Method for detecting the volume of shunt circulation along developed arteriovenous fistula in patients with chronic renal failure upon program hemodialysis

FIELD: medicine, nephrology.

SUBSTANCE: one should detect circulation rate characteristics and vessel's diameter due to dopplerography, moreover, on should measure vessel's diameter directly in area of anastomosis, as for circulation rate characteristics they should be determined in constant-wave Doppler mode in area of circulation's maximal rate. Moreover, one should measure anastomosis' cross-sectional area and heart rate, moreover, one should calculate circulatory volume through anastomosis by the following formula: V(ml/min) = A VTI HR, where A - anastomosis' cross-sectional area (sq. cm), VTI - integral of circulatory linear rate through anastomosis (cm), HR - heart rate.

EFFECT: higher accuracy of detection.

4 ex, 1 tbl

 

The invention relates to medicine, in particular to Nephrology and radiation diagnostics, and can be used when determining the amount of shunt blood flow formed by the arteriovenous fistula in patients with chronic renal failure on software hemodialysis.

In 1966, American researcher M. J. Brescia suggested the formation of an arteriovenous fistula as a permanent vascular access for conducting software hemodialysis patients with chronic renal failure (CRF) [1]. To date, the imposition of anastomosis between a. radialis and v. cephalica no type “the end of the vein in the side of the artery is the most common method of formation of arteriovenous fistula.

Since the 70's. posted quite a large number of articles on the determination of the volume of blood flow through the arteriovenous fistula. So, using plethysmography combined, it was found that blood flow in the fistula placed between the radial artery and the lateral saphenous vein of the hand “side-to-side in the middle reaches 242±72 ml/min [2]. Similar results were obtained when measuring blood flow in the fistula between a. radialis and v. cephalica, rastamozhivanie type “the end of the vein in the side of an artery directly during after angiosurgical surgery [3,4]. Measurement of blood flow in the fistula, sformirovanaya forearm using autograft Vienna, showed that the average flow rate of blood in it is 304 ml/min [5].

In the 80's, with the development of ultrasonic methods have made possible the determination of the volume of blood flow through arteriovenous fistula using Doppler.

On the closest in technical essence as a prototype we have chosen the method of determination of shunt blood flow formed by the arteriovenous fistula in patients with ESRD on software hemodialysis using a Doppler, which involves measuring the diameter of the discharge fistulas Vienna with the definition of high-speed characteristics of blood flow in the same area using pulsed-wave Doppler mode. The volumetric rate of blood flow was calculated taking into account the diameter of the vessel (usually discharge fistulas Vienna), measured in b-mode, and the flow velocity measured by pulsed-wave Doppler mode. The results of these studies describe the blood flow through the arteriovenous fistula in the range from 728±53 ml/min [6] to 3070±100 ml/min [7].

The disadvantages of the method include the fact that the calculation of the volume rate of blood flow in the flow rate depends on the estimation of cross-sectional area of the orifice or vessel through which blood flows. The definition of a square is the weakest link in the assessment of volumetric blood flow velocity; it is Asano with the that measure cross-sectional area using In-mode are not accurate or reliable. Due to the fact that when calculating the diameter of squares, a slight error in the measurement leads to a noticeable error in the calculation of the area [8]. Outlet fistulina Vienna, used as a permanent vascular access for conducting hemodialysis, experiencing constant load arterial pressure inside arteriovenous fistula, inappropriate tone of venous walls, and exposed to chronic trauma of the punctures. Uneven expansion of the lumen and a sharp deformation of the walls of the venous segment arteriovenous fistula, which greatly complicates the measurements. In addition, in the lumen fistulas Vienna registers high-speed arterializing turbulent flow whose velocity is maximum at the center and becomes lower as it approaches the wall of the vessel. Therefore, the wider fistulina Vienna, the greater the difference between the linear velocities in the center and on the periphery of the vessel, and the higher the flow velocity, the greater this difference. As a result, measuring the profile of the blood flow in the heart, out deliberately inflated data, making it virtually impossible an adequate assessment of the speed characteristics of the flow.

Task izopet the tion is to improve the accuracy of the method by reducing the number of possible error in determining the cross-sectional area of the vessel.

The problem is solved in that the measurement of the diameter of the vessel is produced at the site of anastomosis, and speed characteristics of blood flow is determined using a constant-wave Doppler mode.

After angiosurgical peculiarities of formation of vascular anastomosis (used for sewing the edges of the anastomosis continuous blanket and fixing seams) and further development of fibrous connective tissue formed around the anastomosis allow to exclude the possibility of its dilation over time.

Because the rate of blood flow through the arteriovenous anastomosis fistula is extremely high and reaches 400-500 cm/s, to measure it is absolutely impossible to apply pulsed-wave Doppler mode, which allows to estimate the blood flow, the speed of which does not exceed 200 cm/sec. To obtain the speed characteristics of blood flow through the arteriovenous anastomosis fistula is proposed to use a constant-wave Doppler mode is used in echocardiography and no speed limit [9, 10].

The method is as follows: ultrasound arteriovenous fistula is made on the apparatus VIVID-3 GE Medical Systems linear sensor with a scanning frequency of 7 MHz in b-mode with color Doppler mapping, Orient ruas filling of a vessel “color”. The diameter of the arteriovenous anastomosis fistula is defined in the place where the maximum speed of blood flow. Check the profile of the blood flow through the anastomosis is performed sector by the sensor scanning frequency 3.5 MHz in the ever-wave Doppler mode in the area of maximum flow velocity. Calculation of the volume of blood flow through the anastomosis is determined by the formula laid down in the ultrasound scanner:

V(ml/min)=A×VTI×HR

where V is the volume of blood flow (ml/min), And the cross - sectional area of the anastomosis (cm2), VTI - integral linear velocity of blood flow through the anastomosis (cm), HR - heart rate.

The amount of blood flow correlated with the value of cardiac output (SV), measured at standard echocardiographic study [9, 10].

To standardize the results of the volumetric rate of flow is recalculated to the standard surface area (1.73 m2) by the formula:

where S is the surface area of the patient's body (m2).

Example 1. Patient, 40 years. Case history No. 65. Clinical diagnosis of Chronic-proliferative glomerulonephritis. Complications: chronic kidney disease end-stage (anemia, azotemia, metabolic acidosis, dyselectrolytemia, secondary hypertension), correctable what hemodialysis with 12.06.01 year. Inspection 14.01.03. Results: the diameter of the vessel at the anastomosis of 0.20 cm; maximum speed of blood flow through the anastomosis, measured in constant-wave Doppler mode, - 492 cm/s; VTI - 315,9 cm; HR - 81 beats/min Estimated amount of shunt blood flow - 504,9 ml/min (5.9% of SV), in terms of surface area - 468,0 ml/min

Example 2. Patient B., 40 years. Case history No. 80. Clinical diagnosis: Toxic nephropathy. Complications: chronic kidney disease end-stage (anemia, azotemia, metabolic acidosis, dyselectrolytemia, secondary hypertension), correctable hemodialysis with 14.08.02 year. Inspection 24.10.02. Results: the diameter of the vessel at the anastomosis - 0,23 cm; maximum speed of blood flow through the anastomosis, measured in constant-wave Doppler mode - 625 cm/s; VTI - 321,8 cm; heart rate of 102 beats/min Estimated amount of shunt blood flow - 1261,3 ml/min (10.0% of SV), in terms of surface area - 1154,1 ml/min

Example 3. Patient L., 37 years. Case history No. 34. Clinical diagnosis: Chronic glomerulonephritis. Complications: chronic kidney disease end-stage (anemia, azotemia, metabolic acidosis, dyselectrolytemia, secondary hypertension), correctable hemodialysis with 20.12.96 year. Inspection on the 26.06.02. Results: the diameter of the vessel at the anastomosis to 0.18 cm; the maximum speed of the blood is the eye through the anastomosis, measured in constant-wave Doppler mode - 295 cm/s; VTI - 163,5 cm; HR - 87 beats/min Estimated amount of shunt blood flow - 341,7 ml/min (3.9% of SV), in terms of surface area - 365,2 ml/min

Example 4. Patient P., 29 years. Case history No. 90. Clinical diagnosis: Chronic glomerulonephritis. Complications: chronic kidney disease end-stage (anemia, azotemia, metabolic acidosis, dyselectrolytemia, secondary hypertension), correctable hemodialysis with 10.01.96 year. Inspection 19.03.03. Results: the diameter of the vessel at the anastomosis is 0.17 cm; maximum speed of blood flow through the anastomosis, measured in constant-wave Doppler mode, - 545 cm/s; VTI - 330,2 cm; heart rate of 78 beats/min Estimated amount of shunt blood flow - 695,9 ml/min (10.3% of SV), in terms of surface area - 863,7 ml/min

Proposed method the study included 97 patients with chronic kidney disease who are on chronic hemodialysis, 55 of them are male and 42 female. Average duration of dialysis, i.e. the period of existence of arteriovenous fistula, amounted to 60±52 months.

The results of the study arteriovenous fistula presented in the table for comparison, a known volume of shunt blood flow formed by the arteriovenous fistula, which was determined using the prototype (6) and during after angiosurgical the operations on the formation of vascular anastomosis [4].

The results obtained are significantly different from the prototype (see table), which is associated with the measurement of the diameter of the vessel directly in the anastomosis and with the definition of high-speed characteristics of blood flow in the ever-wave Doppler mode, which allowed us to minimize errors in determining the cross-sectional area of the vessel and gave an assessment of the speed characteristics of blood flow in the area of anastomosis.

Thus, the claimed method of determining the volume of shunt blood flow formed by the arteriovenous fistula in patients with ESRD on software hemodialysis significantly increases the accuracy of determining blood flow in comparison with the prototype.

References

1. Brescia M.J., Cimino J.E., Appel K, Hurwich B.J. Chronic hemodialysis using venipuncture and a surgically created arteriovenous fistula. New Engi J Med 1966 275:1089-92.

2. Anderson C.B., Etheredge E.E., Harter H.R. at all. Local blood flow characteristics of arteriovenous fistulas in the forearm for dialysis. Surg Gynecol Obstet. 1977 Apr;144(4):531-3.

3. Anderson C.B., Etheredge E.E., Harter H.R. at all. Blood flow measurements in arteriovenosus dialysis fistulas. Surgery. 1977 Apr; 81(4):459-61.

4. Sharmila Sivanesan, Thien V. How, Ali Bakran. Characterizing flow distributions in AV fistulae for haemodialysis access. Nephrol Dial Transplant. 1998 13:3108-3110.

5. Voulez, Beaunis. After angiosurgical aspects of the preparation of the patient for hemodialysis. Vilnius: Muscles, 1980, 204 S.

6. Bouthier JD, Levenson JA, Simon AC at all. A noninvasive determination of fistula blood flow in dialysis patints. Artif Organs. 1983 Nov; 7(4):409-9.

7. Thinkin, Begleitet, Any, Kmini. Correction of blood flow through the arteriovenous fistula as a method of treating heart failure in patients with chronic renal failure on software hemodialysis. Nephrology, 1999, №1.-102-104 C.

8. Aviance, Vminstance, AIESEC, Suvorovsky. Assessment of hemodynamics in patients with congenital heart defects and pulmonary hypertension with dopplerechocardiography. Manual for doctors. - M.: Bakulev them. After Bakulev PAMH. - 2001. - 23 c.

9. Schiller N., Osipov, M.A. Clinical echocardiography. - M., 1993, 347 S.

10. Clinical guidelines for ultrasound diagnostics. Ed. Thu, Vasantha. V volume. - M: - Vidar, 1998, 360 S.

The method for determining the amount of shunt blood flow formed by the arteriovenous fistula in patients with chronic renal failure on software hemodialysis by determining the speed characteristics of blood flow and vessel diameter with dopplerography, characterized in that the measurement of the diameter of the vessel is made directly in the anastomosis, speed characteristics determine blood flow in the ever-wave Doppler mode in the area of maximum flow velocity, measure the cross-sectional area of the anastomosis and heart rate to reduce the response the calculation of the volume of blood flow through the anastomosis is determined by the formula V (ml/min) = A VTI HR, where a is the cross-sectional area of the anastomosis, cm2, VTI - integral linear velocity of blood flow through the anastomosis, cm, HR - heart rate.



 

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