title: Differential effects of post-dilation after stent deployment in patients presenting with and without acute myocardial infarction.
abstract: BACKGROUND
  In the practice of percutaneous coronary intervention, post-dilation often is performed after stent deployment to improve stent expansion. However, aggressive mechanical expansion is a risk factor of distal embolization and microvascular injury, especially for patients with acute myocardial infarction (AMI). Few studies have investigated the effects of post-dilation on medium-term clinical outcomes.
  
  
  RESULTS
  Patients enrolled in the multicenter NHLBI Dynamic Registry between 2001 and 2006 were evaluated. Patients who were treated with ≥ 1 stent were studied. Patients with cardiogenic shock or history of coronary artery bypass graft surgery were excluded. Patients were followed up to 1 year. Because of the significant statistical interaction (P = .02) between post-dilation and AMI status on the hazard of death/myocardial infarction (MI), post-dilation effects were estimated separately for patients who did and did not present with an AMI. Among the 1,358 patients who presented with an AMI, post-dilation was associated with a significantly higher risk of death/MI (hazard ratio [HR] = 1.78, 95% CI 1.12-2.83, P = .01), not associated with the risk of repeat revascularization (HR = 1.15, 95% CI 0.81-1.62, P = .43). Among the 3,001 patients who did not present with AMI, post-dilation was not associated with risks of death/MI (HR = 1.08, 95% CI 0.77-1.50, P = .67) or repeat revascularization (HR = 1.17, 95% CI 0.93-1.47, P = .19). Similar effects were observed for the restricted analysis with additional adjustment for lesion characteristics among the 1,039 AMI patients and 2,179 non-AMI patients with a single lesion treated.
  
  
  CONCLUSIONS
  Stent post-dilation is associated with an increased risk of death/MI in AMI patients but not in non-AMI patients. Further investigation is warranted.
authors.affiliation: Department of Epidemiology, School of Public Health, Shanghai Jiao Tong University, School of Medicine, Shanghai, China. zhang.zj@msn.com
authors.forename: Zhi-Jiang
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Oscar C
authors.initials: OC
authors.lastname: Marroquin
authors.forename: Roslyn A
authors.initials: RA
authors.lastname: Stone
authors.forename: Joel L
authors.initials: JL
authors.lastname: Weissfeld
authors.forename: Suresh R
authors.initials: SR
authors.lastname: Mulukutla
authors.forename: Faith
authors.initials: F
authors.lastname: Selzer
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Kip
mesh_terms: D002423:Cause of Death / Q000639:trends; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000473:pathology*; D004108:Dilatation, Pathologic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D011446:Prospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects*; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology