the initial moment of the analysed heart contraction, to a dicrotic moment, the dynamic reflected impedance Zd_R(t) is determined for each of one or more characteristic points and the value of impedance ZR of reflected pressure waves is determined, energy efficiency is determined as a ratio between the impedance ZD of the direct pressure wave and the impedance ZR of the reflected waves RES=ZD/ZR. The method is realised by an automatic device for processing the blood pressure signal with the application of a storage medium, which contains stored software.

EFFECT: application of the invention makes it possible to increase the reliability of energy efficiency estimation.

14 cl, 6 dwg

FIELD: medicine.

SUBSTANCE: group of inventions relates to medical diagnostics. Method of determining degree of vessel narrowing contains stages at which obtained are: sequence of first pressure measurements P1 and sequence of respective first rate measurements U1 in first location inside vessel, sequence of second pressure measurements P2 and sequence of respective second rate measurements U2 in second location inside vessel. Wave rate c in fluid medium is determined for each location depending on square of pressure change divided by square of respective rate change. For first location change of direct pressure is determined depending on the sum of pressure change and rate change. For second location change of direct pressure is determined depending on the sum of pressure change and rate change. Reserve of separated direct flow, representing drop of pressure through target area is determined, with said drop of pressure indicating degree of local narrowing or compression of vessel between said first location and second location. Device for determining degree of vessel narrowing is described.

EFFECT: inventions provide measurement of localised flow restriction.

14 cl, 6 dwg

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine. An automatic method for blood pressure signal processing is implemented by means of an automatic device for blood pressure signal processing, which comprises a processing unit. That involves A. sampling a recorded pressure signal P(t) for one or more cardiac contractions. Each cardiac contraction starts at the initial moment coinciding with one of initial points of diastolic pressure, and finishes at the final moment coinciding with the following point of diastolic pressure, and contains a dicrotic point. Each contraction comprises a systolic phase continuing from the initial diastolic point to dicrotic point; B. analysing and identifying the morphology of the pressure signal P(t) sample automatically for each cardiac contraction. A pressure moment and value are determined for one or more characteristic pressure signal P(t) points specified in a group containing: an initial point of diastolic pressure, a point of systolic pressure, a dicrotic point and one or more resonant points, each of which coincides with the moment, when the second derivative d2P/dt2 of the pressure signal P(t) has a local maximum. At least one characteristic pressure signal P(t) point belongs to a systolic phase of the cardiac contraction of interest and differs from the initial point of diastolic pressure. C. determining an energy efficiency RES for each cardiac contraction is ensured by C1. measuring a direct dynamic impedance Zd_D(t) for each of one or more characteristic points belonging to the systolic phase of the cardiac contraction of interest and different from the initial point of diastolic pressure. The direct dynamic impedance Zd_D(t) equals to a relation of the pressure signal P(t) in the characteristic point to a period of time from the initial point of the cardiac contraction of interest to the moment of the above characteristic point. A direct pressure wave impedance ZD is calculated by deriving a reverse-sign sum of the direct dynamic impedances Zd_D(t) pre-ordered in accordance the moments starting from the initial point of the cardiac contraction of interest to the moment of the dicrotic point. The first mechanical dynamic impedance Zd_D(t) in accordance with the moment pre-order is taken with a positive sign. C2. A reflected dynamic impedance Zd_R(t) is determined for each of one or more characteristic points. The reflected dynamic impedance Zd_D(t) equals to a relation of the pressure signal P(t) in the characteristic point to a period of time from the final point of the cardiac contraction of interest to the moment of the characteristic point. A reflected pressure wave impedance ZR is calculated by deriving a reverse-sign sum of the reflected dynamic impedances Zd_R(t) post-ordered in accordance the moments starting from the final point to the initial point of the cardiac contraction of interest. The first reflected dynamic impedance Zd_R(t) in accordance with the moment post-order is taken with a positive sign. C3. The energy efficiency RES is described as a relation of the direct wave impedance ZD to the reflected wave impedance ZR: RES = ZD/ZR. D. For the energy efficiency RES determined at the stage C, it needs verifying if the first derivative dP/dt of the pressure signal P(t) is sure to be less than the first maximum threshold Td throughout the duration of the cardiac contraction of interest, and the second derivative d2P/dt2 of the pressure signal P(t) is sure to be less than the second maximum threshold Td2 throughout the duration of the cardiac contraction of interest. If the verification procedure appears to give a negative result, the stage E is supposed to be performed, whereas the verification with a positive result is followed by the stage F. E. A low-pass filter frequency cut-off is specified in accordance with the energy efficiency RES determined at the stage C, first derivative dP/dt and second derivative dP/dt of the pressure signal P(t). The low-pass filter is applied to the pressure signal P(t) to produce thereby a new pressure signal sample, and the previous stages are performed starting with B. F. The pressure signal P(t) which was the last to processed through the stage B is presented.

EFFECT: achieving higher reliability of the blood pressure measurement ensured by dynamic adjustment to blood pressure variability.

19 cl, 7 dwg

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment. The device for long-term remote invasive monitoring of state and critical changes in the cardiovascular system for patients with comorbidities comprises an implantable pressure sensor equipped with a wireless charger. The pressure sensor is configured to be mounted outside the vessel by a cuff. A wireless data transmitter is located in the electronics unit arranged in a sealed housing with the possibility of location outside the container, and connected to the sensor via a conductor. The pressure sensor is a MEMS sensor configured to monitor blood pressure, as well as for monitoring for status and critical changes in the cardiovascular system for patients with comorbidities for a predetermined period of time.

EFFECT: invention provides wireless connection to power supply for the pressure sensor.

3 cl, 3 dwg

FIELD: medicine.

SUBSTANCE: device consists of a flexible guide catheter with metric markings on the outer surface and a tapered front portion. The catheter is installed in a semicircular metal trough with a bend. A truncated cone bushing is rigidly connected to the rear part of the trough. An elliptical ring is rigidly fixed to the outer surface of the bushing. The catheter is fixed to the groove by bushings. An adapter is installed to the rear part of the catheter for endoscope connection.

EFFECT: safety of optical inspection of the eustachian tube and a possibility of treatment of eustachian tube patency disorders.

1 dwg

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