Method for measuring pulse wave propagation speed in cerebral arteries

FIELD: medicine.

SUBSTANCE: method involves synchronously recording electrocardiogram in standard lead and pulse wave dopplerogram taken from M1 segment of medial cerebral artery using transducer of 1.7-2.5 MHz frequency and scanning speed of 50-100 mm/s. Delay time of rise onset is determined on dopplerogram relative to S-tooth peak or descending R-peak slope end on electrocardiogram. Pulse wave propagation speed on aorta-M1-segment part of the medial cerebral artery is calculated in cm/s from formula V=0.93*(S1+S2)/t, where 0.93 is the coefficient of measurement error on body surface of length of aorta-M1-segment of medial cerebral artery, S1 is the distance from sternal jugular fossa to mandible angle, S2 is the distance from mandible angle to point of intersection of the anterior auricle edge and upper edge of zygomatic arch in cm, t is the delay time in s.

EFFECT: wide range of functional applications.

3 dwg, 2 tbl

 

The invention relates to medicine, namely cardiology, angiology, neurology, and can be used in functional and ultrasound diagnostics for non-invasive determination of the propagation velocity of the pulse wave at the section of aorta - M1 segment of the middle cerebral artery (MCA).

One of the leading causes of death today is atherosclerotic disease of cerebral vessels. The pathogenesis of atherosclerosis involves a change upregulations properties of the arterial bed. The inventive method provides the ability to diagnose disorders upregulations properties of the vessels supplying the brain, allows you to monitor the effectiveness of vascular therapy, as well as to reveal the hidden changes in the walls of cerebral arteries when conducting functional tests.

There is a method of measuring the velocity of propagation of pulse wave (pwpv)based on simultaneous registration of the electrocardiogram and peripheral be noticed, which determine the delay time of the beginning of the pulse rise be noticed (peripheral pulse) from the top of the tooth S II standard lead electrocardiogram (Central pulse in seconds. To calculate pwpv measure the distance from the jugular notch of the sternum to the location of the sensor pulse (Ajzen G.S. Some modern the military methods of the study of blood circulation apparatus. Gorky. 1961. - 57 S.).

The disadvantage of this method is the inability to determine pwpv on cerebral arteries.

The closest achieved a positive result is a method of determining pwpv the aorta, based on simultaneous recording of two dopplergram using dual dopplerography. At the same time record the blood flow in the aortic arch and the femoral artery and calculate the delay time of the pulse wave between two points of registration (Blacher J. pulse wave Velocity - a new risk factor for cardiovascular complications / Blacher j, Safar M.E. Ter-Minassian // Clinical studies of drugs in Russia. - 2000. No. 1. - S-15).

The disadvantages of this method are:

1. The need for dual dopplerography.

2. The impossibility to determine pwpv on cerebral arteries.

The authors offer an affordable way of measuring the velocity of propagation of pulse wave in cerebral arteries.

A positive result of the proposed method is able to diagnose disorders upregulations properties of the vessels supplying the brain, to monitor the effectiveness of vascular therapy, as well as to reveal the hidden changes in the walls of cerebral arteries when conducting functional tests.

A positive result is achieved by the fact that accessories the historical take the pulse of the pulse-wave dopplergram, derived from the M1 segment of the middle cerebral artery and recorded synchronously with one of the standard ECG leads. Determining the time delay of the pulse wave produced from the top of the S-wave, or the end of the R-wave of the electrocardiogram to the beginning of the systolic rise of the LDF. The velocity of propagation of pulse wave calculated by the formula: V=0,93×(S1+S2)/t,

where V is the propagation velocity of the pulse wave at the section of aorta - M1 segment of middle cerebral artery (cm/s)

0,93 - coefficient taking into account the measurement error on the surface of the body section length aorta - M1 segment of the middle cerebral artery

S1- the distance from the jugular notch of the sternum to the angle of the mandible (cm)

S2- the distance from the mandibular angle to the point of intersection of the front edge of the ear and the upper edge of the zygomatic arch (see).

The method is as follows: during the examination the patient is in a horizontal position; ultrasound apparatus, such as a HEWLETT PACKARD SONOS 100, or any other device with simultaneous registration of the LDF and the electrocardiogram and, in picking transcranial ultrasonic transducer with a frequency of 1.7-2.5 MHz, register pulse-wave dopplergram of the M1 segment of the MCA (peripheral pulse); registration PR is performed at scan rate of 50-100 mm/s

The essence of the method is illustrated with drawings figure 1 shows the determination of the lag time of the beginning of recovery LDF of the M1 segment of MCA from a point on the ECG taken for the Central pulse (peak S-wave, or the end of the downward bend R-wave in the standard ECG leads where they are most clearly recorded). Length measurement (S1+S2see the section of the aorta - M1 segment of MCA produced on the surface of the body with regard to the anatomical course of the vessels. Anatomical landmarks shown in figure 2:

- point 1 - jugular notch of the sternum;

- point 2 - the angle of the mandible;

- point 3 - point intersection of the front edge of the ear and the upper edge of the zygomatic arch.

Pwpv calculated by the formula:

V=0,93×(S1+S2)/t,

where V is the propagation velocity of the pulse wave at the section of aorta - M1 segment of middle cerebral artery (cm/s)

0,93 - coefficient taking into account the measurement error on the surface of the body section length aorta - M1 segment of the middle cerebral artery

S1- the distance from the jugular notch of the sternum to the angle of the mandible (cm)

S2- the distance from the mandibular angle to the point of intersection of the front edge of the ear and the upper edge of the zygomatic arch (see).

The necessity of introduction of the coefficient due to the presence of physiological changes in stroke cerebral art the bacilli on the mouth area of the internal carotid artery (ICA) - M1 segment of MCA. The coefficient obtained as a result of experimental studies by comparing the measured data of the length of a cerebral artery by magnetic resonance angiograms (Mr-angiograms) with measurements on the body surface. The ratio was calculated according to the following formula:

K=L+LMp/S1+S2,

where L is the distance (cm) from the jugular notch of the sternum to the point of intersection 4, the line connecting the jugular notch and the angle of the mandible with a horizontal line drawn through the upper edge of the thyroid cartilage (figure 2),

LMrlength (cm) plot mouth ICA - M1 segment of MCA, as measured by Mr-angiogram (figure 3),

S1+S2distance (cm) from the jugular notch of the sternum below the upper edge of the zygomatic arch, measured on the body surface.

The L value is entered in the numerator as to the mouth of the ICA, the level of which coincides with the level of the upper edge of the thyroid cartilage (the Puddle D. X-ray anatomy of the vascular system. Budapest. - 1973, - s), stroke and vascular linear, the accuracy of measuring the length of this area on the surface of a body high, and there is no need for measurement of this site on Mr-angiogram.

The results of measurements on the basis of which the calculated correction factor, shown in table 1.

The method is illustrated with the patient, (1)where the length of S1+ 2was 25 cm, the lag time (t) 0,09 C.

V=0,93×25/0,09=258,3 cm/S.

In order to confirm the possibility of measuring pwpv conducted a series of studies on the site of the aorta - common femoral artery in 17 healthy men at the age of 19.5±0,26 years way simultaneous recording of the electrocardiogram and be noticed (analog) and claimed a method of simultaneous recording of ECG and pulse-wave LDF. The lag time was determined from the peaks of the S-wave in the electrocardiogram prior to the beginning of the pulse rise be noticed and LDF respectively. The probe pulse and the ultrasonic sensor was located at the same point. Values pwpv obtained by the above methods are presented in table 2. The table shows that the values pwpv obtained at the section of aorta - common femoral artery method using sphygmogram and method using dopplergram, not statistically different (mean values are 381,5±10.9 and 382,3±6,9, respectively; p>0.75 in). Thus it is possible to measure pwpv with simultaneous ECG recording and LDF.

Table 2 shows the results of the research pwpv in cerebral arteries of the inventive method using dopplergram and electrocardiogram. Average values pwpv section of the aorta - M1 segment of MCA less than pwpv section of the aorta - BOTH (334,6±1.4 cm/s and 382±7 SMS respectively, p<0.01), which is comparable with the known fact lower peripheral resistance cerebral arteries.

Thus, the inventive method provides the ability to diagnose disorders upregulations properties of the vessels supplying the brain, to monitor the effectiveness of vascular therapy, and also to reveal the hiding changes in the wall of cerebral arteries in conducting functional tests.

Table 1

The method of measuring the velocity of propagation of pulse wave in cerebral arteries
no patientLLMrS1+S2
1812,623,3
27a 12.720,8
37,7the 13.422,8
4813,723,5
57,511,722
6813,622
78the 13.423,5
871120,1
97,51222,2
10711,920,5
11813,222,1
127,713,622,2
13812,423
146,613,319,3
156,214,919,3
166,5the 11.619,3
mean±error7,6±0,112,8±0,121,8±0,1

Table 1. The individual measurements and the mean values used to calculate the correction factor that takes into account the physiological changes of stroke cerebral arteries on the mouth area of the internal carotid artery M1 segment of the middle cerebral artery.

Table 2

The method of measuring the velocity of propagation of pulse wave in cerebral arteries
no patientPwpv on the site
aorta-MCAaorta-BOTH
ECG-the beginning of the LDFECG-the beginning of the LDFECG-start be noticed
1 258,3406,3427,6
2227,3364,7360,5
3403393,8362,1
4279322,2318,7
5387,5388,2471,4
6483,6393,8450
7409,2392,9423,1
8165,3347,1339,1
9483,6362,5322,2
10258,3383,7358,8
11313,9349394,1
12219,8427,7395,4
13186350,7329,3
14341406,7396,1
15289,9406,7412,2
16227,9407,2354,2
17248396,2370,6
mean±error334,6±1,4382,3±6,9381,5±10,9
dost the loyalty of differences (p) <0,01
>0,75

Table 2. The results of individual studies, mean values and significant differences of the propagation velocity of the pulse wave at the section of aorta - M1 segment of the middle cerebral artery, obtained by the claimed method ECG beginning of the LDF, and the section of aorta - common femoral artery, obtained by the method of ECG beginning of the LDF and the way ECG - start be noticed.

The method of measuring the velocity of propagation of pulse wave in cerebral arteries, including the registration of the LDF, wherein the simultaneously recorded electrocardiogram (ECG) standard lead and pulse-wave dopplergrams from the M1 segment of middle cerebral artery sensor with frequency of 1.7-2.5 MHz at scan rate of 50 to 100 mm/s, determine the lag time of the beginning of recovery LDF on top of the S-wave, or the end of the downward bend R-wave of the ECG, and the propagation velocity of the pulse wave at the section of aorta - M1 segment of middle cerebral artery (cm/s (V) calculated by the formula

V=0,93·(S1+S2)/t,

where 0,93 - coefficient taking into account the measurement error on the surface of the body section length aorta - M1 segment of middle cerebral artery;

S2- the distance from the mandibular angle to the point of intersection of the front edge of the ear and the upper edge of the zygomatic arch, cm;

t is the time lag, C.



 

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