title: Clinical and procedural predictors of no-reflow in patients with acute myocardial infarction after primary percutaneous coronary intervention.
abstract: BACKGROUND
  The treatment of acute myocardial infarction (AMI) is thought to restore antegrade blood flow in the infarct-related artery (IRA) and minimize ischemic damage to the myocardium as soon as possible. The present study aimed to identify possible clinical predictors for no-reflow in patients with AMI after primary percutaneous coronary intervention (PCI).
  
  
  METHODS
  A total of 312 consecutive patients with AMI who had been treated from January 2008 to December 2010 at the Cardiology Department of East Hospital, Tongji University School of Medicine were enrolled in this study. Inclusion criteria were: (i) patients underwent successfully primary PCI within 12 hours after the appearance of symptoms; or (ii) patients with ischemic chest pain for more than 12 hours after a successful primary PCI within 24 hours after appearance of symptoms. Exculsion criteria were: (i) coronary artery spasm; (ii) diameter stenosis of the culprit lesion was <50% and coronary blood flow was normal; (iii) patients with severe left main coronary or multivessel disease, who had to require emergency revascularization. According to thrombolysis in myocardial infarction (TIMI), the patients were divided into a reflow group and a no-reflow group. The clinical data, angiography findings and surgical data were compared between the two groups. Univariate and multivariate logistic regressions were used to determine the predictors for no-reflow.
  
  
  RESULTS
  Fifty-four (17.3%) of the patients developed NR phenomenon after primary PCI. Univariate analysis showed that age, time from onset to reperfusion, systolic blood pressure (SBP) on admission, Killip class of myocardial infarction, intra-aortic balloon pump (IABP) use before primary PCI, TIMI flow grade before primary PCI, type of occlusion, thrombus burden on baseline angiography, target lesion length, reference luminal diameter and method of reperfusion were correlated with no-reflow (P<0.05 for all). Multiple logistic regression analysis identified that age >65 years [OR=1.470, 95% confidence interval (CI) 1.460-1.490, P=0.007], long time from onset to reperfusion >6 hours (OR=1.270, 95%CI 1.160-1.400, P=0.001), low SBP on admission <100 mmHg (OR=1.910, 95%CI 1.018-3.896, P=0.004), IABP use before PCI (OR= 1.949, 95%CI 1.168-3.253, P=0.011), low (≤1) TIMI flow grade before primary PCI (OR=1.100, 95%CI 1.080-1.250, P<0.001), high thrombus burden (OR=1.600, 95%CI 1.470-2.760, P=0.030), and long target lesion (OR=1.948, 95%CI 1.908-1.990, P=0.019) on angiography were independent predictors of no-reflow.
  
  
  CONCLUSIONS
  The occurrence of no-reflow after primary PCI for acute myocardial infarction can predict clinical, angiographic and procedural features.
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: He
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Shao-Wei
authors.initials: SW
authors.lastname: Zhuang
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Wei-Gang
authors.initials: WG
authors.lastname: Qi
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Yi-An
authors.initials: YA
authors.lastname: Yao
authors.affiliation: Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
authors.forename: Xue-Bo
authors.initials: XB
authors.lastname: Liu
keywords: Acute myocardial infarction; No-reflow phenomenon; Percutaneous coronary intervention; Thrombus