| BackgroundThe incidence of chronic totally coronary occlusion(CTO)accounts for 15-30%of patients with coronary heart disease referred for coronary angiography.CTO was considered to be the last barrier of coronary intervention therapy on account of low success rate and high complications.The fundamental purpose of CTO revascularization is to save survival myocardium.Collateral can only meet the basic physiological needs of survival myocardium,was unable to avoid the occurrence of myocardial ischemia at stress condition Previous studies suggested that patients with better collateral collateral would have more viable myocardium.However,recent studies have found that collateral size can not predict the number of viable myocardium.Sufficient myocardial perfusion was the necessary condition for the existence of survival myocardium,but collateral size of CTO did not match the distal myocardial real perfusion.We also found that transmural myocardial infarction accompanied with good collateral circulation,even the vascular network beyond occlusion was completely fibrotic.It’s important to comprehend that the relationship between collateral size and distal myocardial perfusion of CTO and realize the real situation of recovery of distal ventricular wall perfusion after CTO-PCI.Which can help to deepen our understanding of distal myocardial perfusion of CTOObjectives1.To investigate the relationship between CPI and distal myocardial perfusion of CTO2.To clarify the influence of CPI on recovery of distal myocardial perfusion of CTO after CTO revascularization3.To discuss the influence of pre-operativel distal myocardial perfusion level of CTO on perfusion recovery after CTO revascularization4.To investigate the influence of pre-operativel distal myocardial perfusion level of CTO on restoration of cardiac function after CTO revascularizationMethodsA total of 39 consecutive patients with chronic totally occluded lesion were enrolled in our study between January 2018 and October 2018 in Department of cardiology,Xijing hospital.Myocardial contrast echocardiography(MCE)was used to evaluate distal myocardial perfusion of CTO.Collateral pressure index(CPI)was used to evaluate collateral blood flow.Echocardiography and MCE were made for all patients before CTO revascularization in order to evaluate distal myocardial perfusion level of CTO and cardiac function.After CTO revascularization,CPI was obtained by temperature-pressure guide wire to evaluate collateral function.After 1 day and lmonth,echocardiography and MCE were made for all patients again to assess the recovery of distal myocardial perfusion of CTO and cardiac functionCPI was measured by a temperature-pressure guide wire.The guide wire was inserted to distal coronary artery as far as possible,then a balloon was used to block the coronary artery at least two minutes.We could record the distal coronary pressure(Pd)and aortic pressure(Pa).The Pd was coronary wedge pressure(Pw),stands for the collateral blood flow pressure.After correcting for central venous pressure(Pv),CPI is calculated by the formula CPI=(Pw-Pv)/(Pa-Pv).Pv is supposed to be 10mmhg.The parameters of evaluate myocardial perfusion were A,β and A×β.A was peak intensity,on behalf of myocardial blood volume,reflecting vascular network volume;β was myocardial flow velocity,and A×β was myocardial blood flowCPI>0.25 was supposed to be well-developed collateral group,and CPI<0.25 was supposed to be poor-developed collateral group.Compare the parameters of MCE between the two groups before CTO-PCI,after CTO-PCI lday and lmonth later.According to the presence of myocardial infarction measured by MCE or not,patients were divided into perfusion-delay group and perfusion-defects group.Compare the parameters of MCE and cardiac function between the two groups before CTO-PCI,after CTO-PCI lday and lmonth later.Results1.There was no significant difference between CPI>0.25 group and CPI<0.25 group regarding the distal myocardial perfusion of CTO at rest or stress condition2.The difference of distal myocardial perfusion of CTO between CPI>0.25 group and CPI<0.25 group was not significance after CTO-PCI 1 day and 1 month3.The A(4.88±0.64 dB,5.78±0.82 dB,,P<0.01)and β(14.08±2.41/s 16.17±2.24/s,P<0.01)of perfusion-defects group were significant lower than perfusion-delay group,there was statistical difference between the two groups.There was no difference in regard to β between the two groups(P>0.05).No significant difference was found at aspect of β and A×β between perfusion-defects group and perfusion-delay group at CTO-PCI lday and lmonth follow-up(P>0.05).A of perfusion-defects group was still lower than perfusion-delay group at CTO-PCI 1 day(6.14±0.82 dB,6.91 ±0.93 dB,P=0.01)and 1 month later(7.71 ±1.07 dB,8.52± 1.02 dB,P=0.02),the difference were significance4.After CTO-PCI lmonth,the ejection fraction of perfusion-defects group was higher than the ejection fraction before PCI(0.50±0.03,0.49±0.04,P=0.02).However,compared with the ejection fraction before PCI,it was unchanged after CTO-PCI lmonth(0.45±0.07,0.45±0.06,P=0.54)Conclusions1.CPI can not predict distal myocardial perfusion of CTO before CTO revascularization;2.CPI has nothing to do with the recovery of distal myocardial perfusion of CTO after CTO revascularization,3.After CTO revascularization,the recovery of distal myocardial perfusion is subject to the level of original myocardial perfusion of the CTO territory4.After CTO revascularization,the recovery of cardiac function is subject to the level of original myocardial perfusion of the CTO territory... |
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