title: Improving outcome over time of percutaneous coronary interventions in unstable angina.
abstract: OBJECTIVE
  This study was performed to evaluate the recent changes in the outcome of coronary interventions in patients with unstable angina (UA).
  
  
  BACKGROUND
  An early invasive strategy has not been shown to be superior to conservative treatment in patients with UA. Earlier studies had utilized older technology. Interventional approaches have changed in the recent past, but to our knowledge, no large studies have addressed the impact of these changes on the outcome of coronary interventions.
  
  
  METHODS
  We analyzed the in-hospital and intermediate-term outcome in 7,632 patients with UA who underwent coronary interventions in the last two decades. The study population was divided into three groups: group 1, n = 2,209 who had coronary intervention from 1979 to 1989; group 2, n = 2,212 with interventions from 1990 to 1993; and group 3, n = 3,211 treated from 1994 to 1998.
  
  
  RESULTS
  Group 2 and 3 patients were older and sicker compared with group 1 patients. The clinical success improved significantly in group 3 (94.1%) compared with group 2 (87%) and group 1 (76.5%) (p < 0.001). There was a significant reduction in in-hospital mortality, Q-wave myocardial infarction and need for emergency bypass surgery in group 3 compared with the earlier groups. One-year event-free survival was also significantly higher in the recent group compared with the earlier groups: 77% in group 3, 70% in group 2 and 74% in group 1 (p < 0.001). With the use of multivariate models to adjust for clinical and angiographic variables, treatment during the most recent era was found to be independently associated with improved in-hospital and intermediate-term outcomes.
  
  
  CONCLUSIONS
  There has been significant improvement in the in-hospital and intermediate-term outcome of coronary interventions in patients with UA in recent years; newer trials comparing conservative and invasive strategies are therefore needed.
authors.affiliation: Division of Internal Medicine and Cardiovascular Diseases, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA.
authors.forename: M
authors.initials: M
authors.lastname: Singh
authors.forename: C S
authors.initials: CS
authors.lastname: Rihal
authors.forename: P B
authors.initials: PB
authors.lastname: Berger
authors.forename: M R
authors.initials: MR
authors.lastname: Bell
authors.forename: D E
authors.initials: DE
authors.lastname: Grill
authors.forename: K N
authors.initials: KN
authors.lastname: Garratt
authors.forename: G W
authors.initials: GW
authors.lastname: Barseness
authors.forename: D R
authors.initials: DR
authors.lastname: Holmes
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000628:therapy*; D015906:Angioplasty, Balloon, Coronary / Q000592:standards*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011787:Quality of Health Care; D016019:Survival Analysis; D016896:Treatment Outcome