title: Effects of the number and interval of balloon inflations during primary PCI on the extent of myocardial injury in patients with STEMI: does postconditioning exist in real-world practice?
abstract: Postconditioning reduces infarct size in animal models and clinical studies. The present retrospective study aimed to evaluate the effects of the number and interval delay of balloon inflations during primary percutaneous coronary intervention (PCI) on enzymatic infarct size, myocardial perfusion and cardiac function in patients with ST-segment elevation myocardial infarction (STEMI) in routine clinical practice.
  
  
  METHODS
  Of the 433 STEMI patients who underwent primary PCI at Vanderbilt University Medical Center from October 2003 to August 2007, 85 (19.6%) met criteria and were enrolled into two groups: those with > or = 3 versus with < or = 2 balloon inflations. Peak CK, ST-segment resolution, myocardial blush grade (MBG) and left ventricular (LV) function were compared between the two groups. Correlations of peak CK, MBG and LV ejection fraction (LVEF) with the number, average duration and the first delay interval of balloon inflations were analyzed. A stepwise multiple regression analysis was used to identify the possible determinants of echocardiographic LVEF.
  
  
  RESULTS
  The LV end-systolic volume (LVESV) index in the group with > or = 3 inflations was significantly lower than that with < or = 2 inflations (33.1 +/- 7.9 ml/m square vs. 37.5 +/- 11.2 ml/m square p = 0.036), while LVEF was significantly higher (50.4 +/- 6.3% versus 46.1 +/- 8.5%; p = 0.009). Post hoc analysis showed peak CK in patients with 4 inflations was significantly lower than that with < or = 2 inflations (1,698 +/- 1,266 IU/L vs. 2,603 +/- 1,532 IU/L; p < 0.05). There was a positive correlation between LVEF and the number of balloon inflations (r = 0.222, p = 0.041).
  
  
  CONCLUSIONS
  Repetitive balloon inflations during primary PCI appear to confer cardioprotection. The data suggest that postconditioning may exist in real-world practice and contribute to myocardial protection.
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
authors.forename: Guisong
authors.initials: G
authors.lastname: Wang
authors.forename: Sanguo
authors.initials: S
authors.lastname: Zhang
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Joggerst
authors.forename: John
authors.initials: J
authors.lastname: McPherson
authors.forename: David X
authors.initials: DX
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000628:therapy*; D015428:Myocardial Reperfusion Injury / Q000453:epidemiology / Q000503:physiopathology / Q000517:prevention & control*; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology