title: Findings of intravascular ultrasound during acute stent thrombosis.
abstract: OBJECTIVE
  To evaluate the potential role of intravascular ultrasound (IVUS) in evaluating patients experiencing an episode of acute stent thrombosis.
  
  
  METHODS
  Prospective observational study in a cardiac catheterisation laboratory in a university teaching hospital.
  
  
  METHODS
  IVUS was used to examine 12 patients undergoing coronary interventions for stent thrombosis to gain further mechanistic insights and to guide treatment. IVUS studies were obtained before and after intervention with a motorised pullback device.
  
  
  METHODS
  Qualitative and volumetric IVUS analyses.
  
  
  RESULTS
  Angiographically, 10 patients had occluded vessels and two patients had intraluminal filling defects within the stent. IVUS showed an occlusive thrombus in all patients. Thrombus volume was 90 (77) mm3, which was 51 (21)% of total stent volume. There was evidence of severe stent underexpansion in most patients and no patient fulfilled standard criteria for optimal stent implantation. Stent malapposition was detected in four patients, edge dissections were seen in two patients, and significant inflow-outflow disease was present in 11 patients. During interventions IVUS findings led to the use of higher pressures or larger balloons than those used during initial stenting in 10 patients. In addition, four patients required additional stenting, whereas a thrombectomy device alone was selected for one patient. After the procedure final minimum stent area (7.1 (2.1) v 5.3 (2) mm2, p < 0.005) and stent expansion (83.2 (17) v 62.1 (15)%, p < 0.005) improved compared with pre-interventional values. However, residual lining thrombus was still visualised in eight patients (25 (19) mm3, accounting for a 17% of final stent volume).
  
  
  CONCLUSIONS
  IVUS provides an attractive technique to characterise fully the pattern of stent thrombosis, to identify readily the underlying mechanical predisposing factors, and to guide repeated coronary interventions.
authors.affiliation: Interventional Cardiology Department, Cardiovascular Institute, San Carlos University Hospital, Madrid, Spain. falf@hotmail.com
authors.forename: F
authors.initials: F
authors.lastname: Alfonso
authors.forename: A
authors.initials: A
authors.lastname: Suárez
authors.forename: D J
authors.initials: DJ
authors.lastname: Angiolillo
authors.forename: M
authors.initials: M
authors.lastname: Sabaté
authors.forename: J
authors.initials: J
authors.lastname: Escaned
authors.forename: R
authors.initials: R
authors.lastname: Moreno
authors.forename: R
authors.initials: R
authors.lastname: Hernández
authors.forename: C
authors.initials: C
authors.lastname: Bañuelos
authors.forename: C
authors.initials: C
authors.lastname: Macaya
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods; D006328:Cardiac Catheterization / Q000009:adverse effects; D017023:Coronary Angiography; D003327:Coronary Disease / Q000601:surgery; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000601:surgery; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D011446:Prospective Studies; D015607:Stents / Q000009:adverse effects*; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods