Mechanism Study Of The Peripheral Arterial Hemodynamics By Doppler Ultrasound

Objective1. To observe the relation of the peripheral limb arterial Doppler flow velocity curve(DFC) to the cardiac cycles (CC), and to analyze the hemodynamic mechanism of themain waveform of the Doppler flow velocity curve in healthy adults.2. To simulate the peripheral resistance increase state by adding extra pressure on thenormal limbs, and to compare its Doppler blood flow velocity curve changes with thepathological state of peripheral arteriosclerosis to help for better understanding of theperipheral arterial diseases by ultrasound.3. To explore the value of hemodynamic changes in the diagnosis of the peripheral arterialvascular lesions.Methods1.TheDoppler blood flow velocity curves of the brachial artery (BA), radial artery(RA), common femoral artery (CFA) and the popliteal artery (POA) at resting state wererecorded in40healthy volunteers using MylabTwice ultrasound instrument. The peaksystolic blood flow velocity (PSV), the early diastolic reverse blood flow peak (PRV) andthe resistance index (RI) were measured and averaged for three continuous cardiac cycles.The mechanism of the formation of the Doppler flow velocity curves in these arteries was analyzed.2. The Doppler blood flow velocity curves of BA, RA, CFA and POA under differentgrades (20,40,60,80,100,120mmHg) of distal as well as proximal limb pressuring wererecorded in40healthy volunteers using MylabTwice ultrasound instrument. PSV, PRV andRI of these arteries were measured and averaged for three continuous cardiac cycles. Themechanism of the formation of the Doppler flow wave curves in above arteries underdifferent pressuring was analyzed.3. The two-dimensional、color Doppler flow state of the lesion location and theDoppler blood flow velocity curve of the distal BA，RA of the patient with rightsubclavian artery atherosclerotic plaques were recorded using Acusons2000colorultrasound instrument of the Siemens to analyze the changes of the peripheral arterialblood flow patterns compared with the normal and pressuring according to the fluidmechanics principle.4. The left subclavian arterial Doppler flow velocity curve in a patient withcongenital double vertebral arteries malformation was recorded usingSiemensAcuson2000ultrasound instrument. The mechanism of the formation of the curvewas analyzed.Results1. Three-phase waveform was seen in the peripheral arterial Doppler blood flowvelocity curve at resting healthy adults, including the rapid-increased peak systolic wave,the rapid decreased early diastolic reversed wave, and the low forward late diastolic wavecorresponding with the cardiac cycles. The blood flow velocities were（BA：74.91±9.75cm/s; RA：45.43±5.45cm/s; CFA：116.32±14.87cm/s. POV：70.16±7.14cm/s）for PSV;（BA：9.23±0.81cm/s RA：9.02±0.73cm/s CFA：38.31±4.12cm/s POA：16.62±2.39cm/s）for PRV, and（BA：1.07±0.03RA：1.10±0.03CFA：1.29±0.03POA：1.22±0.04）for RI.2. The distal and proximal pressuring experiments in normal subjects could simulatethe hemodynamic changes of the arteries with the peripheral arterial resistance change. The Doppler blood flow velocity curves change regularly from the three-phase wave formto the two-phase wave form with the increase of distal pressuring grades. To be specific,the early diastolic reversed flow velocity increases and the late diastolic forward bloodflow velocity gradually reduces and even disappears with pressuring. These changesfurther reveal the peripheral arterial blood flow pattern in the human beings.3. Regional stenosis was seen in the patient with right subclavian arterialatherosclerosis by two-dimensional echocardiography, where color Doppler showedmosaic accelerated blood flow. The distal isolateral brachial and radial arterydemonstrated “Tardus and Parvus” flow pattern, i.e., low velocity with low resistance.4."Steal blood phenomenon" was unexpectedly not seen in the isolateral vertebralartery in the patient with left subclavian atherosclerosis, while the lumen was hypoechoicby two-dimensional echocardiography and no blood flow was detected by color Dopplerechocardiography in the distal isolateral vertebral artery, suggesting an occlusion occurred.Conclusions1. The blood flow is not continuous in the arterial system due to the cardiac cyclecharacteristics. Continuous blood flow pattern could only been seen in the tissues andorgans (for example, the brain)with lower resistance, while this is not true for the higherresistant arteries (for example, the peripheral limb arteries) under the same diastolic bloodpressuring. The result of the current study further confirms the peripheral arterial bloodflow pattern from the Doppler ultrasound point of view.2. The peripheral arterial resistance change by adding extra pressure on the limbscauses the hemodynamics changes in the corresponding vascular. The hemodynamics ofthe corresponding vascular regularity when the pressure on the limb according the fluidmechanics principle. The early diastolic reverse blood flow increase with the pressureincreasing step by step and the late diastolic blood flow turn into disappear from normalbefore reverse. These regularity changes further demonstrate the fluid mechanics principlein the body.3. The pressure and blood flow reduced at the back of the right subclavian artery plaque stenosis according to the fluid mechanics principle and poiseuille formula cause thelow pressuring state in the distal artery, proving the fluid mechanics principle of thehuman body again.4. The reason for no “steal blood phenomenon” in the proximal vertebral artery inpatients with isolateral subclavian arterial stenosis is that a stenosis or an occlusion existsdistal to the isolateral vertebral artery, which obeys the hemodynamic principles. Ourstudy further verifies these points by Doppler ultrasound. These results indicate that thecombination of the knowledge of the hemodynamic principles and the Doppler ultrasoundtechnique could be helpful in clinic for an accurate diagnosis of the peripheral arterialdiseases.