title: Development and validation of a stent thrombosis risk score in patients with acute coronary syndromes.
abstract: OBJECTIVE
  This study sought to develop a practical risk score to predict the risk of stent thrombosis (ST) after percutaneous coronary intervention (PCI) for acute coronary syndromes (ACS).
  
  
  BACKGROUND
  ST is a rare, yet feared complication after PCI with stent implantation. A risk score for ST after PCI in ACS can be a helpful tool to personalize risk assessment.
  
  
  METHODS
  This study represents a patient-level pooled analysis of 6,139 patients undergoing PCI with stent implantation for ACS in the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) and ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trials who were randomized to treatment with bivalirudin versus heparin plus a glycoprotein IIb/IIIa inhibitor. The cohort was randomly divided into a risk score development cohort (n = 4,093) and a validation cohort (n = 2,046). Cox regression methods were used to identify clinical, angiographic, and procedural characteristics associated with Academic Research Consortium-defined definite/probable ST at 1 year. Each covariate in this model was assigned an integer score based on the regression coefficients.
  
  
  RESULTS
  Variables included in the risk score were type of ACS (ST-segment elevation myocardial infarction, non-ST-segment elevation ACS with ST deviation, or non-ST-segment elevation ACS without ST changes), current smoking, insulin-dependent diabetes mellitus, prior PCI, baseline platelet count, absence of early (pre-PCI) anticoagulant therapy, aneurysmal/ulcerated lesion, baseline TIMI (Thrombolysis In Myocardial Infarction) flow grade 0/1, final TIMI flow grade <3, and number of treated vessels. Risk scores 1 to 6 were considered low risk, 7 to 9 intermediate risk, and 10 or greater high risk for ST. Rates of ST at 1 year in low-, intermediate-, and high-risk categories were 1.36%, 3.06%, and 9.18%, respectively, in the development cohort (p for trend <0.001), and 1.65%, 2.77%, and 6.45% in the validation cohort (p for trend = 0.006). The C-statistic for this risk score was over 0.65 in both cohorts.
  
  
  CONCLUSIONS
  The individual risk of ST can be predicted using a simple risk score based on clinical, angiographic, and procedural variables. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966) (Comparison of Angiomax Versus Heparin in Acute Coronary Syndromes [ACUITY]; NCT00093158).
authors.affiliation: Department of Cardiology, Mount Sinai Medical Center, New York, NY 10029, USA. george.dangas@mssm.edu
authors.forename: George D
authors.initials: GD
authors.lastname: Dangas
authors.forename: Bimmer E
authors.initials: BE
authors.lastname: Claessen
authors.forename: Roxana
authors.initials: R
authors.lastname: Mehran
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Martin
authors.initials: M
authors.lastname: Fahy
authors.forename: Helen
authors.initials: H
authors.lastname: Parise
authors.forename: José P S
authors.initials: JP
authors.lastname: Henriques
authors.forename: E Magnus
authors.initials: EM
authors.lastname: Ohman
authors.forename: Harvey D
authors.initials: HD
authors.lastname: White
authors.forename: Gregg W
authors.initials: GW
authors.lastname: Stone
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000601:surgery; D005544:Forecasting; D006801:Humans; D062645:Percutaneous Coronary Intervention; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D015607:Stents / Q000009:adverse effects*; D013927:Thrombosis / Q000209:etiology*