The Study Of Angiographic Evaluation On Tissue Level Perfusion In Patients With Non-ST-eleva-tion Acute Coronary Syndrome

ObjectivesOur treatment strategies focus on the reflow of epicardial coronary arteries more other than the coronary microvasculature's reflow when we undergo percutaneous coronary interventions (PCI) . After relief of the occlusion, blood flow to the ischemic tissue may still be impeded, a phenomenon known as no - reflow.Coronary Doppler flow wire, Nuclear Imaging, contrast - enhanced magnetic resonance, photon emission computed tomography(PET) and myocardial contrast echocardiography are helpful in identifying no - reflow zones. However, those not only are expensive and will give patients extra burden, but also are difficult to be used in many areas because of complex technique and economy. The purpose of this study were to examine the relationships between elevations of tro-ponin and tissue level perfusion as assessed using the TIMI mycocardial perfu-sion grade (TMP) in non - ST - elevation acute coronary syndrome (NSTE -ACS) patients; this study was also designed to observe TMP's effect on patients 'prognosis. One more aim of this study was to expend the clinical practice of coronary angiography, that is to evaluate tissue level perfusion using coronary angiography.Meathods1. Patients selection: From 2002. 2 to 2003. 10, percutaneous coronary interventions were performed on patients with ESTE - ACS (including unstable angina and non - ST - segment myocardial infarction).2. Troponin testing and CKMB testing: cTnT was measured on the Elecsys 10/10, CKMB was measured on rate method.3. TIMI grade was used to evaluate the flow of coronary artery.4. Corrected TIMI frame count was used to evaluate the flow of coronary artery.5. TIMI myocardial perfusion grade (TMP) was used to evaluate tissue level perfusion.6. Clinical follow - up and main endpoint: all patients were monitored tele-metrically for 24 hours after the PCI procedure and were given Aspirin and Clo-pidogrel , other medicines such as lipid - lowing medicine, ACEI, β - block and so on were used as usual. Patients were asked to come to clinic on the 1st, 2nd, 3rd months after PCI or telephones were used to ask patients or their GP (general practitioner) in order to know whether there were MI or heart - related death event happened.ResultsThere are totally 291 cases, 212 male and 79 female. The mean age is 61.08 ±10.52, the minimum age is 34, the maximum one is 86. 260 cases(89. 3% ) had TIMI 3 flow after PCI.1. The comparison of angiographic results with cTnT1) The comparison of TIMI with cTnT before PCICTnT - positive patients were less likely to have patent (TIMI 2/3) epicar-dial arteries before intervention (61. 8% versus 79. 9% , P =0.001) or normal epicardial (TIMI3) flow (57. 8% versus 69. 8% , =0.040) compared with cT-nT - negtive patients.2) The comparison of cTnT with the incidence of thrombus, percent stenoses and rates of vessel occlusionCTnT - positive patients had a higher incidence of thrombus (43. 1 % versus 28.6% , P =0. 012) ; tighter percent stenoses (79. 2 ± 15. 6% versus 64.9 ±16.7% , P =0.027) ; higher rate of vessel occlusion ( TIMI epiardial grade 0/1 flow; 38.2% versus 20.1% , P =0.001) and longer CTFC ( 42.0 ±4.2 versus30.9±2.6, P =0.026).2. The relationship between cTnT and TMP1) The relationship between cTnT and myocardial tissue perfusion before PCICTnT - positive patients were more likely to have a closed microvasculature ( TMP 0/1 perfusion ) before intervention than cTnT - negtive patients (57. 8% versus 41. 8% , P =0.009) , meanwhile quantitatively, cTnT levels were significantly higher in patients with TMP 0/1 perfusion ( mean, 0. 49ng/mL; median, 0. 14ng/mL ) compared with those with TMP 2/3 perfusion ( mean, 0. 21ng/mL ; median, 0.03ng/mL, P =0.04 ). A multivariate model demonstrated that the presence of a closed microvasculature ( TMP 0/1 ) was independently associated with cTnT elevation > 0.01 ng/ mL (OR 2.647; P =0. 002 ) after adjusting for epicardial TIMI flow grade , CTFC, percent stenoses and thrombus.2) The relationship between cTnT and myocardial tissue perfusion in patients with TIMI 3 after PCIThere are 260 cases who got TIMI 3 flow after PCI, among them there are 166 cases who had cTnT negtive before PCI. CTnT - positive patients in 166 cases with TIMI 3 were more likely to have a closed microvasculature ( TMP 0/1 perfusion ) after intervention than cTnT — negtive patients (32.6% versus 18. 3%, P =0.048).3. The relationship of elevated CKMB and TMP after interventionTissue level perfusion using TMP was related to postintervention CKMB release : only 4.6% of patients with normal tissue level perfusion( TMP 2/3 ) had CKMB leak > 2 times the upper limit of normal, compared with 41. 5% of CKMB after PCI in abnormal tissue level perfusion ( TMP 0/1 ).4. Myocardial tissue level perfusion and events of AMI and heart - related death in patients with successful PCI ( TIMI 3)In patients with successful PCI ( TIMI 3 ) , compared with normal tissue level perfusion ( TMP 2/3 ) , patients with abnormal tissue level perfusion (TMP 0/1 ) were at increased risk of death or AMI at 6 months after intervention ( 7.3% versus 1.8% , P =0.046 ).DiscussionOur treatment strategies focus on the reflow of epicardial coronary arteries more other than the reflow of coronary microvasculature when we undergo percutaneous coronary interventions (PCI). After relief of the occlusion, blood flow to the ischemic tissue may still be impeded, a phenomenon known as no reflow. Coronary Doppler flow wire, Nuclear Imaging, contrast - enhanced magnetic resonance, PET and myocardial contrast echocardiography are helpful in identifying no - reflow zones. However, those not only are expensive and will give patients extra burden, but also are difficult to be used in many cities because of complex technique and economy.The purpose of this study were to examine the relationships between elevations of troponin and tissue level perfusion as assessed using the TIMI mycocar-dial perfusion grade (TMP) in NSTE - ACS patients; this study was also designed to observe the effect on patients'prognosis. One more aim of this study was to expend the clinical practice of coronary angiography, that's to evaluate tissue level perfusion using coronary angiography.1. Angiographic features in cTnT - elevated patients with ACS Elevations in cardiac troponins identify a high - risk subgroup of patientswho present with unstable angina or MI without ST elevation. These patients have more extensive coronary artery disease, more complex and severe coronary lesions, and a greater burden of intracoronary thrombus on coronary arteriogra-phy. The present report is consistent with these previous observations: a grater impairment of epicardial flow, a larger CTFC, severer stenoses and a greater thrombus burden were present among cTnT - positive patients. These data also demonstrated that elevations in troponin are associated with angographically abnormal tissue level perfusion, which persisted even after controlling for epicardial flow grade and presence of thrombus.2. The association of CKMB with TMP after interventionTIMI study group found the relationship between abnormal tissue fevel perfusion on diagnostic angiography and elevated cTnT first. The present data alsodemonstrated the same result. The postintervention CKMB release was not explained by TIMI grade 3 flow, because patients with TIMI grade 3 also had elevated CKMB. Thus, abnormality in tissue level perfusion rather than epicardial artery perfusion seems to explain the release of CKMB after intervention.3. TMP and long clinical anticipationThe clinical importance of the TMP grading system is demonstrated by the ability to provide independent risk stratification among patients with normal epicardial TIMI grade 3 flow. The TMP grading system offers prognostic information independent of the TIMI epicardial flow grades. TMP grade was shown to be a multivariate predictor of mortality independent of age, sex, pulse at admission, anterior myocardial infarction location, TIMI frame count or TIMI flow grade. The present data was similar to that report, that is the abnormal myocardial tissue perfusion is related with long clinical malignant results. Compared with patients with normal myocardial tissue perfusion (TMP 2/3 ) , the ones with abnormal myocardial tissue perfusion ( TMP0/1) were at increase risk of death or MI, 7.3% versus 1.8% respectively.4. The principal pathophysiologic mechanism of no - reflow phenomenon in ACS patientsA variety of factors probably contribute to no - reflow phenomenon. The capillary endothelium and cellular edema lead to no - reflow zone at the initial stage of ischemic period. Intravascular plugging by fibrin, platelets or leukocyte appears to play an important role in enlarged no - reflow zone. An additional mechanism plays a role during intervention in acute myocardial infarction. Mi-croemboli of atherosclerotic debris, blood clots, and platelet plugs are released into the microcirculation.5. The TIMI myocardial perfusion grade ( TMP ) systemThe arrival of radiographic contrast agents in the distal microvasculature of the downstream myocardium after passage of the epicardial coronary artery has been previously studied with semiquantitative techniques. But these semiquanti-tative methods are cumbersome, time consuming, and difficult to apply in routine clinical practice. However, qualitative visual assessment is feasible and applicable in routine clinical practice. TMP adds more important prognostic infor-...