title: Long-term outcome of patients with silent versus symptomatic ischemia six months after percutaneous coronary intervention and stenting.
abstract: OBJECTIVE
  We sought to evaluate the incidence of silent ischemia versus symptomatic ischemia six months after percutaneous coronary intervention (PCI) and its impact on prognosis and to test the utility of myocardial perfusion single-photon emission computed tomography (SPECT), or MPS, for risk stratification in these patients.
  
  
  BACKGROUND
  Silent ischemia is frequent after PCI. However, little is known about silent ischemia and long-term outcome after PCI and stenting.
  
  
  METHODS
  In 356 consecutive patients with successful PCI and stenting and follow-up MPS after six months, long-term follow-up (4.1 +/- 0.3 years) was performed. The MPS images were interpreted by defining summed stress, rest, and difference scores (summed difference score [SDS] = extent of ischemia) and related to symptoms and outcome. Critical events included cardiac death, myocardial infarction, and target vessel revascularization.
  
  
  RESULTS
  Eighty-one patients (23%) had evidence of target vessel ischemia, which was silent in 62%. The only independent predictor of silent ischemia was SDS (odds ratio 0.64, p = 0.001). During follow-up, 67 critical events occurred. For patients with an SDS of 0, 1-4, and >4, the critical event rates were 17%, 29%, and 69%, respectively. Similarly, patients without ischemia, silent ischemia, and symptomatic ischemia had 17%, 32%, and 52% of critical events, respectively. Diabetes (relative risk 1.98, p = 0.03) and SDS (relative risk 1.2, p < 0.001) were independent predictors of critical events. The MPS image added incremental information for the prediction of critical events.
  
  
  CONCLUSIONS
  Six months after PCI and stenting, 23% of patients had target vessel ischemia, which was silent in 62%. Silent ischemia predicted a worse outcome than did no ischemia and tended to have a better outcome than symptomatic ischemia. This was closely related to the extent of ischemia. The SDS added incremental value to pre-scan findings with respect to diagnosis and prognosis, indicating the utility of MPS for risk stratification after PCI and stenting.
authors.affiliation: Department of Cardiology, University Hospital, Petersgraben 4, CH-4031 Basel, Switzerland. mzellweger@uhbs.ch
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zellweger
authors.forename: Markus
authors.initials: M
authors.lastname: Weinbacher
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Zutter
authors.forename: Raban V
authors.initials: RV
authors.lastname: Jeger
authors.forename: Jan
authors.initials: J
authors.lastname: Mueller-Brand
authors.forename: Christoph
authors.initials: C
authors.lastname: Kaiser
authors.forename: Peter T
authors.initials: PT
authors.lastname: Buser
authors.forename: Matthias E
authors.initials: ME
authors.lastname: Pfisterer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000175:diagnosis* / Q000453:epidemiology*; D023921:Coronary Stenosis / Q000628:therapy*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D018570:Risk Assessment; D015607:Stents; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome