Pulse Wave Velocity Detected By Ultrafast Ultrasound Imaging:The Normal Ranges Of Value And Its Clinical Value In Coronary Slow Flow

Objective:Ultrafast imaging(UFI)is an emerging technique in early diagnosis of atherosclerosis by detecting carotid pulse wave velocity(PWV).However,there is no uniform normal value for PWV.To explore the normal ranges and discuss the influencing factors,we measured and studied carotid PWV of normal people by UFI.In addition,we used UFI to detect carotid PWV of in patients with coronary slow flow(CSF),discuss the mechanism of CSF preliminarily and clear clinical value of UFI.Methods:181 healthy people were recruited from our hospital physical examination center(age: 20-82 years).They were classified into 6 groups by age(20–29,30–39,40–49,50–59,60–69,70-years).Routine carotid ultrasonography was used to measure bilateral carotid artery intima-media thickness(LIMT and RIMT);Carotid arterial pulse wave velocity was measured by UFI,including beginning of systolic value(LBS and RBS)and end of systolic value(LES and RES);Brachial ankle pulse wave velocity(Lba PWV and Rba PWV)were measured using an automated oscillometric device.The mean value of each parameter(IMT,BS and ES,and ba PWV)of bilateral carotid artery was calculated.20 healthy cases were selected randomly to perform the intra and inter-observers repetitiveness test.In the same period,34 patients with CSF were recruited(CSF group).Vascular ultrasound was used to measure IMT and UFI was used to measure arterial BS and ES,method as above.40 cases matched for age and gender were selected as the control group(CON group)from the above healthy individuals.IMT,BS and ES parameters were compared between the two groups.Results:1.Normal value ranges of PWV detected by UFI and the influencing factors.(1)There was no significant difference between BS and ES of healthy people in gender,left and right sides and probe pressure;BS and ES were both positively correlated with IMT(r=0.22,P=0.004;r =0.28,P=0.001)and ba PWV(r=0.63,P < 0.001;r =0.58,P <0.001).(2)Ranges and mean values of BS in healthy people(2.70-8.04m/s,5.37 ± 1.36m/s);Ranges and mean values of ES in healthy people(3.23-10.95m/s,7.09±1.97m/s).BS and ES are increases with age in healthy people(P < 0.001),but there were no significant difference in BS and ES between 20-29 vs 30-39 years,40-49 vs 50-59 years,and 60-69 vs ≥70 years(P > 0.05).(3)Ranges and mean values of BS and ES in healthy people.20-39 years(young-aged group)(BS:3.03-5.77m/s,4.40±0.70m/s;ES: 3.98-7.42m/s,5.70±0.88m/s),40-59 years(middle-aged group)(BS: 3.38-7.96m/s,5.67±1.17m/s;ES: 4.24-11.30m/s,7.77±1.80m/s)and ≥60years(old-aged group)(BS: 3.86-9.20m/s,6.53±1.36m/;ES: 5.38-12.36m/s,8.87±1.78m/s).(4)The intra-observers variation of BS(6.53±2.54)%,ES(6.78±3.56)%;The interobservers variation of BS(4.56±1.37)%,ES(5.01±2.11)%.(5)In healthy people,BS and ES were both positively correlated with arterial systolic blood pressure(r=0.43,P < 0.001;r=0.40,P < 0.001),diastolic pressure(r=0.31,P <0.001;r=0.33,P < 0.001)and body mass index(r=0.23,P=0.003;r=0.29,P < 0.001).2.The clinical value of PWV detected by UFI in coronary slow flow.(1)BS and ES in CSF group were both higher than the CON group(BS: 6.11± 1.63 vs5.37±1.07m/s,P < 0.05;ES: 8.70±1.92 vs 7.52±1.73m/s,P < 0.05),while IMT showed no significant difference.(2)Comparison between CSF and the normal reference values above: BS of 5.9%patients were higher;ES of 14.7% patients were higher.(3)Receive operating characteristic(ROC)curve shows that BS and ES can be used to differentiate CSF from control.BS have the maximum area under curve(AUC=0.80).The sensitivity of BS in diagnosis of CSF was 72.0%,and the specificity was 82.1%;ES have the maximum area under curve(AUC=0.84).The sensitivity of ES in diagnosis of CSF was 96.0%,and the specificity was 64.3%.Conclusions:(1)BS and ES detected by UFI increases with age.(2)The reference ranges of BS and ES in the young-aged group,middle-aged group and the old-aged group are presented.(3)Age,blood pressure and body mass index are the main influencing factors of PWV.(4)UFI is an emerging technique to evaluate atherosclerosis in early stage accurately and sensitively.(5)PWV of carotid artery increases in patients with CSF.(6)UFI measurement of PWV can sensitively detect CSF early,which has important clinical application value.