Intravascular Pressure Measurement In The Stenting Of Cerebral Artery Stenosis:A Preliminary Study

Background and purpose: Even treating by standard medical treatment a part of patients with Cerebral artery stenosis suffered ischemic events,To find those high-risk patients with cerebral stenosis is current issues,To evaluate the hemodynamics by using pressure measurement for patients with high risk of vascular disease may be a promising method.the Fraction flow reserve(FFR)was used in coronary stenosis artery by the pressurewire,which was used to reflect the degree of coronary ischemia.Several studies have shown that FFR can be used to guide percutaneous coronary intervention(PCI),and FFR has a better outcome than PCI alone.The application of intravascular pressure measurement in the treatment of cerebral artery stenosis was still less or less clear.This study aim to explore the vascular stenosis of cerebral artery in the intravascular treatment,we have observed:(1)If intravascular pressure measurement in cerebral arteries is safe(2)The relationship between intravascular pressure measurement and stenosis rate(3)Factors that may affect the pressure gradient(4)If stenting can improve pressure gradient and pressure ratio(5)the relationship among the ischemic degree and pressure gradient and the stenosis rate(6)the relationship between the the steal degree of subclavian steal syndrome and pressure gradient? two brachial artery systolic blood pressure and the degree of stenosis.Methods: Patients who accept endovascular stent implantation were included,patients with Subclavian artery stenosis had steal phenomenon.The degree of the artery stenosis and SIR scale were calculate by DSA,Transcranial Doppler ultrasonography was used to measure the degree of steal in patients with subclavian steal syndrome.MRI was used to observe the degree of ischemia in the area of vascular which were measured.Intravascular blood pressure was measured by the pressurewire system.The head of pressurewire across the stenosis to get the distal pressure measurement(Pd),at the same time the guiding catheter which was connected with the pressure sensor measured the proximal stenosis pressure(Pa),and record the value of pressure and calculated the pressure gradient(Pa-Pd)and pressure ratio(Pd/Pa).The(Pa-Pd)and(Pd/Pa)were measured in the same way after stenting.Perioperative complications and adverse events were observed.Correlation among cerebrovascular stenosis rate and pressure gradient and pressure ratio,the relationship between the steal degree and subclavian artery stenosis rate? the Pa-Pd and two systolic blood pressure difference were caculated by Spearman correlation test,preoperative Pa-Pd and Pd/Pa measured by Wilcoxon rank test calculation?pressure and the level of collateral circulation?SIR score?degree of ischemia were caculated by multiple linear regression analysis,and the Pa-Pd and the stenosis rate of different degree of ischemic were caculated by ROC curve calculation and Wilcoxon rank.Results: 28 vascular 31 patients compeleted stenting and pressure measurementt,including 9 cases of carotid artery(3 cases of left,and 6 cases of right),12 cases of vertebral artery(7 cases of left and 5 cases of right),10 cases of subclavian artery (8cases of left,2 cases of right),One patient with 2 vessels had no postoperative blood pressure measurements value.there were no perioperative complications and adverse events.The preoperative stenosis rate of 31 cases was correlated with preoperative pressure gradient(r=0.747,p<0.001).The preoperative stenosis rate was correlated with preoperative pressure ratio(r=-0.655,p<0.001).The stenosis rate and SIR score are the factors that affect the Pa-Pd.Preoperative pressure stenosis rate,pressure gradient,pressure ratio was 60% ~ 95%(72.58%),2~ 72(11.42)mm Hg,0.22 ~ 0.98(0.87),the corresponding value after stenting is 0% ~ 30%(12.17%),0 ~ 18(2.55)mm Hg,0.74 ~ 1(0.97).Pressure gradient and the pressure ratio before and after stent has the difference(Z=-4.704,P < 0.001)?(Z=-4.728,p < 0.001).Pa-Pd was significant difference in two degree of ischemia group(Z=-2.004,P=0.045).Preoperative steal degree was correlated with preoperative stenosis rate and pressure gradient(r=0.833,P=0.003)?(r=0.718,P=0.019).Conclusion: the pressurewire used in the stenting of cerebral artery is safe and feasible.Cerebral vascular stenosis can lead to an increase in intravascular pressure gradient,endovascular stent treatment can make the pressure gradient better.